AU2013318334A1

AU2013318334A1 - Process for filtration enhancement of aqueous dispersions

Info

Publication number: AU2013318334A1
Application number: AU2013318334A
Authority: AU
Inventors: Lawrence J. Andermann; Michael J. Bluemle; Jeffrey H. Peltier
Original assignee: Solenis Technologies Cayman LP
Current assignee: Solenis Technologies Cayman LP
Priority date: 2012-09-19
Filing date: 2013-09-13
Publication date: 2015-03-05
Anticipated expiration: 2033-09-13
Also published as: BR112015005846A2; CA2883633C; MX2015003298A; CL2015000672A1; EP2897707A4; AU2013318334B2; WO2014046979A1; ZA201502608B; CA2883633A1; CN104640612A; EP2897707A1; PE20150931A1; BR112015005846B1

Abstract

A method for enhancing filtration performance in separating solids from liquids in an aqueous dispersion comprising a solids phase and a liquid phase in a two step process having a physical separation step and a filtration step comprising adding at least one filtration aid promoter and at least one synthetic polymer to the aqueous dispersion during and/or before the physical separation step resulting in concentrate and filtering the concentrate. The method may be applied in mining operations for dewatering mining slurry. Also, a composition applied in such method comprising at least one filtration aid promoter and at least one synthetic polymer. The filtration aid promoter comprises natural polymers, semi-natural polymers, coagulants and combinations thereof.

Description

WO 2014/046979 PCT/US2013/059694 PROCESS FOR FILTRATION ENHANCEMENT OF AQUEOUS DISPERSIONS BACKGROUND OF THE INVENTION Field of the Invention [0001] The invention relates to compositions and methods which enhance the filtration of aqueous dispersions. For example, in dewatering aqueous mineral slurries by adding a filtration aid promoter and synthetic polymer to the aqueous dispersion prior to filtration. In particular, 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 Related Art [0002] Conventional metallurgical processing techniques involve the separation of valuable minerals from the low value gangue in an aqueous medium. Mineral ores go through numerous processing operations to extract valuable constituents. Processing operations, such as crushing, grinding, sieving, cycloning, and flotation are used to enrich the most desirable components to form a mineral concentrate. Valuable minerals that are concentrated include precious metals (gold, silver, platinum), base metals (copper, nickel, zinc, lead, molybdenum), iron and coal. Once concentrated the aqueous mineral slurry is typically subjected to a mechanical dewatering process to remove liquid water from the mineral slurry concentrate. Excess moisture content in the dewatered WO 2014/046979 PCT/US2013/059694 mineral slurry may have deleterious effects on the downstream process operations, which may include pelletizing, autoclaving, calcining, or smelting, or greatly increase transportation costs. [0003] Wet processing is used because this type of process improves efficiency, increases recovery, lowers costs, and minimizes air pollution. Ore enrichment techniques, such as flotation processes, produce a mineral concentrate that contains an excessive amount of water. In order to reduce energy costs associated with downstream operations and decrease transportation costs, as much of the water should be removed as possible. Generally, dewatering is accomplished with gravity thickeners, clarifiers, hydrocyclones, vacuum filtration and/or pressure filtration. [0004] For example, 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. [0005] Gravity thickeners, clarifiers and hydrocyclones are typically used to dewater mineral concentrates with the aid of coagulating and flocculating agents. While beneficial to sedimentation, these agents hinder further downstream mechanical dewatering. 2 WO 2014/046979 PCT/US2013/059694 [0006] All parts and percentages set forth herein are on a weight by weight basis unless otherwise specified. 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. SUMMARY OF THE INVENTION [0007] 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. [0008] Typically, the composition is applied in dewatering processes in mining operations. Such 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 3 WO 2014/046979 PCT/US2013/059694 separation step. The liquid solid separation step produces concentrate or underflow which requires further dewatering through a separate filtration step. [0009] Without being bound to any theory, the inventors believe that the application of the filtration aid promoter and synthetic polymer prior to and/or during the physical separation step affects the rheology of the resulting concentrate (or underflow) which enhances the filtration process in the subsequent filtration step. For example, 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. DETAILED DESCRIPTION OF THE INVENTION [0010] Among 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. Typically, the polydispersity 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. 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. [0011] The natural polymer preferably comprises dextran, which is generally available from various suppliers. Dextran having a Mw 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 4 WO 2014/046979 PCT/US2013/059694 ranges and values within these explicitly stated ranges are contemplated. Natural polymers sold under the trade names ZALTA@ VM 1120 and ZALTA VM 1122, both available from Ashland Inc., Wilmington, Delaware, U.S.A. ("Ashland"), may be used. [0012] The semi-natural polymers include lignosulfonates, such as calcium lignosulfonate, 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. [0013] The coagulant is typically selected from an inorganic coagulant, organic coagulant and combinations thereof. Inorganic coagulants include aluminum sulfate, aluminum chloride, polyaluminum 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. [0014] Synthetic polymers include water-soluble anionic, cationic, nonionic and amphoteric polymers. For purpose of this disclosure, synthetic polymer shall include copolymers and terpolymers, as well as homopolymers. Typically the synthetic polymer has a Mw of from about 40,000 to about 25,000,000, and 5 WO 2014/046979 PCT/US2013/059694 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. [0015] 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. [0016] 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 dialkylamino 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. Of particular interest are the copolymer of acrylamide with the methyl chloride quaternary ammonium salts of dimethylamino ethyl acrylate (ADAME); the copolymer of acrylamide and acrylamidopropyl trimethyl ammonium chloride (APTAC); and the copolymer of acrylamide and acryloloxyethyl trimethyl ammonium chloride (AETAC); and the copolymer of epichlorohydrin and dimethylamine. 6 WO 2014/046979 PCT/US2013/059694 [0017] 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 sulfonic acid, allyl sulfonic acid, 2-acrylamido-2 methylpropane sulfonic acid (AMPS), acrylamide, mixtures thereof, and salts thereof. [0018] Of particular interest are copolymers and/or terpolymers of monomers selected from the group consisting of acrylamide, AMPS, acrylic acid, and (meth)acrylic acid. For example, the anionic polymer may be selected from the group consisting of copolymers derived from 2-acrylamido 2-methylpropane sulfonic acid, copolymers of acrylic acid and acrylamide, homopolymers of acrylic acid, homopolymers of acrylamide, and combinations thereof. Typically used as anionic polymer are the copolymer of sodium acrylate and acrylamide and the copolymer of acrylic acid and acrylamide. [0019] Also of particular interest are copolymers of AMPS and acrylamide wherein the mole percent of AMPS is from about 10 mole percent to about 25 mole percent, and 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, and the mole percent of acrylic acid is from about 20 mole percent to about 40 mole percent. Otherwise, homopolymers of acrylic acid or copolymers of acrylic acid and acrylamide are of particular interest. 7 WO 2014/046979 PCT/US2013/059694 [0020] 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. [0021] 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. Typically, 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. Typically, 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 8 WO 2014/046979 PCT/US2013/059694 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. EXAMPLES Preparation of Aqueous Dispersions for Filtration [00221 Unless otherwise indicated, 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. [0023] Next, the synthetic polymer was added to the aqueous dispersion using the same mixing technique and number of tamps. Synthetic Polymer A used in the Examples is an anionic copolymer available under the trade name FLOPAM* AN 113 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. [0024] The aqueous dispersion settled and was allowed to rest in the graduated cylinder for 72 hours. The supernatant was then siphoned out of the graduated cylinder until there were only concentrated solids, i.e. the concentrate, left in the cylinder. The resulting slurries were quantitatively transferred into appropriately sized beakers for filtration. Pressure Filtration 9 WO 2014/046979 PCT/US2013/059694 [0025] Unless otherwise indicated, filtration of concentrated slurries was conducted at 30 psig with a FANN® Filter Press (FANN Instrument Company, Houston, Texas, U.S.A.) and hardened, low-ash FANN filter paper with a particle size retention range of 2-5 pm. Prior to transferring to the filter press, samples were first hand-mixed for 15 seconds. After transferring the sample, the filter press was sealed and pressurized air was applied to the filter press. The volume of liquid removed from the concentrated sample was measured as a function of time after application of the pressurized air. _________ ________ TableI 1._ __ Sample Composition M,(g/mol) lonicity Synthetic Polymer A 1,200,000 Anionic Coagulant A Cationic Coagulant B Cationic Coagulant C Cationic Natural Polymer A Dextran Syrup 11,600,000Non-ionic Natural Polymer B Dextran Syrup 9,200,000 Non-ionic Natural Polymer C Dextran Syrup 24,600,000 Non-ionic Natural Polymer D Dextran Syrup 28,700,000 Non-ionic Natural Polymer E Dextran Syrup 1,360,000 Non-ionic Natural Polymer F Dextran Syrup 4,910,000 Non-ionic Natural Polymnerb Dextran 677,000 Non-ionic Natural Polymer H Dextran 500,000 (1) Non-ionic Natural Polymer I Dextran 44,000 Non-ionic Natual olyer HDexran 500,000(1)Non-ionic Natural Polymer J Dextran 40,000(1) Non-ionic Semi-natural Polymer A Cationic Guar Cationic Semi-natural Polymer B Cationic Guar Cationic Note No minal molecular weight 10 WO 2014/046979 PCT/US2013/059694 1111Tabl'e IA. -- Sample Tradename Synthetic Polymer A SNF Flopam AN 113 Coagulant A Chargepac 7 Coagulant B Amersep 5320 Coagulant C Chargepac 60 Natural Polymer A Zalta VM 1120 Natural Polymer B Zalta VM 1120 Natural Polymer C Zalta VM 1122 Natural Polymer D Zalta VM 1122 Natural Polymer E Zalta VM 1120 Natural Polymer F Zalta VM 1122 Natural Polymer 0 Zalta VM 1120 Natural Polymer H Zalta VM 1122 Natural Polymer I ZaltaVM 1120 Natural Polymer J Zalta VM 1122 Semi-natural Polymer A N-Hance BFI17 Semi-natural Polymer B N-Hance 3215 Examples 1-16 and Comparative Examples A and B [0026] These examples illustrate the use of natural polymers of Table I with a synthetic polymer (Synthetic Polymer A) to enhance the filtration of an aqueous dispersion containing gold concentrate. Comparative Examples A and B used only Synthetic Polymer A as the polymer treatment. For Examples 6, 15 and 16, an additional 30 grams per ton of Natural Polymer A was added prior to filtration. [0027] In all examples, except for Examples 4 and 5, the natural polymers of varying molecular weight were added first followed by the addition of Synthetic Polymer A. The amount of solids in the aqueous dispersion was 47.1 grams per liter prior to settling. The dosage of flocculant (Synthetic Polymer A) was kept constant at 53.1 grams per ton, while the ratio of natural polymer to synthetic 11 WO 2014/046979 PCT/US2013/059694 polymer varied from 0 to 100%. The natural polymers used and the ratio of natural polymer to Synthetic Polymer A are set forth in Table 11. The times for filtering 10 and 20 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 (% 10 mLs and % 20 mLs). These values and the average of % 10 mLs and % 20 mLs are set forth in Table H1. [0028] The data in Table 11 demonstrate that the filtration rate of aqueous dispersion containing gold concentrate increased when natural polymers were used in conjunction with Synthetic Polymer A. Examples 4 and 5 indicate that order of addition (Synthetic Polymer A dosed prior to Natural Polymer A) does not negatively impact the filtration rate of the aqueous dispersion. Examples 6, 15 and 16 demonstrate that additional Natural Polymer A does not positively or negatively impact the filtration rate. Flcclan Ti me eo T1+e for Rate Rate % % Exriple # Substrate Scl ds (l ) Rayer1(s). . Rai Dsa ::T: 16 iS e 20 ini (6) i n:Ls 20 iLe 10 ru.. 20 MLs Averaon A Geldi C: enhtale 47.1 Sy"rhetic Polymer A On ly ' 5371 21 7 348 C 26 1 Geld Conertrate 471 Na:Lrn PelyrerA plus Synectic PclymerA 25% 53 1 9 68 l 353 029 10b 11 12 0 2 Geld Concentrate 47.1 Natul Pclymer A plus Synthetic Polymer A 75% 53.1 'a 61 0.56 033 167 7 5 23 3 Geld Concentrate 41.1 Natral PclymerA plus Synthetic PclyrerA CC0% 03.1 '. 63 053 033 105 3 0 3 4 '-ld C l 5 5 t rat e 471 Syuthsi P0 y mr A plus N et: Puly erA 5 31 1 V01 0 55 33 235 27.9 257 5 Zld Concerirue 471 Synthetic PclymerA pihs Na.ra Polyner A 0% 031 10 05 053 31 1 5 20. C 15 3 6 Gold Concentrate 47:1 Natral PclyrnerA plusSynthllt PolyrerA(': 5% 531 15 64 056 3 3' ' 7 21,9 193 B Geld Cnce true 471 Synthetic Polyrrer A Only 0% 53 1 22 73 0 45 327 7 Cold e r 471- Natal Polymer usSynlhtllP y' erA 25% 53.1 15 64 050 3 31 22 14.1 181 8 Gold Cuncer true 471 Nalural Pclymer B plus Synthetic Polymer A 37 5% 531 r 05 0 53 330 100 1306 133 9 Gold Concetrate 411 Natural PciymerBU plus Synthetic Pioy--er A 53% :31 15 E5 C050 0 31 22 123 173 10 Gold Geneorale 471 Nalure] Polymer C plu 5yrthei c Plytmer A 37 5% 53.1 1 60 0.55 0.33 332 21 7 21 Q 11 -Gld Cesrnate 471 P.C :.s . rIl Polyner A . 50' 53.1 1 52 C55 032 232 177 230 12 Gold Ccne r.'rate 471 Natural Polyrrer C pl.s Syrittetc Pclymer A 25% 53.1 17 aI a 59 0:33 254 19/ 245 13 Gold Cctetrate 41 Nature PolyrrerD plusSyrtetlic PclymerA 375% 53.1 15 Eb 0 53 030 I5 10 5 13 2 14 Cid C" nuee-aln 47 1 aur Psly er 13 .Sy'the PolynerA 50% 53.1 1 00 053 03 15 100 13 2 15 God Ccncenurtc 47 Isatura. Pulyrrr pus Synthetic Pn yrnerA(1) 25 £41 10 5 0.56 0 222 50 143 16 Geld Concenrate 4.1 Natura Polymer . plus Synthetic P ymer A (1) 37 5% 53 11 64 C56 031 ?3 23 14i 101 tieot (1) 30 gIT at Natural Polyrer A appi nd aterseling prdrto ::.e1en 12 WO 2014/046979 PCT/US2013/059694 Examples 17-74 and Comparative Examples C, D, E and F [0029] These examples illustrate the use of natural polymers of Table I with a synthetic polymer (Synthetic Polymer A) to enhance the filtration of an aqueous dispersion containing phosphate ore. Comparative Examples C, D, E and F used only Synthetic Polymer A as the polymer treatment. The amount of solids in the aqueous dispersion ranged from 215.9 to 285.3 grams per liter prior to settling. The dosage of flocculant (Synthetic Polymer A) in the examples ranged from 39.4 to 52.1 grams per ton while the ratio of natural polymer to synthetic polymer varied from 0 to 200%. The natural polymers used and the ratio of natural polymer to Synthetic Polymer A are set forth in Table Ill. The times for filtering 15 and 30 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 (% 15 mLs and % 30 mLs). These values and the average of % 15 mLs and % 30 mLs are set forth in Table Ill. [0030] The data in Table Ill demonstrate that the filtration rate of aqueous dispersions containing phosphate ore increased when natural polymers of varying molecular weight were added to the aqueous dispersion prior to Synthetic Polymer A and allowed to settle. The data indicate that natural polymers with a wide range of molecular weights are effective filtration aid promoters over a broad range of product ratios. 13 WO 2014/046979 PCT/US2013/059694 ...........Table I1L Flocculent Timefor TIrr for Rate iRate % Exanili # SLrate Sois (o/L) Reagent(s) Ratio Dose (g/T) 15 mLs () O mrLS ci) IS nks 30 rnLe 15 m"s 3d rnLs Average C Phosptate Ore 285 3 Synthetc o yne-A Only (') '% S 11 95 0.37 G.32 17 Phoptle Ore 2853 lNato a y-nr B pluys Sy-ntic Psly.cr kA ( 25% 3.4 . 3 7 7 3 C.41 041 6.5 303 1u 16 Phosphete Ore 268.3 Aatura oyner B plus Sy-t-etic Po ymer A (1) 506 3 37 ?9 041 0.38 11.0 196 153 1s Phosp-ate Ore 285.3 Natura. =elymer B plus y-t-etic Po ymer A 75% 394 28 61 C 54 0.49 44.6 549 40 3 20 Ph'elte Oe 2652 Natural Po ymer C plus Synthetic PolynerA1 25t) 32 66 C 47 043 26.6 370 31 5 Phsphole Ore 265 2 naturall Poymner C plus Syiheto PclymerA/1) 50% 39 4 29 66 0 52 6 46 38.7 44 3 42 0 2 Ph.sphate Ore 25 3 Natural *u ynr C plus Synthetc PclymerA 75% 390 31 7 1 6 42 C42 6 33.1 31 6 3 Phephal nOe 253 Natural inymer E plus Synrrteti Poymer A (1) 2% 39.4 34 77 044.5+ 9 18.1 235 21 2 24 Phospht Ore 365N3 uitual Punul tarEpiu Synthehi Po ymn e A (1) 50% 394 38 82 40 040 37 E0 103 11 5 25 Phosphate Ore 385 3 NaturatPuymruE us Synthetic PP yin A 7% 38 4 , 29 66 0.53 045 39. 7 432 41 4 28 Phosphat Orc 253 NatsuralPuiyms FRp.s sy'rtb.:iPcyirA(I 50% 394 31 75 3.4 0.40 33.0 268 287 27 Phosphate Crc 285 3 Natural Po.r F 1:. ie Sy' inti: Pol yer A 7% 394 33 76 3.43 0.38 157 21 2 6 4 2 Phospthate Ore. 63 Natural Pclyr0 plus Synrhncio Pn ymer A (1) 20 354 73 72 3.46 0.43 24 332 2 26 4 29 Phosphate Ore 25.3 Natural PclymerG plus Synthctic Pu ymer A S0% 364 36 75 : 42 30 125 16.6 161 30 Phosphate ;re 285.3 Natural PolymerG plus Synthetic Polymer A (1) 75% 354 3C 7' 3.5. 342 35.0 33.1 34.0 31 Phosphate Ore 285 3 Natural Polymer H plts Synthetic Putymer A (1) 25% 354 33 71 5.46 243 246 345 263 32 Phuphate Ore 25t.3 Natural Pulymer t plus Synthetic PolyrerA(1 5CM 394 33 78 0.45 340 2 7 25 0 24 4 33. hunpihls Ore. ?2 3 Natural Polymer H plus Synthetic PolyrerA 7' 36 4 34 77 : ,44 0 3 16 1 32 7 2 0 2 5.ihsphAls Ore 2' 5A Syleh.i Polyrer A Only (2) 0% 2 5 157 0.36 315 34 hosphate Ore 2188 Natural Polymer p us Synthetic Polymer A (1) 25% 32.1 4C 545 0 37. 035 43.2 85.4 64 3 35 P hosphate Ore 21 8 9 Natorol Polymer plus SyntIhetic PcPlymer A, .1) ' 321 333 70 4.5 043 73 1 1236 s5 36 hosphaOr2te re. i Naurail Polymers plus Syrrhe PulyomerA 75% 3 *6 0.45 0.44 87.1 1304 1087 37 Phosphate Ore 213.9 Natr-lPolymerc iuSyriteiotc PiynerA () 25% 5 '1 296 62 0 .51 04 5 66. 1527 124.5 36 Phosphate Ore 215.9 Nattral Polyrrer C pL5syrttetlc Polyrr A (1) 50% 52 1 29 5 613 ' 0.51 U 49 666 1547 125.7 38 Phosphate Ore 2159 Nattral Polyrrr 6 plys ytti P. y .ucr A 75% 152 2 8 60 0 554 U.5C 1071 161.1 34.1 40 hoaphate Ore 2159 Natural Polymer E plus Synthetc Polymer A 1) 25% 52 1 28 595 054 U3c 1071 163.3 : 13.52 41 Phouphale Ore 2158 Natral Palymr E p us Synthei c Pclyr A 50% 82 . 3- 55 0.48 U.46 07.1 139.2 1131 42 Phosphate Ore 2169 Natral Polymer L plus Synthetc Pclymer A 75%.3231 25 64 075 047 1500 1440 167.4 43 Phosphale Ore 2159 Nat'ral Polytrer plus Synthetl PolymrarA.) 25% 521 24 63 0.63 048 141 7 1457 145.2 44 P-hosphal Ore 215 9 NeIral Polymer F plus Sythec PolymeA (1) 50% 521 238 725 0 54 0 41 7 1 1161 111.6 45 hepthain Ole 2158 N.tural Polymer - plus Synthetic olymr A 75% 52.1 32 67 047 0.45 81 3 1336, (i. 4.6 pru brs C 2158 Natral Polymer Iplhs Synteti: Poi y A(; 25% 52.1 375 61 0.43 037 54 7 34 74C 4. hosphate Oro 21559 Nat.ral Polymer lus Pyntleti: Pl ymer A (' 5% 51 32 505 047 0.44 E1 3 1287 105.0 4o. Ph-hal eOre 7136 Nat.rt lPoyoer plusSyl-utl.Pc ymcrA 75% 52 1 34 73 044 041 76 1146 52 48 Phosphate Ore. 2153. Na'_ral Polyrer J plus Syntheic Polymer All) . 25%.531 35 873 036 034 506 760 548 53 -'osphate Ore 2156 Nat.raPatyrrer J p usSynthe-u PlreA (11. 53%.52 1 366 73 5 42 0 40 3 4 1006 136.1 51 Plthuphate Ore 2150 Na..rai Polyrer J plus Synthe-tc PlyrA 75% 52.1 36 73 P 42 0.41 611 1140 79 F Ituat. .re 231 1 Synthetic Plymer A Only (1) 0% 487 31 as C 40 0 44 52 Phoshate Ore 23'1 Nla.rl Plyter 34 plus Synthet c Polynmer A (1) 53% 40 7 25 57 C 05 0 53 10 9 25 4 1 6 3 Posphate Ore 231 1 Ntura Polyer 6 p'is Synthel c Polymer A . 7% 46 7 27 57 C L6 0 53 - 30 133 1 1 54 .Posphat Or 3311- Nature Ptlyr phrls Syne ch ymaA (1). 25%.46 35 54 060 05 22C 27 - 24.6 55 iProspae Ore 231 1 Natura Polyer 0 plus Synthctic Pu ymnerA (1) 5'% 487 21 45 07/3 067 498 52 8 52 3 5 Pospntte Ore 231 1 Natura Poer c 6 olus Synthoic Po yme A 75%.4 7 22 45 060 067 38 511 44 D 57 Pnosphate Ore 231 1 Natura Polym.er . plus 3Y-ithcPti yrcr A ( - % 48 7 25 53 0 61 0357 245 20.3 :254 Ss Prospiate 0- 231 1 Astora Po.ynnr =p us Syntht-coPclymer A:1) . 25% 48 7 26 65 5 53 0 35 7 0 13.3 :13.2 56 P+rosphate Ore 2311 Nature Po ymer Opus Synthet c Polyrer A 1) .50% 48 7 23 48 567 502 356 42 2 37.6 60 Ptesphate Ore 231 '. Nature Po ymer S plcs Syrthet.c Polyrrer A (1; 25% . 46 7 28 64 5 6:0 0: 36 2250 27/.1 24.0 61 Phosptlate Ors 231 1 Aeurn Po y'mer F pluc Synthetic Polymer A (1) .0% 4 2 40 073 C E 41 6 01.1 46.5 82 Phosp-ete Ore-2311 Alulhu ymu.G pl.nSyrtl'etoPsyrrer A 76% 47 .17 2 48- 67 - 3- .5 17 51 1 83 Pho.pate Ore 231 1 Natura[l -ysr H plus Synthetic Polymer A (1) 25% 46/ 23 58 0.67 C52 36 183 26 84 Phsrete Ore 231 1 Natural Folyme. H pies Synthete Pulymer A(1) 501 48.7 26 45 0.56 34 15 6 21 4 30 5 60 Phosphate Ore 231 1 Natoral.ymo H plus Synthetic Polymer A 75% 487 21 46 071 063 452 41 7 43 5 1' Phoste Ore 232 2 Synthet c Polymer A On y .(3) 0% 40 4 26 .5 055h 0354 6 Phuopate Ore 232 2 Natural Polymer C plus Synthet c Polymer A (1) 30% 43.4 23 48 ' 7 03 17 3 183 '6 2 67 Phosphat Ore ?32 Natural Polymer G plus Synthe: Plymer A (i) 100% 4 4 23 1 967-051 173 -1 0 14 80 Phi:>hate Ore 7322? NalislPulynrG pus synthe:ic Polymer A (1) 150% 4 54 32 47 2.5 060 2'3 167 y 84 0 Phosphate Ore 332 2 hNotural Puiye C pe Opt/ynhate Polymr A 200% 45 4 10 30 3.03 0 70 46 7 40 3 46 0 20 Phosphat+ Ore 232.2 nteralt PolymE Alu: Sye-hulh PrlymnrA (1) 103% -54 23 40 3.6 0463 148 162 15 71 Phosphate Ore 232.2 Natural Polymer s plus Synthetic Polymrn A (1) 103% 4 4 22 47 2. 7 0 64 23 6 174 201 72 Phosphate Ore 3232 Natural Polymer F pLs Syrthetle P'lyrer A (1) 103% 484 21 43 2.73 0.71 286 26 6 20 3 73 Phcephale Ore 232 2 Natural Pclymer F pls Sytilinetic PolymerA(1 153% 484 31 4 43 3.71 0.7 25.7 20.4 27. 74 Phosphate Ore 232.2 -Natural Pclymer F pts SyrItetc PeeyrlrA 200% 4.4 20 43 3 0.0 32 20.4 30.2 Nie (.Average of .wo experiments . ( uAerage of three experiments (3) Aerage of four oxpotnmonts. Examples 75-94 and Comparative Examples G and H tO3l lThese examples illustrate the use of natural and/or semi-natural polymers of Table I with a synthetic polymer (Synthetic Polymer A) to enhance the filtration of an aqueous dispersion containing gold concentrate. Comparative Examples G and H used only Synthetic Polymer A as the polymer treatment. Examples 92-94 14 WO 2014/046979 PCT/US2013/059694 used both natural and semi-natural polymers, which were applied prior to Synthetic Polymer A. The amount of solids in the aqueous dispersion was 200.6 or 209.1 grams per liter prior to settling. The dosage of flocculant (Synthetic Polymer A) in the examples was 112.2 or 143.5 grams per ton, while the ratio of natural or semi-natural polymer to synthetic polymer varied from 0 to 100%. 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 mLs and % 60 mLs). These values and the average of % 30 mLs and % 60 mLs are set forth in Table IV. FlToabln limr for Tm, lee Rate Rate % Exaemplea A Sbstrate :Soldo 4L) Pegnt~ atl aDose (griT 30 rots (Gl R5 mle, Al L0 moo L:e30 mLo Ot n 0L -aeO 3 Solo Conoentale 2Di S ynnti Pu y t n+ A l.!y 2 % 1430 122 426 021 0 3 76 Sole Con:....eo 203 1 Natural Pelyr-er P plu synotlo Folyrer A 7% 043 1 110 41 0 0 1 + 4 1 -: 9 7 1c - 75 ;lo Co.-n-rM- 2091 _ature T.yrlrC plo Syntlelo FGTsoer A:% 143 106 40: 0 01 125 139 13.7 77 Sol: Conoenoat: 20: 1 Nuloaur ol uyrom Cple.. o.:!i 9!XrT1p r A 7% 143 1 109 405 028 0 1 9 0 ; 3.2 78 Sol-.on:;enat, 2091 haurdt PlyrrerlpussyrhaiPoymolA % 1429 107 400 020 010 140 141 '4.1 9 Solo7 Conr- er-:e 203 1 A ur Folyrrer F :pus l3ynthelt Po lymr A 040 108 400 02 0r 1 - -0 14.1 13.5 0 Solo:Conoenale 2001 Notauld or 50uS. onh.l a Pa yorA.:' "% 1.431 10 400 028 00. 14813.: 81 3lo Con'.unt'sto 209 1 tatura 1 plr . s sy7n-rl's y =rA 75% 143.E 107 410 U 014 140 1 00 12.0 : - Soie Cn.en-a- 2008 Syn-t e 7ttr Py-A ny b% 112 05 192 02; 008 82 Gnld Con-rnt , 200C 1.atura Folymero B pl.. Syoittlic Polymer A 2% 1137 49 170 00 1 9 1r. 4 3 129 1. 83 S0ol Cor oen:a:t 2000 C tooui Folg ai le l.. ol.-oeo 1-lpmer A 1 1 130 : 1 179 0 3 01 1 0 0 4 1..1 84 Sol:..Cu::*.ntl e 20 .: Nd Bal lol r hpt. Pte Polymer A 1003 2.2 4C 62 030 01 6 07 178 172 8O 'At Coenrenera 200. Smi-tora P olyrer A pl... 'ynt.etic Polymer A 2.% 113.2 47 16 0 T, t 191 14 3 1. 7 O Geld Co:contrato 200 C een aturd F olerAploo Synthuol:. Folmor A I 50% 1122 50 79 030 0 17 120 1 00 11.0 87 Gold Cur.ental 200.6 Saei-tura Polymer A pl. ynthen: Polyr-er A . .7. % 1' 2.2 46 16 031 .*0 1 120 l 1. Be 0ld Cno.rtii 2004. Semmrr PlymrA pl.s Synthe'ic Folyr-orA 10006 112.2 6 160 03:: 01 4 219 242 9 Geld Con- otrtet 2000 ~ SeT-atura FolymerE plus Sy-heio olPeyor nuA '-/ 1 50 . 173 01 c17 120 113 11 9 0 1l-Jid Caerpalt 20.9 ':e'nrsal Polymer pl..s ynthelt F PolyoerA (11 06. . '2.2 1 00 00 :1 7 1 07 102 91 Sold Cueno.ntral 2000 . Sore roatr] Polymer R8plus Synte .l1!sI.A . . 21 1 12.JI 2 41 044 027 2 1 16 312 250 I 2 oild Cno-rtt, 20-. 5.1crN Polymer B- Semi-atural Polyrer A pLc SynI- .y e.oA 26 112.2 49 171 92 000 142 123 132 93 Gld Co-ce-rate 200 0 Na- Poly.r6-Pe l-aturl 1-lymerS pl.S eon+:oie'yre+A)1) /7 ''? 2 - 163 039 -. 1 2 102 26 7 r-Gld OCroor':lte 2000 Nana'a l'on* 3 ernalral Polymer 0 pl. Synn Fy-1rA . 100%.112.2 . 49 172 C1 020 0 10 143 1*10 1 2. 1:) Aveg of hvn exp rrrnt. 2) Average ofthre. cxp: mon. [0032] The data in Table IV demonstrate that the filtration rate of aqueous dispersions containing gold concentrate increased when natural polymers of varying molecular weight were added to the aqueous dispersion prior to Synthetic Polymer A and allowed to settle. Semi-natural polymers were also 15 WO 2014/046979 PCT/US2013/059694 effective filtration enhancers when used alone or in combination with Natural Polymer B. Examples 95-106 and Comparative Example I [0033] These examples illustrate the use of natural or semi-natural polymers with coagulants of Table I with a synthetic polymer (Synthetic Polymer A) to enhance the filtration of an aqueous dispersion containing gold concentrate. Comparative Example I used only Synthetic Polymer A as the polymer treatment. Examples 95-100 and 104-109 used natural or semi-natural polymers in combination with a coagulant, which were applied prior to Synthetic Polymer A. In Examples 108 and 109, Natural Polymer B and the coagulant were mixed together prior to dosing. The amount of solids in the aqueous dispersion was 208.1 grams per liter prior to settling. 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. [0034] The data in Table V demonstrate that the filtration rate of aqueous dispersions containing gold concentrate increased when Natural Polymer B or 16 WO 2014/046979 PCT/US2013/059694 Semi-natural Polymer B in combination with coagulants were added to the aqueous dispersion prior to Synthetic Polymer A and allowed to settle. Combinations of Natural Polymer B and Coagulant A or B were effective filtration enhancers whether mixed or dosed separately. Flocculant| Time for TTmefor Rate Rate; -A % Example # SubrtAe Sa oll.)- Leagntns Ratio Done (gr)|30 mLe (80 Mill) 30 mLs 60 msi30 .X onr 0 mmAerage * lodConcentrate 2081 *ynthetiauyinoA Ry(') *% 1441 120 477 0.24 0.13 35 God Concentrate 208 1 NaraPolymerfDo Coaglan A4pus jyirec lrrA . 50% 1441 113 429 027 014 12,8 11 6 .Gold Concentrate 2081 Nature Pver. .Co.lant AplusSyr.l1 ent olyr Ir A 7, 144* 100 414 20 01 l 1 140G 13 9/ 7 G.: Corrcent'ate 208 1 Natura Polymer B + Congolant A plu Sytletc Polymer A 100% 144 1 106 307 0 20 0 I5 20 3 2C 1 202 38 Go d Coroert'ate 238.1 Natural Plym'er B + Con..nt plusyot'-e c'olye:erA 7 144* 1'1 421 027 014 148 132 140 90-God.cent-ate 2301 Nalura: Polymer D + Coagelant D plue Synt-elc Polymer A 100% 144.1 114 436 C.2E 0.14 11 03 100 0C -God Concentrate 2381 Natual Po liner B + Cogulant C plus Sy'trn'elic yIyrnr A 7Y. 1441 103 :0 r29 01 238 195 210 01 -God Concentrate 23801 Snre-reau-al Polyrer B pIun Synthetl Polymer A V07, 144* 113 421 C 27 014 120 13 2 13 0 i02 Go d Corcentrae 238 1 Scorn-atu 'al PolynreB pi psotyrallo oprA P . / 144 1 1h§ 400 020 01 17 0 100 160 3 Gold Concentrate 20 1 mr-natural Polyrre: B plus Syntheti Po yme-rA 1007< 1441 103 386 C29 0:16 23 8 23 5 23 E 04 God Coracentra 2381 Somnrr-IspualPlywe.6rCoapui:A:usSy'+thelkticP A 50% 1+ 4 113 424 027 014 10 124 12E 10 Gold Concentalte 301 Ser-ritl Po1ymr B - Coagulant plan Sy-thetic Pclyme-r 7P%.144;.f10 390 02 051 17 1. itO 16 Gold Corcentrate 2301 SO-eerl Pulyrrw B 4 Coa.ulan! A plus Synthetic PolymerA 10.A 1441 91 33 033 u 4C1 410C 42 6 107 God Corcentrae.200.1 Grris aur3l Polyrer B + Coagulant C plus Synthetic Polymer A - 03 1441 115 424 C 26 0 14 100 124 :1 1! 100 -Gaid Corrcontrare 206.1 itatualatP yern..:S l 7.1r1 A pluaS yrlttl PolymrerA - 1441 11'7 420 C 20 0.14 105 11.4 1 .1 100 God Corceritrate 200.1 naturall Pymer OrCoagulant B plus Syrttetic PolyrrerS A 0% 144; 115 423 36 014 100 10:0 126 17

Claims

1. A method for enhancing filtration performance in separating solids from liquids in an aqueous dispersion comprising a solids phase and a liquid phase in a two step process having a physical separation step and a filtration step comprising adding at least one filtration aid promoter and at least one synthetic polymer to the aqueous dispersion during, before or both during and before the physical separation step resulting in a concentrate and filtering the concentrate.

2. The method of Claim 1 wherein the filtration aid promoter comprises at least one of a natural polymer, a semi-natural polymer or a coagulant.

3. The method of Claim 2 wherein the natural polymer comprises a polysaccharide.

4. The method of Claim 3 wherein the polysaccharide is selected from the group consisting of potato starch, xanthan gum, guar, dextran, cellulose derivative and glycosaminoglycan.

5. The method of Claim 2 wherein the coagulant is an inorganic coagulant selected from the group consisting of aluminum sulfate, aluminum chloride, polyaluminum chloride, aluminum chlorohydrate, ferric chloride, ferric sulfate, ferrous sulfate and sodium aluminate.

6. The method of Claim 2 wherein the coagulant is an organic coagulant selected from the group consisting of polymers comprising diallyl dimethyl ammonium chloride, ethylene mine and comonomers of epichlorohydrin and dimethylamine, cationically-modified tannins and melamine formaldehyde. 18 WO 2014/046979 PCT/US2013/059694

7. The method of Claim 2 wherein the semi-natural polymer is selected from the group consisting of lignosulfonate, chemically modified polysaccharide and combinations thereof.

8. The method of Claim 1 wherein the synthetic polymer is a nonionic polymer comprising monomers selected from the group consisting of acrylamide, methacrylamide, hydroxyethyl acrylate and N-vinylpyrrolidone.

9. The method of Claim 1 wherein the synthetic polymer is an anionic polymer comprising monomers selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, vinyl sulfonic acid, allyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, acrylamide, combinations thereof and salts thereof.

10. The method of Claim 1 wherein the wherein the synthetic polymer is a cationic polymer comprising monomers selected from the group consisting of dialkylamino alkyl (meth) acrylate, acid addition salts of dialkylamino alkyl (meth) acrylate, quaternary ammonium salts of dialkylamino alkyl (meth) acrylate, dialkylamino alkyl (meth) acrylamide, acid addition salts of dialkylamino alkyl (meth) acrylamide, quaternary ammonium salts of dialkylamino alkyl (meth) acrylamide, diallyl dimethyl ammonium chloride, acid addition salts of diallyl dimethyl ammonium chloride, and quaternary ammonium salts of diallyl dimethyl ammonium chloride.

11. The method of Claim 1 wherein the synthetic polymer comprises an amphoteric polymer. 19 WO 2014/046979 PCT/US2013/059694

12. The method of Claim 1 wherein the aqueous dispersion comprises a mineral selected from the group consisting of gold, phosphate, silver, platinum, copper, nickel, zinc, lead, molybdenum, iron and coal.

13. A composition for enhancing filtration of mining slurries comprising at least one filtration aid promoter and at least one synthetic polymer.

14. The composition of Claim 13 wherein the filtration aid promoter comprises at least one of a natural polymer, a semi-natural polymer or a coagulant.

15. The composition of Claim 14 wherein the natural polymer comprises polysaccharide.

16. The composition of Claim 15 wherein the polysaccharide is selected from the group consisting of potato starch, xanthan gum, guar, dextran, cellulose derivative and glycosaminoglycan.

17. The composition of Claim 14 wherein the semi-natural polymer is selected from the group consisting of lignosulfonate, chemically modified polysaccharide and combinations thereof.

18. The composition of Claim 14 wherein the coagulant is selected from the group consisting of a) an inorganic coagulant selected from the group consisting of aluminum sulfate, aluminum chloride, polyaluminum chloride, aluminum chlorohydrate, ferric chloride, ferric sulfate, ferrous sulfate and sodium aluminate; b) an organic coagulant selected from the group consisting of polymers comprising diallyl dimethyl ammonium chloride, ethylene imine and comonomers 20 WO 2014/046979 PCT/US2013/059694 of epichlorohydrin and dimethylarnine, cationically-modified tannins and melamine formaldehyde; and c) combinations thereof.

19. The composition of Claim 13 wherein the synthetic polymer is selected from the group consisting of a) anionic polymer comprising monomers selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, vinyl sulfonic acid, allyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, acrylamide, combinations thereof and salts thereof; b) cationic polymer comprising monomers selected from the group consisting of dialkylamino alkyl (meth) acrylate, acid addition salts of dialkylamino alkyl (meth) acrylate, quaternary ammonium salts of dialkylamino alkyl (meth) acrylate, dialkylamino alkyl (meth) acrylamide, acid addition salts of dialkylamino alkyl (meth) acrylamide, quaternary ammonium salts of dialkylamino alkyl (meth) acrylamide, diallyl dimethyl ammonium chloride, acid addition salts of diallyl dimethyl ammonium chloride, and quaternary ammonium salts of diallyl dimethyl ammonium chloride; and c) nonionic polymer comprising monomers selected from the group consisting of acrylamide, methacrylamide, hydroxyethyl acrylate and N vinylpyrrolidone.

20. The composition of Claim 13 wherein the synthetic polymer comprises amphoteric polymer, 21