Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
  • C02F1/56—Macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/5263—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using natural chemical compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities

Definitions

• the invention relates to compositions and methods which enhance the filtration of aqueous dispersions.
• a filtration aid promoter and synthetic polymer for example, in dewatering aqueous mineral slurries by adding a filtration aid promoter and synthetic polymer to the aqueous dispersion prior to filtration.
• the method enhances filtration when the filtration aid promoter and synthetic polymer are added prior to and/or during separation of solids phase from liquid phase in an aqueous slurry but prior to the filtration of the concentrated aqueous phase.
• the compositions and methods have particular application with respect to mining slurries.
• the mineral slurry may be dewatered in a two step method comprising liquid solid separation, such as in a gravity thickener, clarifier and/or hydrocyclone, which produces a liquid phase, supernatant, and a concentrate or underflow.
• the concentrate or underflow comprises the valuable minerals which require further dewatering which occurs in a second step in which the concentrate or underflow is filtered, such as through vacuum filtration and/or pressure filtration.
• Mw is the weight average molecular weight as determined by SEC-MALLS analysis.
• MALLS shall mean and refer to multi- angular laser light scattering.
• SEC-MALLS shall mean and refer to a size exclusion chromatography technique using MALLS to determine Mw.
• the invention pertains to compositions comprising filtration aid promoters and synthetic polymer. These compositions are applied in methods for separating solids from liquids in aqueous dispersions comprising a filtration step.
• the filtration aid and synthetic polymer are added to the aqueous dispersion prior to and/or during the physical separation of a solid phase from a liquid phase, such as allowing the solids to settle from the dispersion.
• the solid phase may then be filtered.
• Filtration aid promoters include at least one of natural polymers, semi-natural polymers or coagulants. Combinations of such may be used.
• the composition is applied in dewatering processes in mining operations.
• dewatering processes generally comprise two steps, the first step involving liquid solid separation and the second separate step involving filtration of concentrate or underflow from the liquid solid separation step.
• the liquid solid separation is typically accomplished with gravity thickeners, clarifiers, hydrocyclones and the like. Filtration is generally accomplished by vacuum filtration, pressure filtration and the like.
• the filtration aid promoter and synthetic polymer are added to a mineral slurry prior to the liquid solid separation step, during the liquid solid separation step or both during and prior to the liquid solid separation step.
• the liquid solid separation step produces concentrate or underflow which requires further dewatering through a separate filtration step.
• the combination of the filtration aid promoter and synthetic polymer when applied prior to and/or during the liquid solid separation step in mining operations increases the production of the filter cakes resulting from the separate filtration step.
• the natural polymers that can be used for the filtration aid promoter are polysaccharides, such as potato starch, xanthan gums, guars, dextran, cellulose derivatives and glycosaminoglycans.
• the poiydispersity index (“PDI") of the polysaccharide is from about 1.0 to about 10.0, more typically from about 1 :1 to about 9.0, and most typically from about 1.2 to about 8.0.
• the natural polymer preferably comprises dextran, which is generally available from various suppliers. Dextran having a w of from about 5,000 to about 40,000,000, preferably from about 50,000 to about 25,000,000 and more preferably from about 200,000 to about 10,000,000, may be used. Persons of ordinary skill in these arts, after reading this disclosure, will appreciate that all ranges and values within these explicitly stated ranges are contemplated.
• the semi-natural polymers include !ignosulfonates, such as calcium lignosuifonate, and chemically modified polysaccharides. Modified
• polysaccharides typically useful in the process include modified starches, such as cationic starch; modified guar gum, such as cationic guar gum; and modified celluloses such as anionic carboxymethyl cellulose and hydroxyethyl cellulose. Combinations of semi-natural polymers may be used.
• the coagulant is typically selected from an inorganic coagulant, organic coagulant and combinations thereof.
• Inorganic coagulants include aluminum sulfate, aluminum chloride, poiyaluminum chloride, aluminum chlorohydrate, ferric chloride, ferric sulfate, ferrous sulfate and sodium aluminate.
• Organic coagulants include polymers formed from the monomers diallyl dimethyl ammonium chloride, ethylene imine and the comonomers of epichlorohydrin and dimethylamine.
• Inorganic coagulants also include cationically-modified tannins and melamine formaldehyde. Such coagulants include CHARGEPAC® 60, CHARGEPAC® 7 and AMERSEP® 5320, all available from Ashland.
• Synthetic polymers include water-soluble anionic, cationic, nonionic and amphoteric polymers.
• synthetic polymer shall include copolymers and terpolymers, as well as homopolymers.
• the synthetic polymer has a Mw of from about 40,000 to about 25,000,000, and persons of ordinary skill in these arts, after reading this disclosure, will appreciate that all ranges and values within these explicitly stated ranges are contemplated.
• the synthetic polymer may be linear, branched, or cross-linked. Typically, the synthetic polymer functions as a flocculant.
• Nonionic polymers include polymers formed from one or more water soluble ethylenically unsaturated nonionic monomers, for instance acrylamide, methacrylamide, hydroxyethyl acrylate and N-vinylpyrrolidone, preferably acrylamide. Nonionic polymers also include alkoxylated multifunctional alcohols.
• Cationic polymers are formed from one or more ethylenically unsaturated cationic monomers optionally with one or more of the nonionic monomers mentioned previously.
• the cationic polymer may also be amphoteric provided such that there are predominantly more cationic groups than anionic groups.
• the cationic monomers include diaikylamino alkyl (meth) acrylates, dialkylamino alkyl (meth) acrylamides, and diallyl dimethyl ammonium chloride, including acid addition and quaternary ammonium salts thereof.
• Typical cationic monomers include the methyl chloride quaternary ammonium salts of dimethylamino ethyl acrylate and dimethyl aminoethyl methacrylate.
• ADAME dimethylamino ethyl acrylate
• AETAC copolymer of acrylamide and acrylamidopropyl trimethyl ammonium chloride
• AETAC copolymer of acrylamide and acryloloxyethyl trimethyl ammonium chloride
• the anionic synthetic polymers are formed from one or more ethylenically unsaturated anionic monomers or a blend of one or more anionic monomers with one or more of the nonionic monomers mentioned previously.
• the anionic monomers include acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, vinyl suifonic acid, allyl suifonic acid, 2-acrylamido-2- methylpropane sulfonic acid (AMPS), acrylamide, mixtures thereof, and salts thereof.
• copolymers and/or terpolymers of monomers selected from the group consisting of acrylamide, AMPS, acrylic acid, and (meth)acrylic acid are copolymers and/or terpolymers of monomers selected from the group consisting of acrylamide, AMPS, acrylic acid, and (meth)acrylic acid.
• the anionic polymer may be selected from the group consisting of copolymers derived from 2-acrylamido 2-methyipropane suifonic acid, copolymers of acrylic acid and acrylamide, homopolymers of acrylic acid, homopolymers of acrylamide, and combinations thereof.
• anionic polymer are the copolymer of sodium acrylate and acrylamide and the copolymer of acrylic acid and acrylamide.
• copolymers of AMPS and acrylamide wherein the mole percent of AMPS is from about 10 mole percent to about 25 mole percent
• terpolymers of AMPS, acrylamide, and acrylic acid wherein the mole percent of AMPS is from about 10 mole percent to about 30 mole percent
• the mole percent of acrylamide is from about 40 mole percent to about 60 mole percent
• the mole percent of acrylic acid is from about 20 mole percent to about 40 mole percent.
• homopolymers of acrylic acid or copolymers of acrylic acid and acrylamide are of particular interest.
• the filtration aid promoter and synthetic polymer are applied in methods for separating solids from a liquid dispersion.
• This process comprises the steps of adding the filtration aid promoter and synthetic polymer to an aqueous dispersion of solids in liquids prior to and/or during the physical separation of the solids from the liquid resulting in a concentrate comprising solids, recovering the concentrate and then filtering the concentrate.
• Enhanced filtration is achieved with this method.
• Physical separation can occur by allowing the solids to settle from the liquid through force of gravity, optionally with flocculation and/or agglomeration of the solid particles.
• the method may be applied in mining operations.
• a method for dewatering mining slurries, in particular enhanced filtration performance, in a two step process having a liquid solid separation step and a filtration step comprises adding at least one filtration aid promoter and at least one synthetic polymer to the mining slurry during or before, or both during and before, the liquid solid separation step and then filtering the concentrate or underflow from the liquid solid separation step.
• the mining slurries are aqueous dispersions comprising minerals, such as those selected from the group consisting of gold, phosphate, silver, platinum, copper, nickel, zinc, lead, molybdenum, iron, coal and the like.
• the liquid solid separation step is performed in a means for separating liquids from solids, such as a gravity thickener, clarifier or hydrocyclone and the filtration aid promoter and synthetic polymer may be added to the aqueous dispersion while the dispersion is in such means and/or prior to the dispersion entering such means.
• the filtration step is generally conducted in a means for filtering solids from liquids, such as a filter press or vacuum filter.
• aqueous dispersion samples were prepared by adding 1000 mL of an aqueous dispersion to a graduated cylinder, where it was treated by adding the specified components of the filtration aid promoter (i.e. coagulant, natural polymer and/or semi-natural polymer) as set forth in Table I, and tamping the filtration aid promoter into the dispersion three times with a plunger having perforated holes.
• the filtration aid promoter i.e. coagulant, natural polymer and/or semi-natural polymer
• Synthetic Polymer A used in the Examples is an anionic copolymer available under the trade name FLOPA ® AN 1 13 from SNF Floerger, Andrezieu, France.
• the suppliers and/or trade names for the synthetic polymer and the component(s) of the filtration aid promoter are set forth in Table IA.
• filtration rates were then calculated and compared to the corresponding comparative example to provide a percentage measure of the increase in filtration rate (% 10 mLs and % 20 mLs). These values and the average of % 10 mLs and % 20 mLs are set forth in Table II.
• the natural and semi-natural polymers used and the ratio of natural and semi-natural polymers to Synthetic Polymer A are set forth in Table IV.
• the times for filtering 30 and 60 mL were measured.
• the filtration rates were then calculated and compared to the corresponding comparative example to provide a percentage measure of the increase in filtration rate ⁇ % 30 ml_s and % 60 mLs).
• These values and the average of % 30 mLs and % 60 mLs are set forth in Table IV.
• the dosage of flocculant (Synthetic Polymer A) in the examples was 144.1 grams per ton, while the ratio of natural or semi-natural polymers with coagulant to synthetic polymer varied from 0 to 100%.
• the natural or semi- natural polymers with coagulant used and the ratio of such natural or semi- natural polymers with coagulant to Synthetic Polymer A are set forth in Table V.
• the times for filtering 30 and 60 mL were measured.
• the filtration rates were then calculated and compared to the corresponding comparative example to provide a percentage measure of the increase in filtration rate (% 30 mLs and % 60 mLs). These values and the average of % 30 mLs and % 60 mLs are set forth in Table V.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Treatment Of Sludge (AREA)

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Publications (1)

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• 2013
  • 2013-09-13 BR BR112015005846-9A patent/BR112015005846B1/pt active IP Right Grant
  • 2013-09-13 WO PCT/US2013/059694 patent/WO2014046979A1/en active Application Filing
  • 2013-09-13 AU AU2013318334A patent/AU2013318334B2/en active Active
  • 2013-09-13 MX MX2015003298A patent/MX2015003298A/es unknown
  • 2013-09-13 EP EP13839337.6A patent/EP2897707A4/en not_active Withdrawn
  • 2013-09-13 CA CA2883633A patent/CA2883633C/en active Active
  • 2013-09-13 PE PE2015000323A patent/PE20150931A1/es active IP Right Grant
  • 2013-09-13 CN CN201380048874.8A patent/CN104640612A/zh active Pending
• 2015
  • 2015-03-18 CL CL2015000672A patent/CL2015000672A1/es unknown
  • 2015-04-17 ZA ZA2015/02608A patent/ZA201502608B/en unknown

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