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Title:
PROCESSING OF WOOD FIBRE FRACTION
Document Type and Number:
WIPO Patent Application WO/2012/052617
Kind Code:
A1
Abstract:
The invention is based on performing, in an alternative step, biological or biochemical processing on a wood fibre fraction generated in connection with pulp making and unsuitable for paper making, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres. The fraction is subjected to physical processing whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a biocatalyst or not processed with a biocatalyst gellify, forming a gel-like pulp. The method then comprises recovering the formed gel-like pulp.

Inventors:
MAEENTAUSTA OLLI (FI)
HARINEN KALEVI (FI)
RAESAENEN KIMMO (FI)
ROUVINEN JARI (FI)
SOINI JAAKKO (FI)
Application Number:
PCT/FI2011/050901
Publication Date:
April 26, 2012
Filing Date:
October 17, 2011
Export Citation:
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Assignee:
MZYMES OY (FI)
MAEENTAUSTA OLLI (FI)
HARINEN KALEVI (FI)
RAESAENEN KIMMO (FI)
ROUVINEN JARI (FI)
SOINI JAAKKO (FI)
International Classes:
D21H11/18; D21B1/02; D21C5/00; D21C9/00; D21H11/20; B02C13/00; C12S3/04
Foreign References:
EP2236545A12010-10-06
US6372085B12002-04-16
US20040168783A12004-09-02
Other References:
PAAKKO M. ET AL.: "Enzymatic Hydrolysis Combined with Mechanical shearing and High-Pressure Homogenization for Nanoscale Cellulose fibrils and strong Gels", BIOMACROMOLECULES, vol. 8, January 2007 (2007-01-01), pages 1934 - 1941, XP003026928
SIRO I. ET AL.: "Microfibrillated cellulose and new nanocomposite materials: A review", CELLULOSE, vol. 17, no. 3, June 2010 (2010-06-01), pages 459 - 494, XP055068118
DATABASE CA [online] 24 January 2012 (2012-01-24), XP003032701, accession no. STN Database accession no. 2010:847645
See also references of EP 2630296A4
Attorney, Agent or Firm:
KOLSTER OY AB (P.O.Box 148, Helsinki, FI)
Download PDF:
Claims:
CLAIMS

1. A method of processing a wood fibre fraction, characterized in that the method comprises

performing, in an alternative step, biological or biochemical processing on the fraction, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres;

performing physical processing on the fraction whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a biocatalyst or not processed with a biocatalyst gellify, forming a gel-like pulp, whereby the method comprises

recovering the formed gel-like pulp;

whereby the wood fibre fraction comprises fibre containing waste generated in pulp or papermaking industry.

2. A method as claimed in claim ^ characterized in that the physical processing is based on kinetic energy applied to the wood fibre fraction non-uniformly in respect of time and place.

3. A method as claimed in claim 1 or 2, characterized in that the physical processing is based on strong solid and/or liquid material flows which are applied to the wood fibre fraction and which contain organic and/or inorganic microparticles and/or nanoparticles.

4. A method as claimed in claim 1, 2 or 3, characterized in that the physical processing utilizes a ball mill, a stone mill, and/or a counter impact mill.

5. A method as claimed in any one of the preceding claims 1 to 4, characterized in that the physical processing is based on defibrating the wood fibres in the fraction by means of mineral particles contained in the fraction and/or added thereto.

6. A method as claimed in claim 5, characterized in that the mineral particles comprise CaC03 particles.

7. A method as claimed in any one of the preceding claims 1 to 6, characterized in that the physical processing is based on ultrasound, whereby ultrasound is applied to the wood fibre fraction in order to produce a gel-like pulp.

8. A method as claimed in any one of the preceding claims 1 to 7, characterized in that the particles disclosed in the method are separated from the gel-like pulp by dissolving the pulp into a solvent and separating the liquid phase from the pulp.

9. A method as claimed in any one of the preceding claims 1 to 8, characterized in that the biocatalyst comprises a living microbial growth and/or an enzyme produced by it when present in the fraction.

0. A method as claimed in any one of the preceding claims 1 to 8, characterized in that the biocatalyst comprises a single enzyme, an enzyme mixture or a mixture of several enzyme mixtures.

11. A method as claimed in any one of the preceding claims 1 to 10, characterized in that the biological or biochemical processing comprises the steps of

adding a chosen enzyme to the wood fibre fraction prior to feeding the fraction to a counter impact mill;

allowing the enzyme to work for a given period of time; and running, after the given period of time, the enzyme containing wood fibre fraction through the counter impact mill.

12. A method as claimed in claim 9, 10 or 11, characterized in that the enzyme comprises one or more enzymes having a disintegrating influence on lignocellulose or the bonds between wood fibres.

13. A method as claimed in any one of the preceding claims 1 to 12, characterized in that the recovered gel-like pulp contains cellulose microfibrils.

14. A method as claimed in any one of the preceding claims 1 to 13, characterized in that the recovered gel-like pulp contains molecular and/or amorphous cellulose such that the recovered gel-like pulp is usable for manufacturing nanocomposites.

15. A method as claimed in any one of the preceding claims 1 to 14, characterized in that the wood fibre fraction comprises waste sludge generated in pulp and paper industry.

16. A method as claimed in any one of the preceding claims 1 to 15, characterized in that the wood fibre fraction comprises fibrous clay, OPA precipitate, and/or flour.

17. A method as claimed in any one of the preceding claims 1 to 16, characterized in that water is removed from the gel-like pulp.

18. A method as claimed in any one of the preceding claims 1 to 17, characterized in that the water in the gel-like pulp is replaced by an organic solvent.

19. A system (S) for processing a wood fibre fraction, characterized in that the system (S) comprises

alternatively means for performing biological or biochemical processing on the fraction, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres;

means (M) for performing physical processing on the fraction whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a biocatalyst or not processed with a biocatalyst gellify, forming a gel-like pulp, and

means for recovering the formed gel-like pulp;

whereby the wood fibre fraction comprises fibre containing waste generated in pulp or papermaking industry.

20. A system as claimed in claim 19, characterized in that the means for performing the physical processing comprise a ball mill, a stone mill, and/or a counter impact mill.

21. A system as claimed in claims 19 or 20, c h a r a c t e r i z e d in that the means for performing the physical processing comprise means for producing ultrasound and applying it to the wood fibre fraction in order to provide a gel-like pulp.

22. A wood fibre gel, characterized in that it is produced by a method according to any one of claims 1 to 18.

23. A wood fibre containing product, characterized in that it comprises a wood fibre pulp according to claim 22, water having been removed from the wood fibre gel.

24. A use of a wood fibre gel according to claim 22 for manufacture of a carbon nanotube, a fuel pellet, a super capacitor electrode, an electromagnetic shielding material, a building board, a thermal board, and/or an antistatic material.

Description:
PROCESSING OF WOOD FIBRE FRACTION

FIELD OF THE INVENTION

[0001] The invention relates to processing a wood fibre fraction.

BACKGROUND OF THE INVENTION

[0002] Pulp manufacture is based on separating wood fibres contained in a wood material from one another. Pulp may be manufactured by a chemical pulp manufacturing process and/or a mechanical pulp manufacturing process. In the chemical pulp manufacture, wood chips are boiled in lye. In the mechanic pulp manufacture, wood fibres are detached from one another by means of mechanical stress by grinding or refining. A refining process may be enhanced by chemicals or heat, a grinding process by pressure.

[0003] Wood fibres lose some of their strength as they become shorter. Too short a fibre cannot be used in paper making, in which case they have to be separated and removed from the pulp. This results in waste material flows, which are recovered and used as a fuel for energy production of a pulp or paper mill.

[0004] A problem with the arrangement described above is that it has been impossible to utilize all waste and side flows generated in pulp and paper making for energy production and, further, their efficiency in energy production is poor.

BRIEF DESCRIPTION OF THE INVENTION

[0005] An object of the invention is thus to provide a method and an arrangement so as to enable the aforementioned problems to be solved. The object of the invention is achieved by a method, a " system, a wood fibre gel, a wood fibre product and a use which are characterized by what is stated in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

[0006] The present solution is based on processing a wood fibre fraction by performing, in an alternative step, biological or biochemical processing on the fraction, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres, and performing physical processing on the fraction whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a bio- catalyst or not processed with a biocatalyst gellify, forming a gel-like pulp, whereby the formed gel-like pulp is recovered.

[0007] An advantage of the solution according to the invention is that it is environmentally friendly as it becomes possible to utilize unsuitable waste or corresponding flows generated in connection with pulp manufacture and/or paper manufacture more efficiently. This is because owing to its state, it is easier to think of potential practical uses for the gellified wood fibre containing material than for the original waste pulp.

BRIEF DESCRIPTION OF THE FIGURES

[0008] The invention is now described in closer detail in connection with preferred embodiments and with reference to the accompanying drawing, in which

Figure 1 illustrates a system according to an embodiment of the present solution.

DETAILED DESCRIPTION OF THE INVENTION

[0009] A gel refers to a mixture wherein liquid is dispersed in an inner part of a porous solid matter. In a gel, solids may absorb liquid and swell. In a gel, the continuous phase (outer phase) is solid while the dispersed phase (inner phase) is liquid. Gels are semisolid products. Gels consist of a large molecular gellifier and liquid. Hydrogels consist of a gellifier and a hydrophilic medium (e.g. water).

[0010] According to the present solution, a wood fibre gel is produced when a fibre containing material is processed biologically or biochemically by means of a biocatalyst (such as an enzyme) as well as physically (e.g. mechanically in a counter impact mill or by ultrasound processing). However, the biological/biochemical processing is alternative (optional), i.e. a wood fibre gel may be achieved 1 ) as a result of "mere" physical processing or 2) as a result of physical processing and biological (or biochemical) processing. A fibre containing material used as the raw material may refer to pulp and paper industry waste, side and/or reject flows or any other suitable material containing wood and/or paper fibres. Examples of such fibre containing materials include i) fibrous clay, i.e. fibre containing sludge consisting of pulp and paper industry side flows, ii) OPA precipitate, i.e. a paper making side flow containing a coating material and reject fibre, and iii) flour, i.e. reject fibre unsuitable for paper making (e.g. too short a fibre which passes through a wire of a paper ma- chine). The invention is not, however, intended to be restricted to these raw materials only, but the invention may also utilize any other at least partly gellifi- able wood or paper fibre containing material.

[0011] Biological/biochemical processing may refer to influencing pulp properties by adding to the pulp a suitable amount of one or more active biocatalysts (e.g. an enzyme) and by allowing it/them to work in the pulp (become mixed therewith) in suitable conditions for a given period of time (e.g. an hour or more; e.g. about 1 to 2 hours). Enzyme activity may be directed e.g. at disintegrating the adhesive agents in fibre bundles contained in the pulp.

[0012] The influence of the biocatalyst processing may be enhanced by physical processing, wherein the biologically or biochemically processed pulp is fed to a so-called counter impact mill (it is also possible to omit the biocatalyst processing). Such a counter impact technique may be used for influencing the fibre bundles by disintegrating them and spreading the disintegrated fibre bundles uniformly within the pulp. The influence may be enhanced by repeating a cycle several times. Instead of a counter impact mill or a corresponding device, it is feasible to use any other device suitable for mechanically breaking the fibre bundles, such as an ultrasound device. The biological/biochemical step improves the efficiency of the physical step by influencing the bonds between the fibre bundles. In the physical step, the fibre bundles disintegrate, whereby enzyme activity is allowed to influence surfaces inside the fibre bundles.

[0013] It is also possible that a biocatalyst (enzyme(s)) is added to the pulp as late as during the physical (e.g. counter impact mill) processing, before or after it. The number of mechanical and/or enzymatic (biological, biochemical and/or physical) processing steps may be one or more, and the processings may have a given duration (e.g. about 1 to 2 hours). The processing may be a continuous process or a batch process, and it may include recycling of the biocatalyst (enzyme(s)) and/or the material being processed in order to enhance the processing.

[0014] A counter impact mill refers to one or more mills which are based on a rotor blade rotating in the same or different direction and which are suitable for breaking the bonds between fibres by producing a kind of tearing influence on the fibres. Instead of/in addition to a counter impact mill, the present solution may also utilize a ball mill or a stone mill. [0015] As a result of the biological/biochemical and physical simultaneous or alternate processing (or "mere" physical processing), a wood fibre gel is achieved wherein microfibrils of the fibre containing pulp are located separately from one another and dispersed uniformly into a gel-like pulp. The gel-like pulp is suitable (after a possible water removal step) for use e.g. as an additional material in a pellet, a super capacitor electrode material, and in electromagnetic shielding. The properties of the wood fibre gel according to the present solution enable it to be utilized e.g. in the following applications:

a) electronics industry

• electromagnetic shielding (EMI shielding)

• super capacitor

• antistatic materials

b) construction industry

• building boards

• thermal boards

• antistatic materials

c) energy industry

• additional material for a fuel pellet

• other biofuel applications

d) · nanotechnology applications, such as (carbon) nanotubes, nanocomposites and functionalized carbon nanotubes.

[0016] An advantage of the present solution is the significant commercial potential of the wood fibre gel in the aforementioned applications. The raw material for the wood fibre gel is inexpensive, and it is available in abundance. Manufacturing costs are reasonable in proportion to the value of the applications. Instead, an unprocessed (non-gellified) wood fibre fraction is typically not applicable to these purposes.

[0017] Typically, the wood fibre gel obtained as a result of the physical and biocatalyst processing is dried, i.e. water is removed therefrom, making it strong enough for sheet manufacture carried out by pressing, for instance. The strength properties, electric insulating properties and thermal insulation properties of the gel improve clearly as compared with waste pulp (sludge) used as the raw material, even if this requires water removal and, when insulating properties are in question, additives to be blended with the gel as well. Gelation is clearly observable in approximation and by a microscope as compared with the appearance of the waste pulp used as the raw material since in the waste pulp liquid the fibres are randomly (non-uniformly, vaguely) dispersed in the pulp. In a gel, instead, the fibre is dispersed more homoge- nously (uniformly) in the material, whereby it is easier to think of potential uses for such a material. The gelation does not have to be complete but it may suffice that some of the wood fibres gellify.

[0018] In the present solution, the wood fibres may disintegrate such that single fibres are separated (detached) from other fibres, whereby microfibrils are formed. In the present solution, the wood fibres may also break down such that a single fibre is defibrated into a smaller one, whereby amorphous cellulose is formed. Thus, the physical bonds between the fibres and/or the physical bonds inside a fibre may disintegrate. Both manners of disintegration, together and/or separately, enhance gelation.

[0019] The present invention was developed in laboratory tests and test runs which were carried out in connection with corresponding materials and processings and wherein the purpose was to find practical uses for industrial side flows.

[0020] In a method according to an exemplary embodiment of the present solution, a wood fibre fraction is processed such that physical processing is performed on the fraction whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a biocatalyst or not processed with a biocatalyst gellify, forming a gel-like pulp. The wood fibre fraction is processed in an alternative step such that the fraction is subjected to (e.g. prior to the physical processing) biological or biochemical processing, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres. The gel-like pulp formed is recovered.

[0021] According to an embodiment, the physical processing is based on kinetic energy applied to the wood fibre fraction non-uniformly in respect of time and place. According to an embodiment, the physical processing is based on strong solid and/or liquid material flows which are applied to the wood fibre fraction and which contain organic and/or inorganic microparticles and/or nanoparticles. According to an embodiment, the physical processing employs a ball mill, a stone mill, and/or a counter impact mill. According to an embodiment, the physical processing is based on defibrating the wood fibres in the fraction by means of rock and/or mineral particles contained in the fraction and/or added thereto. According to an embodiment, the particles comprise calcium carbonate particles (CaCOa).

[0022] According to an embodiment, the physical processing is based on ultrasound, whereby ultrasound is applied to the wood fibre fraction in order to produce a gel-like pulp. According to an embodiment, the particles are separated from the gel-like pulp by dissolving the pulp into a solvent and separating the liquid phase from the pulp.

[0023] According to an embodiment, the biocatalyst comprises a living microbial growth and/or an enzyme produced by it when present in the fraction. According to an embodiment, the biocatalyst comprises a single enzyme, an enzyme mixture or a mixture of several enzyme mixtures. According to an embodiment, the biological or biochemical processing comprises steps of adding a chosen enzyme to the wood fibre fraction prior to feeding the fraction to a counter impact mill, allowing the enzyme to work for a given period of time, and running, after the given period of time, the enzyme containing wood fibre fraction through the counter impact mill (or ball mill/stone mill). According to an embodiment, the enzyme comprises one or more enzymes having a disintegrating influence on lignocellulose or the bonds between wood fibres.

[0024] According to an embodiment, the recovered gel-like pulp is used as a reinforcing material in composite structures. According to an embodiment, the recovered gel-like pulp is used as a matrix for particles having electromagnetic properties. According to an embodiment, the recovered gel-like pulp is used as a matrix for carbon nanotubes. According to an embodiment, the recovered gel-like pulp is used as a filler in a building material.

[0025] According to an embodiment, the recovered gel-like pulp contains cellulose microfibrils. According to an embodiment, the recovered gellike pulp contains molecular and/or amorphous cellulose such that the recovered gel-like pulp is useful for the manufacture of nanocomposites. According to an embodiment, the wood fibre fraction comprises chemically, chemi- mechanically and/or mechanically produced cellulose pulp. According to an embodiment, the wood fibre fraction comprises waste or reject material from pulp or papermaking industry. According to an embodiment, the wood fibre fraction comprises fibrous clay, OPA precipitate, and/or flour. According to an embodiment, the wood fibre fraction comprises chemically, mechanically and/or chemi-mechanically produced fibre. [0026] According to an embodiment, water is removed from the gellike pulp. According to an embodiment, the water in the gel-like pulp is replaced by an organic solvent.

[0027] A system S for processing a wood fibre fraction according to an exemplary embodiment of the present solution comprises alternatively means for performing biological or biochemical processing on the fraction, whereby one or more biocatalysts having a disintegrating influence on the structure of wood fibres and wood fibre bundles are added to the fraction for weakening the bonds between the wood fibres, means M for performing physical processing on the fraction whereby, as a consequence of the physical processing, at least some of the wood fibres processed with a biocatalyst or not processed with a biocatalyst gellify, forming a gel-like pulp, and means for recovering the formed gel-like pulp.

[0028] According to an embodiment, the means for performing the physical processing comprise a ball mill, a stone mill, and/or a counter impact mill. According to an embodiment, the means for performing the physical processing comprise means for producing ultrasound and applying it to the wood fibre fraction in order to provide a gel-like pulp. In such a case, sonication is performed e.g. by a sonicator or an ultrasonicator, whereby ultrasound is used for applying energy to an object, enabling nano- and microparticles to be mixed with one another, for instance.

[0029] An exemplary embodiment of the present solution comprises a wood fibre gel produced by the aforementioned method. An exemplary embodiment of the present solution comprises a wood fibre containing product comprising a wood fibre gel produced by the aforementioned method, water having been removed from the wood fibre gel. An exemplary embodiment of the present solution comprises a use of a wood fibre gel produced by the aforementioned method for the manufacture of a nanotube, a fuel pellet, a super capacitor electrode, an electromagnetic shielding material, a building board, a thermal board, and/or an antistatic material.

[0030] In the present solution, the raw material, i.e. a wood fibre containing material, may contain a rock and/or mineral containing material, or the method comprises adding such a material to the wood fibre containing material. This results in a gel-like pulp comprising noncrystalline (amorphous) cellulose and/or microfibrils, i.e. the cellulose fibre is disintegrated into amorphous cellulose or microfibrils. Next, the rock and/or mineral containing material may be removed from the amorphous cellulose by dissolving it with a suitable solvent (such as sulphuric acid or hydrochloric acid). The rock and/or mineral containing material (the micro- and/or nanoparticles comprising it) in the wood fibre containing material enhances the disintegration of the wood fibre containing material into amorphous cellulose by enhancing the grinding influence.

[0031] Figure 1 illustrates a system S according to an embodiment of the present solution. Referring to Figure 1 , the system S comprises a feed of the raw material, i.e. a pulp or paper mill waste flow, for instance, to filtering means F. The system S may comprise filtering means F configured to remove liquid from the feed flow, resulting in dried sludge. The system is configured to feed the dried sludge, which in this connection is also called a wood fibre fraction, to means M for physically processing the fraction, wherein the means may comprise e.g. a counter impact mill or a corresponding device suitable for grinding wood fibre bundles (grinding means M) or a device M for producing ultrasound and/or applying it to the fraction so as to process the fraction physically. The system S may further comprise a biocatalyst feed to the system for biological/biochemical processing of the fraction. The biocatalyst is mixed with the wood fibre fraction either during, before or after the physical processing. Figure 1 illustrates a situation wherein the biocatalyst is fed during grinding. After the physical and possibly biological/biochemical processing, the system may be configured to feed the formed wood fibre gel (gel-like pulp) to drying means K for the removal of water (or some of the water) from the wood fibre gel. The wood fibre gel, possibly having water removed therefrom, may be processed further e.g. by pressing means P, resulting e.g. in wood fibre gel containing sheets or bars. These may be further used for the manufacture of wood fibre gel containing products in construction or electronics industry, for instance.

[0032] In the present solution, various ligninolytic (i.e. wood deligni- fying) and/or softening enzymes and/or other enzymes having an influence on wood cells and fibres, such as pectinases, laccases, resinases, hemicellulases and/or cellulases, may be used, depending on the wood species. The amounts of enzyme to be used may depend on the wood species and quality of the raw material as well as on the enzyme used.

[0033] The present solution may be applied to processing the reject and side flows of the production of both chemical and mechanical pulp (TMP, cTMP, PGW). The present solution provides a method of processing a wood fibre fraction generated in connection with pulp making and unsuitable for pa- permaking into a form enabling better utilization for another purpose.

[0034] In future, as environmental permits and licences become stricter, it will be less acceptable to take any solid (fibre, lint) that has been removed from sludge prior to entry into a waste water purification plant to a waste dump. The present invention enables this waste which, for the time being, ends up in a waste dump to be utilized and pulp making to better conform with the ever-tightening environmental norms. It is also possible to decrease the waste water load caused by pulp making as it becomes possible to separate a material from the waste water for a practical use.

[0035] Paper fibres lose strength with each recycling. They become shorter and shorter until they are no longer suitable for paper making, in which case they have to be separated and removed from circulation. A single wood fibre can be recycled about 4 to 7 times. The present invention is also applicable to the utilization of unusable recycled paper since fibres unsuitable for recycling can be processed in accordance with the present invention.

[0036] A short fibre fraction unsuitable for paper making is not necessarily as such suitable to be burnt for energy production but some combustion enhancing material, such as peat, may be necessary to be added to the sludge prior to burning. The energy efficiency of the wood fibre containing sludge is rather poor. On the other hand, if the wood fibre containing sludge ends up in a waste water plant, this would be a problem to the waste water purification plant since as far as the waste water purification plant is concerned, wood fibres are difficult to purify from the waste water and they cause problems to the purification process. Consequently, the present solution is a very welcome alternative in processing and utilizing a wood fibre fraction.

[0037] Typically, in the formed gel-like pulp, some of the wood fibres have become gellified (jellified) but the pulp may also contain non-gellified wood fibres. In any case, the state of the formed gel-like pulp differs significantly from the original wood fibre fraction. Consequently, the method enables pulp mill waste liquid, for which it is otherwise difficult to find useful applications, to be processed into a state wherein it is easier to think of applications for the pulp (it is, among other things, compressible mechanically into a strong plate or tube, which is not possible when using non-processed pulp making waste liquid). [0038] It is to be noted that in this connection the terms "wood fibre", "wood fibre containing", "wood fibre gel", etc. may also refer to paper fibre, paper fibre containing, paper fibre gel, etc., respectively.

[0039] In the technology according to the present solution, the raw material is thus other than the actual cellulose fibre. The raw material of the present solution, i.e. waste fibre, has been subjected to a separation phase wherein small fibre is separated, e.g. on a paper wire, from fibre to be supplied to the paper pulp.

[0040] A product according to the present solution, a wood fibre gel, differs from the prior art nano- and microcrystalline cellulose such that the product according to the present solution has a good binding capability, enabling it to be used for making a paper-like product. In addition, the wood fibre gel product according to the present solution has properties like those of nano- and microcrystalline cellulose, i.e. it contains small and microfibrillated fibre. A raw material according to a preferred embodiment comprises fibre containing waste generated in pulp and paper making. Basically, it is a different raw material than cellulose pulp. The wood fibre gel produced is a gel-like pulp which, however, has fibre-like properties, i.e. the fibres bind to one another. On the other hand, it has properties of the nano- and microcrystalline cellulose since it contains a large amount of small and microfibrillated fibre. These properties may be utilized in nanotechnological applications when nanoparticles are mixed with pulp in order to provide functional properties (e.g. electrical conductivity).

[0041] Thus, in the present solution, a version which is more "refined" than the ordinary cellulose pulp and which has been subjected to an additional separation process while passing through wires and screens used in pulp and/or papermaking is used as the raw material. In practice it is the small fibres and mineral particles that pass through the wire.

[0042] In the present solution, the production process (i.e. Enzymatic Mechanical Treatment or EMT processing) considerably differs from the prior art production of nano- and microcrystalline cellulose owing to the smaller energy consumption and lower costs of the present solution.

[0043] In the present solution, the product, i.e. wood fibre gel, differs from the prior art nano- and microcrystalline cellulose such that in the present solution the product is still fibrous or at least it contains fibre-like compo- nents that bind to one another. The prior art microcrystalline cellulose does not bind in a similar manner.

Example 1

[0044] Waste fibre as such cannot be used for making paper sheets, or the strength of the sheets is extremely poor. The EMT processing improved the strength clearly.

Case 1 : Waste pulp fibre content about 15%

• Pulp 1.0 (no EMT processing): Sheet making unsuccessful, particle size 37.4 pm

• Pulp 1.1 (EMT processed): tensile strength 13.7 kNm/kg, particle size 12.8 pm

• Pulp 1.2 (EMT processed): tensile strength 13.1 kNm/kg, particle size 12.9 pm

Case 2: Waste pulp fibre content about 30%

• Pulp 2.0 (no EMT processing): tensile strength 12.2 kNm/kg

Pulp 2.1 (EMT processed): tensile strength 30.2 kNm/kg

• Pulp 2.2 (EMT processed): tensile strength 29.1 kNm/kg

• Pulp 2.3 (EMT processed): tensile strength 29.1 kNm/kg.

Example 2

[0045] EMT processing was performed on waste fibre, a combination of waste fibre and microcrystalline cellulose, and mere microcrystalline cellulose. Addition of microcrystalline cellulose reduced the strength as compared with waste fibre.

Waste fibre: Sheet making successful, tensile strength 30.2 kNm/kg

Waste fibre + microcrystalline cellulose (20%): Sheet making successful, tensile strength 23.0 kNm/kg

Microcrystalline cellulose: Sheet making unsuccessful, microcrystalline cellulose did not bind.

Example 3

[0046] EMT processing was performed on waste fibre and waste fibre mixed with 10% and 20% carbon nanotubes (HNP), and test sheets were made wherefrom resistivity was measured.

Sheet 1 (waste fibre): not electrically conductive (resistivity infinite) Sheet 2 (waste fibre + 10% HNP): resistivity p = (31.9 ± 3.2) · 10 "3 Sheet 3 (waste fibre + 20% HNP): resistivity p = (8.7 ± 0.5) · ^ 0 ' .

[0047] It is apparent to one skilled in the art that as technology advances, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not restricted to the above- described examples but may vary within the scope of the claims.