WO2008154614A1 - Procédés servant à déshydrater des boues d'argile kaolin et gâteaux de filtration d'argile kaolin et boues d'argile kaolin produits à partir de ceux-ci - Google Patents

Procédés servant à déshydrater des boues d'argile kaolin et gâteaux de filtration d'argile kaolin et boues d'argile kaolin produits à partir de ceux-ci Download PDF

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Publication number
WO2008154614A1
WO2008154614A1 PCT/US2008/066650 US2008066650W WO2008154614A1 WO 2008154614 A1 WO2008154614 A1 WO 2008154614A1 US 2008066650 W US2008066650 W US 2008066650W WO 2008154614 A1 WO2008154614 A1 WO 2008154614A1
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Prior art keywords
kaolin
slurry
less
filter cake
solids
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PCT/US2008/066650
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English (en)
Inventor
Ismail Yildirm
Robert J. Pruett
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Imerys Pigments, Inc.
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Application filed by Imerys Pigments, Inc. filed Critical Imerys Pigments, Inc.
Publication of WO2008154614A1 publication Critical patent/WO2008154614A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/02—Preparing or treating the raw materials individually or as batches
    • C04B33/04—Clay; Kaolin
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/02—Preparing or treating the raw materials individually or as batches
    • C04B33/13—Compounding ingredients
    • C04B33/132—Waste materials; Refuse; Residues
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/24—Manufacture of porcelain or white ware
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/30—Drying methods
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/349—Clays, e.g. bentonites, smectites such as montmorillonite, vermiculites or kaolines, e.g. illite, talc or sepiolite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/604—Pressing at temperatures other than sintering temperatures
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Definitions

  • kaolin-clay filter cakes and methods for dewatering finely disseminated particulate materials, such as a kaolin clay slurry.
  • Kaolin is a white inorganic pigment obtained from kaolin clay. Large deposits of kaolin clay exist in Devon and Cornwall, England and in Georgia and South Carolina, United States of America. Important deposits also occur in Brazil, Australia, and in several other countries. Kaolin clay, also referred to as china clay or hydrous kaolin, comprises predominantly mineral kaolinite (AI 2 Si 2 O 5 (OH) 4 ), anhydrous aluminum silicate, and small amounts of various impurities.
  • mineral kaolinite AI 2 Si 2 O 5 (OH) 4
  • Kaolinite generally exists in the form of hydrous aluminosilicate crystals in the shape of thin hexagonal plates or booklets of platelets called "stacks".
  • the individual plates may have mean diameters of 1 ⁇ m or less, but kaolinite particles in the form of stacks of plates may have an equivalent spherical diameter ("esd") of 10 ⁇ m or more.
  • esd equivalent spherical diameter
  • kaolin clay particles having an esd of 2 ⁇ m or more are in the form of stacks of kaolinite plates, rather than individual plates.
  • Transporting kaolin clays usually includes either transporting slurries comprising the kaolin clay to the end user or preparing dry or substantially dry particulates from slurries comprising the kaolin clay.
  • Current practices are thermally inefficient due to low amount of solids in the slurries fed to drying apparatus.
  • the method comprises providing a fine kaolin slurry having a particle size distribution such that at least about 70% by weight of the kaolin particles have a particle size less than about 0.5 microns and a solids content of less than about 55%, and filtering said flocculated kaolin slurry in a membrane pressure filter to produce a filter cake having a solids content of at least about 60%.
  • the particle size distribution of the kaolin slurry is up to 98% by weight less than 0.5 microns.
  • the particle size distribution of the kaolin slurry is at least about 85% by weight less than 2 microns.
  • the filter cake may be re-dispersed, forming a high solids slurry.
  • the fine kaolin slurry may be further processed by at least one of drying, milling, and calcining.
  • the filter cake may undergo drying, milling, and/or calcining.
  • the fine kaolin slurry may undergo at least one of a beneficiation step, flocculating, degritting, classification, and other refining steps before undergoing the filtering step.
  • kaolin-clay filter cakes comprising at least about 60% clay solids is disclosed. In another embodiment, the kaolin-clay filter cake comprises at least about 62% solids. In a further embodiment, the kaolin-clay filter cake comprises at least about 64% solids. In yet another embodiment, the kaolin-clay filter cake comprises at least about 68% solids.
  • a nanodimensional particulate material is one having at least one dimension less than 1 ⁇ m.
  • the nanodimensional particulate material is kaolin clay.
  • the nanodimensional particulate material is calcium carbonate
  • the nanodimensional particulate material is precipitated calcium carbonate.
  • the skilled artisan readily understands that the embodiments disclosed herein may utilize any nanodimensional particulate material, but for illustrative purposes, the material is described as a kaolin clay.
  • the nanodimensional kaolin clay may be referred to as a nanokaolin.
  • Nanokaolin comprises a particle size distribution such that about 70% to about 75% by weight of the kaolin is less than about 0.25 micron.
  • the d 50 of a nanokaolin is about 0.1 micron.
  • the d 50 of a nanokaolin is about 0.12 micron.
  • the term “d 50" refers to the median particle size, or the particle size value less than about which there are 50% by weight of the particles.
  • a membrane filter press may be utilized to remove at least a portion of the water from the fine kaolin clay slurries.
  • the method comprises filtering at least one fine kaolin clay slurry using at least one membrane filter press, and producing at least one kaolin-clay filter cake having a solids content of at least about 60%.
  • the method may comprise any one or more of those steps and/or parameters disclosed in the Great Britain Patent Application filed on June 13, 2007, entitled "Dewatering Kaolin,” which is incorporated by reference herein in its entirety.
  • fine kaolin clays refer to kaolin clays having a particle size distribution ("psd") such that at least about 70% of the clays have a psd less than about 0.5 ⁇ m.
  • psd particle size distribution
  • the psd of a particulate product may be determined by measuring the sedimentation speeds of the dispersed particles of the particulate product through a standard dilute aqueous suspension using a SEDIGRAPH instrument, e.g., SEDIGRAPH 5100 (Micromeritics Instrument Corporation; Norcross, GA, USA).
  • the size of a given particle is expressed in terms of the diameter of a sphere of equivalent diameter that sediments through the suspension, that is, an equivalent spherical diameter or esd.
  • the SEDIGRAPH instrument records the percentage by weight of particles having an esd less than a particular esd value, versus that esd value.
  • the kaolin slurry may comprise at least two kaolin clay slurries, each slurry having a different particle size distribution.
  • at least one micron-sized kaolin clay slurry may be combined with at least one nanokaolin slurry.
  • the kaolin slurry may be provided by any method now known or hereafter discovered.
  • the kaolin slurry is provided by blunging at least one kaolin clay chosen from at least one of crude kaolin clay and processed kaolin clay with water to form an aqueous suspension.
  • the suspension can be a blended kaolin suspension, comprising a combination of crude and processed kaolin clays. Blunging the kaolin clay disseminates the clay particles.
  • blunging comprises mixing the kaolin clay with at least one dispersing agent.
  • Exemplary dispersing agents include, but are not limited to, sodium polyacrylate, ammonium polyacrylate, sodium hexametaphosphate, tetrasodium pyrophosphate, and sodium silicate.
  • blunging comprises mixing the kaolin clay with at least one pH regulator.
  • Exemplary pH regulators include, but are not limited to, sodium hydroxide and ammonium hydroxide.
  • blunging comprises mixing the kaolin clay with at least one dispersing agent and at least one pH regulator.
  • the kaolin slurry may also undergo at least one degritting step to reduce the particle size of the kaolin slurry to less than about 45 ⁇ m.
  • Degritting is directed to removing larger-size particles by passing the clay through separation equipment.
  • Exemplary degritting equipment includes, but is not limited to, hydrocyclones, spiral classifiers, screen bowl centrifuges, and sieve screens having 325 mesh openings.
  • the kaolin slurry may also undergo at least one classifying step to classify the clay into coarse and fine fractions by using any known or hereafter discovered method.
  • classifying methods include, but are not limited to: gravity sedimentation or elutriation; a hydrocyclone apparatus; a solid bowl decanter centrifuge; and a disc-nozzle centrifuge.
  • the coarse fraction may be discarded, used as a separate product, and/or directed to a blend tank as an auxiliary source of coarse kaolin.
  • Classification may separate the kaolin slurry such that from about 70% to about 98% of the particles have an esd of less than about 0.5 ⁇ m.
  • Classifying the kaolin clays using, for example, disc-nozzle centrifuges may also assist in partially, substantially, or fully removing at least one impurity from the kaolin slurry.
  • Impurities that may be partially, substantially, or fully removed include, but are not limited to, anatase, iron oxides, silica, and mica.
  • Nanodimensional kaolin clays may be prepared using at least one of disc-nozzle centrifuges and solid bowl decanter centrifuges.
  • the kaolin slurry may be subjected to at least one grinding step now known or hereafter discovered.
  • the at least one grinding step comprises wet media grinding with at least one particulate grinding medium.
  • the particulate grinding medium is silica sand.
  • the particulate grinding medium has a relatively high specific gravity, for example, about 2 or more.
  • the particulate grinding medium comprise grains of silica sand having diameters not larger than about 2 ⁇ m and not smaller than about 0.25 ⁇ m.
  • the kaolin slurry may be separated from the at least one particulate grinding medium by any manner now known in the art or hereafter discovered.
  • the kaolin slurry is separated from the at least one particulate grinding medium by passing the slurry through a sieve of appropriate aperture size, for example, a sieve having nominal aperture sizes ranging from 0.1 mm to 0.25 mm.
  • the at least one grinding step is a comminution step in order to assisting in breaking down composite particles or aggregates of individual particles.
  • Such composite particles generally comprise coherent stacks or blocks of individual hexagonal plate-like particles, and may be particularly present in the kaolin slurry when the kaolin clay is from a sedimentary deposit.
  • the comminution step comprises relatively gentle grinding with a wet particulate grinding medium.
  • relatively gentle grinding indicates grinding in an attrition-grinding mill with at least one particulate grinding medium, the contents of the attrition-grinding mill being agitated by an impeller rotating at a speed not sufficient to set up a vortex in the suspension, such as at a peripheral speed below 10 m/s, and in which the amount of energy dissipated in the suspension during grinding ranges up to about 200 kW- hr/ton.
  • the amount of energy dissipation ranges from about 0 to about 35 kW-hr/ton.
  • the amount of energy dissipation ranges from about 35 to about 200 kW-hr/ton.
  • the amount of energy dissipation is equal to or less than about 75 kWh-hr/ton.
  • the amount of energy dissipation is equal to or less than about 55 kWh-hr/ton.
  • comminution at least partially breaks down many of the composite particles in the kaolin slurry into individual thin, substantially hexagonal plates (a process that may also be referred to as delamination), the result being an increase of the average shape factor of the kaolin clay in the slurry.
  • comminition may increase the shape factor of the kaolin clay from a starting value of about 5 to about 10 to a shape factor of at least about 50.
  • comminution may increase the shape factor of the kaolin clay by about 40 or more.
  • the kaolin slurry may be subjected to at least one conventional leaching (bleaching) agent now known or hereafter discovered.
  • the at least one leaching agent is a reductive leaching agent.
  • Exemplary reductive leaching agents include, but are not limited to, sodium hydrosulfite and formamidine sulphinic acid.
  • the at least one leaching agent is added to the kaolin slurry in a dose range of about 0.5 to about 5 pounds per ton of kaolin clay. In a further embodiment, less than about 4 pounds of leaching agent per ton is added.
  • the kaolin slurry is subject to at least one conventional leaching agent at an acidic pH, for example, in the range of 2 to 4.
  • the kaolin slurry may be subjected to at least one beneficiation step, either now known or hereafter discovered, to remove at least one impurity.
  • the at least one beneficiation step is a selective separation method now known in the art or hereafter discovered.
  • the at least one beneficiation step is a froth flotation treatment operation to remove titanium-containing impurities.
  • the froth floatation treatment operation comprises conditioning the kaolin slurry with an oleic acid to coat the air bubbles produced in the float cells. The titanium-containing materials adhere to the air bubbles and are floated out of the kaolin slurry.
  • a flotation process is described in U.S. Pat. No. 3,450,257 to Cundy.
  • the froth floatation treatment operation results in an improved brightness in the kaolin slurry, for example, a brightness gain ranging from about 0.1 to 3 GE units.
  • the at least one beneficiation step comprises passing the kaolin clay through a high intensity magnetic separator to remove iron-containing impurities.
  • a standard high intensity wet magnetic separator is used.
  • the magnetic separation process results in an improved brightness in the kaolin slurry, for example, a brightness gain ranging from about 0.1 to 3 GE units.
  • the at least one beneficiation step is a flocculation process, in which impurities are flocced out of suspension while the kaolin slurry remains in suspension.
  • the at least one flocculating step occurs before the slurry is fed directly to a filter membrane press.
  • the slurry undergoes further processing steps before being fed to a filter membrane press.
  • Any suitable flocculation polymer now known or hereafter discovered may be used.
  • the flocculation polymer is a high molecular weight anionic polymer having a molecular weight in excess of about one million.
  • the flocculation polymer has a molecular weight in the range of about 10 to about 15 million.
  • Exemplary anionic flocculation polymers include, but are not limited to, a copolymer of a polyacrylamide and a polyampholyte.
  • the flocculation polymer is a cationic polymer.
  • Exemplary cationic polymers include, without limitation: quaternary polyamines, for example, poly D AD MAC; polyethyleneimine; and polyguanidine.
  • the flocculation polymer is a non- ionic polymer.
  • Exemplary non-ionic polymers include, but are not limited to, acrylamide homopolymers, polyacrylamides, and polyethylene oxides.
  • the flocculation process may comprise at least one of ozoning, leaching (bleaching), filtering, re-dispersing in a makedown tank, and spray-drying. Details of exemplary flocculation processes can be found in U.S. Pat. No. 4,227,920 to Chapman and Anderson, and U.S. Pat. No. 5,685,900 to Yuan et al., which includes ozonation.
  • the flocculation process may comprise the addition of at least one acid used to effect a pH of the kaolin slurry of from about 2 to about 5.5.
  • Appropriate examples of the at least one acid are now known to the skilled artisan and further acids may be hereafter discovered.
  • the at least one acid is sulfuric acid.
  • the pH is from about 2.5 to about 5.
  • the pH is from about 3 to about 4.5.
  • the pH is from about 3.5 to about 4.
  • the kaolin slurry may undergo a first flocculation and a second flocculation, the second flocculation comprising adding at least one flocculation polymer and alum to the slurry.
  • the second flocculation step floes the kaolin clay, aiding in the removal of water in any subsequent filtration step.
  • the methods disclosed herein further comprise filtering the kaolin slurry using at least one membrane filter press.
  • a membrane filter press as used herein, is a filtration apparatus having at least one inflatable chamber, a filter plate, and at least one filter cloth. Upon inflation, the at least one inflatable chamber presses the face of the filter plate against the filter cake of kaolin forming or disposed thereon, removing water homogenously or substantially homogeneously throughout the filter cake through the at least one filter cloth.
  • the inflation pressure for the at least one inflatable chamber may be provided by techniques now known or hereafter discovered.
  • water is used to provide the inflation pressure.
  • a fluid other than water is used to provide the inflation pressure.
  • air is used to provide the inflation pressure.
  • the at least one inflatable chamber may be made of any compound or compounds now known or hereafter discovered, for example, at least one of polypropylene, rubber, and thermoplastics.
  • the pressure of the at least one membrane filter press may reach up to about 250 psi. In one embodiment, the pressure reaches up to about 200 psi. In a further embodiment, the pressure reaches up to about 150 psi.
  • the number of inflatable chambers may vary according to the volume and solids content of slurry being filtered. In one embodiment, the at least one filter press comprises 6 or less inflatable chambers. More than one membrane filter press may be used in parallel operation to accommodate increased volumes of kaolin slurry.
  • the thickness of the at least one inflatable chamber may be adjusted to produce a sufficiently dewatered filter cake. In one embodiment, the thickness is less than or equal to about 45 mm. In another embodiment, the thickness is less than or equal to about 35 mm. In a further embodiment, the thickness is less than or equal to about 30 mm. In yet another embodiment, the thickness ranges from about 30 mm to about 40 mm. In yet a further embodiment, the thickness ranges from about 33 mm to about 37 mm.
  • the composition of the at least one filter cloth may be chosen according to the kaolin slurry and the desired filtration solids amount.
  • Exemplary materials for the at least one filter cloth include, but are not limited to, at least one of polyester, polypropylene, polyethylene, nylon, polyamide 11 , polyamide 12, polyvinylidene fluoride, and polyethylene terephthalate.
  • Exemplary weaves include, but are not limited to, plain, twill, basket, leno, and satin weaves.
  • Exemplary filaments include, but are not limited to, at least one of multifilament yarns, continuous filament yarns, monofilament yarns, and staple yarns.
  • the resulting filter cake may comprise at least about 60% solids. In one embodiment, the filter cake comprises at least about 62% solids. In another embodiment, the filter cake comprises at least 64% solids. In a further embodiment, the filter cake comprises at least 66% solids. In yet another embodiment, the filter cake comprises from about 60% to about 70% solids. In yet a further embodiment, the filter cake comprises from about 62% to about 68% solids. In still another embodiment, the filter cake comprises from about 64% to about 68% solids. In still a further embodiment, the filter cake comprises from about 66% to about 68% solids.
  • the filter cakes may exhibit a conductivity ranging from about 100 mS/cm to about 650 mS/cm. In one embodiment, the conductivity ranges from about 200 mS/cm to about 550 mS/cm. In another embodiment, the conductivity ranges from about 300 mS/cm to about 450 mS/cm.
  • the filter cake may undergo at least one additional processing step.
  • the at least one additional processing step is re-dispersing the filter cake into an aqueous solution, resulting in a high solids slurry.
  • the high solids slurry may be prepared by adding water and at least one dispersant to the filter cake.
  • Exemplary dispersants include, but are not limited to, sodium polyacrylate, ammonium polyacrylate, sodium hexametaphosphate, tetrasodium pyrophosphate, and sodium silicate.
  • the at least one dispersant may be added to the filter cake slurry in an amount from about 0.25 pounds ("pds")/ton to about 2.0 pds/ton on an active basis.
  • the at least one dispersant ranges from about 0.5 pds/ton to about 0.7 pds/ton. In a further embodiment, the at least one dispersant is added in an amount of about 0.6 pds/ton.
  • At least one pH regulator may be added to the kaolin cake slurry. Exemplary pH regulators include, but are not limited to, sodium hydroxide and ammonium hydroxide.
  • the pH of the high solids slurry after the addition of the at least one pH regulatory ranges from about 8 to about 12. In another embodiment, the pH ranges from about 9 to about 11. In a further embodiment, the pH ranges from about 9.5 to about 10.5. Re-dispersing may be aided by the application of mechanical energy.
  • the filter cake, water, the at least one dispersant, and any optional pH regulator may be agitated in a high-shear mixer, including but not limited to a Waring blender or other suitable mixing apparatus now known to the skilled artisan or hereafter discovered.
  • the high solids slurry resulting from re-dispersing the filter cake may comprise at least about 60% solids. In one embodiment, the high solids slurry comprises at least about 62% solids. In another embodiment, the high solids slurry comprises at least about 64% solids.
  • the high solids slurry may have a low-shear viscosity ranging from about 100 cps to about 120 cps, when measured as Brookfield viscosity at 20 rpm using a #2 spindle. In one embodiment, the low- shear viscosity ranges from about 105 cps to about 115 cps. In another embodiment, the low-shear viscosity ranges from about 108 cps to about 112 cps.
  • the high solids slurry may have a high-shear viscosity ranging from about 4 dynes to about 5 dynes, when measured as Hercules viscosity at 4400 rpm using an "A" bob.
  • the high-shear viscosity ranges from about 4.2 dynes to about 4.8 dynes. In another embodiment, the high-shear viscosity ranges from about 4.4 dynes to about 4.6 dynes.
  • the particle size distribution of the re-dispersed filter cake slurry is the same or similar to the particle size distribution of the filter cake feed.
  • the kaolin particle size distribution of the re-dispersed filter cake slurry may range from 85% to 98% less than 0.5 ⁇ m.
  • the kaolin particle size distribution of the re-dispersed filter cake slurry may range from 85% to 90% less than 0.5 ⁇ m.
  • the d 50 of the kaolin particles is less than 0.5 microns.
  • the d 50 of the kaolin particles is less than 0.3 micron.
  • the d 5 o of the kaolin particles is less than 0.2 micron.
  • the d 50 of the kaolin particles is less than 0.15 micron.
  • the re-dispersed filter cake slurry may undergo at least one processing steps as described above for the kaolin slurry.
  • the filter cake or the high solids slurry prepared from the filter cake may be suitable for transport. These filter cakes are useful for transporting as a source of hydrous clay. The filter cakes may also be useful as feed to dryers without first undergoing re-dispersion to a slurry.
  • the filter cake or the high solids slurry is dried, which allows transport in a substantially dry form.
  • the filter cake or high solids slurry is dried by evaporation.
  • the filter cake or high solids slurry is thermally dried, such as in a flash dryer, apron dryer, rotary dryer, and the like.
  • the high solids slurry is dried by introducing the slurry into a spray dryer.
  • the moisture content of the spray-dried high solids slurry may be less than about 1 %. In one embodiment, the moisture content is less than about 0.8%. In another embodiment, the moisture content is less than about 0.5%.
  • the dried filter cake or the dried high solids slurry is milled.
  • the dried filter cake or the dried high solids slurry is calcined.
  • calcining may comprise exposing the dried filter cake or the dried high solids slurry to temperatures of about 1000 0 C or more for about 30 minutes.
  • a 34.0% solids diluted slurry was prepared from a 53.5% solids beneficiated kaolin clay slurry and a 4.0-5.0% solids nanodimensional kaolin clay slurry.
  • the particle size of the nanodimensional kaolin clay was consistent with the particle size distribution of INFILM 939 kaolin clay (Imerys Pigments, Inc.; Roswell, Georgia, USA). The particle size distribution of those two feed streams and the resulting diluted slurry are provided in Table 1.
  • the diluted slurry was fed to the MERCO process before undergoing filtration.
  • the MERCO product slurry was then filtered using an ANDRITZ filter (Andritz AG; Graz, Austria) press to investigate the effect of processing variables, as shown in Table 2 .
  • the filter cloth material was PRIMAPOR multifilament polyester cloth (Madison Filter Ltd.; Lancashire, England) having a surface coating designed to capture extremely fine particles.
  • the filter cake produced in run 2 had a thickness sufficient to preclude homogenous squeezing. Thickness was measured at various locations of the filter cake and the average provided in Table 3. The thickness of the filter cakes in the other runs were homogenous or substantially homogeneous, and the provided thickness data is indicative of the thickness of the cake in general.
  • the low-shear viscosity was measured using a Brookfield machine with spindle #2.
  • the low-shear viscosity was 108 cps at 20 rpm and 70 cps at 100 rpm.
  • the high-shear viscosity was measured using a Hercules apparatus with an "A" bob.
  • the high-shear viscosity was 4.31 dynes at 4400 rpm.
  • the particle size distribution was determined using a SEDIGRAPH analyzer (Micromeritics Instruments Corporation, Norcross, GA, U.S.A.) and is provided in Table 4. Table 4

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  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Environmental & Geological Engineering (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé servant à déshydrater une argile kaolin. On peut filtrer une boue d'argile kaolin floculée en utilisant un filtre-presse à membrane pour enlever l'eau, laissant de cette manière un gâteau de filtration. On peut facultativement disperser à nouveau et/ou sécher le gâteau de filtration. L'invention concerne également un gâteau de filtration d'argile kaolin ayant au moins 60 % de matières solides.
PCT/US2008/066650 2007-06-13 2008-06-12 Procédés servant à déshydrater des boues d'argile kaolin et gâteaux de filtration d'argile kaolin et boues d'argile kaolin produits à partir de ceux-ci WO2008154614A1 (fr)

Applications Claiming Priority (2)

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US94356807P 2007-06-13 2007-06-13
US60/943,568 2007-06-13

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WO2008154614A1 true WO2008154614A1 (fr) 2008-12-18

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PCT/US2008/066650 WO2008154614A1 (fr) 2007-06-13 2008-06-12 Procédés servant à déshydrater des boues d'argile kaolin et gâteaux de filtration d'argile kaolin et boues d'argile kaolin produits à partir de ceux-ci

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WO (1) WO2008154614A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017156088A1 (fr) * 2016-03-08 2017-09-14 Basf Corporation Pigment à base de kaolin ayant subi un traitement thermique à blancheur d'au moins 92 pour papier et revêtements
CN111170327A (zh) * 2020-01-16 2020-05-19 内蒙古超牌建材科技有限公司 Pvc绝缘煅烧高岭土的制备方法、生产设备和应用

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US4280849A (en) * 1979-03-06 1981-07-28 Tioxide Group Limited Aqueous dispersions
US5522924A (en) * 1995-03-17 1996-06-04 Ecc International Inc. Method for producing high brightness low abrasion calcined kaolin pigment
US5584394A (en) * 1995-03-15 1996-12-17 Engelhard Corporation Colored titaniferous coating pigment obtained as a flocculated by-product in a kaolin purification process
US7122080B2 (en) * 2001-09-14 2006-10-17 Imerys Pigments, Inc. Integrated process for simultaneous beneficiation, leaching, and dewatering of kaolin clay suspension

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4280849A (en) * 1979-03-06 1981-07-28 Tioxide Group Limited Aqueous dispersions
US5584394A (en) * 1995-03-15 1996-12-17 Engelhard Corporation Colored titaniferous coating pigment obtained as a flocculated by-product in a kaolin purification process
US5522924A (en) * 1995-03-17 1996-06-04 Ecc International Inc. Method for producing high brightness low abrasion calcined kaolin pigment
US7122080B2 (en) * 2001-09-14 2006-10-17 Imerys Pigments, Inc. Integrated process for simultaneous beneficiation, leaching, and dewatering of kaolin clay suspension

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017156088A1 (fr) * 2016-03-08 2017-09-14 Basf Corporation Pigment à base de kaolin ayant subi un traitement thermique à blancheur d'au moins 92 pour papier et revêtements
KR20180120242A (ko) * 2016-03-08 2018-11-05 바스프 코포레이션 종이 및 코팅을 위한 92 이상의 ｇｅ 휘도를 갖는 열처리된 카올린 안료
CN109247020A (zh) * 2016-03-08 2019-01-18 巴斯夫公司 用于纸和涂料的具有至少92的ge亮度的经热处理的高岭土颜料
US10253186B2 (en) 2016-03-08 2019-04-09 Basf Corporation Pigment for paper and coatings
CN109247020B (zh) * 2016-03-08 2021-04-09 巴斯夫公司 用于纸和涂料的具有至少92的ge亮度的经热处理的高岭土颜料
US10988621B2 (en) 2016-03-08 2021-04-27 Basf Corporation Pigment for paper and coatings
AU2017229605B2 (en) * 2016-03-08 2021-09-09 Basf Corporation Heat treated kaolin pigment with a GE brightness of at least 92 for paper and coatings
KR102410413B1 (ko) * 2016-03-08 2022-06-17 바스프 코포레이션 종이 및 코팅을 위한 92 이상의 ｇｅ 휘도를 갖는 열처리된 카올린 안료
CN111170327A (zh) * 2020-01-16 2020-05-19 内蒙古超牌建材科技有限公司 Pvc绝缘煅烧高岭土的制备方法、生产设备和应用
CN111170327B (zh) * 2020-01-16 2022-04-05 内蒙古超牌新材料股份有限公司 Pvc绝缘煅烧高岭土的制备方法、生产设备和应用

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