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WO2024184288A1 - Procédé de production d'un produit cellulosique rigide - Google Patents

Procédé de production d'un produit cellulosique rigide Download PDF

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Publication number
WO2024184288A1
WO2024184288A1 PCT/EP2024/055536 EP2024055536W WO2024184288A1 WO 2024184288 A1 WO2024184288 A1 WO 2024184288A1 EP 2024055536 W EP2024055536 W EP 2024055536W WO 2024184288 A1 WO2024184288 A1 WO 2024184288A1
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WO
WIPO (PCT)
Prior art keywords
fibres
industrial waste
cellulosic
rigid
product
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/055536
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English (en)
Inventor
Sebel LEE YUN
Adrián ROMANÍ VÁZQUEZ
Sara ALONSO JIMÉNEZ
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honext Material Sl
Original Assignee
Honext Material Sl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/EP2023/086449 external-priority patent/WO2024126871A1/fr
Application filed by Honext Material Sl filed Critical Honext Material Sl
Priority to KR1020257033581A priority Critical patent/KR20250156807A/ko
Priority to AU2024233343A priority patent/AU2024233343A1/en
Priority to CN202480015527.3A priority patent/CN121039342A/zh
Publication of WO2024184288A1 publication Critical patent/WO2024184288A1/fr
Priority to MX2025010258A priority patent/MX2025010258A/es
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02—Working-up waste paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/14—Secondary fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J3/00—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds

Definitions

  • the present invention is directed to a process for producing rigid cellulosic product from raw fibrous industrial waste. Specifically, the present invention relates to the enzymatic treatment of industrial waste cellulosic fibres and the subsequent processing of those enzymatically treated fibres to produce a fire retardant rigid cellulosic product such as a board, and to the fire retardant rigid cellulosic product.
  • Industrial waste is defined as waste that is non-reusable and cannot therefore be re-used or recycled to produce another useful product, and which otherwise, for example, would be deposited in landfill sites, or incinerated, with the associated negative environmental impact and cost.
  • the present invention is focused on re-using the cellulosic fibres of the aforementioned industrial waste to obtain rigid cellulosic products with mechanical properties suitable for use as, for example, construction boards.
  • Cellulosic fibres are considered non-reusable when at least one of the following characteristics applies: the fibres have an average length of less than 5mm, the fibres have an average thickness below 0.1 mm, the percentage of fines inside the cellulosic waste is above 10% in mass, where fines are defined as the smallest components in cellulosic fibres fraction that can pass through holes of 76 micrometres of diameter [SCAN. Mechanical and chemical pulps - Fines content. Standard CM 66:052005], or the cellulosic fibres are mixed with other compounds provoking complexity in recycling, such other compounds include inorganic charges, synthetic compounds, and material impurities.
  • Waste paper and waste cardboard can be effectively recycled when it contains low levels of glues, inks, water resistant resins and other additives.
  • these water-resistant resins and additives are alkyl ketene dimers, alkenyl succinic anhydrides, epichlorohydrin, melamine, urea-formaldehyde, polymines, styrene’s, dextrin or other polymers that enhance specific material properties (i.e. polyurethane, vinyl’s, acrylic adhesives improve mechanical properties).
  • the recycling cost and the quality of the cellulosic products obtained can be significantly affected if the wastepaper and cardboard contains large amounts of those additives, requiring additional treatment steps and/or increasing the consumption of additives or energy during the treatment of said cellulosic material.
  • the paper and cellulose manufacturing industry also generates significant quantities of industrial waste, including what is referred to as a liquid or primary sludge which contains cellulosic material considered non-reusable as defined by the above-mentioned characteristics.
  • This sludge is considered to be an effluent with serious environmental liability for the manufacturer, but which the Applicant has discovered can be mitigated by suitable processing, including enzymatic treatment to produce a cellulosic product, such as a construction board.
  • suitable processing including enzymatic treatment to produce a cellulosic product, such as a construction board.
  • the starting cellulose fibre for paper manufacturing can be any fibre, wood, or other plant-based fibres for example, including fastgrowing species such as miscanthus.
  • Primary sludge is composed of around 40 to 90% by weight of cellulose fibres and around 10 to 60% by weight of inorganic fillers. These inorganic fillers are added during the paper manufacturing process to improve the properties of the paper.
  • the raw cellulosic material derived from primary sludge described in this invention stands out for comprising a large amount of fines, more than 15% of cellulose fibres. Fines are small particles composed of cellulose, but which do not have the shape of a fibre due to their size. This particularity means that the raw cellulosic material used in the method of the present invention cannot be used for the manufacture of paper or other products that require good mechanical properties, as the ends do not confer mechanical bonds. The above-mentioned particularities of this raw cellulosic material make it very difficult to obtain products requiring processes of low humidity, pressure and temperature.
  • Another source of industrial waste which meets the above characterisation of the fibres is the cellulosic fibre residue stream or sludge from the textile industry where, for example, the presence of different types of cellulose fibres and plastic mixtures provokes difficulty in reusing or recycling those residues.
  • a further source of industrial waste which meets the above characterisation of the fibres, but is not a residue due stream from a plant which produces paper or textile is construction waste cellulose fibre, for example, the cardboard recovered when recycling gypsum boards.
  • the gypsum-based recovery process through a mechanical crushing action and a subsequent dry double compression, is able to separate the gypsum from the paper, obtaining a finished product with the same characteristics as natural gypsum.
  • the recovered gypsum powder is 97.6% pure and practically free from paper. Whilst the gypsum by-product is reusable, the cellulosic fibres are typically incinerated without being used to form a useful product.
  • a further source of industrial waste which meets the above characterisation of the fibres is vegetal or plant-based waste, such as miscanthus, which has been used in a consumer product, that is, it is post-consumer, and considered not suitable to form a useful product.
  • the Applicant has discovered that with suitable processing, including enzymatic treatment of the fibres, and processing of those treated fibres, the previously non-reusable cellulosic fibres derived from industrial waste can ultimately be used to produce useful cellulosic products such as construction boards with the environmental benefits associated with re-using material that would otherwise end up in landfill, and importantly, offering cellulosic products which can perform at least as well as products derived from other cellulosic fibres and using alternative processes, which have a greater negative environmental impact.
  • construction boards exhibit good fire reaction properties to meet regulatory requirements, without negatively impacting the base properties of the board such as mechanical strength, humidity resistance, and that the boards retain their environmental credentials.
  • the process of the present invention produces a fire retardant rigid cellulosic product using a proportion of raw fibrous cellulosic material derived from industrial processes, such as industrial process for the production of paper, cardboard, textile, or construction materials, or some other waste source where the residue cellulosic material would otherwise not be reusable for the reasons defined in the fibre characterisation above, typically low quality fibrous cellulosic material mainly comprising fibres shorter than 5mm, and/or fragile fibres, and/or recycled fibres which are typically partially bonded with impurities and therefore have a reduced bonding capacity with other cellulosic fibres.
  • the rigid cellulosic product of the present invention is not only sustainably produced, but meets at least Class C fire classification without negatively impacting the base properties of the board.
  • the industrial waste cellulosic fibres such as primary sludge from the paper industry, cannot be reused to produce useful cellulosic products without using resins or glues, as the fibres are too short to provide sufficient mechanical properties to the board.
  • the process further comprises the step of selecting a quantity of industrial waste cellulosic fibres such that a calcium carbonate content of the industrial waste cellulosic fibres compared to the weight of the rigid cellulosic product is sufficient to obtain a rigid cellulosic product having at least a Class C fire classification when tested according to European Standard EN 13501-1.
  • the rigid cellulosic board has a calcium carbonate content of greater than 7 wt.% and preferably greater than 7 wt.% and less than 50%, more preferably greater than 7 wt.% and less than 35 wt.% compared to the weight of the rigid cellulosic product.
  • the calcium carbonate content will be sufficient to obtain a rigid cellulosic product with at least a Class C fire classification.
  • the process further comprises the step of adding a fire retardant, preferably an expandable volcanic mineral, more preferably vermiculite or perlite, to the industrial waste cellulosic fibres to further improve the fire retardancy beyond that achievable by relying on the calcium carbonate content alone.
  • a fire retardant preferably an expandable volcanic mineral, more preferably vermiculite or perlite
  • the expandable volcanic mineral is added in sufficient quantity such that the rigid cellulosic product has an expandable volcanic mineral content of greater than 5wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the source of the industrial waste cellulosic fibres is chosen so that it does not contain calcium carbonate, for example textile sludge residues from the textile production industry, or construction waste cellulose fibre, and the process further comprises the step of adding a fire retardant, preferably aluminium hydroxide to the non-calcium carbonate containing industrial waste cellulosic fibres.
  • a fire retardant preferably aluminium hydroxide
  • the aluminium hydroxide is added to the non-calcium carbonate containing industrial waste cellulosic fibres in sufficient quantity such that the rigid cellulosic product has an aluminium hydroxide content of greater than 15wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the step of producing pulped industrial waste cellulosic fibres comprises pulping the raw fibrous industrial waste.
  • the process further comprises the step of diluting the raw fibrous industrial waste in water prior to or during pulping.
  • the raw fibrous industrial waste may not require a separate pulping step prior to enzymatic treatment, and can be supplied as already pulped fibres, that is, fibres that are sufficiently individualised to be substantially free of agglomerations, which if left, leads to ineffective enzyme treatment, and reduced distribution of the fibres during forming, resulting in a non-homogeneous final product.
  • the supply of already pulped fibres can be the direct output from an industrial plant, preferably a sludge output feed from a plant to produce paper or textiles.
  • the supplied pulped fibres can be directly fed from the sludge output to the process for producing rigid cellulosic product via a conduit to the sludge output, or can be indirectly fed to the process for producing rigid cellulosic product via an intermediate storage tank.
  • raw fibrous cellulosic material material mainly composed from fibres made of cellulose and other vegetal compounds able to generate bonds with other cellulose fibres.
  • the enzymatic process increases the number of free hydroxyls of the fibres and enables the industrial waste fibres to crosslink and bond with other non-industrial fibres and/or each other to produce cellulosic products such as construction boards or panels with mechanical properties sufficient for their intended end use.
  • the raw fibrous industrial waste comprises fibres having one or more of an average length of less than 5mm, preferably less than 2mm, and/or an average width of less than 0.1 mm, and/or a mass percentage of fines greater than 10%.
  • the industrial waste fibres are derived from one or more of primary sludge obtained from the paper production industry or sludge residues from the textile production industry.
  • industrial waste fibres it is meant fibres that have been derived from an industrial process such as paper, cardboard or textile production to produce paper, cardboard or textile products, or some industrial process where the cellulosic fibres are not considered to be re-usable to form a useful cellulosic product. Waste or recycled cardboard is not considered to be industrial waste.
  • the process further comprises the step of diluting the raw fibrous industrial waste in water prior to or during pulping.
  • the step of enzymatically treating the pulped industrial waste cellulosic fibres to produce enzymatically treated industrial waste cellulosic fibres comprises maintaining the water content during enzyme treatment above 80%.
  • the step of enzymatically treating the pulped industrial waste cellulosic fibres to produce enzymatically treated industrial waste cellulosic fibres comprises maintaining the water content during enzyme treatment above 90%.
  • the step of maintaining the water content during enzymatic treatment above 80% comprises maintaining the water content during enzymatic treatment greater than 80% and up to 99%, more preferably greater than 80% and up to 95%.
  • the step of diluting the enzymatically treated industrial waste fibres to obtain diluted enzymatically treated industrial waste fibres with a water content of greater than 90% comprises diluting to ensure the water content remains greater than 90% and less than 99%, preferably greater than 95% and less than 99%.
  • the raw fibrous cellulosic material from the industrial waste will be free of large particles or clusters, bigger than 5mm, because such particles or clusters will have a reduced or no capacity to generate bonds with other cellulose fibres.
  • a particle size reducer such as a crusher, a shredder, can be used prior to pulping to reduce the size or eliminate particles or clusters depending on the type of raw fibrous cellulosic material. For example, materials difficult to pulp when not reduced in size, such as miscanthus or textile waste, may require this additional particle size reduction step.
  • the raw fibrous cellulosic material can include large particles or clusters bigger than 5mm if such particles or clusters are soluble or breakable in small particles or clusters smaller than 5mm or fibres of any length during pulping.
  • An example of large soluble or breakable particles or clusters can be for example cardboard or sludge lumps.
  • the step of enzymatically treating the industrial waste cellulosic fibres comprises adding one or more enzymes to the industrial waste cellulosic fibres to one or more of, smooth the fibres, remove radicals from the outside of the fibres and increase the specific surface area of the fibres.
  • the step of enzymatically treating the industrial waste cellulosic fibres comprises one or more of the following: keeping the pH of the pulped fibres between 5 and 9, maintaining the temperature above 40°C, preferably greater than 40°C and less than 70°C during the enzymatic treatment of step (b), adding one or more enzymes selected from the group of xylanase, laccase, and cellulase, adding between 0.05% to 0.5% of enzymes with respect to the dry weight of the industrial waste cellulosic fibres, enzymatically treating the industrial waste cellulosic fibres for a period of greater than 5 minutes, preferably greater than 5 minutes and less than 60 minutes.
  • the Applicant has realised that for industrial cellulosic waste, the enzymatic treatment process is key, not only for the fibrillation of the fibres, but also cleaning the fibre surface using xylanase and laccase enzymes.
  • Xylanase enzymes attack hemicellulose, which facilitates the extraction of surface layers of the cellulose fibre, thus eliminating impurities that may be carried by the various additives, residues from the process prior to the generation of the residue.
  • Laccase enzymes also help to eliminate impurities, mainly lignin, which hinders pulping.
  • the Applicant has also discovered that the presence of fines hinders the processing of the diluted cellulosic industrial waste fibres, for example, they reduce the capacity for dewatering when the enzymatically treated industrial waste cellulosic fibres are compressed to produce compressed fibres.
  • the transformation of fines into glucose helps in dewatering, but it is a process that must be controlled, as more fines could be generated from the larger cellulose fibres.
  • the enzymatic treatment times and the enzyme concentration therefore needs to be controlled in order to control this transformation process in the industrial waste pulp.
  • the process further comprises:
  • the step of producing pulped non-industrial waste cellulosic fibres comprises pulping the raw fibrous cellulosic material.
  • the raw fibrous non-industrial waste cellulosic waste may not require a separate pulping step prior to enzymatic treatment, and can be supplied as already pulped fibres, that is fibres that are sufficiently individualised to be substantially free of agglomerations.
  • a supply can be the direct output from a non-industrial plant, preferably a pulped output from a cardboard production plant.
  • the supplied pulped fibres can be directly fed from the pulped output from the cardboard production plant to the process for producing rigid cellulosic product via a conduit to the pulped output, or can be indirectly fed to the process for producing rigid cellulosic product via an intermediate storage tank.
  • the step of enzymatically treating the pulped non-industrial waste cellulosic fibres to produce enzymatically treated non-industrial waste cellulosic fibres comprises maintaining the water content during enzyme treatment above 80%.
  • the step of enzymatically treating the pulped non-industrial waste cellulosic fibres to produce enzymatically treated non-industrial waste cellulosic fibres comprises maintaining the water content during enzyme treatment above 90%.
  • the step of maintaining the water content during enzymatic treatment of the nonindustrial waste cellulosic fibres above 80% comprises maintaining the water content during enzymatic treatment greater than 80% and up to 99%, more preferably greater than 80% and up to 95%.
  • the step of diluting the enzymatically treated non-industrial waste fibres to obtain diluted enzymatically treated non-industrial waste fibres with a water content of greater than 90% comprises diluting to ensure the water content remains greater than 90% and less than 99%, preferably greater than 95% and less than 99%.
  • the process includes the step of maintaining the water content during enzyme treatment of the industrial and non-industrial waste fibres between 20% and 80 to define a semi-dry process.
  • the raw fibrous industrial waste and the raw fibrous non-industrial waste cellulosic material are pulped independently of each other.
  • the step of enzymatically treating the non-industrial waste cellulosic fibres comprises one or more of the following: keeping the pH of the pulped fibres between 5 and 9, maintaining the temperature above 40°C, preferably greater than 40°C and less than 70°C during the enzymatic treatment of step (b), adding one or more enzymes selected from the group of xylanase, laccase, and cellulase, adding between 0.05% to 0.5% of enzymes with respect to the dry weight of the industrial waste cellulosic fibres, enzymatically treating the industrial waste cellulosic fibres for a period of greater than 5 minutes, preferably greater than 10 minutes and less than 90 minutes.
  • the industrial waste and the non-industrial waste cellulosic fibres are enzymatically treated independently of each other.
  • the industrial waste and the non-industrial waste cellulosic fibres are cleaned to remove contaminants independently of each other.
  • the step of providing industrial waste cellulosic fibres comprises providing at least two sources of industrial waste cellulosic fibres, in which each source of industrial waste cellulosic fibres is pulped independently and enzymatically treated independently from each other.
  • the industrial waste and the non-industrial waste cellulosic fibres are combined and mixed in a dilution step.
  • the step of compressing the enzymatically treated industrial waste and/or nonindustrial waste cellulosic fibres to form a rigid cellulosic product is one of moulding, preferably injection moulding, or pressing in a forming unit and/or between drums to form a partially wet cellulosic product.
  • the step of compressing the enzymatically treated industrial waste and/or nonindustrial waste cellulosic waste fibres to form a partially wet cellulosic product comprises pressing the enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres in a forming unit to obtain a partially wet cellulosic product with a water content of preferably greater than 40% and less than 80%, preferably greater than 40% and less than 70%.
  • the step of pressing the enzymatically treated industrial waste and/or nonindustrial waste cellulosic fibres in a forming unit comprises: (a) providing a forming unit, the forming unit having a mould defined by an outer side wall having open upper and lower ends, upper and lower plates configured to sealingly close the respective open upper and lower ends to retain the enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres within the mould,
  • a filter belt is provided between the lower plate and the mould such that a lower surface of the enzymatically treated and industrial waste and/or non-industrial waste cellulosic fibres are in contact with the filter belt.
  • the filter belt has a porosity sufficient to substantially retain the solids content of the treated fibres with the mould and enable at least a proportion of the water content to pass therethrough, preferably the filter has a porosity rating of between 400 to 500 cubic feet per meter.
  • a vacuum is applied to one or both of the upper and lower plates to remove water from the enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres.
  • the step of introducing the enzymatically treated industrial waste and/or nonindustrial waste fibres into the mould comprises introducing the enzymatically treated industrial waste and/or cellulosic waste fibres through apertures provided on the outer side wall.
  • the step of compressing the diluted enzymatically treated and pulped industrial waste and/or non-industrial waste cellulosic waste fibres to form a rigid cellulosic product comprises or further comprises pressing between drums, preferably to obtain a partially wet cellulosic product with a water content of greater than 40% and less then 80%, preferably less than 70%.
  • the step of drying the compressed fibres to form a rigid cellulosic product comprises introducing the partially wet cellulosic product into a drying tunnel to reduce the water content, preferably at a temperature below 140°C, to reduce the water content preferably to below 40%, more preferably below 30%, most preferably below 25%.
  • the step of drying the compressed fibres to form a rigid cellulosic product further comprises introducing the compressed and partially dried fibres into a hot plates press to reduce the water content, preferably to below 20%.
  • the hot plates press comprises an upper plate and a lower plate, both plates configured to allow steam produced from water present in the partially wet cellulosic product to escape from the partially wet cellulosic product, preferably both plates comprise a meshlike structure or are porous.
  • the upper and lower plates of the hot plates pressure are maintained at a temperature of greater than 60°C and up to 200°C.
  • a pressure is applied to the partially wet cellulosic product in a first stage and a second stage.
  • a pressure of lower than 2kg/cm 2 is applied.
  • a pressure of greater than 0.5kg/cm 2 is applied to obtain the rigid cellulosic product with the required density or thickness, preferably with a water content of lower than 20%.
  • the process is a continuous process.
  • the raw fibrous industrial waste comprises other compounds, such as inorganic compounds and/or other impurities.
  • the rigid cellulosic product is a board, preferably a construction board.
  • the board has one or more of the following properties: at least 20% by weight of industrial waste fibres compared to the final rigid cellulosic product weight, a thickness of between 3mm and 22mm, an internal bond strength of at least 0.1 MPa, a flexural strength of at least 4MPa, and a density of at least 400kg/m 3 .
  • the process further comprises adding a fire retardant, preferably aluminium hydroxide or an expandable volcanic mineral, preferably vermiculite, to the non-industrial waste cellulosic fibres, preferably waste cardboard.
  • the step of adding a fire retardant is after the step of enzymatically treating the pulped non-industrial waste cellulosic fibres and more preferably before step of combining the enzymatically treated and pulped industrial and non-industrial waste cellulosic fibres.
  • the aluminium hydroxide is added in sufficient quantity to the non-industrial waste cellulosic fibres such that the rigid cellulosic product has an aluminium hydroxide content of greater than 15wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the expandable volcanic mineral is added in sufficient quantity to the non-industrial waste cellulosic fibres such that the rigid cellulosic product has an expandable volcanic mineral content of greater than 5wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the step of compressing the enzymatically treated industrial waste and/or nonindustrial waste cellulosic fibres comprises depositing multiple different layers of enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres in the forming unit, and pressing the multiple different layers to produce a multiple layered partially wet cellulosic product.
  • the different layers can comprise industrial waste or non-industrial waste cellulosic fibres, with different or the same fire retardants in each of those different layers.
  • the step of depositing multiple different layers of enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres in the forming unit comprises depositing an upper outer layer comprising the fire retardant, preferably one of aluminium hydroxide or expandable volcanic mineral and/or a lower outer layer comprising the fire retardant, preferably one of aluminium hydroxide or expandable volcanic mineral.
  • the step of depositing multiple different layers of enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres in the forming unit comprises depositing a middle layer of enzymatically treated industrial waste and/or non-industrial waste cellulosic fibres containing no fire retardant between the upper and outer layers.
  • the non-industrial waste cellulosic fibres are any cellulosic fibres that are not derived from raw fibrous industrial waste, more preferably one or more of virgin cellulosic fibres, preferably wood or plant fibres, more preferably miscanthus fibres, or preferably wastepaper or waste cardboard fibres, preferably OCC fibres.
  • the non-industrial waste cellulosic fibres are any cellulosic fibres that are not derived from raw fibrous industrial waste, more preferably one or more of virgin cellulosic fibres, preferably wood or plant fibres, more preferably miscanthus fibres, or preferably wastepaper or waste cardboard fibres, preferably OCC fibres.
  • the cellulosic fibres are 100% waste cardboard fibres, in which the process further comprises adding a fire retardant, preferably aluminium hydroxide, to the waste cardboard fibres, preferably adding the fire retardant after step (b) of enzymatically treating the waste cardboard fibres.
  • a fire retardant preferably aluminium hydroxide
  • the process does not include the step of adding a binder, glue or adhesive to bind the fibres together.
  • the rigid cellulosic product comprises a proportion of rejected rigid cellulosic product.
  • the process further comprises the step of adding the rejected rigid cellulosic product to the step of diluting or pulping or enzymatically treating the industrial waste or nonindustrial waste cellulosic fibres.
  • the combined industrial waste and non-industrial waste cellulosic fibres comprise at least 20wt.%, preferably between 20 and 80wt.%, preferably between 30 and 70wt.%, preferably between 40 and 60wt.% of the industrial waste cellulosic fibres, the remainder of the combined industrial and non-industrial waste cellulosic fibres being cellulosic fibres.
  • a rigid cellulosic product comprising one or both of enzymatically treated industrial waste cellulosic fibres and enzymatically treated non-industrial waste cellulosic fibres.
  • the rigid cellulosic product does not include a binder, glue or adhesive to bind the fibres together.
  • the rigid cellulosic product has a calcium carbonate content of greater than 7 wt.% and preferably less than 50%, more preferably less than 35 wt.% compared to the weight of the rigid cellulosic product.
  • the rigid cellulosic product includes a fire retardant.
  • the fire retardant is aluminium hydroxide, the product having an aluminium hydroxide content of greater than 15 wt.% dry mass compared to the weight of the rigid cellulosic product.
  • the fire retardant is an expandable volcanic mineral, the product having an expandable volcanic mineral content of greater than 5wt.% dry mass compared to the weight of the rigid cellulosic product.
  • the rigid cellulosic product comprises multiple compressed overlapped or structural layers, in which at least one of the layers comprises the fire retardant.
  • At least one of the multiple compressed overlapped layers does not comprises the fire retardant.
  • the multiple compressed overlapped layers comprises an upper outer layer and a lower outer layer, in which the upper and/or the lower outer layer comprises the fire retardant.
  • a middle layer between the upper outer layer and the lower outer layer does not comprises the fire retardant.
  • the industrial waste cellulosic fibres are derived from primary sludge obtained from the paper production industry.
  • the non-industrial waste cellulosic fibres are derived from waste cardboard.
  • the rigid cellulosic product comprises between 20 and 80wt.%, preferably between 30 and 70wt.%, preferably between 40 and 60wt.% of the industrial waste cellulosic fibres, the remainder of the combined industrial and non-industrial waste cellulosic fibres being nonindustrial waste cellulosic fibres.
  • the expandable volcanic mineral is concentrated in one of an upper or lower outer region of the rigid cellulosic board, and the aluminium hydroxide is concentrated in the other of the upper or lower outer region of the rigid cellulosic board.
  • the expandable volcanic mineral is concentrated in one of an upper or lower outer region of the rigid cellulosic board, the aluminium hydroxide concentrated in the other of the upper or lower outer region of the rigid cellulosic board.
  • the rigid cellulosic product has one or more of the following properties: at least 20% by weight of industrial waste fibres compared to the final rigid cellulosic product weight, a thickness of between 3mm and 22mm, an internal bond strength of at least 0.1 MPa, a flexural strength of at least 4MPa, and a density of at least 400kg/m 3 .
  • the process further comprises the step of selecting a quantity of industrial waste cellulosic fibres such that a calcium carbonate content of the industrial waste cellulosic fibres compared to the weight of the rigid cellulosic product is sufficient to obtain a rigid cellulosic product having at least Class C fire classification when tested according to European Standard EN 13501-1.
  • the calcium carbonate content is greater than 7 wt.% and preferably greater than 7 wt.% and less than 50%, more preferably greater than 7 wt.% and less than 35 wt.% compared to the weight of the rigid cellulosic product.
  • the process further comprises the step of adding a fire retardant, preferably an expandable volcanic mineral, preferably vermiculite, to the industrial waste cellulosic fibres.
  • the expandable volcanic mineral is added in sufficient quantity such that the rigid cellulosic product has an expandable volcanic mineral content of greater than 5wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the industrial waste cellulosic fibres do not contain calcium carbonate, preferably the industrial waste cellulosic fibres are textile sludge residues from the textile production industry, or construction waste cellulose fibre, the process further comprises adding a fire retardant, preferably aluminium hydroxide to the industrial waste cellulosic fibres.
  • a fire retardant preferably aluminium hydroxide
  • the aluminium hydroxide is added to the industrial waste cellulosic fibres in sufficient quantity such that the rigid cellulosic product has an aluminium hydroxide content of greater than 15wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the process further comprises adding a fire retardant, preferably aluminium hydroxide or an expandable volcanic mineral, preferably vermiculite, to the non-industrial waste cellulosic fibres, preferably waste cardboard.
  • a fire retardant preferably aluminium hydroxide or an expandable volcanic mineral, preferably vermiculite
  • the step of adding a fire retardant is after the step of enzymatically treating the pulped non-industrial waste cellulosic fibres and before the step of combining the enzymatically treated and pulped industrial and non-industrial waste cellulosic fibres.
  • the expandable volcanic mineral is added in sufficient quantity to the non-industrial waste cellulosic fibres such that the rigid cellulosic product has an expandable volcanic mineral content of greater than 5wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • the aluminium hydroxide is added to the non-industrial waste cellulosic fibres in sufficient quantity such that the rigid cellulosic product has an aluminium hydroxide content of greater than 15wt.% dry mass compared to the weight of the rigid cellulosic product to provide the rigid cellulosic product with a Class B fire classification when tested according to European Standard EN 13501-1.
  • Figure 1 is a schematic view of the process of the present invention.
  • Figure 2 is a front sectional view of a forming unit used in the process of the present invention prior to the injection of pulp
  • Figure 3 is a side sectional view of the forming unit of Figure 2 prior to the injection of pulp
  • Figure 4 is a front sectional view of the forming unit of Figure 1 , after the injection of pulp,
  • Figure 5 is a plan sectional view of the forming unit of Figure 1 after the injection of pulp (with upper plate removed for clarity),
  • Figures 6 to 18 are schematic sectional views of alternative rigid cellulosic boards
  • Figure 19 is a schematic view of an embodiment of the enzymatic treatment system adapted to apply the proposed method for obtaining different fractions of the dried treated cellulosic material
  • Figure 20 is a schematic view of the system of Figure 19 but also including a product former station for producing a stratified rigid cellulosic product.
  • references to water content are weight percentage, and further mean the percentage of water compared to the amount of solids, for example, 80% water content will contain 20% solids.
  • references to percentage proportions of industrial and non-industrial materials mean the dry mass of that material compared to the total dry mass of industrial and non-industrial material.
  • raw fibrous non-industrial waste cellulosic material A is provided in the form of waste cardboard, specifically, old corrugated cardboard (OCC), and raw fibrous industrial waste cellulosic material B is provided in the form of raw papermill sludge, that is, primary sludge from the paper production industry.
  • OCC old corrugated cardboard
  • raw fibrous industrial waste cellulosic material B is provided in the form of raw papermill sludge, that is, primary sludge from the paper production industry.
  • the raw fibrous content is 50% sludge and 50% OCC (both measured in dry weight). It will be understood that the sludge content can be up to 100%, with the remainder being OCC, for example, 70% sludge and 30% OCC.
  • the sludge and OCC are independently diluted, pulped, and enzymatically treated as will be described below.
  • the OCC is then loaded into the pulper P1 and stirred in water for at least 8 minutes to individualize and improve the fibre distribution in the OCC before the enzymes are added, to produce pulped OCC.
  • water is added to the OCC in the pulper P1 to ensure a water content of 95%.
  • the OCC could be supplied with a water content of greater than 95%, in which case, water is removed or more solids added, to establish a water content of 95% in this example.
  • individualize it is meant the process of dispersing the fibres which are agglomerated in the raw OCC.
  • Enzymes in the form of xylanase, laccase, and cellulase are then added to the diluted and pulped OCC fibres in the pulper P1 and agitated or stirred for at least 5 minutes and up to 90 minutes (depending on the pulping equipment) to produce pulped and enzymatically treated OCC with a water content maintained above 90%, in this example, at about 95%.
  • the enzymes are preferably liquid or dissolved in liquid and are added to the pulped OCC waste fibres.
  • the added enzymes are preferably selected to smooth the fibres, remove radicals from the outside of the fibres and increase the specific surface area of the fibres. Those effects can be obtained for example by different combinations of the following enzymes: xylanase, laccase, cellulase and/or combinations thereof.
  • the pH of the pulped fibres is maintained between 5 and 9.
  • the temperature of the pulped fibres is maintained above 40°C, preferably between 40°C and 70°C, to improve the enzymatic treatment. In this example, the temperature of the pulped fibres is maintained at 60°C.
  • the total quantity of enzymes added is between 0.05% to 1% with respect to the dry weight of the OCC fibres.
  • Alkyl ketene dimer is added as part of the water treatment additions in T2B to the pulped and enzymatically treated OCC fibres.
  • the amount of AKD added is less than 15% compared to the weight of the OCC. After adding the AKD, the agitator continues to run for about 4 minutes.
  • the diluted, pulped and enzymatically treated OCC contents of the pulper P1 are then subjected to a cleaning process by being transferred to a tank T1 via a sieving tank P2 where contaminants, such as plastic, wood or metal, with a size larger than 6 mm are removed in a first cleaning stage, and further contaminants which are smaller than 6mm and therefore are not removed in the first cleaning stage, but heavier than the aforementioned contaminants are removed using a hydrocyclone in a second cleaning stage.
  • contaminants such as plastic, wood or metal
  • the OCC pulp independently produced in tank T1 is then transferred to tank T2B and the stirrer is started.
  • the OCC pulp is diluted to a water content of 97%.
  • the dilution, pulping and enzymatic treatment steps described above are repeated in the pulper P1 (after the pulped, diluted and enzymatically treated OCC has been removed) using the sludge, other than that that the enzyme treatment stage is required for greater than 5 minutes, but less than 60 minutes, and the enzyme concentration is between 0.05% and 0.5% with respect to the dry weight of the sludge fibres.
  • the enzyme treatment time and concentration is approximately 50% less for the sludge fibres compared to the OCC fibres.
  • the sludge can be pulped in a different pulper, that is not the same pulper used for the dilution, pulping and enzymatic treatment of the OCC.
  • the pulped and enzymatically treated sludge contents of the pulper P1 are cleaned according to the same process described above in relation to the OCC.
  • the sludge pulp independently (either before or after the OCC pulp is produced) produced in tank T1 is then transferred to tank T2A and the stirrer is started.
  • the sludge pulp is diluted to a water content of 97%.
  • the OCC and the sludge are independently pulped and enzymatically treated in steps (a) and (b) above, that is, the OCC is pulped and enzymatically treated and transferred to tank T1 , and then the sludge is independently pulped and enzymatically treated and transferred to tank T1.
  • the sludge and OCC independently undergo the two- stage cleaning process by being sieved in sieving tank P2 and cleaned in tank T 1 .
  • aluminium hydroxide-based fire also referred to as a flame
  • aluminium hydroxide-based fire also referred to as a flame
  • the OCC pulp is then circulated in tank T2B.
  • additives such as odour powder, biocides, and inks/dyes are added to the combined sludge and OCC pulp in tank T3.
  • the combined sludge and OCC pulp is further diluted by adding more to ensure a water content of greater than 90%.
  • the forming unit 10 includes a rectangular mould 12 defined by an outer side wall 14 having an open upper end 16 and an open lower end 18.
  • the outer side wall 14 includes multiple apertures 20 distributed on each longer side of the outer side wall 14, through which the combined sludge and OCC pulp 11 is injected as will be described below.
  • the distribution and number of apertures can vary to ensure an equal distribution of pulp 11 inside the mould 12. This is important as it enables control of the density and thickness of the final rigid cellulosic product.
  • 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 which is driven by an electric motor (not shown).
  • the upper 22 and lower 24 plates have a compartmentalized structure that acts as a box that can temporarily store extracted water from the pulp 11.
  • a PET conveying filter belt 28 is positioned between the lower plate 24 and the mould 12 such that it sealingly engages against the outer side wall 14 of the mould 12 to retain the pulp 11 within the mould 12.
  • the filtering belt 28 has a porosity sufficient to substantially retain the solids content of the treated fibres with the mould and enable at least a proportion of the water content to pass therethrough, in this example, a porosity rating of between 400 to 500 cubic feet per meter which is sufficient to enable the extraction of water from the pulp 11 , but at the same time avoiding undesired extraction of cellulose fibres from the pulp 11.
  • the combined sludge and OCC pulp 11 is injected through the apertures 20 into the mould 12 of a forming unit 10.
  • the pulp 11 is retained horizontally by the outer side wall 14 and vertically by the filter belt 28 ( Figures 2 and 3).
  • a dewatering step is initiated 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 inside the lower plate 24.
  • no vacuum is applied, and the water can be extracted under gravity.
  • the upper plate 22 is lowered via the mechanical screw system until it comes into contact with the pulp 11 and applies a pressure which depends on the density of product required (Figure 4).
  • a vacuum is applied to the upper plate 22 to extract more water from the pulp 11 through upper plate 22 where it is deposited.
  • a positive pressure can be applied inside the mould instead of applying a vacuum.
  • a partially wet cellulosic product in the form of a board is formed.
  • the water content is greater than 40% and less then 80% and enables the partially wet cellulosic board to be removed from the forming unit 10.
  • the partially wet cellulosic board is removed from the forming unit 10 by firstly raising the upper plate 22 to its starting position ( Figure 2), lifting the mould 12 from the filter belt 28, and then starting the conveying filter belt 28 to move the partially wet cellulosic board to a transfer unit (not shown) where it undergoes an optional compression step in the form of pressing rollers or drums to squeeze remaining water from the wet partially wet cellulosic board and reduce the water content further, typically to less than 70% to about 40%.
  • the combined pulp 11 can be compressed between pressing rollers to form a partially wet cellulosic board without requiring forming in the forming unit 10.
  • the partially wet cellulosic board is dried in two stages as follows:
  • the board In a first drying stage, the board is introduced into a convection drying tunnel and is moved on 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.
  • the water content of the board is between 20 and 30%.
  • the board is removed from the drying tunnel and positioned between two plates of a hot plates press.
  • the hot plates press includes an upper hot press plate and a lower hot press plate, both plates configured to allow steam produced when the board is heated from water present in the partially wet cellulosic board to escape.
  • both the upper and lower plates have a mesh-like structure to allow the steam to escape.
  • the plates can be made of a porous material, or include micro-perforations.
  • the upper and lower plates of the hot plates press are maintained at a temperature of greater than 60°C and up to 200°C during pressing.
  • a pressure of lower than 2kg/cm 2 is applied to the board.
  • the board contacts the press hot plates and is heated through conduction.
  • the pressure applied during this first stage depends on the required final board density but must be lower than 2kg/cm 2 .
  • the board achieves a water content of lower than 50%.
  • a pressure of greater than 0.5kg/cm 2 is applied to the board so as to obtain the rigid cellulosic product with the required density or thickness.
  • the maximum pressure that can be applied to the board is not limited as in the first press drying stage due to the reduced compressibility of the board as it has a lower water content.
  • the now rigid cellulosic board has a water content of about 20%.
  • the partially wet cellulosic board is transferred from the forming unit via the press rollers and the drying tunnel to the hot plates press.
  • the partially wet cellulosic board can be transferred directly from the forming unit to the hot plates press without the need for the drying tunnel.
  • the board After exiting the hot plates press, the board is allowed to cool for at least 30 minutes on a support that is covered by a mesh to allow remaining water vapour to evaporate from both sides of the board.
  • the partially wet cellulosic board undergoes a first drying stage in a drying tunnel.
  • a single stage drying process is possible requiring only the use of the drying tunnel or the hot plates press.
  • the board produced has the properties defined in Table 1 , particularly noting the board achieves a Class B fire classification (SBI) when tested according to European Standard EN 13501-1.
  • SBI Class B fire classification
  • the aluminium hydroxide fire retardant is not added to the pulped and enzymatically treated OCC. Instead, the quantities of calcium carbonate in the sludge are sufficiently high, about 10% compared to the weight of the final board in this example to achieve a Class C fire classification (SBI) when tested according to European Standard EN 13501-1 as opposed to the Class B fire classification (SBI) of Example 1.
  • SBI Class C fire classification
  • the calcium carbonate content of the raw sludge is measured for each batch prior to compressing the fibres, and the measured calcium carbonate content is compared with a look-up reference which correlates the calcium carbonate content of the sludge with an expected calcium carbonate content of the rigid cellulosic product based on the proportion of sludge in the final product. If the calcium carbonate content is too low, it is adjusted to ensure the quantity is sufficient, that is, greater than 7wt.% and less than 50wt.% compared to the weight of the final board to achieve a Class C fire classification (SBI). Adjustment of the calcium carbonate level is achieved by adjusting the ratio of OCC to sludge.
  • SBI Class C fire classification
  • the calcium carbonate content is measured by calcination of a known weight of a sludge sample and then comparing the weight of the ashes (from the calcination) with the total dry weight of the sludge sample to obtain an ash percentage.
  • the ash percentage is an accurate representation (to within 95%) of the calcium carbonate content.
  • the final board properties of the Class C rated board are 5 to 10% higher than those for the Class B rated board of Example 1 .
  • the pulped and enzymatically treated sludge and the pulped and enzymatically treated OCC are not independently sieved in sieving tank P2 and cleaned in tank T1 , but undergo the two-stage cleaning process after being combined.
  • Example 2 is identical to Example 1 except that the mixture content is 60% wastepaper sludge and 40% OCC.
  • the board produced has the properties defined in Table 1.
  • Example 3 Other than the differences shown in Table 1 , the process of Example 3 is identical to Example 1 except that in addition to the 50% OCC, the mixture content comprises 50% industrial waste in the form of miscanthus fibres.
  • the board produced has the properties defined in Table 1.
  • Example 4 is identical to Example 3 except that the mixture content comprises 100% non-industrial waste in the form of plant fibres, in this example, miscanthus fibres.
  • the board produced has the properties defined in Table 1.
  • Example 5 is identical to Example 3 except that the mixture content comprises 100% non-industrial waste in the form of OCC.
  • the board produced has the properties defined in Table 1.
  • Example 6 is identical to Examples 1 and 3 except that, in addition to the 50% OCC, the mixture content comprises 50% industrial waste in the form of textile sludge, that is sludge originating from the textile processing industry.
  • the board produced has the properties defined in Table 1.
  • Example 7 is identical to Example 6 except that the mixture content comprises 100% industrial waste in the form of textile sludge, that is, the mixture does not comprise any non-industrial waste such as OCC.
  • OCC non-industrial waste
  • an alternative fire retardant, vermiculite is added to the sludge to achieve a Class B fire classification (SBI) when tested according to European Standard EN 13501-1.
  • the board produced has the properties defined in Table 1.
  • aluminium hydroxide instead of vermiculite can be added to the textile sludge.
  • Example 8 is identical to Example
  • the textile sludge has shorter fibres and includes a mixture or organic and synthetic fibres which do not generate hydrogen bonds.
  • the board produced has the properties defined in Table 1.
  • Example 9 is identical to Example
  • the textile sludge has shorter fibres and includes a mixture or organic and synthetic fibres which do not generate hydrogen bonds.
  • the board produced has the properties defined in Table 1.
  • Example 10 is identical to Examplel , 3 and 6 except that, in addition to the 50% OCC, the mixture content comprises 50% industrial waste in the form of construction waste (calcium sulphate) as opposed to paper sludge.
  • the board produced has the properties defined in Table 1.
  • Example 11 is identical to Example 10 except that the mixture content comprises 100% industrial waste in the form of construction waste (calcium sulphate).
  • the mixture content comprises 100% industrial waste in the form of construction waste (calcium sulphate).
  • an alternative fire retardant, vermiculite is added to the construction waste to achieve a Class B fire classification (SBI) when tested according to European Standard EN 13501-1.
  • the board produced has the properties defined in Table 1.
  • aluminium hydroxide instead of vermiculite can be added to the textile sludge.
  • Examples 4, 5, 7, 9 and 11 above there is only a single cellulosic fibre source (industrial or non-industrial waste), and therefore no requirement to independently clean that single fibre source, or to combine another cellulosic fibre source as is the case in Examples 1 , 2, 3, 6, 8 and 10 (industrial and non-industrial waste),
  • a fire retardant in the form of aluminium hydroxide is added to the OCC to achieve a Class B rating.
  • an expandable volcanic mineral such as vermiculite or perlite, can be added to the OCC instead of, or in addition to adding aluminium hydroxide to the OCC to achieve a Class B rating for each of Examples 1 to 11 above.
  • a fire retardant in the form of aluminium hydroxide or an expandable volcanic mineral is added to the OCC (non-industrial waste cellulosic material) to achieve a Class B rating.
  • the expandable volcanic mineral can be added to the industrial waste cellulosic material instead of or in addition to the non-industrial waste cellulosic material to achieve a Class B rating.
  • aluminium hydroxide is added to the OCC.
  • the industrial waste cellulosic material is not papermill sludge, that is, not including calcium carbonate, for example, textile or construction waste
  • aluminium hydroxide can be added to the industrial waste cellulosic material instead of or in addition to adding aluminium hydroxide to the OCC.
  • vermiculite and/or aluminium hydroxide is added as a fire retardant.
  • the quantity of calcium carbonate in the papermill sludge is sufficiently high (as described in relation to the alternative example of Example 1) to achieve a Class C rating.
  • the final board properties of the Class C boards of the alternatives to Examples 2 to 11 are 5 to 10% higher than those for the Class B boards of Examples 2 to 11 .
  • the pulped and enzymatically treated industrial waste that is the sludge (textile or paper processing derived), miscanthus, or the construction waste
  • the pulped and enzymatically treated non-industrial waste that is OCC
  • Example 12 is identical to the alternative of Example 1 with no fire retardant added, resulting in a Class C rating as a result of the calcium carbonate content in the sludge being greater than 7 wt.%, in this example, 10 wt.%.
  • the board produced has the properties defined in Table 2.
  • Example 13 is identical to Example 12 except that the board comprises 100% papermill sludge.
  • a Class C rating is obtained as a result of the calcium carbonate content in the sludge being greater that 7 wt.%, in this example, 10 wt.%.
  • Example 14 is identical to Example 1 except the board has both vermiculite and aluminium hydroxide added as a fire retardant as opposed to only aluminium hydroxide.
  • the board produced has the properties defined in Table 3 and has the structure shown in Figure 6.
  • the board of Example 14 is produced by the process described in relation to Example 1 , except that vermiculite is added to the sludge and aluminium hydroxide is added to the OCC.
  • the sludge and the OCC are independently processed in Pulper P1 before the sludge containing the vermiculite and the OCC containing the aluminium hydroxide is then combined in Tank T3.
  • an upper outer region 112 of the board contains the vermiculite and a lower outer region 114 of the board contains aluminium hydroxide, due to vermiculite having a lower density than aluminium hydroxide, imparting Class B fire retardant classification on both the upper and lower outer regions ( Figure 6).
  • Example 15 is identical to Example 14 except that only OCC fibres are used.
  • the board produced has the structure shown in Figure 7.
  • both an upper outer region 212 and lower outer region 214 of the board contains aluminium hydroxide, imparting Class B fire retardant classification on both the upper and lower outer regions.
  • the board of Example 16 is produced by the process described below and is shown in Figure 8.
  • Example 16 The process to produce the board of Example 16 is identical to that described above in Example 15, except that different boards are processed and formed with different compositions and then glued together to form a layered structure comprising a middle layer 316 of enzymatically treated OCC fibres between the upper outer 312 and lower outer 314 layers of OCC fibres containing the aluminium hydroxide.
  • the upper outer layer 312 and lower outer layer 314 of the board contains aluminium hydroxide, imparting Class B fire retardant classification on both the upper and lower outer layers.
  • the dotted lines of Figures 6 and 7 represent regions where the fire retardant has migrated
  • the hard lines represent structural layers resulting from forming rigid boards having different compositions and then gluing those rigid boards to create the structural layers.
  • the middle layer between the upper outer layer and lower outer layer can contain industrial waste, for example sludge, or a combination of non-industrial waste in the form of OCC and industrial waste (not shown).
  • the upper and lower outer layers can comprise industrial waste, for example, sludge, with added vermiculite, with the middle layer comprising industrial and/or non-industrial waste (Figure 9).
  • the upper and lower outer layers can comprise nonindustrial waste, for example, OCC, with added aluminium hydroxide, with the middle layer comprising industrial and/or non-industrial waste (Figure 10).
  • Example 17 is identical to Example 14 ( Figure 6) except that the industrial waste cellulosic fibres are derived from primary sludge obtained from the textile production industry which does not contain calcium carbonate, and therefore the aluminium hydroxide can be added to the sludge as an alternative to the vermiculite. This contrasts to cellulosic fibres derived from primary sludge obtained from the paper production industry where aluminium hydroxide cannot be added to the calcium carbonate containing sludge. It will be understood that the region between the upper and lower regions can contain any combination of OCC and textile sludge, only OCC, or only sludge.
  • Example 18 is identical to Example 16 ( Figure 9) except that the industrial waste cellulosic fibres are derived from primary sludge obtained from the textile production industry which does not contain calcium carbonate, and therefore the aluminium hydroxide can be added to the sludge as an alternative to the vermiculite. This contrasts to cellulosic fibres derived from primary sludge obtained from the paper production industry where aluminium hydroxide cannot be added to the calcium carbonate containing sludge. It will be understood that the layer between the upper and lower layers can contain any combination of OCC and textile sludge, only OCC,
  • EXAMPLES 19 to 24 Examples 1 to 18 above, and the alternatives, describe a process in which the water content during the enzymatic treatment of the industrial and non-industrial waste cellulosic fibres is maintained above 80%.
  • the process is as described in relation to Examples 1 to 18 above, other than as presented in Table 4, notably, the process is a semi-dry process in which the water content is maintained between 20% and 80% (and therefore below 80%) by weight with respect to the total amount of cellulosic fibres during the enzymatic treatment of the industrial and non-industrial waste cellulosic fibres.
  • the boards produced have the properties defined in Table 4, in particular, a Class C fire rating is obtained as a result of the calcium carbonate content in the sludge being greater than 7 wt.%.
  • the industrial cellulosic fibres are derived from papermill sludge. In alternative examples, the industrial cellulosic fibres can be derived from textile or construction waste as described in relation to Examples 1 to 18.
  • Figure 13 corresponds to the rigid board of Figure 6, except that the aluminium hydroxide and the vermiculite are evenly distributed through the board due to the lower water content below 80% compared to the boards produced by the process in which the water content during the enzymatic treatment of the industrial and non-industrial waste cellulosic fibres remains above 80% and where more of the aluminium hydroxide migrates to the lower outer region and the vermiculite migrates to the upper outer region.
  • Figure 14 corresponds to the rigid board of Figure 7, except that the aluminium hydroxide is more evenly distributed through the board due to the lower water content below 80% compared to the boards produced by the process in which the water content during the enzymatic treatment of the industrial and non-industrial waste cellulosic fibres remains above 80% and where more of the aluminium hydroxide migrates to the lower outer region.
  • the rigid cellulosic boards can be formed in individual layers by depositing different compositions of raw material and fire retardants and the forming those different compositions to form a board with structural layers.
  • Examples of such layered rigid boards are shown in Figures 15 to 18 where, other than the lower water content during the enzymatic treatment and the depositing of individual layers in the forming unit, the composition of the individual layers is produced in the same way as described above in relation to Examples 1 to 18.
  • Figures 15 to 18 show examples of the various combinations of industrial (sludge) and non-industrial (OCC) layers with either aluminium hydroxide or vermiculite on one or both the upper and lower outer layers.
  • Figures 15 to 18 show an upper outer, middle and lower outer layer.
  • the middle layer may not be required, with the board comprising only an upper and lower outer layer.
  • the process shown in Figure 19 includes a stirrer 420 which integrates an enzyme applicator 410, a dryer 430 and a screener 440 integrated in a trommel screener.
  • Figure 20 shows a similar embodiment but further includes a product former 450 fed by a dosing device 461 ,462,463 after the screener 440.
  • a raw fibrous cellulosic material 401 is fed into the stirrer 420 where the same enzymes as described in relation to the wet process of Examples 1 to 18 are added and mixed therein by multiple active stirring elements 421 , producing the enzymatic treatment within the stirrer 420 for a specific period of time.
  • industrial waste for example sewage or primary sludge from the paper manufacturing or processing industry and/or non-industrial waste such as cardboard waste (OCC)
  • the active stirrer elements 421 are parallel rotative blades contained in the stirrer 420.
  • the enzyme applicator 410 comprises multiple spray nozzles contained in the stirrer 420, facing the upper surface of the raw fibrous cellulosic material 401 contained in the stirrer 420.
  • the spray nozzles are fed, with liquid enzymes, or with liquid water solutions of enzymes stored in separated deposits, it can also be fed with additional water.
  • a control unit 415 can regulate the amount of each enzyme added to the raw fibrous cellulosic material 401 , for example in response to a measurement of the specific composition of the raw fibrous cellulosic material 401 to be treated.
  • the water content of the raw fibrous cellulosic material 401 is between 20% and 80% to obtain a sufficient flowability for stirring the minimal water content.
  • the water contained in the added enzymes can be adjusted, or additional water can be added to the raw fibrous cellulosic material 401 , for example through the spray nozzles.
  • the flowability of the raw fibrous cellulosic material 401 and/or its water content is preferably measured or deduced from other measurements, for example from the energy consumption of the motor actuating the active stirring elements 421 , or by an analysis of a sample.
  • the control unit 415 can automatically adjust the composition of the enzymes added to the raw fibrous cellulosic material 401 , and/or the exact amount of water added to the raw fibrous cellulosic material 401 for example adding additional water, and/or operational parameters of the stirrer 420.
  • Said operational parameters can be, for example, the movement velocity of the active stirring elements 421 and/or a heater 423 which heats the raw fibrous cellulosic material 401 contained in the stirrer 420.
  • the stirrer 420 includes a stirrer inlet on its top for the introduction of the raw fibrous cellulosic material 401 , and a stirrer outlet 422 on the bottom for the extraction of the treated cellulosic material, which is then transferred to the dryer 430 and screener 440.
  • stirrer 420 can be a horizontal rotative hollow drum with the stirrer inlet on one end and the stirrer outlet 422 on the opposite end, wherein the active stirring elements are blades attached to the inner side of the walls of the rotative drum and are configured not only for stirring but also for pushing the raw fibrous cellulosic material through the stirrer 420 from the stirrer inlet to the stirrer outlet 422 spending the specified period of time within the stirrer 420.
  • This embodiment allows a continuous flow treatment process of the raw fibrous cellulosic material 401 in the stirrer 420.
  • the above mentioned trommel screener integrates the dryer 430 and the screener 440 and comprises a rotating horizontal hollow drum including multiple successive meshes integrated into the walls of the rotating horizontal hollow drum.
  • the enzymatically treated material with a water content comprised of between 20% and 80%, is introduced into the trommel screener through one end, and also air heated by a heater 431 is blown through the rotative horizontal hollow drum while the drum rotates, reducing the water content to produce a treated cellulosic material with a water content below 20%.
  • the successive meshes have increasingly larger sized holes for screening different fractions 402,403,404 of the dried treated cellulosic material with different fibre lengths.
  • Those fractions 402,403,404 due to their water content being lower than 20%, can be stored for future use in a simple manner, or can be used immediately.
  • One proposed use of the dried and treated cellulosic material is the production of a rigid cellulosic product, or more preferably a stratified or structural layered rigid cellulosic product 409 made of overlapped layers 405, 406, 407 of different fractions or layers 402,403,404 in a product former 460.
  • the product former 460 comprises a conveyor belt passing between two opposed compression drums.
  • the first application head 461 deposits a front layer 405 of a controlled thickness of the layered rigid cellulosic product 409 to be produced on the conveyor belt, the layer being made of a fraction 402 of the dried treated cellulosic material 402,403,404.
  • Successive application heads 462,463 deposit additional layers 406,407 of controlled thicknesses of the layered rigid cellulosic product 409 to be produced on top of the front layer 405.
  • the layers are compressed and heated by the compression drums, producing the stratified rigid cellulosic product 409, in this case a flat and rigid board.
  • More complex shapes can be obtained by using a mould or a press as a product former 450. In those cases, the mould, the press, or the application heads 461 ,462,463 can be moved in a controlled manner to produce a deposit of the overlapped layers covering the entire surface of the mould, previous to the closing of the mould and the application of the pressure and heat.
  • One or several of the fractions 402,403,404 can be mixed with an additive such as a fire retardant as described above in relation to Examples 1 to 24, to provide specific layers with improved fire retardancy.
  • an additive such as a fire retardant as described above in relation to Examples 1 to 24, to provide specific layers with improved fire retardancy.
  • different layers can have different fire retardants, or layers, for example, middle layers can have no fire retardants.
  • Examples of such boards that can be produced are identical to those shown in Figures 15 to 18.
  • the above examples describe boards with combinations of industrial and non-industrial waste, such as waste cardboard and different industrial sources of sludge, as well as examples of only a single fibre source such as waste cardboard or different industrial sources of sludge.
  • the board can have combinations of industrial waste only, for example, a mixture of paper sludge and textile sludge.
  • the final thickness of the rigid board is 12mm.
  • the final thickness can be varied between 3 and 22mm by varying the weight of the solids content introduced into the forming unit. It will be understood that different thickness boards will require different drying regimes.
  • the process is not continuous, specifically, transfer of the partially wet board from the forming unit to the transfer unit, and then to the drying tunnel and the hot plates press are manual processes.
  • the process from initial pulping through to the drying of the board can be a continuous process.
  • the raw fibrous industrial and non-industrial waste cellulosic material is pulped prior to being enzymatically treated, formed and dried.
  • either or both of the raw fibrous industrial and non-industrial waste cellulosic material waste may not require a separate pulping step prior to enzymatic treatment, and can be supplied as already pulped fibres.
  • Such a supply can be the direct output from a non-industrial plant, for example, a pulped output from a waste cardboard production plant, and/or a direct output from an industrial plant, preferably a pulped output from a paper production plant.
  • Such a supply can be a direct feed from the industrial and non-industrial plants, in which case a plant which integrates a paper and/or cardboard production plant with the process for producing a rigid cellulosic product is envisaged.
  • the plants need not be integrated, and the pulped output can be stored before being fed or transferred to the process for producing rigid cellulosic product.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Microbiology (AREA)
  • Processing Of Solid Wastes (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)

Abstract

Procédé de production d'un produit cellulosique rigide à partir de déchets industriels fibreux bruts comprenant les étapes consistant (a) à fournir ou produire des fibres cellulosiques de déchets industriels réduits en pâte dérivées de déchets industriels fibreux bruts, (b) à traiter par voie enzymatique les fibres cellulosiques de déchets industriels réduits en pâte pour produire des fibres cellulosiques de déchets industriels traitées par voie enzymatique, (c) à compresser les fibres cellulosiques de déchets industriels traitées par voie enzymatique pour produire des fibres compressées, et (d) à sécher les fibres compressées pour former un produit cellulosique rigide.
PCT/EP2024/055536 2023-03-03 2024-03-04 Procédé de production d'un produit cellulosique rigide Pending WO2024184288A1 (fr)

Priority Applications (4)

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KR1020257033581A KR20250156807A (ko) 2023-03-03 2024-03-04 강성 셀룰로스 제품을 제조하는 공정
AU2024233343A AU2024233343A1 (en) 2023-03-03 2024-03-04 Process for producing rigid cellulosic product
CN202480015527.3A CN121039342A (zh) 2023-03-03 2024-03-04 生产硬质纤维素产品的方法
MX2025010258A MX2025010258A (es) 2023-03-03 2025-08-29 Proceso para producir un producto celulosico rigido

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP23382203.0 2023-03-03
EP23382203 2023-03-03
EPPCT/EP2023/086449 2023-12-18
PCT/EP2023/086449 WO2024126871A1 (fr) 2022-12-16 2023-12-18 Procédé de production d'un produit cellulosique rigide

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WO2024184288A1 true WO2024184288A1 (fr) 2024-09-12

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KR (1) KR20250156807A (fr)
CN (1) CN121039342A (fr)
AU (1) AU2024233343A1 (fr)
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WO (1) WO2024184288A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2386681A1 (fr) * 2010-05-14 2011-11-16 Universitat Politècnica de Catalunya Procédé de recyclage de vieux papiers, produit ainsi obtenu et ses utilisations
WO2013090272A1 (fr) * 2011-12-12 2013-06-20 Enzymatic Deinking Technologies, L.L.C. Prétraitement enzymatique de pâte commercialisée pour améliorer l'égouttement de fibres et les propriétés physiques de fibres

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2386681A1 (fr) * 2010-05-14 2011-11-16 Universitat Politècnica de Catalunya Procédé de recyclage de vieux papiers, produit ainsi obtenu et ses utilisations
WO2013090272A1 (fr) * 2011-12-12 2013-06-20 Enzymatic Deinking Technologies, L.L.C. Prétraitement enzymatique de pâte commercialisée pour améliorer l'égouttement de fibres et les propriétés physiques de fibres

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KR20250156807A (ko) 2025-11-03
CN121039342A (zh) 2025-11-28
MX2025010258A (es) 2025-12-01
AU2024233343A1 (en) 2025-10-16

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