US3895997A - Production of shaped articles from paper sludge - Google Patents

Production of shaped articles from paper sludge Download PDF

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US3895997A
US3895997A US27327972A US3895997A US 3895997 A US3895997 A US 3895997A US 27327972 A US27327972 A US 27327972A US 3895997 A US3895997 A US 3895997A
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layer
process according
slurry
agglomerated
water content
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George Robert Haywood
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National Research Development Corp UK
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National Research Development Corp UK
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B7/00—Combinations of wet processes or apparatus with other processes or apparatus, e.g. for dressing ores or garbage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/20—Agglomeration, binding or encapsulation of solid waste
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
    • B27N3/08—Moulding or pressing
    • B27N3/28—Moulding or pressing characterised by using extrusion presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/0026—Recovery of plastics or other constituents of waste material containing plastics by agglomeration or compacting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0011—Combinations of extrusion moulding with other shaping operations combined with compression moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0017—Combinations of extrusion moulding with other shaping operations combined with blow-moulding or thermoforming
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0019—Combinations of extrusion moulding with other shaping operations combined with shaping by flattening, folding or bending
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0021—Combinations of extrusion moulding with other shaping operations combined with joining, lining or laminating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0022—Combinations of extrusion moulding with other shaping operations combined with cutting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S162/00—Paper making and fiber liberation
    • Y10S162/09—Uses for paper making sludge

Definitions

  • PATENTED L 2 2 I975 SHEET PRODUCTION OF SHAPED ARTICLES FROM PAPER SLUD'GE This invention relates to a process for the production of shaped articles, and is more particularly concerned with the production of shaped articles from industrial waste materials.
  • a variety of industrial waste materials comprise either fibrous or mineral materials, and in many cases mixtures of both.
  • industrial waste materials include those obtained in paper manufacture, asbestos slurry wastes, food wastes such as coffee waste, tobacco waste and various quarry and mineral wastes. The disposal of these materials represents a serious environmental problem which is increasingly becoming one of national concern.
  • the present invention provides a process for the production of shaped articles which may be broadly applied to a variety of industrial waste materials.
  • a process for the production of a shaped article from fibrous and mineral industrial waste materials comprises depositing a layer of an aqueous slurry comprising a mixture of a fibrous component and a mineral component and controlling the water content of the slurry so as to produce a coherent agglomerated layer having a degree of wet strength, and then forming the layer under pressure and drying to produce a shaped article.
  • the invention also comprises an apparatus for the production of shaped articles from fibrous and mineral industrial waste materials comprising means for depositing a layer of an aqueous slurry comprising a mixture of a fibrous component and a mineral component, means for controlling the water content of the slurry so as in operation to produce a coherent agglomerated layer having a degree of wet strength, and means for forming the coherent agglomerated layer under pressure, and for drying the layer so formed.
  • an aqueous slurry comprising a mixture of a fibrous component and a mineral component is deposited on to a liquid permeable support to form a layer, and the water content of the slurry is controlled by applied pressure and/or drying so as to produce a coherent agglomerated layer having a degree of wet strength.
  • the layer may then be moulded under the action of heat and pressure to produce a shaped article.
  • the invention may be applied to a wide variety of industrial waste materials and also to mixtures thereof.
  • the fibrous component of the mixture may be organic, for example cellulose fibres derived from waste paper, waste chopped rags, sisal, jute or hessian or synthetic resin fibres for example nylon, terylene or polypropylene fibres; or inorganic for example asbestos fibres or glass fibres.
  • the mineral component may be a clay, for
  • the invention is particularly applicable to the treatment of paper sludge which is an aqueous slurry comprising a mixture of cellulose fibres of short fibre length, and minerals such as clay, chalk or calcium carbonate, titanium dioxide and antimony trioxide.
  • paper sludge which is an aqueous slurry comprising a mixture of cellulose fibres of short fibre length, and minerals such as clay, chalk or calcium carbonate, titanium dioxide and antimony trioxide.
  • the invention may also be applied to asbestos slurry waste, food wastes, tobacco waste and quarry and mineral wastes as previously mentioned.
  • shredded waste paper may be mixed with a suitable waste mineral material such as micaceous china clay or fine granite dust and water to form a useful aqueous slurry.
  • aqueous slurry it is of course necessary for the aqueous slurry to contain sufficient quantities of solids to enable it to be agglomerated. Simple tests can be made first on filterability and on solids content and from these tests it can be determined what particular procedure in accordance with the invention can be employed and also whether or not the application of the process of the invention to the particular waste material is commercially practicable.
  • slurries containing fibres having an average fibre length outside the range of l/l6th of an inch to 5 inches The nature of the slurry itself determines the particular method of treatment which it is necessary to apply, and addition of further fibrous material or mineral material may be made as desired to give a slurry of the required consistency.
  • slurries containing a relatively large amount of fibrous material frequently require no further additions, but slurries with a very high mineral content for example certain kinds of paper sludge do however appear to require the addition of extra fibrous material or the like to assist in agglomeration of the slurry and to obtain satisfactory products.
  • the fibrous component preferably comprises from 5 to 95% by weight particularly from 20 to by weight and the mineral component preferably comprises from to 5% by weight particularly from 80 to 20% by weight.
  • the aqueous slurry is preferably deposited upon a liquid permeable support to form a layer, the solid materials remaining on the support whilst the excess water is allowed to drain off.
  • the slurry may be deposited from a hopper, or preferably an extruder having means for discharging the slurry at a predetermined rate.
  • the liquid permeable support may be a mesh or gauze of metal or plastic material, for example stainless steel mesh or nylon mesh and is preferably movable relative to the discharge orifice of the hopper or extruder.
  • the liquid permeable support may be in the form of an endless moving belt of metal or plastic mesh or gauze.
  • the slurry may be passed through an extruder equipped with means for removing part of the water content of the slurry prior to deposition of the layer, so that the layer of slurry leaving the extruder is of the desired composition.
  • the liquid permeable support carrying the depos ited slurry is passed through a series of pressure rolls producing a plurality of nip actions which progressively squeeze out water from the deposited slurry and control its thickness to produce a coherent agglomerated layer of the desired water content and strength.
  • the water content and thickness of the deposited layer may be controlled by varying the pressure applied by the pressure rolls and by nip setting adjustment.
  • the pressure rolls may be arranged above the deposited layer so as to squeeze the layer between the rolls and the liquid permeable support, or alternatively the rolls may be arranged in pairs above and below the deposited layer.
  • a cylindrical vacuum filter which is partly immersed in the slurry and rotated so as to deposit a layer of slurry on its circumference.
  • the layer of agglomerated slurry may be removed from the filter in a continuous operation, for example with a take-off knife.
  • the above treatments for reducing the water content of the layer by applied pressure usually produce a layer having a water content of about 45% by weight, i.e. having a solids content of substantially 55% by weight.
  • a drying operation is performed to reduce the water content of the layer to a preferred value.
  • the drying operation may merely consist of cutting the layer into sheets of the desired length and stacking them to dry.
  • the layer is passed through a drying oven to produce an agglomerated layer of the desired water content. The layer should not be completely dried since this will impair the subsequent forming operation.
  • the water content of the slurry is controlled so as to produce a coherent agglomerated layer having a degree of wet strength.
  • the degree of wet strength required of the layer is such that it can be formed under pressure without tearing, and such that it is sufficiently selfsupporting to enable it to be handled without disintegration.
  • the layer should, for example, preferably be able to withstand bending to an angle of 90 without cracking.
  • the layer should be capable of supporting its own weight to such an extent that an 8 foot X 4 foot section will maintain its integrity with minimal support over each 2 feet of its running length and such that an area of at least about 4 square feet will maintain its integrity when supported only at its edges.
  • the wet strength of the agglomerated layer is dependent upon its thickness, density and water content, but it has been found in practice that the desired thickness and density can be attained by an appropriate choice of the method of controlling the water content. Thus if pressure is applied to the deposited layer of slurry, the
  • the water content of the coherent agglomerated layer of slurry may vary from less than 15 to about 85% by weight, based on the total weight of the layer.
  • the agglomerated layer may be used to form flat products and simple mouldings as described later.
  • the water content of the layer should be somewhat higher, for example around 40 to 85% by weight, particularly from 50 to by weight. [n this condition the layer still surprisingly can possess the wet strength required to permit it to be handled without disintegration.
  • the thickness of the agglomerated layer is dependent upon the thickness of the final shaped article and the forming process, but it is usually greater than onesixteenth inch in order to obtain an agglomerated layer having adequate wet strength. Preferably the thickness of the layer is from one-eighth to one-half inch.
  • the process of the invention may also be modified to obtain shaped articles of greater thickness.
  • a plurality of agglomerated layers may be formed and superimposed one on the other. These are then laminated between pressure rollers to obtain a multiple thickness, or slightly less because of slight spread under lamination pressure.
  • a single agglomerated layer is first formed in the usual way and this is then followed by depositing a further layer of aqueous slurry on to the first layer by means of one or more hoppers or extruders situated after the first series of pressure rolls.
  • the composite layer is then passed through further pressure rolls to obtain a laminated coherent agglomerated layer.
  • the density of the agglomerated layer is dependent upon the density required in the final shaped article and the forming process, but is usually from 0.8 to 2.0
  • the coherent agglomerated layer is finally formed under pressure and dried to produce the desired shaped article.
  • the forming operation may comprise passing the layer through pressure rolls to give a board product, or moulding the layer to produce a moulded article.
  • the forming and drying operations are carried out together, and for example the layer may be moulded under heat and pressure. Pressures varying from a few pounds per square inch to several tons per square inch may be used in the forming operation, depending on the desired physical properties of the final shaped article. For boards, pressures of up to 2,400 pounds per square inch have been found to give useful products, whilst for moulded articles rather higher pressures are usually required, preferably from 50 pounds per square inch to 2 tons per square inch.
  • the process of the invention may be used to manufacture various shaped articles: a. Insulation fibre board This is obtained by lightly pressing an agglomerated layer of relatively low water content, say from to 30% by weight to yield a low-density board which has sound insulation properties, comparable with those of existing commercial insulating board. b. Hardboard-type board An agglomerated layer or layers are pressed at a pressure of substantially one-half ton per square inch and subjected at the same time to heating at a temperature of substantially 150C, to obtain a consolidated product similar to hardboard and with similar properties.
  • This hardboard can be laminated to the usual surface finishes including wallpaper, self-adhesive vinyl film or paper of the kind common in home decoration.
  • the layer or board may be sprayed with resin solution on one or both sides to obtain a resin-rich surface of improved finish.
  • Decorative formica"-type board product This product is obtained by direct lamination of an agglomerated layer or layers with melamine printed surface papers and phenolic underlay. Pressures of up to one half of a ton per square inch and temperatures of 1 10 to 170C may be used depending on the density required in the core of the laminate.
  • Packaging board If the agglomerated layer is lightly pressed or rolled, the resulting sheet is suitable for various types of packaging materials and for box making.
  • the material can be hinged at that point to form a right-angled joint and a complete box can be made by forming the necessary joints in this way. Boxes with a fair degree of strength can also be made by using the hardboard-type board (b) and treating it in the same manner.
  • Moulded decorative products are an extension of the decorative formica type product. A radiused or ribbed mould may be used and the product takes on the shape of the mould together with a decorative effect. The board may lso be embossed. This cannot be done with usual formica as such materials are not mouldable in commercial form.
  • Examples of articles which can be produced include moulded chair seats and glove box compartments.
  • moulded articles without a decorative finish can also be produced for particular applications, for example pallets can be produced with a high load bearing capacity.
  • Construction sheets and boards An agglomerated layer or layers pressed at a pressure of about one-fourth ton per square inch and at a temperature of 165 to give products resembling plasterboard or asbestos board. Products resembling stone or slate can also be produced by an appropriate choice of composition. These are more fully described in British Pat. No. 23462/72.
  • a variety of additives may be incorporated into the slurry to improve the properties of the final shaped articles.
  • These include synthetic resins which may be thermoplastic, for example styrene/butadiene resins, acrylic resins, vinyl acetate resins and vinyl chloride resins; or thermosetting, for example phenolformaldehyde resins, melamine formaldehyde resins and urea formaldehyde resins.
  • the resins are preferably mixed with the slurry in liquid form, for example as an emulsion or suspension in water, and precipitated by the addition of a precipitating agent such as alum.
  • the resin content of the slurry may be from 5 to 40% by weight.
  • thermoplastic boards may be obtained which can be stamped out to shape after being plasticized by heating.
  • a similar result can be obtained with phenol-formaldehyde resin containing formulations but a cure-time dwell is then needed.
  • a preferred resin content of the slurry is then 10 to 40% by weight.
  • a fu rther group of useful additives are flame-retardants, particularly in the production of boards and sections for the building industry. Suitable flame retardants include borates, boric acid, monoammonium phosphate, alumi num hydroxide and other commercially available flame retardant materials. Excellent results have been obtained using levels of up to about 8% by weight of the flame retardant.
  • the agglomerated layer may contain a reinforcing medium.
  • a layer of reinforcing fibres such as glass fibres may be deposited upon the agglomerated layer if desired and a light rolling action imparted to the layer to embed the fibres therein.
  • Al ternatively reinforcing fibrous layers or matts may be laminated on to one or both surfaces of the agglomerated layer or deposited layer of slurry. Suitable reinforcing layers include woven hessian backing or glass fibre matts.
  • the reinforcing medium may be sandwiched between two agglomerated layers and the whole laminate integrated by passage through pressure rolls.
  • slurry mineral fillers for example silica, quartz or limestone in finely divided form, or pulverised fuel ash. This leads to harder, denser, more fire resistant products.
  • I. Dickinson Croxley Mill fibre from 20 to 30% and clay from 80 to 70% by weight.
  • Bowater Thames Mill fibre from 40 to 70% by weight and clay from 60 to 30% by weight.
  • Bowater Mersey Mill fibre from 66.6 to 50% by weight and clay from 33.3 to 50% by weight.
  • Bowater Sittingbourne substantially the same as in the case of Bowater Mersey Mill.
  • Bowater Kelmsley Mill fibre substantially 84% by weight and clay substantially 16% by weight. The material was mainly from hardboard making.
  • Paper sludge from each individual mill is concentrated and if necessary further fibre or mineral material added.
  • Concentrated Sludge from Reeds Mill Waste paper sludge concentrated to l% by weight CL-lSl/76 is a 76% solids phenolic resin produced by Sterling Moulding Materials Ltd.
  • Both the above formulations contain added fibres in the form of chopped rags. However, it is not always necessary to add fibres and for example in the case of the Bowater Kelmsley Slurry (5 it is usually necessary to add a quantity of clay or other minerals to the slurry.
  • FIG. 1 shows a flow line for the apparatus from the sludge reservoir through filtering, mixing, the conveyor, dopple roller and pressure rollers to cutting and pressing,
  • FIG. 2 shows a fiow line of an alternative layout using extrusion, ovens and a multi-daylight press
  • FIG. 3 shows dewatering of the slurry between top and bottom belts moving between fixed plates and conveying on one another
  • FIG. 4 shows an alternative arrangement to FIG. 3 in which the plates are replaced by an array of pressure rolls acting on the belts from the outside.
  • the apparatus comprises a container for paper sludge which discharges into a rotary vacuum filter in which the sludge is concentrated to a solids content of from 7% to 30% by weight. From the filter the concentrated sludge is passed to a mixer such as a Gardner Ribbon, Baker-Perkins dough type mixer or alternatively a Hobart dough mixer. In the mixer the various additives such as the phenolic resin are mixed with the sludge and the resulting slurry is then pumped to a storage bin which acts as a feed reservoir for the board manufacturing unit. From the storage bin the slurry is deposited on to a vibrating conveyor in the form of a continuous layer.
  • a mixer such as a Gardner Ribbon, Baker-Perkins dough type mixer or alternatively a Hobart dough mixer.
  • the various additives such as the phenolic resin are mixed with the sludge and the resulting slurry is then pumped to a storage bin which acts as a feed reservoir for the board manufacturing unit. From the storage bin the slurry is
  • the layer of slurry carried on the belt of the vibrating conveyor is then passed through a dopple roller and then through a dewatering device.
  • the dewatering device may comprise a pair of fixed plates forming a continuous nip as illustrated in FIG. 3 in which the slurry is conveyed between top and bottom belts thereby squeezing out excess water from the layer of slurry.
  • the dewatering device may comprise a series of pressure rolls as illustrated in FIG. 4, the layer of slurry again being conveyed through the rolls by top and bottom belts.
  • the nip action of the dewatering device is arranged to be such that the agglomerated layer of slurry leaving the device has the desired thickness, density, and water content.
  • the agglomerated layer of slurry is then cut into boards and stacked to dry. Finally the boards are pressed to form the desired shaped articles and sent for despatch.
  • FIG. 2 An alternative embodiment is shown in FIG. 2 in which after mixing of the additives with the paper sludge, the slurry is fed to an extruder feeding mechanism which deposits a predetermined amount of the mixture in the form of a continuous layer which is then conveyed to the dewatering device.
  • the dewatering device reduces the water content of the layer, and when the layer emerges from the device its water content is substantially 45% by weight, ie it has a solids content of substantially 55% by weight.
  • the agglomerated layer is then passed to a drying oven where it is dried to an extent sufficient to lower the moisture content to around 15% by weight or less depending upon the properties required of the final shaped article.
  • the continuous agglomerated layer emerging from the oven is then cut into boards and stored for pressing. Finally the boards are pressed in a multi-daylight press and sent for dispatch.
  • Example I Analyses of a variety of paper sludge effluents from commercial paper mills are given in Example I. These effluents are processed in the apparatus shown diagrammatically in section in FIG. 5 of the accompanying drawings.
  • the apparatus comprises a slurry hopper I, provided with an agitator 2, mounted upon and communicating with a screw extruder 3.
  • the extruder has a slit diehead 4 which discharges on to the top surface of an endless stainless steel mesh belt 5.
  • the belt is carried on driven rollers 6 and passes beneath chain driven pressure rolls 7. Water squeezed out of the slurry by the pressure rolls is pumped to a large header tank (not shown) from which any subsequent water demands of the process may be met, or returned to filtration equipment to remove any solids content.
  • the endless belt is provided with cleaning water sprays 8 and rotary brushes 9 on its lower surface.
  • a take-off conveyor 10 adjacent the endless belt leads to pairs of nip rolls 1 I and 12 positioned on either side of an automatic cutter 13.
  • a series of conveying rollers 14 leads to a power operated loader 15 which feeds a multi-platen daylight press 16.
  • Each platen of the press has a high surface finish and is labyrinth drilled to ensure even heat distribution.
  • An unloader 17 receives boards from the press, and the boards are then transferred to an automatic stacking machine 18.
  • sludge from the hopper l is metered into the screw extruder 3 at a predetermined rate and emerges from the slit diehead 4 as a continuous layer of slurry which is deposited on the endless belt 5.
  • the belt carrying the layer of slurry passes beneath the pressure rolls 7 and water is squeezed out from the layer.
  • the progressive action of the pressure rolls is variable and enables the water content of the layer to be reduced to the desired value.
  • the action of the rolls controls the thickness and density of the layer.
  • the layer leaves the endless belt and is passed by the conveyor 10 to the nip rolls 1!.
  • the cutter 13 automatically cuts the layer into boards of the desired length which are removed by the nip rolls l2 and conveyed by the conveying rollers 14 into the loader 15.
  • the loader inserts the boards into the press 16 where they are heated to a temperature of 160C and subjected to a pressure of 525 lbs. per square inch.
  • the dwell time in the press is of the order of l minutes. From the press the unloader l7 removes the boards which are then stacked by the automatic stacking machine 18.
  • Compositions 3, 4 and 5 have been found to give boards having an excellent degree of flame retardance.
  • a process for the production of a shaped article from paper sludge which comprises depositing a layer of an aqueous slurry of said sludge, controlling the water content of the layer by applied pressure and drying so as to produce a coherent agglomerated layer having a degree of wet strength and a water content of from about to 30% by weight based on the total weight of the layer and then forming the layer under pressure with drying to produce a shaped article.
  • liquid permeable support comprises an endless moving belt of metal or plastic mesh or gauze.
  • the synthetic resin is a styrene/butadiene resin, an acrylic resin, a vinyl acetate resin, a vinyl chloride resin, a phenol formaldehyde resin, a melamine formaldehyde resin, or a urea formaldehyde resin.
  • a pressure-formable coherent agglomerated layer of paper sludge having a thickness greater than one-sixteenth of an inch, a density of from 0.8 to 2.0 grams per cubic centimeter and a water content of from to 30% by weight based on the total weight of the layer, the layer being sufficiently self-supporting to enable it to be handled without disintegration.
  • a layer according to claim 30 having a wet strength sufficient to withstand bending to an angle of without cracking.
  • a layer according to claim 30 having a wet strength such that an 8 feet by 4 feet section will maintain its integrity with minimal support over each 2 feet of its running length and such that an area of at least 4 square feet will maintain its integrity when supported only at its edges.
  • a layer according to claim 30 having a thickness of from one-eighth to one-half inch.
  • a laminate comprising a plurality of layers according to claim 30.
  • a process for the production of a pressureformable coherent agglomerated layer which comprises depositing a layer of an aqueous slurry of paper sludge and controlling the water content of the slurry with applied pressure and drying so as to produce a coherent agglomerated layer having a thickness greater than one-sixteenth of an inch, a density of from 0.8 to 2.0 grams per cubic centimeter, and a water content of from l5 to 30% by weight based on the total weight of the layer, the layer being sufficiently self-supporting to enable it to be handled without disintegration.

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  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Paper (AREA)
  • Laminated Bodies (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
US27327972 1971-07-21 1972-07-19 Production of shaped articles from paper sludge Expired - Lifetime US3895997A (en)

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GB3424371 1971-07-21
GB581772A GB1405587A (en) 1971-07-21 1972-02-08 Production of shaped articles

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DE (1) DE2235975A1 (it)
ES (1) ES405055A1 (it)
FR (1) FR2146883A5 (it)
GB (1) GB1405587A (it)
IT (1) IT961467B (it)

Cited By (31)

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US4032393A (en) * 1976-04-05 1977-06-28 The Upson Company Fire retardant webs and internal treatment therefor
US4076871A (en) * 1976-11-02 1978-02-28 Masonite Corporation Method of impregnating wood with boric acid
US4190492A (en) * 1977-12-21 1980-02-26 Armstrong Cork Company Method of producing acoustical fiberboard
US4256491A (en) * 1977-09-01 1981-03-17 Champion International Corporation Waterproofing composition and method of making the same
US4292188A (en) * 1979-06-01 1981-09-29 Martin Marietta Corporation Non-abrasive bauxite-based fire retardant
US4377440A (en) * 1978-05-25 1983-03-22 Stein Gasland Process for manufacturing of formed products
JPS58183753A (ja) * 1982-04-09 1983-10-27 パペトウリ−・ドウ・ジヤンドウ−ル・ソシエテ・アノニム 産業廃棄物，特に製紙スラツジを含む塗装，絶縁及び包装用の新規な生成物並びにそれを得るための方法
US4486234A (en) * 1981-03-20 1984-12-04 Herr Alfons K Fiber material
US4562218A (en) * 1982-09-30 1985-12-31 Armstrong World Industries, Inc. Formable pulp compositions
US4812204A (en) * 1987-07-24 1989-03-14 Ceram-Sna, Inc. Process for obtaining boric acid treated asbestos fiber
US5360586A (en) * 1992-11-06 1994-11-01 Danny R. Wyatt Biodegradable cellulosic material and process for making such material
US5460085A (en) * 1990-03-05 1995-10-24 Roberto Cappellari Process for compacting waste materials
US5496441A (en) * 1993-05-26 1996-03-05 Tran Industrial Research Inc. Utilization of deinking by-product in building materials
US5582682A (en) * 1988-12-28 1996-12-10 Ferretti; Arthur Process and a composition for making cellulosic composites
US5795377A (en) * 1997-04-08 1998-08-18 Kimberly-Clark Worldwide, Inc. Method for modifying papermaking sludge and products made from modified papermaking sludge
US6146498A (en) * 1997-04-30 2000-11-14 Kimberly-Clark Worldwide, Inc. Wound product cores and processes for making them
US6572736B2 (en) * 2000-10-10 2003-06-03 Atlas Roofing Corporation Non-woven web made with untreated clarifier sludge
US6852386B2 (en) * 2001-03-08 2005-02-08 Norbord Inc. Composite board with OSB faces
US20080179775A1 (en) * 2007-01-31 2008-07-31 Usg Interiors, Inc. Transfer Plate Useful in the Manufacture of Panel and Board Products
WO2008092807A1 (en) * 2007-02-01 2008-08-07 Macber S.R.L. Process for manufacturing panels for constructing articles of furniture such as cupboards, modular kitchens and furniture items in general, and panel obtained by the process.
US20090000752A1 (en) * 2007-06-28 2009-01-01 Buckman Laboratories International, Inc. Use of Cyclodextrins For Odor Control In Papermaking Sludges, and Deodorized Sludge and Products
US20090173464A1 (en) * 2008-01-04 2009-07-09 Usg Interiors, Inc. Acoustic ceiling tiles made with paper processing waste
ITUD20110142A1 (it) * 2011-09-13 2013-03-14 Roberta Bas Pannello per uso arredamento intermedia tra mdf e truciolare
US20130212970A1 (en) * 2008-09-04 2013-08-22 Frank Santoro Products made from recycled cardboard
WO2014012756A3 (en) * 2012-06-27 2014-04-03 Jentschura, Rolf Synthetic spongy wood boards
US20150020986A1 (en) * 2013-07-18 2015-01-22 Mario Lessard Paper-Based Malleable Dough for Moulding and Sculpting Applications
CN104385429A (zh) * 2014-11-26 2015-03-04 武汉亿维登科技发展有限公司 真空加热铺装机
EP2993203A1 (en) * 2014-09-05 2016-03-09 UPM-Kymmene Corporation Composite material
US9908982B2 (en) 2014-09-05 2018-03-06 Upm-Kymmene Corporation Composite material
CN108214804A (zh) * 2017-12-02 2018-06-29 张英华 玻璃丝或玻璃纤维与植物纤维的混合物模压生产设备
CN110893638A (zh) * 2018-09-12 2020-03-20 上海昶法新材料有限公司 一种环保型密度板及其制作方法

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US4110281A (en) 1974-02-15 1978-08-29 Gottfried Dreer Process for the manufacture of fillers from solid waste
CH654226A5 (de) * 1981-09-18 1986-02-14 Folli Beteiligungsanstalt Verfahren zur verarbeitung von muell und muellbestandteilen.
LU83899A1 (fr) * 1982-01-26 1983-09-02 Terre Asbl Panneau isolant
WO1988007105A1 (en) * 1987-03-10 1988-09-22 Innofinance Általános Innovációs Pénzintézet Process for treating fibre materials
IT1238836B (it) * 1990-03-05 1993-09-03 Roberto Cappellari Procedimento per la compattazione di materiali di rifiuto urbano, industriale o simili e impianto per l'attuazione del procedimento
GB9016073D0 (en) * 1990-07-21 1990-09-05 Aston Packaging Ltd Pulp moulding tool
DK169925B1 (da) * 1993-02-23 1995-04-03 Dacompa As Fremgangsmåde og anlæg til fremstilling af formet emne og formet emne
JP2005530056A (ja) * 2002-06-21 2005-10-06 メタニテ・アクティーゼルスカブ 繊維状廃棄物から成形品を製造する設備およびそれを使用する方法
ES2229914B2 (es) * 2003-07-03 2007-03-16 Josep Grau Almirall Procedimiento de inertizacion de residuos inorganicos.
GB2444913B (en) * 2006-09-20 2009-08-19 Procurasell Internat Packaging Method and apparatus for manufacturing a food packaging container

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US2114300A (en) * 1938-04-19 Molding composition and process of
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US2690393A (en) * 1950-06-24 1954-09-28 Armstrong Cork Co Method of producing fire-resistant insulation
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US3438847A (en) * 1965-02-26 1969-04-15 Weyerhaeuser Co Process of treating composite boards with borate chemicals produced thereby and product
US3510394A (en) * 1965-01-25 1970-05-05 Conwed Corp Production of water-laid felted mineral fiber panels including use of flocculating agent
US3576710A (en) * 1969-07-28 1971-04-27 Cons Paper Inc Brightening of white water sludge

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US2114300A (en) * 1938-04-19 Molding composition and process of
US1748224A (en) * 1926-07-17 1930-02-25 James J Hinde Apparatus for manufacturing fiber board or analogous material
US2007551A (en) * 1933-01-31 1935-07-09 John D Tompkins Method of and apparatus for making paper board
US2173391A (en) * 1935-11-27 1939-09-19 Insulite Co Process of manufacturing fibrous products
US2441169A (en) * 1943-06-19 1948-05-11 Roman Charles Machine for forming artificial board
US2648262A (en) * 1948-09-03 1953-08-11 American Mfg Company Inc Fibrous material extrusion apparatus
US2690393A (en) * 1950-06-24 1954-09-28 Armstrong Cork Co Method of producing fire-resistant insulation
US2639242A (en) * 1950-08-14 1953-05-19 American Cyanamid Co Acid-resistant wet strength paper
US2699389A (en) * 1951-07-26 1955-01-11 Mosinee Paper Mills Company Reinforced paper and method of making same
US3510394A (en) * 1965-01-25 1970-05-05 Conwed Corp Production of water-laid felted mineral fiber panels including use of flocculating agent
US3438847A (en) * 1965-02-26 1969-04-15 Weyerhaeuser Co Process of treating composite boards with borate chemicals produced thereby and product
US3576710A (en) * 1969-07-28 1971-04-27 Cons Paper Inc Brightening of white water sludge

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4032393A (en) * 1976-04-05 1977-06-28 The Upson Company Fire retardant webs and internal treatment therefor
US4076871A (en) * 1976-11-02 1978-02-28 Masonite Corporation Method of impregnating wood with boric acid
US4256491A (en) * 1977-09-01 1981-03-17 Champion International Corporation Waterproofing composition and method of making the same
US4190492A (en) * 1977-12-21 1980-02-26 Armstrong Cork Company Method of producing acoustical fiberboard
US4377440A (en) * 1978-05-25 1983-03-22 Stein Gasland Process for manufacturing of formed products
US4292188A (en) * 1979-06-01 1981-09-29 Martin Marietta Corporation Non-abrasive bauxite-based fire retardant
US4486234A (en) * 1981-03-20 1984-12-04 Herr Alfons K Fiber material
JPS58183753A (ja) * 1982-04-09 1983-10-27 パペトウリ−・ドウ・ジヤンドウ−ル・ソシエテ・アノニム 産業廃棄物，特に製紙スラツジを含む塗装，絶縁及び包装用の新規な生成物並びにそれを得るための方法
US4562218A (en) * 1982-09-30 1985-12-31 Armstrong World Industries, Inc. Formable pulp compositions
US4812204A (en) * 1987-07-24 1989-03-14 Ceram-Sna, Inc. Process for obtaining boric acid treated asbestos fiber
US5582682A (en) * 1988-12-28 1996-12-10 Ferretti; Arthur Process and a composition for making cellulosic composites
US5460085A (en) * 1990-03-05 1995-10-24 Roberto Cappellari Process for compacting waste materials
US5360586A (en) * 1992-11-06 1994-11-01 Danny R. Wyatt Biodegradable cellulosic material and process for making such material
US5496441A (en) * 1993-05-26 1996-03-05 Tran Industrial Research Inc. Utilization of deinking by-product in building materials
US5795377A (en) * 1997-04-08 1998-08-18 Kimberly-Clark Worldwide, Inc. Method for modifying papermaking sludge and products made from modified papermaking sludge
US6146498A (en) * 1997-04-30 2000-11-14 Kimberly-Clark Worldwide, Inc. Wound product cores and processes for making them
US6572736B2 (en) * 2000-10-10 2003-06-03 Atlas Roofing Corporation Non-woven web made with untreated clarifier sludge
US6852386B2 (en) * 2001-03-08 2005-02-08 Norbord Inc. Composite board with OSB faces
US20080179775A1 (en) * 2007-01-31 2008-07-31 Usg Interiors, Inc. Transfer Plate Useful in the Manufacture of Panel and Board Products
WO2008094917A1 (en) * 2007-01-31 2008-08-07 Usg Interiors, Inc. Transfer plate useful in the manufacture of panel and board products
WO2008092807A1 (en) * 2007-02-01 2008-08-07 Macber S.R.L. Process for manufacturing panels for constructing articles of furniture such as cupboards, modular kitchens and furniture items in general, and panel obtained by the process.
US20090000752A1 (en) * 2007-06-28 2009-01-01 Buckman Laboratories International, Inc. Use of Cyclodextrins For Odor Control In Papermaking Sludges, and Deodorized Sludge and Products
US8147651B2 (en) * 2007-06-28 2012-04-03 Buckman Laboratories International, Inc. Use of cyclodextrins for odor control in papermaking sludges, and deodorized sludge and products
US20090173464A1 (en) * 2008-01-04 2009-07-09 Usg Interiors, Inc. Acoustic ceiling tiles made with paper processing waste
US8133354B2 (en) * 2008-01-04 2012-03-13 USG Interiors, LLC. Acoustic ceiling tiles made with paper processing waste
US20130212970A1 (en) * 2008-09-04 2013-08-22 Frank Santoro Products made from recycled cardboard
ITUD20110142A1 (it) * 2011-09-13 2013-03-14 Roberta Bas Pannello per uso arredamento intermedia tra mdf e truciolare
WO2014012756A3 (en) * 2012-06-27 2014-04-03 Jentschura, Rolf Synthetic spongy wood boards
US20150020986A1 (en) * 2013-07-18 2015-01-22 Mario Lessard Paper-Based Malleable Dough for Moulding and Sculpting Applications
US9297120B2 (en) * 2013-07-18 2016-03-29 Mario Lessard Paper-based malleable dough for moulding and sculpting applications
EP2993203A1 (en) * 2014-09-05 2016-03-09 UPM-Kymmene Corporation Composite material
US20160068668A1 (en) * 2014-09-05 2016-03-10 Upm-Kymmene Corporation Composite material
US9908982B2 (en) 2014-09-05 2018-03-06 Upm-Kymmene Corporation Composite material
CN104385429A (zh) * 2014-11-26 2015-03-04 武汉亿维登科技发展有限公司 真空加热铺装机
CN108214804A (zh) * 2017-12-02 2018-06-29 张英华 玻璃丝或玻璃纤维与植物纤维的混合物模压生产设备
CN110893638A (zh) * 2018-09-12 2020-03-20 上海昶法新材料有限公司 一种环保型密度板及其制作方法

Also Published As

Publication number Publication date
GB1405587A (en) 1975-09-10
FR2146883A5 (it) 1973-03-02
CA1016709A (en) 1977-09-06
AU4470672A (en) 1974-02-07
IT961467B (it) 1973-12-10
ES405055A1 (es) 1976-01-01
DE2235975A1 (de) 1973-02-01

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