The object of the invention is a method as defined in the preamble of claim 1 for the handling of ash classified as waste, as well as a product formed with said method as defined in the preamble of claim 8 and also use of said product as defined in the preamble of claim 12.

The method according to the invention is very well suited for the handling, and conditioning into products fit for further processing, of various materials classified as waste, such as e.g. fly ash produced from coal combustion, fly ash produced from the combustion of wood, peat or other bio-based material, hereinafter referred to as bio-ash, fly ash produced from the combustion recovered fuels (REF) , i.e. fly ash from REF combustion, bottom ash from incinerating plants and power plants, ash from oil shale, i.e. kukersite, or rock containing kerogen and also of the end product of the desulphurization of flue gases, gypsum regarded as waste and various textile wastes. Suitable targets for handling include the fly ash produced as a side product by coal-fired power stations, bio-ash and/or mixed ash formed from coal ash and bio-ash. Other suitable targets are the fly ashes and bottom ashes from the combustion of recovered fuels, such as appropriately pretreated municipal wastes and/or industrial wastes, and/or the fly ashes and bottom ashes from the mixed combustion of recovered fuels and other fuels. These ashes will hereinafter be referred to by the common designation "REF combustion ashes" mentioned earlier. In most cases the aforementioned ashes are nowadays taken as waste to landfill sites, but these ashes can, when suitably sorted according to the invention into different grain sizes, be used for various purposes, such as e.g. as an additive to cement in the manufacture of concrete, in the manufacture of asphalt, as an additive to grouting material, as fertilizer and, e.g. when mixed into waste gypsum or into the end product of the desulphurization of flue gases, also as a soil improvement agent, e.g. when stabilizing a road bed or reinforcing soil, and also for filling decommissioned mines. Hereinafter also the common designation "ash" will be used to refer to all ashes mentioned in this context. Fly ash is already used according to prior art for the aforementioned applications, but the results have not necessarily always been sufficiently good, because the fly ash has generally been used as is, without sorting in any way, in which case e.g. concrete, in which unsorted fly ash has been used as an additive, has been improved in terms of quality only to some extent or not at all. Cements supplemented with fly ash contain, in solutions according to prior art, generally approx. 15-35% fly ash. The use of untreated fly ash is typically seasonal, the amounts used are limited and, given the strict technical limit values set, the advantage to be gained has been small.

So much waste gypsum is produced in industrial processes that finding a way to recover it would be of benefit to the national economy. However, there has not been a viable method for large-scale recovery of waste gypsum, or of the end product resembling waste gypsum that is used for desulphurization of flue gases in power plants. Trials have been conducted of mixing waste gypsum into the fly ash of coal-fired power stations and peat-fired power stations to form a soil improvement agent and for the stabilization of road beds, but the results have not matched expectations because the waste gypsum-fly ash mixture produced did not harden into a sufficiently strong layer.

Cement, e.g. blast furnace cement, has been used as a binder agent according to prior art in, inter alia, the stabilization of road beds. Cement, however, is relatively expensive and, owing to the way it is manufactured, not very environmentally friendly. In order to reduce the amount of cement, fly ash mixed into the cement has also been used in improving and stabilizing road beds and the soil of other land areas. In such cases the fly ash used has generally been the unsorted and untreated fly ash derived from coal combustion or peat combustion that came from power stations, as stated previously.

One stabilization method known in the art and used is base course stabilization, which is a road structure improvement method wherein the bearing stratum of the road, or the top part of the bearing stratum, is bound with bitumen, cement or blast furnace sand. One pilot project for road bed stabilization, in which fly ash derived from peat combustion (8.4%) and dihydrate gypsum, i.e. phosphogypsum, (56.1%) as well as blast furnace cement (35.5%) were used for stabilizing an old road bed, was conducted in 1999 in Maaninka, Finland. In 2008 a UUMA inventory report was published (in Finnish) about the pilot project, entitled: "Pt 16207 /01/30-1700 ja 3600-5240 Kaanninniementie (Maaninka) Fosfokipsi ja lentotuhka; massiivirakenteessa ja kerrosstabiloinnin sideaineena" . A problem in this solution is, however, that it was necessary to use a relatively high proportion of cement in the mixture, which is not very environmentally friendly owing to its method of manufacture. Furthermore, there is no indication in the report that the fly ash was sorted according to its grain size into fractions of a certain size nor that only fly ash containing a precisely defined grain size was used. Toxic residues derived from the fuel often accumulate in the finer-grained portion of bio-ash, in which case that type of ash may not be used as a fertilizer e.g. in fertilizing forests. Toxic residues do not accumulate in the coarse end, so coarser bio-ash can be used for fertilizer. However, ash is generally used as is, i.e. unsorted, in which case regulations exclude its use for fertilizer .

Correspondingly, owing to the various input materials of REF combustion ash, these ashes contain very varying amounts of chemical elements, such as heavy metals and other harmful components, which can not necessarily be used in further processing according to the method presented by the invention nor in the products manufactured with the method. The harmful chemical elements and other components, however, only accumulate in certain grain size classes, so with the solution according to the invention they can easily be eliminated by sorting also REF combustion ashes into exactly the correctly selected grain size classes and by using the products obtained in this way for the purposes exactly suited to them. Those grain size classes that have accumulated a large amount of toxic or otherwise harmful residues can easily be left unused and delivered for appropriate disposal.

As an example of advantages of sorting by grain size can be mentioned cement produced according to invention, which is used as raw material of concrete. In an experiment, strength properties of concrete were measured. When unsorted fly ash was used as an additive of cement, the value of concrete strength was 4. Correspondingly, when the same fly ash sorted to different grain sizes was used, using fly ash containing the smallest grain size, i.e. fine fly ash, gave the value of concrete strength 3 and using fly ash containing big grain size, i.e. coarse fly ash, gave the value of concrete strength 22. The bigger the value mentioned is, the stronger the concrete is. This example shows a significant difference between use of unsorted fly ash and use of sorted fly ash and also between sorted fly ash containing different grain sizes.

The above mentioned applies also to fly ashes produced from other combustions. Different ashes contain different amounts of different chemical elements and other components, some of which are undesirable, as mentioned above. By sorting different fly ashes to different grain size classes, different products are obtained, in which products different chemical elements and other components are enriched in desired way. For example, in different grain size classes, the quantities of chemical elements and other components enriched may have more than tenfold differences. This has a remarkable effect on end products, in which fly ash is used as an additive. The aim of the present invention is to eliminate the aforementioned drawbacks and to provide an inexpensive and reliable method for the handling of ash classified as waste. In this case the aim is to increase the reuse of ash, e.g. fly ash, in the concrete industry, in asphalt construction and in soil improvement, as well as in soil reinforcement and mine fills, and also at the same time to reduce the amount of fly ash and other industrial waste being taken to landfill sites. The method according to the invention is characterized by what is disclosed in the characterization part of claim 1. Correspondingly, the product manufactured with the method according to the invention is characterized by what is disclosed in the characterization part of claim 8, and use of the product is characterized by what is disclosed in the characterization part of claim 12. Other embodiments of the invention are characterized by what is disclosed in the other claims.

One great advantage of the solution according to the invention is getting materials that would otherwise be classified as waste and handled as waste, such as e.g. fly ash from coal combustion, bio-ash, REF combustion ash, ash from oil shale and/or gypsum, as well as the end product of the desulphurization of flue gases, into reuse economically and extremely advantageously. In this case one advantage, among others, is a reduction in the CO2 emissions produced in the concrete industry by the manufacture of cement, because less cement is needed for the manufacture of concrete when some of the cement is replaced with very well sorted fly ash. Correspondingly, ground limestone powder has conventionally been used as a filler in the manufacture of asphalt. Suitably sorted fly ash from coal combustion is, however, well suited for the fine aggregate of asphalt surfacing, because it has homogeneous granularity, good capacity for filling porosity, a suitably low water content and it is alkaline. Since fly ash is in a bound form in asphalt mix, its environmental impacts are minor.

A further advantage is that, e.g. in the bed structures of roads, natural soils can be replaced with ash handled according to the invention, in particular with fly ash/bottom ash from coal combustion and/or from biocombustion and/or from REF combustion, when the ash has been sorted into suitable grain size. These ashes are very well suited to different filler structures, to foundations and to sound barriers in municipal engineering and special structures e.g. in harbors and landfill sites. Furthermore, mixing sorted ash, such as fly ash/bottom ash, sorted by grain size and in a suitable proportion, into gypsum and/or into the end product of the desulphurizat ion of flue gases that resembles the properties of gypsum, enhances the hardening and strength properties of the mixed mass. In addition, mixing textile fibers into the aforementioned mixture mass further enhances inter alia the toughness properties of the mass. When using wood-derived ash mixed into an ash-gypsum mixture, instead of fly ash from coal and peat power stations or mixed into them, a mixture mass that is even better in many respects is obtained e.g. for the stabilization of road beds and other land areas. Wood- derived ash refers in this context to ash in which a part of the fuel was wood or the fuel was wholly wood.

With the solution according to the invention e.g. the following advantages are obtained: the manufactured products are of homogeneous quality and technically reliable; products manufactured in this way replace more cement; the sorting precision and technical quality of the sorted product are better; the amount of ash needed to be used in the manufacture of concrete is smaller than with conventional unsorted fly ash, in which case raw material costs, transport costs and energy costs can be reduced; the ecological footprint is smaller than with conventional fly ash .

One advantage of the solution according to the invention is also its inexpensiveness and the fact that waste handling can be comprehensively and centrally managed, e.g. in a waste handling plant or at the site where the waste is generated. Another advantage also is that all the waste for handling goes for use in different products, in which case the amount of waste decreases. A further advantage is that the heavy metals in the ash to be handled can be concentrated into their own grain size class, in which case it is known in which products of which grain size class there are no heavy metals. These products can then be used freely also in the types of application sites in which products containing heavy metal may not be used. Correspondingly, the type of product according to grain size and in which it is known there are heavy metals can be used e.g. in the manufacture of asphalt and concrete, in which, inter alia, the fly ash is in bound form.

In the following, the invention will be described in greater detail by the aid of some embodiments and by referring to the attached simplified drawings, wherein

Fig. 1 presents the method according to the invention as a simplified diagram,

Fig. 2 presents the more important phases of the method according to the invention, shown in more detail, and

Fig. 3 presents the final phases of the method according to the invention, shown in more detail.

In the solution according to the invention fly ash from coal combustion, fly ash from biocombustion, fly ash from REF combustion and other materials classified as industrial process waste, such as e.g. the bottom ash from the aforementioned combustions, lump slag and granular slag, gypsum and also other suitable crushable waste is processed in such a way that it is no longer classified as waste. In the method according to the invention the fly ashes/bottom ashes of different combustions and/or the aforementioned other materials and other materials used in the method are sorted e.g. with one or more classifiers connected consecutively in series for achieving the desired, essentially precise, grain size distribution. If necessary, the material is ground smaller and delivered for grain size sorting again to one or more classifiers. A fraction sorted according to grain size already once is sorted after grinding again into two fractions of different grain sizes. Sorting into at least two different fractions can also be performed again from a fraction that has previously been sorted, without grinding the material in between. The sorting can be continued by connecting sorting devices into the sorting line, e.g. as many consecutive classifiers as necessary to obtain as an end result smaller and smaller product materials in terms of their maximum grain size, right up to the nanometer scale in grain size. In addition, if necessary, additives are mixed in suitable proportion into the mass that is sorted by grain size, for manufacturing different end products i.e. filler products. According to the invention, their correct applications are determined for each grain size and for each material. The products sorted in this way, being different in their grain size and mixture, are kept each in their own containers or storage spaces for future use.

The fly ash used as raw material can be ash produced in connection with coal combustion, i.e. coal ash. The ash can also be fly ash produced in connection with biocombustion, such as wood combustion or peat combustion, in which case it is called bio-ash, or the ash can also be a mixture of coal ash and bio-ash, i.e. so-called "mixed ash".

Preferably the ash can also be ash produced from the combustion of various recovered fuels or the ash produced from the combined or parallel combustion of recovered fuels and other fuels. These ashes will in this context be referred to by the common designation "REF combustion ash". Suitably pretreated municipal waste, for example, can be used as recovered fuels, such as household wastes, restaurant wastes or retail store wastes and/or office wastes and/or industrial wastes.

In addition, the ash can be ash produced in the combustion of oil shale, i.e. inter alia the oil shale occurring in Estonia . Hereinafter the common designation "ash" will be used in this context to refer to all the fly ashes/bottom ashes presented above, unless it is intended to specifically refer to one of these ashes in particular. Correspondingly, the gypsum used as an additive to ash sorted by grain size in the method according to the invention is preferably dihydrate gypsum, i.e. so-called "phosphogypsum" , which is produced, inter alia, as a side product of phosphoric acid production, and which as is can be regarded as waste. The stored gypsum used in the method according to the invention is essentially untreated.

Fig. 1 presents a simplified diagram of the method according to the invention. In it the ash, e.g. fly ash from coal combustion, fly ash from wood combustion, fly ash from peat combustion, fly ash from REF combustion, the bottom ash of the aforementioned combustions, other ash or material classified as waste and suited to the purpose that is the raw material 7, is delivered from the material storage location 1 according to the invention to the sorting phase 2, in which the material is sorted by means of one or more classifiers according to type of material and grain size into different-sized fractions by means of screens and/or an air current. The air flow can be implemented e.g. by means of suction, i.e. negative pressure, or blowing, e.g. by means of positive-pressure compressed air blowing. Preferably the material is sorted and it is conveyed by means of negative pressure arranged in the process ducting in such a way that the speed of movement of the ash particles remains essentially constant. In such a case, the sorting process is easier to manage. In addition, the use of negative pressure helps to keep the filters used in the sorting process cleaner, in which case the interval for cleaning/replacing the filters increases. Preferably sorting of the raw material 7 is performed when dry in the sorting phase 2. In conjunction with the sorting phase 2, the raw material is ground, if necessary, and is conducted again to sorting until the desired grain size of the material is achieved. Preferably at the beginning of the sorting phase as many so-called round ash particles as possible are removed from the material flow, which particles are sorted into their own product group. Overlarge particles are transferred to grinding, and the ground material is conducted again to the classifier, in which the small particles are separated from the larger particles and conducted again into their own product group. The grinding and type size sorting is continued by circulating the raw material in the sorting ducting until the desired amount of the fractions of different grain sizes is obtained, which fractions can be stored as products in their own right or can be mixed suitably with each other e.g. in such a way that the sorted but unground smaller particles are mixed into the larger- sized ground particles.

The raw material sorted and, if necessary ground, in this way is conducted according to the invention after the sorting phase 2 either to the mixing phase 4 or to the storage location 5. Preferably the storage location 5 is the storage location of the end products, but it can very well also be an intermediate storage location for semifinished products. Preferably the sorted raw material is conducted from the sorting phase 2 to the mixing phase 4 or to the storage location 5 one fraction at a time in such a way that the end products differing in grain size and composition each end up in their own storage locations 5.

Before the mixing phase 4, or at the start of the mixing phase 4, if necessary a supplement phase 3 for additives 8 is performed. In this case the additives 8 needed in the end product for changing or improving the properties of the end product are added to the sorted raw material. The mixing phase 4 can be performed in one or more mixing stations or at the usage location of the end product. No additives 8 at all are mixed into the sorted material that is taken directly from the sorting phase 2 to the storage location 5.

Some of the raw material 7 can be such that it does not need to be sorted or ground. In such a case, the raw material 7 can be transferred directly to the mixing phase 4 or, if there is no need to mix additives into it, the raw material 7 can be transferred directly to its storage location 5.

From its storage location 5, e.g. from a silo functioning as a storage container, the end products 9 manufactured with the method according to the invention are delivered as needed to end users 6. The end products can in this case be e.g. powdery and unmixed ash screened and sorted into a certain different grain size, powdery mixed ash provided with one or more additives, an essentially solid product, e.g. a panel product or building component, pressed from ash and additives, a pelletized product, or some other product manufactured and transferred to its storage location 5 with the method according to the invention.

Fig. 2 presents the more important phases of the method according to the invention, described in more detail but nevertheless in a simplified and diagrammatic manner. Preferably the fly ash of energy plants and/or power plants, the fly ash of REF combustion, the bottom ash of the aforementioned combustions, or some other suitable material classified as waste is used as the raw material 7. The fly ash can be the ash produced from wood combustion, from peat combustion or from the combustion of some other biomaterial, or ash produced from a combination of these, which ashes are hereinafter referred to also by the designation "bio-ash". The fly ash can also be ash derived from coal combustion or ash derived from REF combustion. The common designation "ash" is hereinafter used to refer to fly ash and bottom ash.

An additive 8 can be gypsum, preferably e.g. dihydrate gypsum classified as waste gypsum, the end product of desulphurization used in power plants and energy plants, cement or a cement mixture, e.g. blast furnace cement, in which is granulated blast furnace slag and cement mixed together suitably, carbon, various textiles torn into small pieces, and various chemicals. Additives 8 can be used either one at a time or a number of them together.

Gypsum and/or the end product of desulphurization provides dilution of the ash mixture. Correspondingly, the ash activates hardening of the gypsum, particularly if it is wood ash derived from wood combustion or if it contains wood ash. Correspondingly, torn textiles contain fibers that provide the mixture with toughness and tensile strength. The textiles can be either natural fibers or artificial fibers or both together. Carbon, for its part, improves the durability of natural fibers by preventing their molding and decomposition. Carbon also improves the properties of a product to be made into fertilizer. It is also possible by using chemicals to provide end products with many desired additional properties and to remove toxic substances from the ash.

Fig. 3 presents the final phases of the method according to the invention and the applications of an end product to be produced with the method, described in more detail but nevertheless in a simplified and diagrammatic manner.

By handling the raw material 7, i.e. mixed ash containing preferably ash from coal combustion, ash from REF combustion or bio-ash, or all of these, or only two of these at a time, in a different way, different end products can be made and in this way better re-use of the type of materials classified as waste and which could not be used before, is achieved. Preferably the aforementioned ashes or the mixtures of them can be used in such a way that the ash or ash mixture that is the raw material 7 is sorted according to its grain size into different products and, according to need, additives are mixed into a product in a suitable proportion. For example, fly ash selected according to exactly the correct grain size as an additive to cement used in concrete, among other things, improves the quality of the concrete and lowers the price of concrete and also reduces the consumption of cement. If the ash being handled according to the invention contains toxic heavy metals, they often accumulate in the finer-grained end of the ash, in which case the suitably sorted coarser portion of the ash can be re-used e.g. in fertilizer and also in other environmentally demanding applications, whereas the finer-grained portion containing toxic residues can e.g. be disposed of by conventional methods or used in such applications in which toxins are not detrimental. In this case it can be used e.g. for the stabilization of road beds. Also, by using various chemicals, toxic residues can be removed from the ash being handled. The toxic residues of the ash handled according to the invention also do not cause problems e.g. as a raw material for grouting material.

With the method according to the invention an end product is made e.g. into a filler for asphalt in such a way that the ash from an incinerating plant that is the raw material 7 is sorted and, if necessary, ground in phase 2 into roughly a medium-coarse size class in terms of its grain size, in which class the grain size of the ash particles is roughly between 10-60 μπι, preferably between 20-40 μπι. The end product sorted this way is transferred after the sorting phase either into the mixture 4 or into its own storage location 5 to await end use.

With the method according to the invention an end product is made e.g. into a raw material for the manufacture of concrete in such a way that material of exactly the right size in terms of its grain size is manufactured from the ash that is the raw material 7 for adding into cement that is then used in the manufacture of concrete. In this case the ash that is the raw material 7 is sorted in phase 2 into its own fraction possessing a suitably small grain size, while simultaneously taking care, whenever possible, not to break the small ash articles. For this reason, grinding is not used in this case. The raw material 7 can in this case be e.g. fly ash from coal-fired power stations or the aforementioned bio-ash, in which there is wholly or partly e.g. ash produced in wood combustion with the excess carbon removed.

According to the invention ash grains smaller than the cement grains are mixed into cement suited to the manufacture of concrete to fill the empty spaces between only the cement grains, then selected ash that is precisely sorted in phase 2 by its grain size on the basis of the cement grade desired is mixed into the cement, said ash being only approx . 2-14% of the amount of the cement, suitably e.g. approx. 3-12% and preferably e.g. approx. 5- 10% or whatever suitable percentage whatsoever of the ranges presented above, i.e. 4, 6, 7, 8, 9, 11 or 13 percent or parts thereof. In this way, the amount of ash to be used can thus, owing to the precise grain size sorting, be a lot smaller than the approx. 15-35% of the amount of the cement that is used according to prior art. In this case the grain size of the ash is e.g. as follows: D50 is between 1-8 μπι, D97 is between 2-40 μπι and D100 is between 3-80 μπι. Correspondingly D10 is between 0.5-2 μπι.

With the method according to the invention an end product is made e.g. into fertilizer or into a fertilizer additive in such a way that the ash from an incinerating plant that is the raw material 7 is sorted and, if necessary, ground in phase 2 into roughly a medium-coarse or large size class in terms of its grain size, wherein the grain size of the ash particles is preferably greater than 20 μπι, or even greater than 40 μπι. In such a case the heavy metals, and other toxins in the ash, that have accumulated in the fraction smaller in grain size in the sorting phase 2 are easy to remove by transferring the sorted smaller fraction in its entirety to other use, e.g. to earthworks or hazardous waste. If necessary, additives suited to the purpose are mixed in phase 4 into the material sorted in phase 2 into fertilizer or into fertilizer additive.

When using the method according to the invention for the manufacture of a type of end product that can be used as a soil improvement or soil reinforcement material in earthworks and/or in the stabilization of road beds, the end product being manufactured is more environmentally friendly the less cement it contains, since the manufacture of cement is not per se environmentally friendly. According to one preferred method, the soil improvement or soil reinforcement material and/or the end product to be used in the stabilization of road beds is manufactured in such a way that the ash sorted and, if necessary, ground in phase 2 and the gypsum to be added as an additive are mixed together in suitable proportion in phase 4. The ash used in the method is preferably fly ash from the combustion furnace of an energy plant or power plant or the fly ash of some other combustion plant, and preferably the ash is also ground in conjunction with the sorting phase 2 for crushing the ash particles. The use of ground ash considerably increases the hardening speed of the ash-gypsum mixture and improves the hardness and strength of the end result. The ash can in this case also be the aforementioned REF combustion ash, either on its own or mixed into other ash.

A very good end result from the viewpoint of the final hardness and final strength of the mixture, as well as of its hardening speed, is achieved by using the ash produced in connection with wood combustion, i.e. wood-derived ash. In such a case, the ash can be wholly wood ash or only partly wood ash, e.g. mixed into some other bio-ash or even into coal ash or REF combustion ash. A wood-derived ash- gypsum mixture, used e.g. as a base course in the stabilization of road beds, hardens quickly into a layer that is strong and sufficiently hard. Those types of ashes that are produced in combustion in which wood-derived material was included in the combustion as one fuel component, and was not just mixed in afterwards, are also suited to the purpose.

When manufacturing an end product to be used for soil reinforcement and/or for the aforementioned stabilization of road beds, it is advantageous to also add fiber, e.g. torn textile mass, to the ash-gypsum mixture. This provides the mixture with toughness and tensile strength, as already stated above. The carbon in the ash, or the carbon added as an additive, also improves the durability of natural fibers by preventing their molding and slowing down their decomposition.

One suitable mixture ratio for an end product to be used in the stabilization of road beds is one containing the following percentages by weight: gypsum approx. 25-75%, ash approx. 25-60% and other materials, such as torn textile mass, carbon, cement if necessary and chemicals, approx. 0- 15%. Preferably the mixture ratio is one containing approx. 40-50% gypsum, approx. 40-50% ash and approx. 0-15% torn textile mass. For example, a mixture containing approx. 45% gypsum, approx. 45% ash and approx. 10% torn textile mass as a stabilization layer for a road bed provides a tough stabilization layer hardening quickly to become extremely strong and hard, and remaining hard for a long time. In the mixing phase of the aforementioned stabilization mass mixture, particularly if the mixing is performed at the usage location, it is advantageous to wet the mixture in conjunction with the mixing and/or compacting. According to a preferred embodiment, the wetting is done e.g. with lye solution, i.e. an NaOH solution, which functions as an activator, in which case the stabilization mass mixture hardens more quickly and becomes harder. With the method according to the invention an end product is made e.g. into a filler for a mine in such a way that the ash from an incinerating plant that is the raw material 7 is sorted and, if necessary, ground in phase 2 into the desired size class in terms of its grain size and in the mixing phase 4 gypsum is added to the ash so that the mixture hardens in conjunction with the filling after water has been added to it, by means of which water the mixture is made to be very fluid. Also, other additives can be added to the mixture, but avoiding or minimizing the use of cement .

With the method according to the invention an end product can be manufactured also for other intended uses, e.g. powdery material, which can be pressed into flexible construction panels of gypsum board or corresponding panel structures or pieces of different shapes and different sizes, such as building components, which can be e.g. bricks or blocks. In this case the ash from an incinerating plant that is the raw material 7 is sorted and, if necessary, ground in phase 2 into the desired size class in terms of its grain size, and in the mixing phase 4 gypsum and other necessary additives are added to the ash so that the mixture can be made, when pressed and after the addition of suitable liquid, to harden into its desired final shape. In addition, the sorted and mixed end product can also be pelletized, which prevents the product from generating dust e.g. when being transported.

In the above examples, the gypsum is preferably dihydrate gypsum, i.e. so-called phosphogypsum, or even natural gypsum. Correspondingly the ash is preferably fly ash from the incinerating plants of power plants and/or energy plants and suitably e.g. fly ash from coal combustion, fly ash from wood combustion and/or fly ash from REF combustion. Preferably the ash to be used has been sorted into different fractions according to its grain size, which fractions each form their own separate products, which contain different amounts of enriched chemical elements and other components. This way, fractions of different sized compositions of various chemical elements and components are formed with help of sorting. According to the invention, essentially fine ash sorted by grain size is selected for a filler product, i.e. for the end product being manufactured, for cement, concrete, panel products, building components, grouting material and/or for mine fill. In this case the grain size of the ash is suitably less than approx. 30 μπι, preferably less than approx. 20 μπι.

Correspondingly, essentially fine and/or medium-coarse ash sorted by grain size is selected for a filler product, i.e. for the end product being manufactured, in the stabilization of a road bed and other land areas. In this case the grain size is suitably less than approx. 50 μπι, preferably less than approx. 40 μπι. Essentially medium-coarse ash sorted by grain size is selected for a filler product, i.e. for the end product being manufactured, for the manufacture of asphalt, for earthworks and for soil reinforcement . In this case the grain size is suitably between 10-50 μπι, preferably between 20-40 μπι.

On the other hand, essentially medium-coarse and/or coarse ash sorted by grain size is instead selected for a filler product, i.e. for the end product being manufactured, in the manufacture of fertilizer. In this case the grain size is suitably more than approx. 10 μπι, preferably more than approx. 20 μπι. The handling and sorting of fly ash or other usable waste material into products of exactly a certain size in terms of their grain size enables the inexpensive and appropriate productive re-use of these products in different applications, in which the use of unsorted waste or other material could not earlier have been implemented. For example, the use of sorted fly ash of essentially homogeneous quality used in the stabilization of a road bed in earthworks, when mixed into waste gypsum of the correct quality, enables a support layer that hardens quickly and becomes sufficiently hard under the road covering. Likewise, fly ash correctly selected according to exactly the correct grain size as an additive to cement used in concrete, among other things, improves the quality of the concrete and lowers the price of concrete and also reduces the consumption of cement.

It is obvious to the person skilled in the art that different embodiments of the invention are not limited to the example described above, but that they may be varied within the scope of the claims presented below. What is essential is that an additive product, such as fly ash or other material classified as waste, sorted by grain size according to the intended use, is used, in which case the grain size of the aforementioned additive product is essentially precisely known.

It is also obvious to the person skilled in the art that a sorted additive product according to the invention can also be made with other methods than those presented above.

It is further obvious to the person skilled in the art that an additive product according to the invention can be made at least partially of also other materials than materials classified as waste. In that case, for example, gypsum can be some other gypsum than waste gypsum, e.g. gypsum produced for this purpose or for some other purpose.