Manufacturing process for rigid cellulose products

Abstract

1. A process for producing a rigid cellulose product from raw fibrous industrial waste, comprising: (a) providing or producing pulped industrial waste cellulose fibers derived from the raw fibrous industrial waste; (b) enzymatically treating the pulped industrial waste cellulose fibers to produce enzyme-treated industrial waste cellulose fibers, maintaining a moisture content of greater than 80% during the enzyme treatment; (c) compressing the enzyme-treated industrial waste cellulose fibers to produce compressed fibers; and (d) drying the compressed fibers to form a rigid cellulose product.

Description

[Technical Field]

[0001] The present invention relates to a process for producing rigid cellulosic products from raw fibrous industrial waste. Specifically, the present invention relates to the enzymatic treatment of industrial waste cellulosic fibers and the subsequent processing of the enzymatically treated fibers to produce rigid cellulosic products, such as boards, and the rigid cellulosic products. [Background technology]

[0002] Industrial waste is defined as non-reusable waste, and therefore cannot be reused or recycled to produce other useful products, or would otherwise be disposed of, for example, in landfills or incinerated, with associated adverse environmental impacts. The present invention focuses on the recycling of cellulose fibers from said industrial waste to obtain rigid cellulose products with mechanical properties suitable for use, for example, as construction boards.

[0003] Cellulose fibers are considered non-recyclable if they have at least one of the following characteristics: - average fiber length less than 5 mm, - average fiber thickness less than 0.1 mm, - The proportion of fines (or fines) in the cellulosic waste exceeds 10% by mass (fines are defined as the smallest fraction of cellulose fibres that can pass through a pore with a diameter of 76 micrometres [SCAN. Mechanical and chemical pulps - Fines content. Standard CM 66:052005]), or - Cellulose fibers are mixed with other compounds that complicate recycling (these other compounds include inorganic fillers, synthetic compounds, and material impurities).

[0004] Waste paper and waste cardboard can be effectively recycled if they contain low levels of adhesives, inks, water-resistant resins, and other additives. Examples of these water-resistant resins and additives include alkyl ketene dimers, alkenyl succinic anhydrides, epichlorohydrin, melamine, urea-formaldehyde, polymines, styrene, dextrins, or other polymers that improve certain material properties (i.e., polyurethane, vinyl, and acrylic adhesives improve mechanical properties).

[0005] However, when waste paper and cardboard contain large amounts of these additives, the cost of recycling and the quality of the resulting cellulosic product can be significantly affected, requiring additional processing steps or increasing the consumption of additives or energy during processing of the cellulosic material.

[0006] The paper and cellulose manufacturing industries also generate large amounts of industrial waste, including what is called primary sludge, a liquid containing cellulosic material that is considered non-recyclable as defined by the characteristics described above. While this is considered a discharge that carries serious environmental liability for manufacturers, Applicant has discovered that this can be mitigated by appropriate treatment, including, for example, appropriate enzyme treatment to produce cellulosic products such as building boards. It will be understood that the starting cellulose fibers for papermaking can be any fiber, including wood and fibers derived from other plants, such as fast-growing species like Miscanthus.

[0007] Primary sludge is composed of approximately 40-90% by weight of cellulose fiber and approximately 10-60% by weight of inorganic fillers. These inorganic fillers are added during the papermaking process to improve the properties of the paper. The raw cellulose material obtained from primary sludge described in this invention is distinguished by its fine content of more than 15% of the cellulose fiber. The fine content is small particles of cellulose that, due to their size, do not have a fibrous shape. This peculiarity means that the raw cellulose material used in the method of this invention cannot be used to manufacture paper or other products that require good mechanical properties, because the edges do not provide mechanical bonding. The above-mentioned peculiarities of this raw cellulose material make it very difficult to obtain products that require low-humidity, pressure, and temperature processes.

[0008] Another source of industrial waste that meets the above characteristics of fibers is cellulosic fiber residue streams or sludge from the textile industry, where the presence of mixtures of, for example, different types of cellulosic fibers and plastics makes it difficult to reuse or recycle these residues.

[0009] Another source of industrial waste that meets the above characteristics of fiber, but is not a residual stream from factories producing paper or textiles, is construction waste cellulose fiber, for example, cardboard recovered when recycling gypsum board. Gypsum-based recovery processes separate the gypsum from the paper through mechanical crushing and subsequent dry double pressing, resulting in a finished product with the same properties as natural gypsum. The recovered gypsum powder has a purity of 97.6% and is virtually paper-free. While the gypsum by-product can be reused, the cellulose fiber is typically incinerated without being used to form a useful product.

[0010] Another source of industrial waste that meets the above characteristics of fiber is post-consumer vegetable or plant based waste, such as miscanthus, which has been used in consumer products and is considered unsuitable for forming useful products. DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0011] Applicant has discovered that by appropriate processing, including enzyme treatment of the fibers and subsequent processing of the enzyme-treated fibers, cellulosic fibers from industrial waste that were previously deemed non-recyclable can ultimately be used to produce useful cellulosic products, such as construction boards, thereby achieving the environmental benefits associated with recycling materials that would otherwise be disposed of in landfills, and importantly, providing cellulosic products that perform at least as well as products obtained from other cellulosic fibers or using alternative processes that have a greater environmental impact. [Means for solving the problem]

[0012] Thus, according to the present invention, there is provided a process for producing rigid cellulose products from raw fibrous industrial waste, comprising the steps of: (a) providing or producing pulped post-industrial cellulose fibers from raw fibrous post-industrial waste; (b) enzymatically treating the pulped industrial waste cellulose fiber to produce an enzyme-treated industrial waste cellulose fiber, and maintaining the water content (or water content) during the enzyme treatment at more than 80%; (c) compressing the enzyme-treated industrial waste cellulose fibers to produce compressed fibers; and (d) drying the compressed fibers to form a rigid cellulosic product.

[0013] Advantageously, the process of the present invention makes it possible to use a certain proportion of raw fibrous cellulosic material from industrial processes, such as those for the production of paper, cardboard, textiles or construction materials, or from other waste sources where the residual cellulosic material is not reusable for the reasons defined in the fiber characteristics above, and which usually comprises mainly recycled fibers shorter than 5 mm and / or brittle fibers and / or recycled fibers that are usually partially bound with impurities and therefore have a reduced ability to bind with other cellulosic fibers.

[0014] Without enzyme treatment, industrial waste cellulose fibers, such as primary sludge from the paper industry, cannot be reused to make useful cellulose products without the use of resins or adhesives because the fibers are too short to provide sufficient mechanical properties for boards.

[0015] Preferably, the step of producing pulped post-industrial cellulose fibers comprises pulping raw fibrous post-industrial cellulose fibers.

[0016] Preferably, the process further comprises the step of diluting the raw fibrous industrial waste with water before or during pulping.

[0017] Alternatively, however, the raw fibrous industrial waste may not require a separate pulping step prior to enzymatic treatment, but may be supplied as already-pulped fibres, i.e. fibres sufficiently individualised to be substantially free of clumping (which, if left unattended, would render the enzymatic treatment ineffective and result in poor distribution of the fibres during formation, leading to a non-uniform end product). The already-pulped fibre supply may be the direct output from an industrial plant, preferably a sludge output supply from a plant producing paper or textiles.

[0018] The supplied pulped fibers can be supplied directly to the process for producing rigid cellulosic products from the sludge output via a conduit to the sludge output, or indirectly to the process for producing rigid cellulosic products via an intermediate storage tank.

[0019] By raw fibrous cellulosic material is meant a material that is composed primarily of fibers that consist of cellulose and other vegetable compounds that are capable of forming bonds with other cellulosic fibers.

[0020] The enzymatic process increases the number of free hydroxyl groups in the fibers, allowing the industrial waste fibers to crosslink and bond with other non-industrial fibers and / or with each other to produce cellulosic products such as construction boards or panels with sufficient mechanical properties.

[0021] Preferably, the raw fibrous industrial waste comprises fibers having one or more of an average length of less than 5 mm, preferably less than 2 mm, and / or an average width of less than 0.1 mm, and / or a mass percentage of fine components greater than 10%.

[0022] Preferably, the post-industrial waste fibers are derived from one or more of primary sludge obtained from the paper industry or sludge residues from the textile industry.

[0023] Post-industrial fiber means fiber obtained from an industrial process, such as papermaking, cardboard manufacturing, textile manufacturing, to produce paper, cardboard, or textile products, or from any industrial process in which the cellulosic fiber is not considered reusable to form a useful cellulosic product. Discarded or recycled cardboard is not considered post-industrial waste.

[0024] In the present invention, the terms primary sludge and sewage sludge may be used interchangeably.

[0025] Preferably, the process further comprises the step of diluting the raw fibrous industrial waste with water before or during pulping.

[0026] Preferably, the process further comprises the step of diluting the enzyme-treated post-industrial cellulose fiber to obtain diluted enzyme-treated post-industrial cellulose fiber having a moisture content of greater than 90%.

[0027] Preferably, the step of maintaining the moisture content above 80% during the enzyme treatment comprises maintaining the moisture content above 80% to 99% or less, more preferably above 80% to 95% or less, during the enzyme treatment.

[0028] Preferably, the raw fibrous cellulosic material from industrial waste does not contain large particles or clusters greater than 5 mm, since such particles or clusters have reduced or no ability to form bonds with other cellulosic fibers. Depending on the type of raw fibrous cellulosic material, a particle size reducer, such as a crusher or shredder, can be used prior to pulping to reduce particle size or remove particles or clusters. For example, materials that are difficult to pulp without size reduction, such as miscanthus or textile waste, may require this additional particle size reduction step.

[0029] Alternatively, the raw fibrous cellulosic material can include larger particles or clusters greater than 5 mm, provided that they can be dissolved or broken down during pulping into smaller particles or clusters smaller than 5 mm, or fibers of any length. Examples of large soluble or breakable particles or clusters can be, for example, cardboard or sludge lumps.

[0030] Preferably, the step of enzymatically treating the post-industrial cellulose fibers includes adding one or more enzymes to the post-industrial cellulose fibers for at least one of smoothing the fibers, removing radicals from the outside of the fibers, and increasing the specific surface area of ​​the fibers.

[0031] Preferably, the step of enzymatically treating the industrial waste cellulose fibers comprises one or more of the following: -Maintaining the pH of the pulped fiber between 5 and 9; - maintaining the temperature during the enzymatic treatment of step (b) above 40°C, preferably above 40°C and below 70°C; - adding one or more enzymes selected from the group of xylanases, laccases and cellulases, - Adding 0.05% to 0.5% of enzymes based on the dry weight of industrial waste cellulose fiber; - treating industrial waste cellulose fibres with an enzyme for a period of more than 5 minutes, preferably more than 5 minutes but less than 60 minutes.

[0032] Applicant has recognized that in industrial cellulose waste, enzyme treatment processes are important not only for fiber fibrillation but also for cleaning the fiber surface using xylanase and laccase enzymes. Xylanase enzymes attack hemicellulose, facilitating extraction of the surface layer of cellulose fibers. This removes impurities that may be introduced by various additives and residues from the pre-residue process. Laccase enzymes also help remove impurities, primarily lignin, which inhibits pulping.

[0033] Applicant has also discovered that fines can interfere with the processing of diluted cellulose industrial waste fibers. For example, fines reduce the dewatering ability of enzyme-treated industrial waste cellulose fibers when they are compressed to produce compressed fibers. Converting fines to glucose aids in dewatering, but it is a process that must be controlled because larger cellulose fibers can produce more fines. Therefore, to control this conversion process in industrial waste pulp, it is necessary to control the enzyme treatment time and enzyme concentration.

[0034] Preferably, the step of diluting the enzyme-treated industrial waste fiber to obtain diluted enzyme-treated industrial waste fiber having a moisture content of greater than 90% comprises diluting to ensure that the moisture content remains greater than 90% and less than 99%, preferably greater than 95% and less than 99%.

[0035] Preferably, the process further comprises: (a) providing or producing a raw fibrous cellulosic material, preferably either virgin cellulosic fibres or waste cellulosic fibres, preferably pulped non-industrial waste cellulosic fibres derived from waste cardboard; (b) enzymatically treating the pulped non-industrial cellulosic waste fiber and maintaining the moisture content at greater than 80% during the enzymatic treatment; (c) combining the enzyme-treated non-industrial waste cellulosic fiber with the enzyme-treated industrial waste cellulosic fiber; (d) compressing the enzyme-treated non-industrial waste cellulose fibers combined with the enzyme-treated industrial waste cellulose fibers; and (e) drying the compressed industrial and non-industrial waste cellulose fibers to form a rigid cellulose product.

[0036] Preferably, the step of producing pulped non-industrial waste cellulosic fibers comprises pulping a raw fibrous cellulosic material.

[0037] However, raw fibrous non-industrial waste cellulosic waste may not require a separate pulping step before enzymatic treatment and can be supplied as already pulped fibers, i.e., fibers sufficiently individualized to be substantially free of clumps. Such a supply can be the direct output from a non-industrial plant, preferably the pulped output from a cardboard production plant.

[0038] The supplied pulped fibers can be supplied directly to the process for producing rigid cellulosic products from the pulped output from the corrugated board production plant via a conduit to the pulped output, or indirectly to the process for producing rigid cellulosic products via an intermediate storage tank.

[0039] Preferably, the process further comprises diluting the enzyme-treated non-industrial waste cellulose fiber to obtain diluted enzyme-treated cellulose fiber having a moisture content of greater than 90%.

[0040] Preferably, the step of maintaining the moisture content of the non-industrial waste cellulose fiber at greater than 80% during enzyme treatment includes maintaining the moisture content during enzyme treatment at greater than 80% and not greater than 99%, more preferably greater than 80% and not greater than 95%.

[0041] Preferably, the raw fibrous industrial waste and raw fibrous non-industrial waste cellulosic material are each independently pulped.

[0042] Preferably, the step of enzymatically treating the non-industrial waste cellulosic fibers comprises one or more of the following: -Maintaining the pH of the pulped fiber between 5 and 9; - maintaining the temperature during the enzymatic treatment step (b) above 40°C, preferably above 40°C and below 70°C; - adding one or more enzymes selected from the group of xylanases, laccases and cellulases, - adding 0.05% to 0.5% of enzymes based on the dry weight of industrial waste cellulose fibers; - Enzymatic treatment of industrial waste cellulose fibres for a period of more than 5 minutes, preferably more than 10 minutes but less than 90 minutes.

[0043] Preferably, the industrial waste cellulose fibers and the non-industrial waste cellulose fibers are each independently enzyme treated.

[0044] Preferably, the post-industrial cellulosic fibers and the non-industrial cellulosic fibers are each washed independently to remove contaminants.

[0045] Preferably, the step of providing post-industrial cellulose fiber includes providing at least two sources of post-industrial cellulose fiber, each source of post-industrial cellulose fiber being independently pulped and each independently enzyme-treated.

[0046] Preferably, the post-industrial cellulose fibers and the non-industrial cellulose fibers are combined and mixed in the dilution step (c).

[0047] Preferably, the step of compressing the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers to form a rigid cellulose product is either molding, preferably injection molding, or compression between forming units and / or drums to form a partially wet cellulose product.

[0048] Preferably, the step of compressing the enzyme-treated industrial waste cellulose waste fibers and / or non-industrial waste cellulose waste fibers to form a partially moist cellulose product comprises compressing the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers in a forming unit to obtain a partially moist cellulose product having a moisture content preferably greater than 40% and less than 80%, preferably greater than 40% and less than 70%.

[0049] Preferably, the step of compressing the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers in the forming unit comprises: (a) providing a forming unit having a mold defined by an outer wall having open upper and lower ends, and upper and lower plates configured to seal the respective open upper and lower ends and to retain the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers within the mold; (b) introducing enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers into a mold; (c) moving the upper plate relative to the lower plate, preferably using a mechanical screw, to compress the enzyme-treated and / or cellulose fibers between the upper and lower plates.

[0050] Preferably, a filter belt is provided between the lower plate and the mold, so that the lower surface of the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers contacts the filter belt.

[0051] Preferably, the filter belt has sufficient porosity to substantially retain the treated fiber solids with (or within) the mold and to allow at least a portion of the moisture content to pass through, preferably the filter has a porosity rating of 400 to 500 cubic feet per meter.

[0052] Preferably, a vacuum is applied to either or both of the upper and lower plates to remove water from the enzyme-treated industrial waste cellulose fibers and / or non-industrial waste cellulose fibers.

[0053] Preferably, the step of introducing the enzyme-treated post-industrial and / or non-industrial waste fibers into the mould comprises introducing the enzyme-treated post-industrial and / or cellulosic waste fibers through openings in the outer wall.

[0054] Preferably, the step of compressing the diluted enzyme-treated and pulped industrial and / or non-industrial cellulosic waste fibers to form a rigid cellulosic product includes or further includes compressing between drums to obtain a partially moist cellulosic product, preferably having a moisture content of more than 40% and less than 80%, preferably less than 70%.

[0055] Preferably, the step of drying the compressed fibers to form a rigid cellulosic product comprises introducing the partially moistened cellulosic product into a drying tunnel, preferably at a temperature of less than 140°C, to reduce the moisture content, preferably to less than 40%, more preferably less than 30%, and most preferably less than 25%.

[0056] Preferably, the step of drying the compressed fibers to form a rigid cellulosic product further comprises introducing the compressed and partially dried fibers into a hot plates press to reduce the moisture content, preferably to less than 20%.

[0057] Preferably, the hot plate press comprises an upper plate and a lower plate, both plates configured to allow steam generated from water present in the partially moistened cellulose product to escape from the partially moistened cellulose product, and preferably both plates have a mesh-like structure or are porous.

[0058] Preferably, the upper and lower plates of the hot plate press (or pressure) are maintained at a temperature greater than 60°C and less than or equal to 200°C.

[0059] Preferably, pressure is applied to the partially wet cellulosic product in a first and second stage.

[0060] Preferably, in the first stage, 2 kg / cm 2 A pressure of less than 1000 psi is applied.

[0061] Preferably, in the second stage, the density is 0.5 kg / cm to obtain a rigid cellulose product having the required density or thickness, preferably with a moisture content of less than 20%. 2 A pressure exceeding

[0062] Preferably, the process is a continuous process.

[0063] Preferably, the raw fibrous industrial waste contains other compounds such as inorganic compounds and / or other impurities.

[0064] Preferably the rigid cellulosic product is a board, preferably a building board.

[0065] Preferably, the board has one or more of the following characteristics: - at least 20% by weight of post-industrial fibers relative to the weight of the final rigid cellulose product; -Thickness from 3mm to 22mm, - internal bond strength of at least 0.1 MPa; a flexural strength of at least 4 MPa, and -At least 400kg / m 3 density.

[0066] Preferably, the amount of industrial waste cellulose fibres is selected so that the calcium carbonate content relative to the weight of the rigid cellulose product is sufficient to obtain a rigid cellulose product having a fire resistance classification of class C when tested according to European standard EN 13501-1.

[0067] Preferably, the rigid cellulose board has a calcium carbonate content of more than 7% by weight, preferably less than 50%, more preferably less than 35% by weight relative to the weight of the rigid cellulose product.

[0068] Preferably, the method further comprises measuring the calcium carbonate content of the combined enzyme-treated post-industrial and / or non-industrial waste cellulosic fibers before compressing the fibers, and checking the measured calcium carbonate content against a reference relating the calcium carbonate content of the combined enzyme-treated post-industrial and / or non-industrial waste fibers before compressing the fibers to the expected calcium carbonate content of the rigid cellulosic product.

[0069] Preferably, the process further comprises the step of adding a flame retardant, preferably aluminum hydroxide, to the non-industrial waste cellulosic fibres, preferably waste cardboard.

[0070] Preferably, the step of adding the flame retardant occurs after step (b) of enzymatically treating the pulped non-industrial waste cellulose fibers, and more preferably before step (c) of combining the enzyme-treated pulped industrial and non-industrial waste cellulose fibers.

[0071] Preferably, the aluminum hydroxide is added in an amount sufficient to have an aluminum hydroxide content of more than 15% by weight, dry mass, based on the weight of the rigid cellulosic product, so as to impart a fire resistance classification of Class B to the rigid cellulosic product when tested according to European Standard EN 13501-1.

[0072] Preferably, the non-industrial waste cellulose fibers are any cellulose fibers not derived from raw fibrous industrial waste, more preferably one or more of virgin cellulose fibers, preferably wood or plant fibers, more preferably miscanthus fibers, or preferably waste paper or waste cardboard fibers, preferably OCC fibers.

[0073] According to another aspect of the present invention, there is provided a process for producing a rigid cellulose product, comprising the steps of: (a) providing cellulose fibers; (b) enzymatically treating the cellulose fibers and maintaining a moisture content greater than 80% during the enzymatic treatment; (c) compressing the enzyme-treated cellulose fibers to form compressed fibers; (d) drying the compressed fibers to form a rigid cellulosic product.

[0074] Preferably, the cellulose fibres are one or more of virgin cellulose fibres, preferably wood or plant fibres, more preferably miscanthus fibres, or preferably waste paper or waste cardboard fibres, preferably OCC fibres.

[0075] Preferably, the cellulose fibers are 100% waste cardboard fibers, in which case the process further comprises adding a flame retardant, preferably aluminum hydroxide, to the waste cardboard fibers, preferably adding the flame retardant after step (b) of enzymatically treating the waste cardboard fibers.

[0076] Preferably, the process does not include the step of adding a binder, glue or adhesive to bind the fibers together.

[0077] Preferably, the rigid cellulose product includes a percentage of rejected rigid cellulose product.

[0078] Preferably, the process further comprises adding the rejected rigid cellulosic products to a step of diluting or pulping or enzymatically treating industrial or non-industrial waste cellulosic fiber.

[0079] Preferably, the combined industrial waste cellulose fibers and non-industrial waste cellulose fibers comprise at least 20% by weight, preferably 20 to 80% by weight, preferably 30 to 70% by weight, preferably 40 to 60% by weight of industrial waste cellulose fibers, with the remainder of the combined industrial and non-industrial waste cellulose fibers being cellulose fibers.

[0080] According to another aspect of the present invention, there is provided a process for producing rigid cellulosic products from industrial waste fibers, comprising the steps of: (a) providing raw fibrous industrial waste, preferably industrial waste cellulose fibers derived from primary sludge from a papermaking process; (b) enzyme-treating industrial waste cellulose fibers and maintaining the moisture content at 80% or more during the enzyme treatment; (c) providing non-industrial waste fibers, preferably waste cardboard; (d) enzymatically treating the non-industrial waste fibers and maintaining a moisture content greater than 80% during pulping and enzymatic treatment; (e) combining the enzyme-treated non-industrial waste cellulosic fiber with the enzyme-treated industrial waste cellulosic fiber; (f) compressing the combined enzyme-treated industrial and non-industrial waste cellulose fibers; (g) drying the compressed industrial and non-industrial waste cellulose fibers to form a rigid cellulose product.

[0081] Preferably, the industrial and / or non-industrial waste cellulosic fibers are pulped and / or diluted prior to enzymatic treatment.

[0082] Preferably, the process further comprises the step of adding to the industrial or non-industrial waste cellulose fibres, preferably waste cardboard, a fire retardant, preferably an expandable volcanic based material, preferably vermiculite, preferably in an amount sufficient to impart a Class B fire resistance classification to the rigid cellulose product when tested according to European Standard EN 13501-1.

[0083] Preferably, greater than 5% by weight of the intumescent volcanic material based on the weight of the rigid cellulose board is added to the non-industrial waste cellulose fiber, preferably after the step of enzyme treating the non-industrial waste cellulose fiber, more preferably before the step of combining the enzyme-treated industrial waste cellulose fiber with the non-industrial waste cellulose fiber.

[0084] According to another aspect of the present invention, there is provided a rigid cellulosic product comprising either or both of enzyme-treated post-industrial cellulosic fibers and enzyme-treated non-industrial waste cellulosic fibers.

[0085] Preferably, the rigid cellulosic product does not contain binders, adhesives or tackifiers to bind the fibers together.

[0086] Preferably, the rigid cellulose product has a calcium carbonate content of more than 7% by weight, preferably less than 50%, more preferably less than 35% by weight relative to the weight of the rigid cellulose product.

[0087] Preferably, the rigid cellulose product has an aluminium hydroxide content of more than 15% by weight of dry mass relative to the weight of the rigid cellulose product.

[0088] Preferably, the post-industrial cellulosic fibers are derived from primary sludge obtained from the paper industry.

[0089] Preferably, the non-industrial waste cellulosic fibers are derived from waste cardboard.

[0090] Preferably, the rigid cellulose product comprises 20 to 80% by weight of post-industrial cellulose fibers, preferably 30 to 70% by weight, preferably 40 to 60% by weight, with the remainder of the combined post-industrial and non-industrial cellulose fibers being non-industrial cellulose fibers.

[0091] Preferably, the rigid cellulose product has one or more of the following properties: - at least 20% by weight of post-industrial fibers relative to the weight of the final rigid cellulose product; -Thickness from 3mm to 22mm, - internal bond strength of at least 0.1 MPa; - a bending strength of at least 4 MPa, and - density of at least 400 kg / m 3 . [Brief explanation of the drawings]

[0092] The present invention is illustrated below with reference to Figures 1-5, Table 1, and Examples 1-11. [Figure 1] FIG. 1 is a schematic diagram of the process of the present invention. [Figure 2] FIG. 2 is a front cross-sectional view of a forming unit used in the process of the present invention prior to pulp injection. [Figure 3] FIG. 3 is a side cross-sectional view of the forming unit of FIG. 2 prior to pulp injection. [Figure 4] FIG. 4 is a front cross-sectional view of the forming unit of FIG. 1 after pulp injection. [Figure 5] FIG. 5 is a cross-sectional plan view of the forming unit of FIG. 1 after pulp injection (with the top plate removed for clarity). DETAILED DESCRIPTION OF THE INVENTION

[0093] Moisture content is percent by weight and refers to the percentage of water relative to the amount of solids, for example, 80% moisture content includes 20% solids.

[0094] The percentages of industrial and non-industrial materials mean the dry mass of that material relative to the total dry mass of industrial and non-industrial materials. <Example 1>

[0095] Referring to FIG. 1 and Table 1, the raw fibrous non-industrial waste cellulose material A is provided in the form of waste cardboard, specifically old corrugated cardboard (OCC), and the raw fibrous industrial waste cellulose material B is provided in the form of raw papermill sludge, i.e., primary sludge from the paper manufacturing industry.

[0096] In this example, the raw fiber content is 50% sludge and 50% OCC (both measured by dry weight). It is understood that the sludge content can be up to 100%, with the remainder being OCC.

[0097] The sludge and OCC are diluted, pulped, and enzyme-treated independently as described below. <OCC Treatment>

[0098] First, warm water at 60 °C is pumped into the pulper P1.

[0099] Next, the OCC is introduced into the pulper P1 and stirred in water for at least 8 minutes to individualize and improve the fiber distribution of the OCC before the addition of enzymes, producing pulped OCC. If necessary, water is added to the OCC in the pulper P1 to ensure a moisture content of 95%. In an alternative embodiment, the OCC may be supplied with a moisture content exceeding 95%, in which case water is removed or more solids are added to bring the moisture content to 95% in this example. Individualize means the process of dispersing the fibers aggregated in the raw OCC.

[0100] Enzymes in the form of xylanase, laccase, and cellulase are added to the diluted and pulped OCC fiber in pulper P1 and stirred or agitated for at least 5 minutes and up to 90 minutes (depending on the pulping equipment) to produce pulped and enzyme-treated OCC with a moisture content above 90%, maintained at about 95% in this example.

[0101] The enzymes are preferably liquid or dissolved in a liquid and added to the pulped OCC waste fibers. The added enzymes are preferably selected to lubricate the fibers, remove radicals from the exterior of the fibers, and increase the specific surface area of ​​the fibers. These effects can be achieved, for example, by different combinations of the following enzymes: xylanase, laccase, cellulase, and / or combinations thereof.

[0102] During the enzymatic treatment, the pH of the pulped fiber is maintained between 5 and 9.

[0103] To improve the enzyme treatment, the temperature of the pulped fiber is maintained above 40° C., preferably between 40° C. and 70° C. In this example, the temperature of the pulped fiber is maintained at 60° C.

[0104] The total amount of enzyme added is between 0.05% and 1% based on the dry weight of OCC fiber.

[0105] Alkyl ketene dimer (AKD) is added to pulped and enzyme-treated OCC fiber as part of a water treatment additive in T2B. The amount of AKD added is less than 15% by weight of OCC. After adding the AKD, the agitator is allowed to run for approximately 4 minutes.

[0106] Optionally, the diluted, pulped and enzyme-treated OCC content of pulper P1 is transferred to tank T1 via screening tank P2 and subjected to a washing process, in which contaminants larger than 6 mm in size, such as plastic, wood or metal, are removed in a first washing stage, and contaminants smaller than 6 mm that are not removed in the first washing stage but are heavier than the aforementioned contaminants are removed in a second washing stage using a hydrocyclone. Examples of such small but heavy contaminants include staples, crystals and sand.

[0107] The OCC pulp produced independently in tank T1 is then transferred to tank T2B, the agitator is started, and the OCC pulp is diluted to a moisture content of 97%. <Sludge treatment>

[0108] The above dilution, pulping, and enzyme treatment steps are repeated in pulper P1 using the sludge (after the pulped, diluted, and enzyme-treated OCC has been removed), except that the enzyme treatment stage lasts more than 5 minutes and less than 60 minutes, and the enzyme concentration is between 0.05% and 0.5% of the dry weight of the sludge fiber. The enzyme treatment time and concentration are approximately 50% less for the sludge fiber compared to the OCC fiber.

[0109] In an alternative embodiment, the sludge can be pulped in a different pulper, which is different from the pulper used for dilution, pulping and enzyme treatment of the OCC.

[0110] Optionally, the pulped and enzyme treated sludge contents of pulper P1 are washed according to the same process described above in connection with OCC.

[0111] The sludge pulp produced independently in tank T1 (before or after the OCC pulp is produced) is then transferred to tank T2A, the agitator is started, and the sludge pulp is diluted to a moisture content of 97%.

[0112] It is understood that the OCC and sludge are independently pulped and enzymatically treated in steps (a) and (b) above, i.e., the OCC is pulped and enzymatically treated before being transferred to tank T1, and then the sludge is independently pulped and enzymatically treated before being transferred to tank T1. Furthermore, the sludge and OCC are independently subjected to a two-stage washing process by being sieved in screening tank P2 and washed in tank T1.

[0113] An aluminum hydroxide-based fire retardant is added to the OCC pulp in Tank T2B, which is then circulated in Tank T2B.

[0114] 50% of the sludge pulp from tank T2A and 50% of the OCC pulp with added refractory agents from tank T2B are then transferred to tank T3 where they are combined and agitated.

[0115] Additionally, additives such as odor powder, biocides, inks / dyes, etc. are added to the combined sludge and OCC pulp in tank T3.

[0116] If necessary, the combined sludge and OCC pulp is further diluted and topped up to ensure that the moisture content is above 90%. <Formation>

[0117] Referring to forming unit 10 in Figures 2 to 5, the combined sludge and OCC pulp 11 is compressed as follows.

[0118] Forming unit 10 includes a rectangular mold 12 defined by an outer wall 14 having an open upper end 16 and an open lower end 18. Outer wall 14 includes a plurality of openings 20 distributed along each long side of outer wall 14, through which the combined sludge and OCC pulp 11 is injected, as described below. The distribution and number of openings can be varied to ensure even distribution of pulp 11 within mold 12, which is important because it allows for control of the density and thickness of the final rigid cellulosic product.

[0119] The forming unit 10 further includes an upper plate 22 and a lower plate 24, the upper plate 22 being movable relative to the lower plate 24 via a mechanical screw system 26 driven by an electric motor (not shown).

[0120] The upper 22 and lower 24 plates have a compartmentalized structure that acts as a box in which the water extracted from the pulp 11 can be temporarily stored.

[0121] A PET transport filter belt 28 is disposed between the lower plate 24 and the mold 12 and sealingly engages the outer wall 14 of the mold 12 to retain the pulp 11 within the mold 12. The filter belt 28 has sufficient porosity to substantially retain the solids content of the fibers processed with the mold and to allow at least a portion of the moisture content to pass through, in this embodiment having a porosity of 400 to 500 cubic feet per meter, sufficient to allow extraction of water from the pulp 11 while simultaneously avoiding undesirable extraction of cellulosic fibers from the pulp 11.

[0122] In operation, the combined sludge and OCC pulp 11 is poured into the mold 12 of the forming unit 10 through the opening 20. The pulp 11 is held horizontally by the outer wall 14 and vertically by the filter belt 28 (FIGS. 2 and 3).

[0123] Once the desired amount of pulp 11 has been introduced into the mold 12, the dewatering process begins by applying a vacuum to the lower plate 24 to extract water from the pulp 11 through the filter belt 28. The extracted water is deposited within the lower plate 24. Alternatively, the water may be extracted by gravity without applying a vacuum.

[0124] As water is extracted from the pulp 11, the upper plate 22 is lowered via a mechanical screw system until it contacts the pulp 11 and applies pressure according to the desired product density (Figure 4). As the upper plate 22 presses the pulp 11 against the lower plate 24, a vacuum is applied to the upper plate 22, causing more water to be extracted from the pulp 11 through the upper plate 22 and deposited on the upper plate 22. Alternatively, instead of applying a vacuum, a positive pressure can be applied within the mold.

[0125] Once a sufficient amount of water has been removed from the pulp 11, a partially moist cellulose product in the form of a board is formed, typically with a moisture content greater than 40% and less than 80%, and a partially moist cellulose board can be removed from the forming unit 10.

[0126] The partially wet cellulose board is removed from the forming unit 10 by first returning the top plate 22 to its initial position (FIG. 2), lifting the mold 12 off the filter belt 28, and then starting the transport filter belt 28 to move the partially wet cellulose board to a transfer unit (not shown), where it undergoes an optional compression step in the form of compression rollers or drums to squeeze out any remaining water from the partially wet cellulose board and further reduce the moisture content, typically from less than 70% to about 40%.

[0127] In another embodiment, the combined pulp 11 may be compressed between compression rollers to form a partially wet cellulose board without requiring forming in the forming unit 10 . <Drying>

[0128] The partially wet cellulose board is dried in two stages as follows.

[0129] In the first drying stage, the boards are introduced into a convection drying tunnel, moving on a belt at a speed of 0.04 to 0.05 m / min and exposed to a temperature of 120°C for a residence time of 4 to 5 hours.

[0130] When the boards leave the drying tunnel, their moisture content is between 20% and 30%.

[0131] In the second drying stage, the board is removed from the drying tunnel and placed between two plates of a hot plate press.

[0132] The hot plate press includes an upper hot press plate and a lower hot press plate, both of which are configured to allow the escape of steam generated from the water within the partially wet cellulose board when the board is heated. In this embodiment, both the upper and lower plates have a mesh-like structure to allow the escape of steam. Alternatively, the plates may be made of a porous material or include micro-perforations.

[0133] The top and bottom plates of the hot plate press are maintained at temperatures greater than 60°C and up to 200°C during pressing.

[0134] In the first press drying stage, 2 kg / cm 2 In this first stage, the board is placed in contact with the press hotplate and heated by conduction. The pressure applied in this first stage depends on the required final board density, but is typically less than 2 kg / cm. 2 In this first stage, the board achieves a moisture content of less than 50%.

[0135] In the second press drying stage, the pressure is adjusted to 0.5 kg / cm to obtain a rigid cellulose product of the required density or thickness. 2 In the second press drying stage, the board is less compressible due to the reduced moisture content, so the maximum pressure that can be applied to the board is not as limited as in the first press drying stage.

[0136] After the second stage, modern rigid cellulose boards have a moisture content of about 20%.

[0137] In this embodiment, the partially wet cellulose board is transferred from the forming unit via press rollers and a drying tunnel to the hot plate press. In another embodiment, the partially wet cellulose board can be transferred directly from the forming unit to the hot plate press without the need for a drying tunnel.

[0138] After exiting the hot plate press, the board is cooled on a mesh-covered support for at least 30 minutes to allow residual water vapor to evaporate from both sides of the board.

[0139] In the above embodiment, the partially wet cellulose board is subjected to a first drying stage in a drying tunnel. In another embodiment, a single stage drying process using only a drying tunnel or a hot plate press is possible.

[0140] Alternative drying techniques such as radio or microwave frequency drying, infrared drying, or direct conduction drying are contemplated.

[0141] The boards produced have the properties defined in Table 1 and are particularly noted to achieve a fire resistance classification of Class B (SBI) when tested according to European Standard EN 13501-1.

[0142] In another embodiment, no aluminum hydroxide flame retardant is added to the pulped and enzyme-treated OCC. Instead, the amount of calcium carbonate in the sludge is high enough, in this example about 10% by weight of the final board, to achieve a Class C fire classification (SBI) when tested according to European Standard EN 13501-1, unlike the Class B fire classification (SBI) of Example 1.

[0143] To ensure the calcium carbonate content is sufficient to achieve Class C, the calcium carbonate content of each batch of raw sludge is measured before the fibers are compressed and compared to a lookup reference that correlates the measured calcium carbonate content to the expected calcium carbonate content of the rigid cellulose product based on the percentage of sludge in the final product. If the calcium carbonate content is too low, it is adjusted to ensure the amount is sufficient—more than 7 wt.% and less than 50 wt.% by weight of the final board—to achieve a Class C fire classification (SBI). Adjusting the calcium carbonate level is accomplished by adjusting the OCC to sludge ratio.

[0144] Other than the fire rating, the properties of the final board are 5% to 10% higher than those of the board of Example 1.

[0145] In this alternative embodiment, in contrast to Example 1, the pulped and enzyme-treated sludge and the pulped and enzyme-treated OCC are combined and then subjected to a two-stage washing process, rather than being separately screened in screening tank P2 and washed in tank T1. <Example 2>

[0146] Referring to Table 1, Example 2 is identical to Example 1 except that the mixture contains 60% sludge and 40% OCC.

[0147] The manufactured boards have the properties defined in Table 1. Example 3

[0148] Example 3 is identical to Example 1, except that the content of the mixture includes 50% OCC plus 50% industrial waste in the form of miscanthus.

[0149] The manufactured boards have the properties defined in Table 1. Example 4

[0150] Example 4 is identical to Example 3, except that the content of the mixture includes 100% non-industrial waste in the form of vegetable fiber, in this example Miscanthus fiber.

[0151] The manufactured boards have the properties defined in Table 1. <Example 5>

[0152] Example 5 is identical to Example 3, except that the content of the mixture includes 100% non-industrial waste in the form of OCC.

[0153] The manufactured boards have the properties defined in Table 1. Example 6

[0154] Example 6 is identical to Examples 1 and 3, except that the mixture contains 50% OCC plus 50% industrial waste in the form of textile sludge, i.e., sludge from the textile processing industry.

[0155] The manufactured boards have the properties defined in Table 1. Example 7

[0156] Example 7 is identical to Example 6, except that the content of the mixture comprises 100% industrial waste in the form of textile sludge.

[0157] Instead of adding aluminum hydroxide to the OCC, an alternative fire retardant, vermiculite, is added to the sludge to achieve a Class B fire resistance classification (SBI) when tested according to European standard EN 13501-1.

[0158] The manufactured boards have the properties defined in Table 1. Example 8

[0159] Example 8 is identical to Example 6, except that the textile sludge contains a mixture of organic and synthetic fibers that have short fibers and do not form hydrogen bonds.

[0160] The manufactured boards have the properties defined in Table 1. Example 9

[0161] Example 9 is identical to Example 7, except that the textile sludge contains a mixture of organic and synthetic fibers that have short fibers and do not form hydrogen bonds.

[0162] The manufactured boards have the properties defined in Table 1. Example 10

[0163] Example 10 is identical to Examples 1, 3 and 6, except that the mix contents include 50% OCC plus 50% industrial waste in the form of construction waste (calcium sulfate).

[0164] The manufactured boards have the properties defined in Table 1. Example 11

[0165] Example 11 is identical to Example 10, except that the content of the mixture includes 100% industrial waste in the form of construction waste (calcium sulfate).

[0166] Instead of adding aluminum hydroxide to OCC, an alternative fire retardant, vermiculite, is added to the construction waste to achieve a Class B fire resistance classification (SBI) when tested according to European standard EN 13501-1.

[0167] The manufactured boards have the properties defined in Table 1.

[0168] In Examples 4, 5, 7, 9 and 11, there is only a single cellulosic fiber source, and therefore, there is no need to wash that single fiber source separately, as is the case in Examples 1, 2, 3, 6, 8 and 10.

[0169] In Examples 2-11 above, either aluminum hydroxide or vermiculite is added as a flame retardant to achieve a Class B rating.

[0170] In another embodiment, the amount of calcium carbonate in the sludge is high enough to achieve a Class C rating, as described in connection with the alternative embodiment of Example 1. Other than the fire classification, the properties of the final board are 5% to 10% higher than the properties of the boards of Examples 2-11.

[0171] In these alternative embodiments, in contrast to Examples 2 to 11, the pulped and enzyme-treated industrial waste, i.e., sludge (from textile or paper processing), miscanthus, or construction waste, and the pulped and enzyme-treated non-industrial waste, i.e., OCC, are not independently sieved in sieving tank P2 and washed in tank T1, but are combined and then subjected to a two-stage washing process, sieved in sieving tank P2, and washed in tank T1.

[0172] Instead of adding aluminum hydroxide to the OCC, in another embodiment, an expansive volcanic material such as vermiculite or perlite may be added to the OCC to impart a Class B fire resistance classification to the rigid cellulose product when tested according to European Standard EN 13501-1.

[0173] As another alternative, an expansive volcanic material may be added to the sludge to impart a Class B fire resistance classification to the rigid cellulose product when tested according to European Standard EN 13501-1.

[0174] The above embodiments describe examples of boards having a combination of industrial and non-industrial waste, such as waste cardboard and sludge from a different industrial source, and only a single fiber source, such as waste cardboard or sludge from a different industrial source. In another embodiment, the board can have a combination of only industrial waste, for example a mixture of paper sludge and textile sludge.

[0175] In the above embodiment, the final thickness of the rigid board is 12 mm. In another embodiment, the final thickness can be varied between 3 mm and 22 mm by varying the weight of solids introduced into the forming unit. It will be understood that boards of different thicknesses require different drying methods.

[0176] In the above embodiment, the process is not continuous, specifically, the transfer of the partially wet board from the forming unit to the transfer unit, and then to the drying tunnel and hot plate press is a manual process. In another embodiment, the process from initial pulping to drying of the board can be a continuous process.

[0177] The forming and drying process and apparatus described above is not limited to mixtures of industrial and non-industrial waste materials, but can be applied to any cellulosic fiber source, either a single fiber source or a mixture of fiber sources.

[0178] In the above embodiment, the raw fibrous industrial and non-industrial cellulosic material is pulped before being enzymatically treated, formed, and dried. In another embodiment, either or both of the raw fibrous industrial and non-industrial cellulosic material may not require a separate pulping step before enzymatic treatment and can be supplied as already pulped fibers. Such a supply can be direct output from a non-industrial plant, such as pulped output from a waste cardboard production plant, and / or direct output from an industrial plant, preferably pulped output from a paper production plant. Such a supply can be direct supply from industrial and non-industrial plants, in which case a plant integrating a paper and / or cardboard production plant with a process to produce a rigid cellulosic product is envisioned. Alternatively, the plants need not be integrated, and the pulped output can be stored before being supplied or transferred to a process to produce a rigid cellulosic product. JPEG2025542018000002.jpg251136

Claims

1. 1. A process for producing rigid cellulosic products from raw fibrous industrial waste, comprising: (a) providing or producing pulped post-industrial cellulose fibers from raw fibrous post-industrial waste; (b) enzymatically treating the pulped industrial waste cellulose fibers to produce enzyme-treated industrial waste cellulose fibers, and maintaining a moisture content of greater than 80% during the enzyme treatment; (c) compressing the enzyme-treated industrial waste cellulose fibers to produce compressed fibers; and (d) drying the compressed fibers to form a rigid cellulosic product; A process involving:

2. 10. The process of claim 1, wherein said step of producing pulped post-industrial cellulose fibers comprises pulping said raw fibrous post-industrial cellulose fibers.

3. 3. The process of claim 2, further comprising the step of diluting the raw fibrous industrial waste with water prior to or during pulping.

4. 2. The process of claim 1, wherein the pulped industrial waste cellulose fibers are provided as a feed, preferably as a direct feed from an industrial plant, preferably as a sludge output feed from a plant producing paper or textiles.

5. The process of any one of claims 1 to 4, further comprising a step of diluting the enzyme-treated post-industrial cellulose fiber to obtain diluted enzyme-treated post-industrial cellulose fiber having a moisture content of more than 90%.

6. 6. The process according to any one of claims 1 to 5, wherein the raw fibrous industrial waste comprises fibers having an average length of less than 5 mm, preferably less than 2 mm, and / or an average width of less than 0.1 mm, and / or a mass percentage of fine components greater than 10%.

7. The process of any one of claims 1 to 6, wherein the industrial waste fibres are derived from one or more of primary sludge obtained from the paper industry or sludge residues from the textile production industry.

8. 8. The process of any one of claims 1 to 7, wherein the step of maintaining the moisture content at above 80% during enzyme treatment comprises maintaining the moisture content at above 80% but not exceeding 99%, more preferably above 80% but not exceeding 95% during enzyme treatment.

9. 9. The process of claim 1, wherein the step of enzymatically treating the post-industrial cellulose fibers comprises adding one or more enzymes to the post-industrial cellulose fibers for one or more of smoothing the fibers, removing radicals from the exterior of the fibers, and increasing the specific surface area of ​​the fibers.

10. The step of enzymatically treating the industrial waste cellulose fiber comprises: - maintaining the pH of the pulped fibers between 5 and 9; - maintaining the temperature during said enzymatic treatment step (b) above 40°C, preferably above 40°C and below 70°C; - adding one or more enzymes selected from the group of xylanases, laccases, cellulases, - adding 0.05% to 0.5% of enzyme based on the dry weight of the industrial waste cellulose fibers; - treating the industrial waste cellulose fibers with an enzyme for a period of more than 5 minutes, preferably for a period of more than 5 minutes and less than 60 minutes; 10. The process of claim 9, comprising one or more of:

11. 11. The process according to claim 5 or any one of claims 6 to 10 dependent on claim 5, wherein the step of diluting the enzyme-treated industrial waste fiber to obtain diluted enzyme-treated industrial waste fiber having a moisture content of more than 90% comprises diluting so that the moisture content is maintained at more than 90% but less than 99%, preferably more than 95% but less than 99%.

12. (a) providing or producing a raw fibrous non-industrial waste cellulosic material, preferably either virgin cellulosic fiber or waste cellulosic fiber, preferably pulped non-industrial waste cellulosic fiber derived from waste cardboard; (b) enzymatically treating the pulped non-industrial waste cellulosic fibers and maintaining a moisture content greater than 80% during the enzymatic treatment; (c) combining the enzyme-treated non-industrial waste cellulose fibers with the enzyme-treated non-industrial waste cellulose fibers; (d) compressing the enzyme-treated non-industrial waste cellulose fibers combined with the enzyme-treated industrial waste cellulose fibers; and (e) drying the compressed industrial and non-industrial waste cellulose fibers to form a rigid cellulose product; The process of any one of claims 1 to 11, further comprising:

13. 13. The process of claim 12, wherein said step of producing pulped non-industrial waste cellulosic fibers comprises pulping said raw fibrous non-industrial waste cellulosic material.

14. 14. The process of claim 13, further comprising the step of diluting the raw fibrous non-industrial waste cellulosic material with water prior to or during pulping.

15. 13. The process of claim 12, wherein the pulped non-industrial waste cellulosic fibers are provided as a feed, preferably as a direct feed from an industrial plant, preferably as a pulped output feed from a plant producing corrugated board.

16. 16. The process of claim 12 or any one of claims 13 to 15 dependent on claim 12, further comprising diluting the enzyme-treated non-industrial waste cellulose fiber to obtain diluted enzyme-treated non-industrial waste cellulose fiber having a moisture content of greater than 90%.

17. 17. The process of claim 13 or any one of claims 14 to 16 dependent on claim 13, wherein the raw fibrous industrial waste and the raw fibrous non-industrial waste cellulosic material are pulped independently of each other.

18. The process of claim 12 or any one of claims 13 to 17 dependent on claim 12, wherein the industrial waste cellulose fibres and the non-industrial waste cellulose fibres are enzyme treated independently of each other.

19. The process of any one of claims 12 to 18, wherein the post-industrial cellulosic waste fibers and the non-industrial cellulosic waste fibers are washed to remove contaminants independently of each other.

20. 20. The process of any one of claims 1 to 19, wherein providing post-industrial cellulose fiber comprises providing at least two sources of post-industrial cellulose fiber, each source of post-industrial cellulose fiber being pulped and enzyme-treated independently of each other.

21. 21. The process according to any one of claims 1 to 20, wherein the step of compressing the diluted enzyme-treated industrial waste and / or non-industrial cellulose fibers to form a rigid cellulose product is one of molding, preferably injection molding, or pressing between forming units and / or drums to form a partially moist cellulose product.

22. 22. The process of claim 21, wherein the step of compressing the enzyme-treated industrial waste and / or non-industrial waste cellulose fibers to form a partially moist cellulose product comprises pressing the enzyme-treated industrial waste and / or non-industrial waste cellulose fibers in a forming unit to obtain a partially moist cellulose product having a moisture content preferably greater than 40% and less than 80%, preferably greater than 40% and less than 70%.

23. said step of compressing said enzyme-treated industrial waste and / or non-industrial waste cellulose fibers in a forming unit comprising: (a) providing a forming unit having a mold defined by an outer wall having open upper and lower ends, and upper and lower plates configured to seal the respective open upper and lower ends to retain the enzyme-treated industrial waste and / or cellulose fibers within the mold; (b) introducing the enzyme-treated industrial and / or non-industrial waste cellulose fibers into the mold; (c) moving the upper plate relative to the lower plate, preferably using a mechanical screw, to compress the enzyme-treated and / or non-industrial waste cellulose fibers between the upper and lower plates; 23. The process of claim 21 or 22, comprising:

24. 24. The process of claim 23, wherein a filter belt is disposed between the lower plate and the mold, such that a lower surface of the enzyme-treated industrial waste and / or non-industrial waste cellulose fibers contacts the filter belt.

25. 25. The process of claim 24, wherein the filter belt has sufficient porosity to substantially retain the solids of the treated fibers together with the mold and to allow at least a portion of the moisture content to pass through, preferably the filter has a porosity of 400 to 500 cubic feet per meter.

26. 26. The process of any one of claims 23 to 25, wherein a vacuum is applied to either or both of the upper and lower plates to remove water from the enzyme-treated industrial and / or non-industrial waste cellulose fibers.

27. 27. The process of any one of claims 23 to 26, wherein the step of introducing the enzyme-treated industrial waste and / or non-industrial waste fibers into the mold comprises introducing the enzyme-treated industrial waste and / or non-industrial waste fibers through openings in the outer wall.

28. 10. The process of claim 9, wherein the step of compressing the diluted enzyme-treated and pulped industrial and / or non-industrial waste fibers to form a rigid cellulosic product comprises or further comprises pressing between drums, preferably to obtain a partially moist cellulosic product having a moisture content greater than 40% and less than 80%, preferably less than 70%.

29. 28. The process of claim 21 or claim 28 or any one of claims 22 to 27, wherein the step of drying the partially moistened cellulosic product to form a rigid cellulosic product comprises introducing the partially moistened cellulosic product into a drying tunnel, preferably at a temperature of less than 140°C, to reduce the moisture content, preferably to less than 70%, more preferably less than 40%, even more preferably less than 30%, and most preferably less than 25%, to produce partially dried fibres.

30. 30. A process according to claim 21 or claim 28 or any one of claims 22 to 29, wherein the step of drying the partially moistened cellulosic product to form a rigid cellulosic product comprises introducing the partially moistened cellulosic product into a hot plate press to reduce the moisture content, preferably to less than 20%.

31. 31. The process of claim 30, wherein the hot plate press comprises an upper plate and a lower plate, both plates configured to allow steam generated from water present in the partially moistened cellulose product to escape from the partially moistened cellulose product, preferably both plates having a mesh-like structure or being porous.

32. 32. The process of claim 30 or 31, wherein the upper and lower plates of the hot plate press are maintained at a temperature greater than 60°C and less than or equal to 200°C.

33. A process according to any one of claims 30 to 32, wherein pressure is applied to the partially moistened cellulosic product in the first and second stages.

34. 2 kg / cm in the first stage ２ 34. The process of claim 33, wherein a pressure of less than

35. 0.5 kg / cm in the second stage ２ 34. The process of claim 33, wherein a pressure of more than 1000 kJ / cm is applied to obtain the rigid cellulose product having the required density or thickness, preferably with a moisture content of less than 20%.

36. The process of any one of claims 1 to 35, wherein the process is a continuous process.

37. The process according to any one of claims 1 to 36, wherein the raw fibrous industrial waste comprises other compounds such as inorganic compounds and / or other impurities.

38. A process according to any one of the preceding claims, wherein the rigid cellulosic product is a board, preferably a building board.

39. 39. The process of claim 38, wherein the board has one or more of the following characteristics: - at least 20% by weight of post-industrial fibres relative to the weight of the final rigid cellulose product; - thickness from 3 mm to 22 mm, an internal bond strength of at least 0.1 MPa, a bending strength of at least 4 MPa, and - at least 400 kg / m ３ density.

40. 40. The process according to any one of claims 1 to 39, wherein the amount of post-industrial cellulose fibres is selected such that the calcium carbonate content relative to the weight of the rigid cellulose product is sufficient to obtain a rigid cellulose product having a fire resistance classification of Class C when tested according to European Standard EN 13501-1.

41. 33. The process of claim 32, wherein the rigid cellulose board has a calcium carbonate content of more than 7% by weight, preferably more than 7% and less than 50% by weight, more preferably more than 7% and less than 35% by weight, based on the weight of the rigid cellulose product.

42. 34. The process of claim 32 or 33, further comprising measuring the calcium carbonate content of the combined enzyme-treated post-industrial and / or non-industrial waste fibers before compressing the fibers and checking the measured calcium carbonate content against a reference relating the calcium carbonate content of the combined enzyme-treated post-industrial and / or non-industrial waste fibers before compressing the fibers to the expected calcium carbonate content of the rigid cellulosic product.

43. 35. The process of claim 12 or any one of claims 13 to 34 when dependent on claim 12, further comprising the step of adding a flame retardant, preferably aluminium hydroxide, to the non-industrial waste cellulose fibre, preferably waste cardboard.

44. 36. The process of claim 35, wherein the step of adding a flame retardant occurs after step (b) of enzymatically treating the pulped non-industrial waste cellulose fibers and before step (c) of combining the enzyme-treated pulped industrial and non-industrial waste cellulose fibers.

45. 37. A process according to claim 35 or 36, wherein a sufficient amount of aluminium hydroxide is added so that the rigid cellulose product has an aluminium hydroxide content of more than 15% by weight, dry mass, relative to the weight of the rigid cellulose product, to impart to the rigid cellulose product a fire resistance classification of Class B when tested according to European Standard EN 13501-1.

46. 38. The process of claim 12 or any one of claims 13 to 37 when dependent on claim 12, wherein the non-industrial waste cellulose fibres are one of virgin cellulose fibres, preferably wood or plant fibres, more preferably miscanthus fibres, or preferably waste paper or waste cardboard fibres, preferably OCC fibres.

47. 1. A process for producing a rigid cellulose product, comprising: (a) providing cellulose fibers; (b) enzymatically treating the cellulose fibers and maintaining a moisture content greater than 80% during the enzymatic treatment; (c) compressing the enzyme-treated cellulose fibers to produce compressed fibers; and (d) drying the compressed fibers to form a rigid cellulosic product. A process involving:

48. 40. The process of claim 39, wherein the cellulose fibers are one of virgin cellulose fibers, preferably wood or plant fibers, more preferably miscanthus fibers, or preferably waste paper or waste cardboard fibers, preferably OCC fibers.

49. 41. The process of claim 40, wherein the cellulose fibers are 100% waste cardboard fibers, and the process further comprises adding a flame retardant, preferably aluminum hydroxide, to the waste cardboard fibers, preferably adding the flame retardant after step (b) of enzymatically treating the waste cardboard fibers.

50. 50. The process of any one of claims 1 to 49, which does not include the step of adding a binder, adhesive or tackifier to bind the cellulose fibers together.

51. 51. The process of any one of claims 1 to 50, wherein the rigid cellulosic product comprises a percentage of rejected rigid cellulosic products.

52. 44. The process of claim 43, further comprising adding the rejected rigid cellulosic products to a step of diluting or pulping or enzymatically treating the industrial or non-industrial waste cellulosic fiber.

53. 45. The process of claim 12 or any one of claims 13 to 44 when dependent on claim 12, wherein the combined industrial and non-industrial waste cellulose fibres comprise at least 20% by weight, preferably 20 to 80% by weight, preferably 30 to 70% by weight, preferably 40 to 60% by weight, of industrial waste cellulose fibres, the remainder of the combined industrial and cellulose fibres being non-industrial waste cellulose fibres.

54. 1. A process for producing rigid cellulosic products from industrial waste fibers, comprising: (a) providing raw fibrous industrial waste, preferably industrial waste cellulose fibers derived from primary sludge from a papermaking process; (b) enzymatically treating the industrial waste cellulose fibers and maintaining the moisture content at greater than 80% during the enzymatic treatment; (c) providing non-industrial waste fibers, preferably waste cardboard; (d) enzymatically treating the non-industrial waste cellulosic fibers and maintaining a moisture content greater than 80% during pulping and enzymatic treatment; (e) combining the enzyme-treated non-industrial waste cellulosic fibers with the enzyme-treated industrial waste cellulosic fibers; (f) compressing the combined enzyme-treated industrial and non-industrial waste cellulose fibers; and (g) drying the compressed industrial and non-industrial waste cellulose fibers to form a rigid cellulose product. A process involving:

55. 48. The process of claim 47, wherein the industrial and / or non-industrial waste cellulosic fibers are pulped and / or diluted prior to enzyme treatment.

56. 56. The process of any one of claims 1 to 55, wherein the process further comprises the step of adding a fire retardant, preferably an intumescent volcanic material, preferably vermiculite, to the industrial or non-industrial waste cellulose fibres, preferably waste cardboard, preferably in an amount sufficient to impart a fire resistance classification of Class B to the rigid cellulose product when tested according to European Standard EN 13501-1.

57. 49. The process of claim 48, wherein greater than 5% by weight of the intumescent volcanic material based on the weight of the rigid cellulose board is added to the non-industrial waste cellulose fibers, preferably after the step of enzyme treating the non-industrial waste cellulose fibers, and more preferably before the step of combining the enzyme-treated industrial and non-industrial waste cellulose fibers.

58. A rigid cellulose product comprising either or both of enzyme-treated post-industrial cellulose fibers and enzyme-treated non-industrial cellulose fibers.

59. 51. The rigid cellulosic product of claim 50, which does not include a binder, adhesive, or tackifier to bind the cellulosic fibers together.

60. 52. The rigid cellulosic product of claim 50 or 51, comprising an aluminum hydroxide content of more than 15% by weight on a dry basis relative to the weight of the rigid cellulosic product.

61. 53. The rigid cellulosic product of any one of claims 50 to 52, having a calcium carbonate content of more than 7% by weight, preferably less than 50%, more preferably less than 35% by weight relative to the weight of the rigid cellulosic product.

62. 54. The rigid cellulosic product of any one of claims 50 to 53, wherein the post-industrial cellulosic fibers are derived from primary sludge obtained from a paper plant.

63. 55. The rigid cellulosic product of any one of claims 50 to 54, wherein the non-industrial waste cellulosic fibers are derived from waste cardboard.

64. 56. A rigid cellulose product according to any one of claims 50 to 55, having one or more of the following properties: - at least 20% by weight of post-industrial fibers relative to the weight of the final rigid cellulose product; - thickness from 3 mm to 22 mm, an internal bond strength of at least 0.1 MPa, a bending strength of at least 4 MPa, and - at least 400 kg / m ３ density.

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