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Title:
PROCESS FOR RECYCLING A BITUMINOUS WASTE PRODUCT SUCH AS A BITUMINOUS WASTE MEMBRANE PRODUCT
Document Type and Number:
WIPO Patent Application WO/2021/104652
Kind Code:
A1
Abstract:
Process of recycling a bituminous product such as for example a waste bituminous membrane product optionally containing reinforcement layers comprising grinding and melting steps.

Inventors:
MOREELS GUILLAUME (BE)
DORMAL JULIEN (BE)
MARTIN CAROLINE (BE)
SNEIDERS KOEN (BE)
COGNEAU PATRICK (BE)
Application Number:
PCT/EP2019/083168
Publication Date:
June 03, 2021
Filing Date:
November 29, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
IMPERBEL (BE)
International Classes:
C08L95/00; B03B9/06; C10C3/00
Foreign References:
US20050263625A12005-12-01
DE4128014A11993-02-25
US4726846A1988-02-23
US4185784A1980-01-29
EP1534434A12005-06-01
Attorney, Agent or Firm:
CALYSTA NV (BE)
Download PDF:
Claims:
CLAIMS

1 . Process of recycling a bituminous product such as for example a waste bituminous membrane product optionally containing reinforcement layers comprising the steps of :

- Collecting waste bituminous products, preferably waste bituminous membrane products containing bituminous layers and optionally reinforcement layers and sorting the waste bituminous products in a series of n waste bituminous product batch (es),

- A first grinding of each batch of said series of n waste bituminous product batch (es) in a knife shredder for reducing the size of said each batch in a first shredded batch having a mean size comprised between 20 and 50 cm, preferably between 20 and 40 cm,

- A second grinding of each first shredded batch in a rotor granulator where each first shredded batch is reduced in size to a first crushed batch having a mean size between 5 and 25 cm, preferably between 8 and 20 cm,

- A third grinding of each first crushed batch in a rotor granulator where each first crushed batch is reduced in size to a first ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm,

- Conveying the each first ground batch on a vibrating sieve to collect each second ground batch, being each first ground batch substantially depleted from dust and particles having a particle size dioo lower than 8 mm, preferably lower than 7 mm, more preferably less than 6 mm,

- Separating metal pieces from non-metal pieces by application of Foucault current to each second ground batch and collecting each third ground batch, being each second ground batch substantially depleted from metal pieces,

- Introducing at least one third ground batch into a recycling unit having at least a rotor and a stator and an micronization chamber, said third ground batch being heated and melted by shear strength upon the operation of the stator, rotor and micronization chamber and collecting a melted product.

2. Process according †o claim 1 , wherein each third ground batch of said series of n waste bituminous product batch (es) is stored in at least one tank.

3. Process according †o claim 1 or claim 2, wherein each series of n waste bituminous product batch (es) is stored under the form its said third ground batch in a tank, thereby providing n tank of waste bituminous product, containing each a waste bituminous product under its third ground batch.

4. Process according †o any of the claims 1 to 3, wherein said step of introducing at least one third ground batch info a recycling uni† is a step of introducing a batch of x third ground batch(es), where x is an integer comprised between 1 and n and preferably being 1 , 2 or 3.

5. Process according †o any of the claims 1 to 4, wherein the melted product is fed in a mixing tank having a predetermined volume containing fresh carrier at a level of 50% of the predetermined volume, at a residence temperature comprised between 160 and 200°C, preferably between 170 and 190°C, more preferably around 180°C said mixing tank being continuously agitated with horizontal mixing blade, said melted product being fed in said mixing tank until the volume of the melted product is almost 50% of the predetermined volume to provide a fourth bituminous product.

6. Process according †o any of the claims 1 to 4, wherein the melted product is collected in vessels.

7. Process according †o any of the claims 1 to 6, wherein the melted product is further pumped and filtrated in a bag filter.

8. Process according †o claim 5, wherein the fourth bituminous product is further withdrawn by pumping in batches and filtrated in a bag filter.

9. Process according †o any of the claims 1 to 8, wherein said at least one third ground batch is melted at a temperature comprised between 1 10 and 260°C.

10. Process according †o any of the claims 1 to 9, wherein a filler is introduced in the recycling uni†, preferably at an amount of 160 kg/h.

1 1 . Process according †o any of the claims 1 to 10, wherein said at least one third ground batch is fed in the recycling uni† at an flow rate of 500 kg/h.

12. Recycling plan† for recycling a waste bituminous product, preferably a waste bituminous membrane product containing optionally reinforcement material, comprising (i) a† leas† one recycling uni† comprising a firs† rotor housed in a firs† stator, provided with a chamber delimited by an external wall of the firs† rotor, wherein the chamber is a micronizafion chamber formed by a recess arranged in a counter-element mounted on the sfafor which is substantially cylindrical, which micronizafion chamber comprises an adjustment means organized †o adjust the volume and/or shape of the chamber and wherein a† leas† one scraper organized †o scrape the external wall of the rotor is mounted downstream of the micronization chamber

(ii) a firs† grinding means, such as a knife shredder provided for grinding a† leas† one batch of said series of n waste bituminous product batch (es) in a firs† shredded batch having a mean size comprised between 20 and 50 cm, preferably between 20 and 40 cm, said firs† grinding means having a firs† inlet and a firs† exit

(iii) a second grinding means such as a rotor granulator, provided for grinding a† leas† one firs† shredded batch in a firs† crushed batch having a mean size between 5 and 25 cm, preferably between 8 and 20 cm, said second grinding means having a second inlet and a second exit, said second inlet being connected †o said firs† exit a† leas† by conveying means,

(iv) a third grinding means, such as a rotor granulator provided for grinding a† leas† firs† crushed batch in a firs† ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm, said third grinding means having a third inlet and a third exit, said third inlet being connect †o said second exit a† leas† by conveying means

(v) a vibrating sieve provided †o convey and sieve the firs† ground batch and †o provide a second ground batch, being the firs† ground batch substantially depleted from dust and particles having a particle size dioo lower than 8 mm, preferably lower than 7 mm, more preferably lower than 6 mm,

(vi) a separator provided for separating metal pieces from non-metal pieces by application of Foucault current to said second ground batch and for producing a third ground batch, being said second ground batch substantially depleted from metal pieces, said separator being connected directly or indirectly to said recycling unit in order to feed said recycling unit with a† leas† one third ground batch.

13. The recycling plant according to claim 12, wherein said micronization chamber formed by a recess is arranged in a cleat block (31 ) between two counter-elements (21 , 21 ’) mounted on the stator (2).

14. The recycling plant according to any of the claim 12 or 13, further comprising a second micronization chamber or cavity 26 delimited by an external wall of the firs† rotor 15, said cavity 26 being formed in a recess arranged in a cleat block (31 ) between two counter elements 21 ’ and 21 ”. The two cleat blocks 31 , 31 ’ (31 ) being made solidar one †o each other and connected †o a support element 23 comprising adjustment means 24 organized †o adjust the volume and/or shape of the chamber and move the cleat blocks along the counter elements 21 , 21 ’ , 21 ” .

15. The recycling plant according to any of the claims 1 1 †o 13, wherein the rotor is operated by a motor driving a rotation axis connected by a tight connection to the rotor, said motor being coupled †o the rotation axis by a coupling element, said rotation axis passing through a roller bearing block disposed between the tight connection and the coupling element, said tight connection and said roller bearing block being separated by a distance d comprised between 6 and 20 cm, preferably between 7,5 and 15 cm.

16. The recycling plant according to any of the claims 1 1 †o 14, wherein the rotor is on one end connect †o a motor driving a rotation axis and on the other end connected †o a dead end of said rotation axis by a tight connection to the rotor, said rotation axis dead end passing through a roller bearing block disposed between the tight connection and the end of the rotation axis, said tight connection and said roller bearing block being separated by a distance e comprised between 6 and 20 cm, preferably between 7,5 and 15 cm.

17. The recycling plant according to any of the claims 1 1 †o 15, wherein said tight connection comprising a O-ring cord surrounding a metal ring located around said rotation axis, said O-ring cord extending over a length of said rotation axis defined between 2 flanges.

18. The recycling plant according to any of the claims 1 1 †o 16, wherein, in said tight connections, a† leas† one the 2 flanges comprises one mobile flange provided †o move along a direction parallel †o the rotation axis, for example with a tightening clamp.

19. The recycling plan† according †o any of the claims 1 1 †o 17, further comprising a second recycling uni† provided with a second rotor housed in a second stator provided with an interchangeable micronization chamber, which second stator and rotor are mounted downstream of the first stator and rotor.

20. Recycling plan† according †o claim 19, comprising : a mixing tank located below the exit of the recycling uni† having a predetermined volume, and comprising at least a first horizontal screw with mixing blades, provided to agitate a bitumen product contained in said mixing tank.

21 . Recycling plan† according †o claim 20, wherein said mixing tank is provided with a first zone and a second zone, said first zone being above said second zone, said second zone being a bottom zone, said mixing tank having a second horizontal screw with conveying baffles inside said bottom zone, said at least first horizontal screw with mixing blades being provided inside said first zone, said second horizontal screw with conveying baffles being provided to empty the residues and the bitumen product accumulated and having sedimented in said bottom zone while said at least first horizontal screw with mixing blades being provided to agitate said bituminous product located in the first zone, each first zone and second zone being provided with an exit equipped with a valve, eventually connected to a pump.

22. Recycling plan† according †o any of the claim 20 or 21 , further comprising at least a bag filter, connected to the exit of the first zone of the mixing tank.

23. Recycled bituminous product having a viscosity comprised between 500 cPs and 45000 cPs as measured by a parallel plate rheometer, said recycled bituminous product containing a bitumen content comprised between 25 and 100% and a fiber content between 2 and 12%, said recycled bituminous product further showing a ash residue comprised between 5 and 50% upon calcination at 800° C.

24. Recycled bituminous product according †o claim 23, having a 60°C penetrability between 0,2 and 1 ,0 cm as measured by the ASTM-D5 standard.

25. Recycled bituminous product according †o claim 23 or 24, having a softening point between 40/155 and 60/165°C as measured by the bead anneal test.

26. Use of a recycled bituminous product according to any of the claims 23 to 25 for an indoor or outdoor bituminous product, such as for flooring applications, roofing application, wall application or road application.

Description:
PROCESS FOR RECYCLING A BITUMINOUS WASTE PRODUCT SUCH AS A BITUMINOUS

WASTE MEMBRANE PRODUCT

The present invention relates to a process for recycling a bituminous waste product such as a bituminous waste membrane product having at least a bituminous layer and optionally at least one reinforcement layer in a recycling uni† comprising a first rotor housed in a first stator, and a chamber delimited by an external wall of the first rotor and also relates to a recycling plan† as well as to bituminous products.

Bitumen is a very complex material which can be obtained by different kind of processes treating crude oil. Depending on the origin of crude oil and on the process applied, several kinds of bitumen can be obtained with different properties in terms of viscosity, penetrability, shelf life and softening point. For example, a bitumen produced by a crude oil coming from Venezuela, Middle East or Mexico will have different physical properties, which also depend on the kind of process applied for producing the bitumen.

Generally, bitumen is produced during the refining of crude oil. The refining of crude oil comprises two steps. The first step consists to realize an atmospheric distillation in a first fractionating column †o produce mainly liquefied petroleum gas, gasoline and kerosene. The second step consists in realizing a distillation under vacuum in a second column for producing gasoil and distillates. The bottom fraction recovered at the output of the second column can be processed according †o a deasphalting process or by distillation †o separate the lubricants from the bitumen. The deasphalting process corresponds to a physical separation of the remaining components of crude oil by using solvents. Indeed, this step is based on the different solubility of the remaining components of crude oil. Depending on the kind of solvent used (butane or propane), for realizing said separation step, the obtained bitumen will have different physical properties. On the opposite, the distillation of the obtained bottom fraction consists in cracking the crude oil to obtain bitumen on one hand and lubricants on the other hand.

For these reasons, the bitumen will have properties which will depend on the origin of crude oil and on the process applied to produce it.

When bitumen is produced according †o the aforementioned process comprising the first and second distillation steps, it has a crystalline structure corresponding †o a sol. A bitumen having a sol structure, recovered as a bottom fraction in the fracfioned column under vacuum, can be convert into a gel structure by applying an oxidation process, or air blowing. The later consists †o pass air through the heated bitumen to raise an appropriate viscosity of the bitumen. This process produces a bitumen with a maintained flexibility when it is used, a† an ambient temperature. When the bitumen is processed by air blowing, its viscosity is modified and the equilibrium mentioned above is therefore different. More precisely, the sum of the proportions of the saturated oils and asphaltenes are greater to the one of the aromatic oils and resins. The colloidal structure is therefore a gel structure where the amount of asphaltenes in the bitumen is doubled with respect †o the initial quantity of asphaltenes in the sol structure.

A bitumen can also be modified by mixing it with a polymer to form a modified bitumen. In this process, the bitumen is preferably a bitumen with a sol structure. The addition of a polymer to bitumen will lead †o a phase inversion when the amount of the polymer will be sufficient to obtain the phase inversion corresponding to the formation of a polymeric matrix wherein bitumen is retained. When the inversion phase occurs, the bitumen having the behavior of a Newtonian liquid will have the properties of a viscoelastic fluid.

The polymer and the bitumen have particular chemical interactions. The polymer forms a continuous phase (polymeric matrix) and the bitumen forms a dispersed phase. When the phase inversion occurs, the bitumen is retained into the polymeric matrix giving the adequate viscoelastic properties and the stability †o the composition comprising the bitumen and the polymer. Such a modified bitumen can be used for manufacturing a waterproofing membrane having an appropriate flexibility which is an advantageous criteria, for example when the waterproofing membrane is applied on a roof. The phase inversion phenomenon depends on the ratios of the polymer and the bitumen in the composition.

Two main categories of modified bitumen exists today for forming roof- membranes. Either the bitumen is modified with SBS (Sfyrene-bufadiene-sfyrene) and form a SBS-modified bitumen or the bitumen is modified with APP (atactic polypropylene) and form APP-modified bitumen.

The modified bitumen will have different properties depending on the category of its modifying polymer but also thanks †o any additives supplemented †o the bitumen composition. Back to the two main categories of bitumen, the modification of bitumen through SBS or APP allows manufacturers to create a longer- lasting, more durable product -giving it either plastic (APP) or rubber properties (SBS). Modifying bitumen gives it the ability to withstand a wide temperature range, and superior weather proofing.

For instance APP-modified bitumen begins to melt at about 130°- 150°C, it melts into a liquid wax like substance which acts as an almost free-flowing liquid which can then be mopped across a surface allowing an easy torch- application. SBS-modified bitumen is a sticky melt which is more flexible when compared to the plastic used in APP.

Sometimes, SBS-modified bitumen roofing membrane are provided with slate glitter or gravels, sand and their mixture.

Another kind of bitumen also exists where the bitumen for waterproofing membrane is produced with vegetal oil, like crude tall oil pitch or modified tall oil pitch.

Consequently, the origin of the bitumen, the nature of the polymer or the nature of the oil residue, the manufacturing method to produce the bitumen and the subsequent treatment of the bitumen, creates a broad range of bitumen membranes with different nature and diversified composition with production waste that need to be recycled.

Nowadays, a major part of flat roofs are covered by bituminous waterproofing or watertight membrane which are delivered onsite in rolls. The bituminous membranes usually are applied to the roof by torching or hot air welding or subjected to a cold application of the waterproofing or watertight membrane by self-adhesive, glue or by mechanic fixing means.

During the production of waterproofing or watertight bituminous membranes, at least one reinforcement is fed and is covered by bitumen on both sides and sometimes finally surfaced with mineral granules, flakes, sand and/or thin foils.

The reinforcement can be made by a reinforcement structure which is typically flat and thin of a material chosen in the group comprising polyester nonwoven, glass grid or fleece, combination reinforcements (glass and polyester), metal foils (e.g. copper, aluminium)) and their combination.

A recycling unit for bituminous products is known from the patent U.S. Pat. No. 4,185,784. In the known unit, the material to be recycled is introduced into the recycling unit provided with heating means. The material to be recycled thus melts under the effect of the heat and friction with the rotor of the unit. The rotation of the rotor disintegrates the reinforcements present in the material †o be recycled so that the product thus obtained is recyclable. The known unit comprises a chamber that is arranged in the wall of the sfafor so that the width of this chamber is reduced from the input thus causing a funnel effect that pushes the material towards the rotor.

However, this known recycling unit and method are no† entirely appropriate for recycling bituminous membranes provided with a† leas† one reinforcement layer, which comprises fibers. The fibers are difficult †o destroy completely yielding to masses of fibers remaining in the product resulting from the recycling method and prevent this product being used, as a raw material, for the manufacture of new membranes. Further, the non-cylindrical construction of the stator imposes a fairly complex technique for manufacturing the stator.

Another recycling unit has been disclosed in EP 1534434 which includes a micronization chamber formed by a recess arranged in a counter-element mounted on the stator which is substantially cylindrical. The micronization chamber comprises an adjustment means organized †o adjust the volume and/or shape of the chamber and in that a† leas† one scraper organized †o scrape the external wall of the rotor is mounted downstream of the micronization chamber, which scraper extends over a† leas† part of the length of the firs† rotor and has a stepped profile having a† leas† a firs† and a second step, the firs† step, which is situated close †o an output of the recycling unit, being disposed closes† †o the external wall of the firs† rotor.

Subjecting the pieces †o micronization succeeds in disintegrating the reinforcement present in the membrane pieces. The bituminous binder contained in the pieces can thus be melted which makes it possible †o recover it more easily and obtain a recycled material allowing an increased use, in particular as a raw material. The presence of the scraper makes it possible †o clean the wall of the rotor and ensures that the recycled bitumen is guided out of the grinder. The stepped profile of the scraper makes it possible †o make a distinction between the sufficiently triturated material which is then discharged through the output and the insufficiently triturated material which is no† discharged and thus continues †o be processed.

This recycling process and unit has proven its efficiency in recycling production waste, which waste are quite clean waste products and for a restricted number of source of bituminous products, thereby needing a quite simple recycling process. Nowadays, in the context of circular economy, there is a demand to recycle more and more waste products containing bituminous products, not only clean production waste, but also used roofing products which contain contaminated and degraded, aged bitumen and reinforcement parts. There is further a need to obtain a recycled bituminous product which can be widely used.

However, for implementing efficiently recycling processes, many constraints are present. This means that the process should be fluent, properly optimized and enough robust to manage the broad diversity and composition of the products to be recycled.

Indeed, a more complex waste products can’† be treated in the recycling uni† according †o document EP 1534434 as such. When roofing waste products are collected, those are used products having degraded bituminous layer (aged) and sometimes degraded reinforcement layers. Those used products contain many contaminating products such as metallic element and elastomer products such as EPDM (ethylene-propylen-dien-monomers) or oxidized bitumen. Further, the recycling uni† as described in this document is not enough robust to manage the broad diversity of waste bituminous products and is to be repaired very frequently. For example, contaminating products creates a pressure increase in the micronization chamber and a degradation of the several joints therefore creating leakage of bituminous products, resulting in fouling and dir† build-up around the roller bearing of the rotor element and vibration of the recycling uni†. In particular, this leads to the requirement †o stop frequently the recycling uni† for undergoing maintenance and replacement of roller bearing, being expensive wearing pieces. Due to the frequent stop, the recycling uni† do not allow †o carry out efficiently recycling bituminous products.

Of course, in the context of circular economy, while the intention †o provide a lower impact on the environment is clearly the incentive, there is also a need to be industrially viable. This means that the process is to be stable and robust while offering enough profitability to the industrial plan†.

The present invention encounters to solve at least a par† of these drawbacks by providing a process for recycling a broad diversity of waste products containing bituminous products and optionally reinforcement layers, including, without being limited thereto, bituminous membrane production waste, bituminous membrane cutting waste, roofing waste products collected from demolition worksite having many different composition and contamination; which is efficient and optimized to ensure enough profitability †o the industrial player, while requiring a lower maintenance and a† leas† less frequent maintenance operations and providing a recycled bituminous product usable in a large variety of new bituminous final products.

To solve this problem, it is provided according to the present invention, a process of recycling a bituminous product optionally containing reinforcement layers comprising the steps of :

- Collecting waste bituminous products, preferably waste bituminous membrane products containing bituminous layers and optionally reinforcement layers and sorting the waste bituminous products in a series of n waste bituminous product batch (es),

- A firs† grinding of each batch of said series of n waste bituminous product batch (es) in a knife shredder for reducing the size of said each batch in a firs† shredded batch having a mean size comprised between 20 and 50 cm, preferably between 20 and 40 cm,

- A second grinding of each firs† shredded batch in a rotor granulator where each firs† shredded batch is reduced in size †o a firs† crushed batch having a mean size between 5 and 25 cm, preferably between 8 and 20 cm,

- A third grinding of each firs† crushed batch in a rotor granulator where each firs† crushed batch is reduced in size †o a firs† ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm,

- Conveying the each firs† ground batch on a vibrating sieve †o collect each second ground batch, being each firs† ground batch substantially depleted from dust and particles having a particle size dioo lower than 8 mm, preferably lower than 7 mm, more preferably less than 6 mm,

- Separating metal pieces from non-metal pieces by application of Foucault current to said second ground batch and collecting a third ground batch, being said second ground batch substantially depleted from metal pieces,

- Introducing a† leas† one third ground batch into a recycling unit having a† leas† a rotor and a stator and an micronization chamber, said third ground batch being heated and melted by shear strength upon the operation of the stator, rotor and micronization chamber and collecting a melted product.

It has been indeed realized that the present invention allows to recycle the broad diversity of production waste of bituminous products while also being able to recycle used bituminous products such as bituminous membrane but also watertight membrane residues in a robust and efficient process, but also where the production CO2 footprint is reduced with respect to the production of a virgin bitumen thereby providing a recycled bitumen that can be introduced back †o the production process, for example of bituminous membrane with a high ratio, such as with more than 25%, preferably more than 30%, more preferably more than 50% of the bitumen is a recycled bitumen, while being also possible to use a drastically lower amount if wished. Indeed, in some case, the recycled bituminous product obtained by the process according †o the present invention can be diluted with other carrier substances before being used in a final bituminous product.

As it can be see, the process according †o the present invention comprises 3 subsequent and specific grinding steps allowing †o feed the recycling uni† with a third ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm, depleted in dusts and metallic contaminants which is continuously fed at high feed rate and allowing to continuously produce efficiently a recycled bitumen at a constant frequency. The process according †o the present invention provides a good balance of not too small particles and not too big particles, yielding †o optimal shear stress on the particles for recovering bitumen, thereby ensuring the right temperature inside the recycling uni†.

Indeed, when the shear stress inside the recycling uni† is too high, this create abnormal wearing and can create hot spots degrading the quality of the bitumen, when too small particles are provided to the recycling uni†, the insufficient shear stress may impact negatively the temperature in the recycling uni†.

It has been made possible according †o the present invention †o select the right size of particles entering the recycling uni†, where temperature can be easily controlled and not requiring many heating additions, thereby reducing drastically the CO2 footprint of the process.

Further, by the combined effect of providing a sorting step for sorting the waste bituminous products in a series of n waste bituminous product batch(es) and the selection of the subsequent grinding steps, the temperature inside the recycling uni† is more easy †o control, but also a huge diversity of existing roof can be recycled, together with production and cutting waste can be recycled, meaning that the process can manage waste product being at one side diversified, but also quite dirty.

Further, it has been shown that despite the presence of polymer in the existing and used bituminous product such as membrane, the presence of the polymer does not prevent the bituminous product (melted product) to be used back in the production of bituminous membrane, in the contrary, it has been shown that it allows to advantageously reduce polymer consumption during the manufacturing process, due to the fact that a significant portion is already present in the waste product. Indeed, Generally, when using modified bitumen for producing waterproofing membrane, a polymer is added to the bitumen †o reach the phase inversion. For an APP-modified bitumen, the level of polymer with respect to the amount of bitumen is typically comprised between 12and 25 w%. For a SBS-modified bitumen, the level of polymer with respect to the amount of bitumen is comprised between 2 and 20w%, typically between 4 and 12w%.

The process according †o the present invention allows to produce a recycled bitumen product, containing already an amount of polymer, meaning that the amount †o be added to reach the phase inversion is reduced, and sometimes drastically up to less than 50% of the normal required amount. I† should be indeed noted that when a melted product is obtained by the process according †o the present invention, this melted product can contain even more polymer than the amount required for reaching the phase inversion, which is not a problem, and even an advantage because when preparing modified bitumen, the substance being the most expensive one is not the bitumen, but the polymer. Accordingly, even if the amount of polymer carried by the recycled bituminous product represent a higher ratio than the final ratio needed between the polymer and the bitumen, the polymer will be then diluted in the mixture with fresh carrier or another carrier in order †o reduce the ratio between polymer and bitumen (or bitumen + carrier).

By recycling existing roof product, the polymer used in the manufacture of the membrane can play again its role in the bitumen inversion of phase, Finally, the quality of the bitumen obtained by the process according †o the present invention is high enough †o be reintroduced in a bituminous membrane at a level as high as more than 50 weigh† % or 75% even 100% with respect to the total bitumen weigh† in the final product. The process according †o the present invention therefore allows efficient way †o produce recycled bituminous waste product that can be used again in a production process for bituminous membrane.

In addition, the process according to the present invention is very robust. The grinding and sorting steps upstream entering the recycling unit allows a continuous recycling of bituminous waste product despite the variety of origin, age and impurities and with a positive energetic balance with respect †o fresh carrier production which is even more kept positive thanks †o the fact that the maintenance is reduced and hence restarting (and reheating) steps of the recycling unit.

In a preferred embodiment, each third ground batch of said series of n waste bituminous product bafch(es) is stored in a† leas† one tank.

In a variant embodiment of the process according to the present invention, each series of n waste bituminous product batch (es) is stored under the form its said third ground batch in a tank, thereby providing n tank of waste bituminous product, containing each a waste bituminous product under its third ground batch.

Advantageously in the process according to the present invention, said step of introducing a† leas† one third ground batch into a recycling unit is a step of introducing a mixture of x third ground batch (es), where x is an integer comprised between 1 and n and preferably being 1 , 2 or 3.

I† has been indeed observed according to the present invention that the process can handle quite homogeneous waste product or diversified waste products. Depending on the collected waste, different situations are possible such as: a) pure production waste product with a single type of membrane product is collected (for example because there was a problem in the production line and default is present on the roofing membrane). b) pure bituminous waste product from a construction site with a single type is collected (for example after a big project). c) the collect brought on the recycling site waste membrane product from a demolition site which is contaminated with residues from the demolition site and the membranes are aged and degraded. d) the collect brought on the recycling site a† the same time waste membrane product from a), b) and/or c). In practice, the waste membrane product will be sorted in n batch (es) for example SBS-modified membranes will be separated from APP-modified membranes and each will be sorted by kind of waste product such as production waste, cuffing waste from construction site and waste membrane products from demolition site and will be grinded separately and stored in a tank. A mixture will then be prepared with specific ratio of each origin waste membrane product before entering the recycling unit.

Some examples of mixtures depending on the availability of the source of the product are shown in table 1 :

Table 1 I† is indeed preferable in the process according †o the invention †o control the amount of demolition site waste membrane products and have the ratio preferably not exceeding comprised between 10 and 100%. On the other hand, sometimes, depending on the membrane to be produced with the recycled bituminous product, it can be desirable to adapt the proportion between the several batches in the mixture to be introduced in the recycling unit.

In a first preferred embodiment, in the process according to the present invention, the melted product is fed in a mixing tank having a predetermined volume containing fresh carrier at a level of 50% of the predetermined volume, at a residence temperature comprised between 160 and 200°C, preferably between 170 and 190°C, more preferably around 180°C said mixing tank being continuously agitated with horizontal mixing blade, said melted product being fed in said mixing tank until the volume of the melted product is almost 50% of the predetermined volume to provide a fourth bituminous product.

Preferably, in the first preferred embodiment, the fourth batch is further withdrawn by pumping and filtrated in a bag filter optionally before or after being stored in a storage tank.

In a variant of the first preferred embodiment, in the process according to the present invention, the melted product is collected in vessels.

In one advantageous embodiment of the process according to the present invention, said third ground batch is melted at a temperature comprised between 1 10 and 260°C.

A portion of the heat in the recycling unit is provided by the shear strength of the micronization chamber, but generally additional heat shall be furnished. The temperature in the recycling unit will depend on the waste product to be recycled and the additional heat will be adapted accordingly.

In yet another preferred embodiment of the process according to the present invention, said melted product overflowing along the driving axis is collected in a vessel by flowing through a space provided between the stator and a coupling element provided to couple the rotor of the recycling unit and a motor.

Preferably, according to the present invention, said melted product overflowing along the driving axis is collected in a vessel by flowing through a space provided between the stator and an end of a rotation axis at a side opposite to a side connected to the motor. By building the space provided between the stator and the coupling element and/or between the stator and an end of a rotation axis, the melted product can escape in a vessel when overflowing along the driving axis when the tightening is degraded or when more drastic conditions are happening inside the recycling uni† causing high pressure point. This avoid to degrade the roller bearing and having †o undertake expensive and extensive maintenance action and allow the process according †o the present invention †o be more robust and be pursued for a longer time between two normal maintenance operations. It was indeed surprisingly observed that despite the very high strength and very high shear stress applied inside the recycling uni†, it was possible to discard the rotor/stator couple and the motor and have a longer driving axis without distorting the rotation of the rotor inside the stator.

Other embodiments of the process according †o the present invention are mentioned in the appended claims.

The present invention also relates to a recycling plan† for recycling waste bituminous products preferably waste bituminous membrane products optionally containing reinforcement material, comprising :

(i) at least one recycling uni† comprising a first rotor housed in a first stator, provided with a chamber delimited by an external wall of the first rotor, wherein the chamber is a micronization chamber formed by a recess arranged in a counter-element mounted on the stator which is substantially cylindrical, which micronization chamber comprises an adjustment means organized to adjust the volume and/or shape of the chamber and wherein at least one scraper organized to scrape the external wall of the rotor is mounted downstream of the micronization chamber

(ii) a first grinding means, such as a knife shredder provided for grinding at least one batch of said series of n waste bituminous product batch (es) in a first shredded batch having a mean size comprised between 20 and 50 cm, preferably between 20 and 40 cm, said first grinding means having a first inlet and a first exit

(iii) a second grinding means such as a rotor granulator, provided for grinding at least one first shredded batch in a first crushed batch having a mean size between 5 and 25 cm, preferably between 8 and 20 cm, said second grinding means having a second inlet and a second exit, said second inlet being connected to said first exit a† leas† by conveying means,

(iv) a third grinding means, such as a rotor granulator provided for grinding a† leas† firs† crushed batch in a firs† ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm, said third grinding means having a third inlet and a third exit, said third inlet being connect †o said second exit a† leas† by conveying means

(v) a vibrating sieve provided †o convey and sieve the firs† ground batch and †o provide a second ground batch, being the firs† ground batch substantially depleted from dust and particles having a particle size dioo lower than 8 mm, preferably lower than 7 mm, more preferably lower than 6 mm,

(vi) a separator provided for separating metal pieces from non-metal pieces by application of Foucault current to said second ground batch and for producing a third ground batch, being said second ground batch substantially depleted from metal pieces, said separator being connected directly or indirectly †o said recycling unit in order to feed said recycling unit with a† leas† one third ground batch.

The separator provided in the recycling plant according to the present invention can sort the metal piece for the non-metal pieces. Also, in a preferred embodiment, it is possible †o attract on one side the ferrous metal and on another side †o discard the non-ferrous metal while keeping the non-metal material on a conveyor (being said third ground batch).

In a preferred embodiment, said micronization chamber formed by a recess is arranged in a cleat block between two counter-elements mounted on the stator.

In another preferred embodiment, the recycling unit comprises comprising a second micronization chamber or cavity delimited by an external wall of the firs† rotor, said cavity being formed in a recess arranged in a cleat block between two counter elements, said counter elements and the two cleat block being made solidar one †o each other and connected †o a support element comprising adjustment means organized †o adjust the volume and/or shape of the chamber. Advantageously, according to the present invention, wherein the external wall of the rotor has a grooved profile to drive the recycled product and guide it towards the micronization chamber, thereby improving the efficiency of the unit.

Preferably, in the recycling plan† according †o the present invention, said at least one scrapper extends over at least part of the length of the first rotor and has a stepped profile having at least a first and a second step, the first step, which is situated close to an output of the recycling unit, being disposed closest to the external wall of the first rotor.

In a further preferred embodiment, wherein the counter element comprises a first knife blade mounted on a first supporting element so as to make it possible to adjust its distance with respect to the external wall of the rotor and a second knife blade mounted on a second supporting element so as to make it possible to adjust its distance with respect to the external wall of the rotor, said first and second supporting element being fixedly connected to a solidarization element allowing to adjust the distance of both the first and second supporting element together with respect to the external wall of the rotor.

The first and second knife blade are organized, preferably downstream of the chamber, to disintegrate the reinforcement and to increase its disintegration, but also to pulverize the flakes and granules provided on the surface of bituminous membrane as mineral covers.

In yet a further preferred embodiment according to the present invention, the rotor is operated by a motor driving a rotation axis connected by a tight connection to the rotor, said motor being coupled to the rotation axis by a coupling element, said rotation axis passing through a roller bearing block disposed between the tight connection and the coupling element, said tight connection and said roller bearing block being separated by a distance d comprised between 6 and 20 cm, preferably between 7,5 cm and 15 cm.

It has been indeed realized according to the present invention that, contrarily to what is generally applied in mechanical engineering that providing a significant space between the tight connection and the roller bearing block allow to increase the efficiently of the recycling plant according to the present invention, by reducing the off period and thereby increasing drastically the operating life of the plant between two maintenance. The space provided between the tight connection and the roller bearing block allows hot bitumen overflowing from the rotor along the rotation axis to flow downwards, and hereby prevent the roller bearing getting dirt and contaminated by recycled bitumen, which latter would be very detrimental to its lifetime.

In a further advantageous embodiment according to the present invention, the rotor is on one end connect to a motor driving a rotation axis and on the other end connected to a dead end of said rotation axis by a tight connection to the rotor, said rotation axis dead end passing through a roller bearing block disposed between the tight connection and the end of the rotation axis, said tight connection and said roller bearing block being separated by a distance e comprised between 6 and 20 cm, preferably between 7,5 and 15 cm.

In an advantageous embodiment, said tight connection comprising a O-ring cord surrounding a metal ring located around said rotation axis, said O-ring cord extending over a length of said rotation axis defined between 2 flanges.

In a further preferred embodiment, in said tight connections, at least one the 2 flanges comprises one mobile flange which can move along a direction parallel to the rotation axis in order to reduce or to increase the distance between said 2 flanges, for example with a tightening clamp.

According to a preferred embodiment according to the present invention, downstream of the micronization chamber, a deflector is disposed in an output opening of the recycling unit, said deflector being disposed along part of the external wall of the rotor, to keep the recycled material in contact with the rotor for longer and thus lubricate the latter with the recycled material. Moreover, the presence of the deflector downstream of the micronization chamber and the fact that this deflector makes it possible to keep material against the rotor has the additional advantage of extinguishing, in the recycled material, any sparks which might have been created during the grinding of the mineral covering.

Preferably the counter-element and/or the stator are treated with a wear-resistant substance, in particular tungsten carbide. This makes the material of which the stator and the cylindrical body are manufactured more resistant to abrasion and protects them better against the impact of the mineral covering. Preferably the recycling plan† comprises an input opening and an output opening, disposed along the same axis that is offset with respect to a vertical central axis of the rotor. A suction effect is thus created on the material by the actual rotation of the rotor. This allows a better passage of the material in the recycling unit.

In a further preferred embodiment of the present invention, the recycling plant comprises a second recycling unit provided with a second rotor housed in a second stator provided with an interchangeable micronization chamber, which second stator and rotor are mounted downstream of the first stator and rotor. The presence of two rotors placed in series allows the grinding to be carried out in two stages. Thus the pulverization of the flakes and granules will take place in successive granulometric phases if the size of the micronization chamber in the second stator in comparison with that in the first stator is smaller.

Another embodiment of a plant according to the invention includes first and second stators that have a central input and the other a lateral input, the stator having the central input has an output situated at one end of the rotor, with each of the rotors there is associated one of said scrapers, the scraper associated with the rotor situated in the stator having its output at the end of the rotor is disposed so that the scraping is carried out at said end, and the scraper associated with the rotor whose stator has a lateral input is disposed at the center of the rotor with which it is associated. The capacity of the two rotors and the two stators is thus used to the maximum.

Preferably at least one of the scrapers is mounted on a pivot organized to make the scraper pivot between a first position where the scraper scrapes along the rotor, a second position where the scraper closes off.

In a further advantageous embodiment of the process according to the present invention, at least one end of the rotor is equipped with an Archimedes screw oriented in the reverse direction to that along which the material to be recycled circulates.

Advantageously, the recycling plant according to the present invention further comprises : a mixing tank located below the exit of the recycling unit having a predetermined volume, and comprising at least a first horizontal screw with mixing blades, provided to agitate a bitumen product contained in said tank at a residence temperature comprised between 160 and 200°C, preferably between 170 and 190°C, more preferably around 180°C. In a preferred variant of the recycling plan† according †o the present invention, said mixing tank is provided with a first zone and a second zone, said first zone being above said second zone, said second zone being a bottom zone, said mixing tank having a second horizontal screw with conveying baffles inside said bottom zone, said at least first horizontal screw with mixing blades being provided inside said first zone, said second horizontal screw with conveying baffles being provided to empty residues and bitumen product accumulated and having sedimented in said bottom zone while said at least first horizontal screw with mixing blades being provided to agitate said bituminous product located in the first zone, each first zone and second zone being provided with an exit equipped with a valve, eventually connected to a pump.

Preferably, in another variant, the recycling plant also comprises at least a bag filter, connected to the exit of the first zone of the mixing tank.

Other embodiments of the recycling plant according to the present invention are mentioned in the appended claims.

The present invention also relates to a recycled bituminous product. Recycled bituminous product having a viscosity comprised between 500 cPs and 45000 cPs as measured by a parallel plate rheometer, said recycled bituminous product containing a bitumen content comprised between 25 and 100% and a fiber content between 2 and 12%, said recycled bituminous product further showing a ash residue comprised between 5 and 50% upon calcination at 800°C.

Within the meaning of the present invention, the term “viscosity” means the viscosity has been measured by a parallel plate rheometer (Anton Paar - Physica MCR101 ) comprising two parallels discs, one of which rotates. The parallel discs have a diameter of 10mm and a gap between the discs is 1 ,3 mm at a rotation speed higher than sweeping the shear rate from 1 to 60s- 1 .

In a preferred embodiment, the recycled bituminous product present a 60°C penetrability comprised between 0,20 cm and 1 ,0 cm as a mean value between the internal face and superior face in a molded sample. The penetrability has been measured by a penetrometer PNR12 according to the standard ASTM D5 (version dating 2006) for measuring the distance in mm that a standard needle vertically penetrates a sample of the material under know conditions of loading, time and temperature. The weight of the needle and the load is 100 g and the duration time of the penetration test is 5 seconds at a temperature of 25°C and 60°C. The measures were done 5 times and the two extreme values are removed while a mean is calculated for the 3 remaining measures. The sample was poured in a mold of 5 cm * 5 cm * 5 cm and the thickness of the sample should be at least 3.5 cm.

Advantageously, the recycled bituminous product present a softening point between 40/155 And 60/165°C as measured by the bead anneal test according †o the following method. More particularly, the recycled product according †o the present invention has a fiber content between 2 and 12% as measured by the bead anneal test.

Within the meaning of the present invention, the term “density” means the density has been measured in and out of H 2 0 for a penetration cube (5*5*5cm) sample by a scale L420P.

Other embodiments of the recycled bituminous product according †o the present invention are mentioned in the appended claims.

The present invention also relates to a bituminous composition comprising at least 25% and up to 100w% of recycled bituminous product according to the present invention.

The present invention also relates to the use of a recycled bituminous product according †o the aforementioned for an indoor or outdoor bituminous product, such as for flooring applications, roofing application, wall application or road application.

Other characteristics and advantages of the present invention will be derived from the non-limi†a†ive following description, and by making reference to the drawings and the examples.

In the drawings, figure 1 represents a schematic flowchart view of the process according †o the present invention.

Figure 2 is a schematic flowchart view of a variant according †o the present invention.

Figure 3 is a recycling plan† according †o the present invention. Figure 4 represents a schematic view of a recycling uni† having a first and a second rotor/stator assembly.

Figure 5 represents a partial cross section of a recycling uni† having a first and a second rotor/stator assembly along the line 1-1 of figure 6.

Figure 6 represent a cross section along the vertical axis 19 of the rotor of the second recycling uni† 1 ’ illustrated in figure 3.

Figure 7 is an enlarged view of the rotation axis between the rotor and the motor.

Figure 8 is a partial cross-section of a recycling plan† according †o the present invention showing details of the mixing tank.

Figure 9 is a cross section of the mixing tank located below the recycling units.

Figure 10 is a view from above of the mixing tank located below the recycling units.

In the drawings, the same reference numbers have been allocated to the same or analog element.

As it can be seen in figure 1 , the process comprises a first step of collecting waste bituminous products, such as waste bituminous membrane products containing bituminous layers and optionally reinforcement layers (A). The collected waste bituminous used in this example contains only APP-modified bitumen waste product and can contain a) pure production waste bituminous products and/or b) cutting waste bituminous products and/or c) aged and/or degraded roofing membranes.

The waste bituminous product collected is then sorted in n batch (es) for example batch (bi), batch (bx) and batch (bn) . Each batch will be treated in the plan† separately even if, in some cases, it is possible to treat together waste product which are close to each other. Further in some cases, samples will be analyzed to determine the nature and the number of batch(es) (bi, bx, bn) into which the collected waste bituminous product will be sorted.

The result of the sorting step and optionally the analysis step is a series of n batch (es) of waste bituminous products (bi, bx, bn) .

The batch(es) can therefore have different composition (chemical composition, age, level of contamination) with respect to each other or not depending on the nature of the collected waste bituminous product. Also, sometimes, the collected waste bituminous products A will be inspected and will be considered enough homogeneous to be sorted in a single batch bi.

Each batch to recycle will be subjected to a first grinding step in a knife shedder where a size reduction to a d50 comprised between 20 and 50 cm to form a firs† shredded batch B. Accordingly, based on n ba†ch(es) †o be recycled (bi,

. bx . bn) will form intermediately n firs† shredded ba†ch(es) (Bi,bo; B x . B n ). The n firs† shredded batch (es) (Bi . Bx . B n ) will be conveyed by a conveying means

10 †o a second grinding step. Each n firs† shredded ba†ch(es) (Bi . Bx . B n ) will be reduced in size to o n firs† crushed batch (es) (Ci . Cx . Cn) where the particles have a d50 (mean size) between 5 and 25 cm, preferably between 8 and 20 cm.

The n firs† crushed batch (es) ((Ci . Cx . Cn) will be conveyed by a conveying means 1 1 to a third grinding step. Each n firs† crushed ba†ch(es) (Ci .

Cx . Cn) will be reduced in size into a firs† grand batch (Di . D x , D, D a ) where the mean particle size is between 20 and 50 mm, typically between 25 and 40 mim and more particularly between 27 and 35 mm.

Each firs† ground batch (Di . D x . D n ) is then conveyed on a vibrating sieve 12 independently where dust and particles having a d 100 lower than 8 mm, preferably lower than 7 mm, more preferably lower than 6 mm will be removed n second ground batch (es) (Ei E x . E n ) are therefore obtained respectively from the n firs† ground ba†ch(es) (Di D x . D n ). Each n second ground ba†ch(es) (Ei . E x . E n ) is then passed through a Foucault cage where

Foucault current is applied †o remove the metallic elements from each second ba†ch(es) ((Ei . E x . E n ). Preferably, the ferrous metal contaminants (Fe, Ni, Cu,..) are attracted and collected on one side while the non-ferrous metal contaminants (Al, Mg) are repulsed and collected on another side. The remaining particles form the third ground batch (Fi . F x . F n ) which is the second ground batch depleted from metal contamination. Each third ground batch (Fi . F x . F n ) is then stored in a storage tank or silo 60. Preferably the mixture stored in the storage tank or silo is analyzed (before or after being placed in the silo) in order to collect data pertaining †o the chemical composition of the bitumen, the physical properties but also level of polymer contained.

Based on the analysis and based on the features expected from the recycled product, the operator, will then withdraw from silo’s predetermined amount and prepare in a mixer 61 a mixture of several third ground batch (es) chosen amongst (Bi . B x . B n ) to be introduced and fed into the recycling unit 1 . A melted product will be collected a† the end of the recycling unit in a vessel 14.

Figure 2 shows a variant where the bafch(es) are mixed together based on predetermined ratio before being stored as a mixture of predetermined ratio of third ground bafch(es) in a silo’s or a storage tank 61 in order to feed the recycling unit 1 and obtain the recycled product in melted form in vessel 14.

The choice of the mixture †o b performed can be dictated based on many criteria depending on: ultimate use of the recycled product level and nature of bitumen level and nature of polymer level and nature of contaminants level of recycled product in final product,...

As if can be seen in figure 3, the recycling plant is shown schematically for recycling one waste bituminous product batch such as a waste bituminous product batch such as waste bituminous membrane product batch optionally containing reinforcement material, comprises a† leas† one recycling unit 1 comprising a housing 2’ and a feeding means 3. The housing encloses a firs† stator and a firs† rotor driven by a motor 4. The recycling plant comprises further a firs† grinding means 5, such as a knife shredder provided for grinding each firs† batch of waste bituminous product batch products 6 in a firs† shredded batch having a mean size comprised between 20 and 50 cm, preferably between 20 and 40 cm. The firs† grinding means 5 have a firs† inlet for receiving the waste bituminous products 6 and a firs† exit for exiting the firs† shredded batch.

The recycling plant also comprises a second grinding means 7 such as a rotor granulator, which is, in this shown embodiment, while no† being limited thereto, fed by said firs† shredded batch. The second grinding means 7 is provided for grinding said firs† shredded batch in a firs† crushed batch having a mean size between 5 and 25 cm, preferably between 8 and 20 cm. The second grinding means 7 has a second inlet for accommodating the firs† shredded batch and a second exit for exiting the firs† crushed batch. The second inlet of the second grinding means is connected †o the firs† exit of the firs† grinding means 5 a† leas† by conveying means 10.

By the terms “connected”, it is meant according to the present invention that the flow of matter follows the pathway from an element A to an element B, being the same or different than A, which is connected directly or indirectly to the element A, with physical means of simply flowing from element A †o element B, even if passing inside another equipment in between as additional element can be introduced between element A and B.

The recycling plan† further comprises a third grinding means 8, such as a rotor granulator, provided for grinding said first crushed batch in a first ground batch having a mean size between 20 and 50 mm, preferably between 25 and 40 mm, more preferably between 27 and 35 mm. The third grinding means 8 has a third inlet and a third exit. The third inlet is connected to the second exit of the second grinding means at least by conveying means 1 1 .

The plan† according †o the present invention is also provided with a vibrating sieve 12 provided to convey and sieve the first ground batch originating from the third grinding means 8 and to provide a second ground batch, being the first ground batch substantially depleted from dust and particles having a particle size dioo lower than 8 mm, preferably lower than 7 mm and more. The vibrating sieve 12 conveys the second ground batch †o a separator 9 provided for separating metal pieces from non-metal pieces by application of Foucault current †o said second ground batch and for producing a third ground batch, being said second ground batch substantially depleted from metal pieces.

The third ground batch is further conveyed by means of a conveying means 13 to the feeding means 3 of the recycling uni† 1 .

In this shown embodiment, a vessel 14 for collecting the recycled bituminous product is provided below the recycling uni† 1 where an exit is foreseen.

In Figure 4, a detail in cross section of a first embodiment according †o the present invention is shown where two recycling units 1 , 1 'are present. As it can be seen in figure 2, each recycling uni† 1 , 1 ’ comprises comprising a first rotor 15 housed in a first stator 2. The stator 2 has a substantially cylindrical geometry that facilitates its manufacture. The input 16 and the output 17 are situated along the same vertical axis 18 which is offset with respect to the central vertical axis 19 of the rotor 15. This offset has the effect of creating, by the rotation of the rotor 15, a suction effect on the pieces of the third ground batch introduced into the input 16. It is also possible to offset the input 16 and the output 17 with respect to one another within the scope of the present invention. The stator 2 is provided with a chamber 20 delimited by an external wall of the first rotor 15. The chamber 20 is a micronization chamber 20 formed by a recess arranged between two counter-elements 21 , 2G mounted on the stator 2 which is substantially cylindrical and comprises an adjustment means 24 organized to adjust the volume and/or shape of the chamber. A good compromise shall be found between a good level of grinding of the fibers and an acceptable flowrate. If the distance between the rotor and the counfer- elemenf 21 , 21 ’ is too low, the recycled product present a too small particle size of the fibers spread in the melted product (i.e. from reinforcement layer if present) and the flowrate of the recycling uni† is too low. If the distance between the rotor and the counter-element 21 , 21 ’ is too high, the recycled product contain long fibers but present a high flowrate in the exit.

The micronization chamber 20 allows the mass of the third ground batch introduced into the input opening 16 to accumulate there temporarily. Since the chamber 20 is delimited by the external wall of the rotor 15, the bituminous mass, which is situated in this chamber, will be driven rotationally by the rotation of the rotor 15 and thus swirl around in the chamber 20. Thus, the introduced cold third ground batch will heat up more quickly and will be triturated more easily. This is because the centrifugal force imposed on the mass by the rotor 15 will make it heat up more quickly.

The mass thus present in the chamber 20 will be mixed and/or ground in order †o melt it. When the recycling uni† 1 is equipped with heating means, the latter contribute towards heating said mass. The passage 22 that extends between the input opening 16 and the micronization chamber 20 is chosen †o be sufficiently wide so as to facilitate access to the micronization chamber 20.

The micronization chamber 20 is mounted in an adjustable and removable manner in the stator 2. To that end, the micronization chamber 20 is mounted between two supports 23, each being provided with an adjustment means 24, for example formed by a screw and a bolt. The adjustment means 24 allow not only mounting and removal of the chamber, but also make it possible to vary of the size of the chamber by moving i† nearer or further away with respect to the external wall of the rotor 15.

One end of the counter-element 21 , situated downstream of the chamber 20, forms the tip of the blade of a knife which is used to shear the pieces of the third ground batch triturated in the chamber 20 more and to disintegrate the reinforcement if present in the pieces. The blade of the knife is also used to shear and pulverize the mineral covering provided on the surface of the bituminous membrane. A deflector 25 is mounted downstream of the micronization chamber. The deflector 25 is mounted on the stator 2 and disposed in the output opening 21 , along part of the external wall of the rotor 15. The deflector 25 is preferably trapezoidal in shape and delimits a first cavity 26, formed between the lower part of the support 23, the upper part of the deflector 25, the stator 2 and the rotor 15. Thus, the bituminous mass that has passed through the chamber 20 can accumulate temporarily in this first cavity 26 which thus forms a buffer. From this buffer, the melted mass will then be conveyed by the deflector 25 along the rotor 15 and will lubricate the latter.

A scraper 27 is mounted downstream of the deflector 25 also in the output opening 21 . The scraper 27 and the deflector 25 are disposed so as to be at a distance from each other on opposite sides of the output opening 17. Thus, a corridor is created between the deflector 25 and the scraper 27 through which the processed material can reach the output opening 17. The scraper 27 is mounted on a support 28, using adjustment means 29. The scraper 27 is used to scrape the external wall of the rotor 15 so as to scrape the bituminous material which accumulates on this wall. Preferably the scraper 27 extends over at least part of the length of the rotor 15.

In this illustrated embodiment, two recycling unit 1 are comprised where the first and second stators 2 and rotors 15 preferably have a substantially identical construction and are placed in series so that the second recycling unit 1 ’ is downstream of the first recycling unit 1 . Thus an output 17 of the first recycling unit 1 opens into an input 16 of the second recycling unit G. To facilitate understanding, the identical elements of the second member have been indicated using the same reference as that used for the first.

To recycle the bituminous product such as membrane pieces, the third ground batch is introduced into the input opening 16 of the first recycling unit 1 . The rotation, indicated by the arrow 30, of the rotor 15 and the offset of the opening 16 with respect to the central axis 19 cause the suction towards the rotor 15 of the introduced third ground batch. This will at first accumulate in the opening on the external wall of the rotor which passes through the opening during its rotation. The mass can heat up more quickly if the stator 2 and rotor 15 are heated using a heating body. The heated third ground batch will then, by the rotation of the rotor 15, be driven towards the micronization chamber 20 and if applicable towards the first knife blade 21 . Preferably, the counter-element 21 and/or the stator 2 are treated with a wear-resistant substance, in particular tungsten carbide

After having passed the knife blades 21 , the hot mass will temporarily accumulate in the cavity 26 in order to heat up more and reach its melting point in order to be next conveyed along the external wall of the rotor 15 . The hot mass thus lubricates the rotor 15. Next, the mass reaches the corridor between the deflector 25 and the scraper 27 in order to fall into the output opening 17 under the effect of gravity. The scraper 27 takes care of scraping the external wall of the rotor, so as to prevent the mass, which is sticky because of the presence of hot bitumen, accumulating on the rotor 15 and thus preventing its rotation. The distance between the scraper 27 and the external wall of the rotor is chosen so that a little bituminous mass remains on the rotor 15 and lubricates its movement.

In this illustrated embodiment, the central vertical axis 19 of the rotor 15 of the first recycling unit 1 is aligned with the central vertical axis 19 of the rotor 15 of the second recycling unit 1 '.

In a preferred embodiment illustrated in figure 5, the central vertical axis 19 of the rotor 15 of the first recycling unit 1 is offset with the central vertical axis 19 of the rotor 15 of the second recycling unit 1 ’ .

As it can be seen in figure 5, each recycling unit 1 , 1 ’ comprises the same elements as illustrated for the embodiment in figure 4. The stator 2 is provided with a chamber 20 delimited by an external wall of the first rotor 15. The chamber 20 is a micronization chamber 20 formed by a recess arranged in a cleat block 31 between two counter-elements 21 , 21 ’ mounted on the stator 2. A second micronization chamber or cavity 26 is provided delimited by an external wall of the first rotor 15. The cavity 26 is formed in a recess arranged in a cleat block 31 between two counter elements 21 ’ and 21 ”. The two cleat block are made solidary one to each other and connected to a support element 23 comprising adjustment means 24 organized to adjust the volume and/or shape of the chamber. The adjustment means 24 can be operated manually with a wheel 34 (handwheel) or motorized wheel 34. The counter elements 21 , 21 ’ and 21 ” are a structural portion of the recycling plant and guide the cleat blocks 31 an 31 ’ when going forward or backward for adjustment.

The micronization chamber 20 allows the mass of the third ground batch introduced into the input opening 16 to accumulate there temporarily. Since the chamber 20 is delimited by the external wall of the rotor 15, the bituminous mass, which is situated in this chamber, will be driven rotationally by the rotation of the rotor 15 and thus swirl around in the chamber 20.

A sliding trapdoor 32 can be manually driven or by a motor 33.

As it can be seen in figure 6, the rotor 15 is operated by a motor 35 driving a rotation axis 36 connected by a fight connection 37 to the rotor 15. The motor 35 is coupled †o the rotation axis 36 by a coupling element 38. The rotation axis 36 further passes through a roller bearing block 39 disposed between the fight connection 37 and the coupling element 38. The fight connection 37 and the roller bearing block 39are separated by a distance d comprised between 6 and 20 cm, preferably between 7,5 and 15 cm.

If has been indeed realized according to the present invention that, contrarily to what is generally applied in mechanical engineering that providing a significant space between the fight connection 37 and the roller bearing block 39 allow to increase the efficiently of the recycling plant according to the present invention, by reducing the off period and thereby increasing drastically the operating life of the plant between two maintenance.

The rotor 15 is on one end connect †o a motor 35 driving a rotation axis 36 and on the other end connected †o a dead end of said rotation axis 36 by a fight connection 37 to the rotor 15. The rotation axis dead end passing through a roller bearing block 46, on the opposite side of the recycling unit 1 , 1 ’ with respect †o the side connected †o the motor 35. The roller bearing block 46 is disposed between the tight connection 37 and an end of the rotation axis 36. The fight connection 37 and the roller bearing block 39 are separated by a distance e comprised between 6 and 20 cm, preferably between 7,5 and 20 cm.

The space of a distance d or the space of a distance e allows said melted product overflowing along the driving axis (rotation axis) 36 †o be collected in a vessel by flowing through the space provided between the stator and the coupling element provided †o couple the rotor of the recycling unit and a motor or on the opposite side between the stator 2 and the end of the driving axis (rotation axis) 36..

As if can be seen in figure 7, the space of a distance d provided between the fight connection 37 and the roller bearing block 39 allows ho† bitumen overflowing from the rotor 15 along the rotation axis 36 †o flow downwards, and hereby prevent the roller bearing 40 getting dirt and contaminated by recycled bitumen, which later would be very detrimental †o its lifetime. As i† can be seen also in figure 7, The fight connection 37 comprises an O-ring cord 41 surrounding a mefal ring 42 located around said rotation axis 36 and extending over a length of said rotation axis 36 defined between 2 flanges 44, 45.

In a further preferred embodiment, in said tight connections, at least one the 2 flanges 44, 45 comprises one mobile flange 44 which can move along a direction parallel to the rotation axis 36 in order to reduce or to increase the distance between said 2 flanges 44, 45, for example with a tightening clamp 43.

As it can be seen in figure 8, a mixing tank 14 is located below the recycling units 1 , 1 ’. The mixing tank 14 located below the exit 17 of the recycling unit 1 ’ has a predetermined volume, and comprise at least a first horizontal screw 47 with mixing blades 48, provided to agitate a bitumen product contained in said mixing tank 14. The mixing tank comprises heating means to provide a residence temperature comprised between 160 and 200°C, preferably between 170 and 190°C, more preferably around 180°C.

As it will be more apparent from figure 8 and 9, the mixing tank 14 is provided with a first zone 49 and a second zone 50. The first zone 49 is located above said second zone 50, being a bottom zone 50. A second horizontal screw 51 with conveying baffles 52 is provided inside said bottom zone 50. The at least first horizontal screw 47 with mixing blades 48 is provided inside said first zone and the number of first horizontal screw can be higher than 1 , depending on the size of the horizontal section of the first zone 49. In this preferred illustrated embodiment, the number of horizontal screw 47 with mixing blades 48 is 2.

The second horizontal screw 51 acts as a conveying means with a baffles 52 and is provided to remove any waste product located in said bottom zone 50. The crank 53 allows to open a trapdoor on the side of the recycling unit. By rotating the screw 51 , the waste products is evacuated from the mixing tank. This operation is performed after having discharged the mixing tank 14.

Examples.-

The following recycled bitumen products have been obtained from the process according to the present invention.

Example 1.- 10 tons of APP waste bituminous membrane product was collected from the production facility. The collected waste product was sorted in one single batch. The batch was introduced in the plant according to the present invention and was therefore ground 3 times. The firs† grinding step allows †o reduce the mean particle size dso to 300mm; the second grinding step allows †o reduce the mean particle size dso to 150mm while the third grinding step allows †o reduce the mean particle size †o 30 mm forming bituminous flakes. The batch was melted in the recycling plant a† a temperature of about 200°C and form the collected melted material.

The collected melted material showed the features presented in table

2.

Table 2.

Example 2.-

Example 1 was reproduced except that the particles were depleted in fine particles lower than 6mm.

The collected melted material showed the features presented in table

3.

Table _3 Example 3.-

Example 1 was reproduced except that the waste bituminous membrane product collected was mainly used and aged APP roofing membrane from demolition site. The collected material was sorted in a single batch.

The collected melted material showed the features presented in table

4.

Table 4

Example 4.-

Example 3 was reproduced except that the particles were depleted in fine particles lower than 6mm.

The collected melted material showed the features presented in table

5. Tgble_5

Example 5.- 10 tons of SBS waste bituminous membrane product was collected from the production facility. The collected waste product was sorted in one single batch. The batch was introduced in the plant according to the present invention and was therefore ground 3 times. The firs† grinding step allows †o reduce the mean particle size dso to 300mm; the second grinding step allows †o reduce the mean particle size dso to 150mm while the third grinding step allows †o reduce the mean particle size †o 30 mm forming bituminous flakes. The batch was melted in the recycling unit a† a temperature of about 200°C and form the collected melted material.

The collected melted material showed the features presented in table

6.

Table 6.

Example 6.- Collected APP-modified waste membranes have been sorted by kind of waste product as production waste for the firs† waste bituminous membrane batch, cutting waste from construction site for the second waste bituminous membrane batch and waste membrane products from demolition site for the third waste bituminous membrane batch. Each batch of waste has been introduced in the plant according to the present invention and was therefore ground 3 times. The firs† grinding step allows †o reduce the mean particle size dso to 300mm; the second grinding step allows †o reduce the mean particle size dso to 150mm while the third grinding step allows †o reduce the mean particle size †o 30 mm forming bituminous flakes. The particles of each waste product were depleted in fine particles lower than 6mm. Each kind of waste has been grinded separately and stored in a tank.

A mixture has been prepared with specific ratio comprising 53,5% of flakes of waste product (first waste bituminous membrane batch), 16,8% flakes of cutting waste (second waste bituminous membrane batch) and 29,7% flakes of roofing waste (third waste bituminous membrane batch). The mixture has been put info the recycling uni†.

The batch was melted in the recycling uni† at a temperature of about 200°C and a melted material was collected.

The collected melted material showed the features presented in table 7.

Table 7

Example 7.-

The recycled product from example 1 was collected in a mixing tank containing 50% of regular bitumen 70/100 as carrier with respect to the volume of the tank. After another 50% of the volume of the mixing tank was filled in with the recycled bitumen product from example 1 , the final recycled bituminous product was obtained after continuous agitation during filling in.

The collected melted material showed the features presented in table

8.

Table 8

Example 8.-

The recycled product from example 2 was used in the process of example 7.

The collected melted material showed the features presented in table

9.

Table 9 .

Example 9.-

The recycled product from example 3 was used in the process of example 7.

The collected melted material showed the features presented in table

10.

Table JO

Example 10.-

The recycled product from example 4 was used in the process of example 7. The collected melted material showed the features presented in table

1 1.

Table 1 1

Example 11.-

The recycled product from example 6 was used in the process of example 7.

The collected melted material showed the features presented in table

12.

TgbleJ 2 I† should be understood that the present invention is not limited to the described embodiments and that variations can be applied without going outside of the scope of the appended claims.