OA10548A

OA10548A - Method of depressing non-sulfide silicate gangue minerals

Info

Publication number: OA10548A
Application number: OA70155A
Authority: OA
Inventors: D R Nagaraj; Samuel S Wang; James S Lee; Lino Magliocco
Original assignee: Cytec Tech Corp
Priority date: 1995-06-07
Filing date: 1997-12-05
Publication date: 2002-05-30
Also published as: CN1096299C; EP0830208B1; EP0830208A1; PL180674B1; BG62123B1; PL323856A1; RU2139147C1; PT830208E; DE69609507T2; AU701180B2; BR9608582A; CA2222996C; DE69609507D1; ATE194929T1; CN1186456A; AU5733196A; BG102109A; DK0830208T3; CA2222996A1; ES2150672T3

Abstract

A method for the depression of non-sulfide, silicate gangue minerals is provided wherein the depressant is either (1) a polymeric material comprising recurring units of the formula: -[-X-]-x -[-Y-]-y -[-Z-]-z wherein X is the polymerization residue of an acrylamide or mixture of acrylamides, Y is an hydroxy group containing polymer unit, Z is an anionic group containing polymer unit, x represents a residual mole fraction of at least about 35 %, y represents a residual mole fraction of from about 1 to 50 % and z represents a residual mole fraction of from about 0 to about 50 %, or (2) a mixture of said polymer and a polysaccharide.

Description

Λ 010548

METHOD OF DEPRESSING NON-SULFIDE SILICATE GANGUE MINERALS

BACKGROUND OF INVENTION

The présent invention relates to froth flotation processes for recovery of value sulfideminerais from base métal sulfide ores. More particularly, it relates to a method for thedépréssion of non-sulfide silicate gangue minerais in the beneficiation of value sulfideminerais by froth flotation procedures.

Certain theory and practice States that the success of a sulfide flotation processdépends to a great degree on reagents called collectors that impart sélective hydrophobicityto the minerai value which has to be separated from other minerais.

Certain other important reagents, such as the modifiers, are also responsible for thesuccessful flotation séparation of the value sulfide and other minerais. Modifiers include,but are not necessarily limited to, ail reagents whose principal function is neither collectingnor frothing, but usually one of modifying the surface of the minerai so that it does not float.

In addition to attempts at making sulfide collectors more sélective for value sulfideminerais, other approaches to the problem of improving the flotation séparation of valuesulfide minerais hâve included the use of modifiers, more particularly depressants, todepress the non-sulfide gangue minerais so that they do not float along with sulfidesthereby reducing the levels of non-sulfide gangue minerais reporting to the concentrâtes.A depressant is a modifier reagent which acts selectively on certain unwanted minerais andprevents or inhibits their flotation.

In sulfide value minerai flotation, certain non-sulfide silicate gangue minerais présenta unique problem in that they exhibit natural floatability, i.e. they float independent of thesulfide value minerai collectors used. Even if very sélective sulfide value minerai collectorsare used, these silicate minerais report to the sulfide concentrâtes. Talc and pyrophyllite,both belonging to the class of magnésium silicates, are particularly troublesome in that theyare naturally highly hydrophobie. Other magnésium silicate minerais belonging to theclasses of olivines, pyroxenes, and serpentine exhibit various degrees of floatability thatseems to vary from one ore deposit to the other. The presence of these unwanted mineraisin sulfide value minerai concentrâtes causes many problème i.e. a) they increase the massof the concentrâtes thus adding to the cost of handling and transportation of theconcentrais, b) they compete for space in the froth phase during the flotation stage therebyreducing the overall sulfide value minerai recovery, and c) they dilute the sulfide concentratewith respect to the value sulfide minerai content which makes them less suitable, and in 2 010548 some cases unsuitable, for the smelting thereof because they interfère with the smeltingoperation.

The depressants commonly used in sulfide flotation include such materials asinorganic salts (NaCN, NaHS, SO2, sodium metabisulfite etc) and small amounts of organiccompounds such as sodium thioglycolate, mercaptoethanol etc. These depressants areknown to be capable of depressing sulfide minerais but are not known to be depressantsfor non-sulfide minerais, just as known value sulfide collectors are usually not goodcollectons for non-sulfide value minerais. Sulfide and non-sulfide minerais hâve vastlydifferent bulk and surface Chemical properties. Their response to various Chemicals is alsovastly different. At présent, certain polysaccharides such as guar gum and carboxy methylcellulose, are used to depress non-sulfide silicate gangue minerais during sulfide flotation.Their performance, however, is very variable and on some ores they show unacceptabledepressant activity and the effective dosage per ton of ore is usually very high (as muchas 1 to 10 Ibs/ton). Their depressant activity is also influenced by their source and is notconsistent from batch to batch. Furthermore, these polysaccharides are also valuablesources of food l.e. their use as depressants reduces their usage as food and, storagethereof présents particular problems with regard to their attractiveness as food for vermin.Lastly, they are not readily miscible or soluble in water and even where water solutionsthereof can be made, they are not stable. U.S. Patent 4,902,764 (Rothenberg et al.)describes the use of polyacrylamide-based synthetic copolymers and terpolymers for useas sulfide minerai depressants in the recovery of value sulfide minerais. U.S. Patent4,720,339 (Nagaraj et al) describes the use of polyacrylamide-based synthetic copolymersand terpolymers as depressants for silicious gangue minerais in the flotation beneficiationof non-sulfide value minerais, but not as depressants in the beneficiation of sulfide valueminerais. The '339 patent teaches that such polymère are effective for silica dépressionduring phosphate flotation which also in the flotation stage uses fatty acids and non-sulfidecollectors. The patentées do not teach that such polymère are effective depressants fornon-sulfide silicate gangue minerais in the recovery of value sulfide minerais. In fact, suchdepressants do not exhibit adéquate depressant activity for non-sulfide silicate mineraisduring the beneficiation of sulfide value minerais. U.S. Patent 4,220,525 (Petrovich)teaches that polyhydroxyamines are useful as depressants for gangue minerais indudingsilica, silicates, carbonates, sulfates and phosphates in the recovery of non-sulfide mineraivalues. Illustrative examples of the polyhydroxyamines disclosed include aminobutanetriols,aminopartitols, aminohexitols, aminoheptitols, aminooctitols, pentose-amines, hexoseamines, amino-tetrols etc. U.S. Patent 4,360,425 (Lim et al) describes a method for 3 010548 improving the results of a froth flotation process for the recovery of non-sulfide mineraivalues wherein a synthetic depressant is added which contains hydroxy and carboxyfunctionafities. Such depressants are added to the second or amine stage flotation of adouble float process for the purpose of depressing non-sulfide value minerais such asphosphate minerais during amine flotation of the siliceous gangue from the second stageconcentrate. This patent relates to the use of synthetic depressant during amine Notationsonly.

In view of the forgoing and especially in view of the teachings of U.S. 4,902,764which teaches the use of certain polyacrylamide-based copolymers and terpolymers forsulfide minerai dépréssion during the recovery of value sulfide minerais, we hâveunexpectedly found that certain polymers, atone or in conjunction with polysaccharides, areindeed excellent depressants for non-sulfide silicate gangue minerais (such as talc,pyroxenes, olivines, serpentine, pyrophyllite, chlorites, biotites, amphiboles, etc). This resuitis unexpected because such depressants hâve been disciosed only as sulfide ganguedepressants. These synthetic depressants hâve now been found to be excellentalternatives to the polysaccharides used currently alone since they, and the blends withpolysaccharides, are readily miscible or soluble in water, are non-hazartious and their watersolutions are stable. The use thereof will increase the availability of the polysaccharidesas a valuable human food source and their performance is not variable. They can bemanufactured to adhère to stringent spécifications and, accordingly, batch-to-batchconsistency is guaranteed. The synthetic polymers lend themselves readily to modificationof their structure, thereby permitting tailor-making of depressants for a given application.

SUMMARY OF THE INVENTION

In accordance with the présent invention there is provided a method whichcomprises beneficiating value sulfide minerais from ores with the sélective rejection of non-sulfide silicate gangue minerais by. a. providing an aqueous pulp slurry of finely-divided, liberation-sized oreparticles which contain said value sulfide minerais and sald non-sulfidesilicate gangue minerais; b. conditioning said pulp slurry with an effective amount of non-sulfide silicategangue minerai depressant, a value sulfide minerai collector and a frothingagent, sald depressant comprising either (1) a polymer comprising: (i) x units of the formula: 4 010548 (ii) y units of the formula: (iii) z units of the formula: w wherein X is the polymerization residue of an acrylamide monomer or mixture of acrylamidemonomers, Y is an hydroxy group containing polymer unit, Z is an antonio group containingpolymer unit, x represents a residual mole percent fraction of at least about 35%, y is amole percent fraction ranging from about 1 to about 50% and z is a mole percent fractionranging from about 0 to about 50% or (2) a mixture of said polymer and a polysaccharide,and c. collecting the value sulfide minerai having a reduced content of non-sulfide silicate gangue minerais by froth flotation. 5 010548

DESCRIPTION OFTHE INVENTION INCLUDING PREFERRED EMBODIMENTS

The polymer depressants of the above formula may comprise, as the (i) units, thepolymerization residue of such acrylamides as acrylamide per se, alkyl acrylamides suchas methacrylamide, ethacrylamide and the like.

The (ii) units may comprise the polymerization residue of monoethylenicallyunsaturated hydroxyl group containing copolymerization monomers such ashydroxyalkylacrylates and méthacrylates e.g. 1,2-dihydroxypropyl acrylate or méthacrylate;hydroxyethyl acrylate or méthacrylate; glycidyl méthacrylate, acrylamido glycolic acid;hydroxyalkylacrylamidessuchas N-2-hydroxyethylacrylamide; N-1 -hydroxypropylacrylamide;N-bis(1,2-dihydroxyethyl)acrylamide; N-bis(2-hydroxypropyl)acryfamide; and the like.

It is preferred that the (ii) units monomers be incorporated into the polymericdepressant by copolymerization of an appropriate hydroxyl group containing monomer,however, it is also permissibie to impart the hydroxyl group substituent to the alreadypolymerized monomer residue by, for example, hydrolysis thereof or post-reaction of agroup thereof susceptible to attachaient of the desired hydroxyl group with the appropriatereactant material e.g. glyoxal, such as taught In U.S. 4,902,764, hereby incorporated hereinby référencé. Glyoxylated polyacryfamide should, however, contain less than about 50 molepercent glyoxylated amide units, i.e. preferably less than about 40 mole percent, morepreferably less than 30 mole percent, as the Y units. It is preferred that the Y units of theabove formula be a ηοη-α-hydroxyl group of the structure C-0

A-CHR-(CHR)^OH wherein A is O or NH, R and R’ are, individually, hydrogen or a C,-C4 alkyl group and n is 1- 3, inclusive.

The (iii) units of the polymers useful in the depressants herein comprise thepolymerization residue of an anionic group containing monoethylenically unsaturated,copoiymerzable monomer such as acrylic acid, methacrylic acid, alkali métal or ammoniumsalts of acrylic and/or methacrylic acid, viriyl sülfonate, vinyl phosphonate, 2-acrylamido-2-methyl propane sulfonic acid, styrene sulfonic acid, maleic acid, fumaric acid, crotonic acid, 2- sulfoethylmethacrylate; 2-acrylamido-2-methyl propane phosphonic acid and the like. 6 010548

Altematively, but less desirably, the anionic substituents of the (iii) units of thepolymère used herein may be imparted thereto by post-réaction such as by hydrolysis ofa portion of the (i) unit acrylamide polymerization residue of the polymer as also discussedin the above-mentioned '764 patent.

The effective weight average molecular weight range of these polymère issurprisingly very wide, varying from about a few thousand e.g. 5000, to about millions e.g.10 million, preferably from about ten thousand to about one million.

The polysaccharides useful as a component in the depressant compositions usedin the process of the présent invention include guar gums; modified guar gums; cellulosicssuch as carboxymethyl cellulose; starches and the like. Guar gums are preferred.

The ratio of the polysaccharide to the polymer in the depressant blend should rangefrom about 9:1 to about 1:9; respectively, preferably from about 7:3 to about 3:7,respectively, most preferably from about 3:2 to 2:3 respectively.

The dosage of the polymer depressant alone or in combination with thepolysaccharide, useful in the method of the présent invention, ranges from about 0.01 toabout 10 pounds of depressant per ton of ore, preferably from about 0.1 to about 5 ibJton,most preferably from about 0.1 to about 1.0 IbJton.

The concentration of (i) units in the depressants used herein should be at leastabout 35% as a mole percent fraction of the entire polymer, preferably at least about 50%.The concentration of the (ii) units should range from about 1 to about 50%, as a molepercent fraction, preferably from about 5 to about 20%, while the concentration of the (iii)units should range from about 0 to about 50%, as a mole percent fraction, preferably fromabout 1 to about 50% and more preferably from about 1 to about 20%. Mixtures of thepolymère composed of the above X, Y and Z units may also be used in ratios of 9:1 to 1:9.

The new method for benefidating value sulfide minerais employing the syntheticdepressants of the présent invention provides excellent metallurgical recovery with improvedgrade. A wide range of pH and depressant dosage are permissible and compatibility of thedepressants with frothere and sulfide value minerai collectors is a plus.

The présent invention is directed to the sélective removal of non-sulfide silicategangue minerais that normally report to the value sulfide minerai flotation concentrate, eitherbecause of naturel floatability or hydrophobidty or otherwise. More particulariy, the instantmethod effects the dépression of non-sulfide magnésium silicate minerais while enablingthe enhanced recovery of sulfide value minerais. Thus, such materials may be treated as,but not limited to, the following:

Talc 7 010548 - Pyrophyllite

Pyroxene group of MineraisDiopsideAugite

Homeblendes

Enstatite

Hypersthene

Ferrosilite

Bronzite

Amphibole group of mineraisTremoliteActinoliteAnthophyllite

Biotite group of mineraisPhlogopiteBiotite

Chlorite group of mineraisSerpentine group of minerais

Serpentine

Chrysotile

Palygorskite

Lizardite

Anitgorite

Olivine group of mineraisOlivineForsteriteHortonoliteFayalite

The following examples are set forth for purposes of illustration only and are not tobe construed as limitations on the présent invention except as set forth in the appendeddaims. Ail parts and percentages are by weight unless otherwise specified. In theexamples, the following designate the monomers used: AMD = acrylamide DHPM = 1,2-dihydroxypropyl méthacrylate HEM = 2-hydroxyethyl méthacrylate AA = acrylic add MAMD = methacrytamide VP = vinylphosphonate GPAM a glyoxylated poly(acrylamide) APS = 2-acrylamido-2-methylpropane sulfonic add VS = vinylsulfonate CMC = carboxymethyl celluloset-BAMD = t-butylacryiamideHPM s 2-hydroxypropyl méthacrylateHEA = 1-hydroxyethyl acryfateHPA = 1-hydroxypropyl acrylateDHPA = 1,2-dihydroxypropyl acrylateNHE-AMD = N-2-hydroxyethylacrylamideNHP-AMD = N-2-hydroxypropylacrylamide 8 0î0$48 NBHE-AMD = N-bis(1,2-dihydroxyethyl)acrylamide NBEP-AMD = N-bis(1-hydroxypropyl)acryiamide S EM = 2-sulfethylmethacrylate AMPP = 2-acrylamido-2-methylpropane phosphonic acid C = comparative

Exemples 1-41

Test Procedures

Pure Talc Flotation

The depressant activity of the polymers is tested using a high grade talc sample ina modified Hallimond tube. 1 Part of talc of size -200+400 mesh is suspended in water andconditioned for 5 min. at the desired pH. A known amount of polymer depressant solutionis added and the talc is further conditioned for 5 min. The conditioned talc is thentransferred to a flotation cell, and flotation is conducted by passing nitrogen gas for a.prescribed length of time. The floated and unfloated talc are then filtered separately, driedand weighed. Per cent flotation is then calculated from these weights.

The depressant activity (as measured by % talc flotation; the lower the talc flotation,the greater is the depressant activity) of depressants having varying molecular weights isshown in Table 1. These examples dearly demonstrate that the polymer depressants ofthe présent invention depress talc flotation. In the absence of any polymer, talc flotationis 98%; in the presence of the polymers, talc flotation is in the range of 5 to 58%. Thedepressant activity, in general, is greater at the high molecular weight. The depressantactivity also increases with the proportion of the hydroxy group containing comonomer. 010548

Table 1

Depressant Concentration: 100 ppm; 8 min. fiotation; pH 9

Example Depressant % Talc Fiotation 1C None 98 2 AMD/DHPM, 95/5, MW 10,000 31 3 AMD/DHPM, 90/10, MW 10,000 22 4 AMD/DHPM. 80/20, MW 10,000 19 5 AMD/DHPM, 50/50, MW 10,000 20 6 AMD/HEM, 95/5, MW Ί 0,000 56 7 AMD/HEM, 90/10, MW 10,000 23 8 AMD/DHPM, 90/10, MW 3,000 58 9 AMD/DHPM, 90/10, MW 10,000 32 10 AMD/DHPM, 90/10, MW 20,000 25 11 AMD/DHPM, 90/10, MW 297,000 22 12 AMD/DHPM, 90/10, MW 397,000 5 13 AMD/DHPM, 90/10, MW 878,000 7 14 AMD/HEM, 90/10, MW 3000 45 15 AMD/HEM, 90/10, MW 10,000 12 16 AMD/HEM, 90/10, MW 20,000 13 17 AMD/HEM, 90/10, MW 116,000 15 18 AMD/HEM, 90/10, MW 286,000 20 19 AMD/HEM, 90/10, MW 458,000 18 20 AMD/HEM, 90/10, MW 656,000 18 21 AMD/DHPM/AA 80/10/10, MW 7000 24 22 AMD/HEM/AA 80/10/10, MW 8800 38

The depressant activity at varying dosage of various polymer depressants of theprésent invention at molecular weights of 10,000 and 300,000 is given in Table 2. Ingeneral, the depressant activity increases with the dosage of the polymer. At the highmolecular weight, the dosage of the polymer required for a given dépression is significantlylow. 10 010548

Table 2 pH 9; 8 min. Flotation

Example Depressant % TalcFlotation 23C None 98 24 AMD/DHPM, 90/10, MW 10,000, 5 ppm 70 25 AMD/DHPM, 90/10, MW 10,000, 10 ppm 59 26 AMD/DHPM, 90/10, MW 10,000, 40 ppm 40 27 AMD/DHPM, 90/10, MW 10,000, 100 ppm 21 28 AMD/HEM, 90/10, MW 10,000, 5 ppm 52 29 AMD/HEM, 90/10, MW 10,000, 10 ppm 28 30 AMD/HEM, 90/10, MW 10.000,100 ppm 22 31 AMD/DHPM, 90/10, MW 300,000, 1 ppm 30 32 AMD/DHPM, 90/10, MW 300,000, 2.5 ppm 12 33 AMD/DHPM, 90/10, MW 300,000,100 ppm 5 34 AMD/HEM, 90/10, MW 300,000 1 ppm 42 35 AMD/HEM, 90/10, MW 300,000 10 ppm 20 36 AMD/HEM, 90/10, MW 300,000 100 ppm 20

The depressant activity of a 90/10 acrylamide/dihydroxypropylmethacrylate copolymer atdifferent pH values is given in Table 3. These results demonstrate that the depressantactivity is maintained in the wide pH range of 3.5-11.

Table 3 AMD/DHPM 90/10: MW 10,000: DOSAGE 100 PPM; 8 MIN. FLOTATION NO DEPRESSANT: 95-98% FLOTATION IN THE pH RANGE USED Example PH % Talc Flotation 37 3.5 20 38 5 35 39 7 25 40 9 23 41 11 26 11 010548 “ Examples 42-45

Natural Sulfide Ore Flotation

Ore 1

This ore containing approximately 2.25% Ni and 28% MgO (in the form of Mg silicates) isground in a laboratory rod mill to obtain a pulp at size of 80% -200 mesh. This pulp istransferred to a flotation cell, conditioned at the natural pH (-8.5) with 200 parts/ton ofcopper sulfate for 4 min., then with 175 parts/ton of sodium ethyl xanthate for 2 min.,followed by conditioning with the desired amount of the polymer depressant and an alcoholfrother for 1 min. Flotation is then carried out by passing air at approximately 5.5 l/min.,and four concentrâtes are taken. The concentrâtes and the tails are then filtered, dried andassayed.

The results for two terpolymers depressants of the présent invention are compared withthose of guar gum in Table 4. The objective here is to decrease the Mg-silicate recovery(as identified by MgO as an indicator) into the sulfide flotation concentrais while maintainingas high a Ni recovery and Ni grade as possible. The results in Table 4 aemonstrate thatthe two terpolymer depressants of the présent invention provided about 3 units lower MgOrecovery while providing equal of slightly better Ni recovery and Ni grade at only 75% of theguar gum dosage. In the absence of any depressant, the MgO recovery is much higher(27%) which is unacceptable.

Table 4

Feed Assay: 2.25% Ni and 27.7 MgO

Exampie Depressant p/t Cum. Wt.%. C1-4 Ni Rec. Ni Grade MgO Rec. 42C None 0 36.87 80.5 5.0 27.0 43C Guar Gum 175 31.10 76.1 5.4 21.5 44 AMD/DHPM/AA80/10/10, 7K 130 27.88 77.6 6.4 18.6 45 AMD/HEM/AA80/10/10, 9K 130 26.98 75.1 6.3 18.5 12 010548

Examples 46-65

Ore 2

This ore containing approximately 3.3% Ni and 17.6% MgO (in the form of Mgsilicates) is ground in a laboratory rod mill (or 5 min. to obtain a pulp at a size of 81% -200mesh. The ground pulp is then transferred to a dotation cell, and is conditioned at thenaturel pH (-8-8.5) with 150 parts/ton of copper sulfate for 2 min., 50 to 100 parts/ton ofsodium ethyf xanthate for 2 min. and then with the desired amount of a depressant and analcohol for 2 min. First stage dotation is then conducted by passing air at approximately3.5-5 l/min. and a concentrate is collected. In the second stage, the pulp is conditioned with10 parts/ton of sodium ethyf xanthate, and desired amounts of the depressant and thefrother for 2 min. and a concentrate is collected. The conditions used in the second stageare also used in the third stage and a concentrate is collected. Ail of the dotation productsare filtered, dried and assayed.

In Table 5, the depressant activity of several copolymer and terpolymer depressantsis compared with that of guar gum at two different dosages. In the absence of anydepressant, the Ni recovery is 96.6% which is considered very high and désirable; the MgOrecovery is 61.4% which is also very high, but considered highly undesirable. The Ni gradeof 4.7% obtained is only slightly higher than that in the original feed. With guar gum at 420and 500 parts/ton, the MgO recovery is in the range of 28.3 to 33.5% which is considerablylower than that obtained in the absence of a depressant, and Ni recovery is about 93%which is lower than that obtained in the absence of depressant. A réduction in Ni recoveryis to be expected in the process of reducing MgO recovery since there is invariably somemineralogical association of Ni minerais with the Mg-silicates; when the latter aredepressed, some Ni minerais are also depressed. The synthetic polymer depressants ofthe présent invention show much stronger depressant activity than guar gum; the MgOrecoveries are in the range of 6.3 to 15.3% compared with 28.3-33-5% for guar gum.These results indicate that significantly lower dosage of the synthetic depressants can beused if results similar to those of guar gum are desired. The terpolymer containing 10 partseach of methacrylamide and dihydroxypropyl méthacrylate provides depressant activity thatis similar to that of guar gum. Similarty, a terpolymer of AMD, DHPM and vinylphosphonate provides metallurgy that is similar to guar gum.

It is pertinent to note here that polyacrylamide reacted with glyoxylic acid, containing pendant hydroxyl and carboxyl groups, shows depressant activity at a degree of substitution of 10% (i.e. 10 parts of the amide groups in the polyacrylamide are reacted with glyoxylic acid.) At a degree of substitution of 50%, depressant activity is weaker. 13 0 1 0548

Table 5

Feed Assay: 3.31% Ni and 17.58% MgO

Example Depressant p/t Ni Rec. Ni Grade MgO Rec. 46C None 0 96.6 4.7 61.4 47C Guar Gum 350+70+80 93.0 7.7 28.3 48C Guar Gum 300+60+60 92.9 6.7 33.5 49 AMD/DHPM 90/10, 397K 350+60+60 84.5 10.5 12.6 50 AMD/DHPM 90/10, 878K 350+70+80 81.8 12.6 8.2 51 AMD/DHPM 90/10, 878K 280+56+64 84.2 8.0 15.3 52 AMD/DHPM 80/20, 500K 350+70+80 80.3 11.5 9.8 53 AMD/DHPM 80/20, 800K 350+70+80 71.4 11.8 6.3 54 AMD/MAMD/DHPM80/10/10, 6.23K 350+85+ 100 92.3 7.2 37.6 55 AMD/MAMD/VP 80/10/10,12.1K 350+85+ 100 93.1 7.8 31.8 56 GPAM (90/10) 350+70+80 93.3 6.3 43.7 57C GPAM (50/50) 350+70+80 99.0 4.7 63.4 58 AMD/HPM 90/10 350+85+ 100 94.6 6.4 44.0 59 AMD/HEM 90/10, 656K 250+60+70 86.4 7.0 27.9 60 AMD/DHPM/HEM 95/5/5 280+56+64 84.1 6.9 23.9 61 AMD/DHPM/AA 80/10/10,750K 250+60+70 91.8 5.6 39.2 62 -do- 280+56+64 89.6 6.2 28.1 63 AMD/DHPM/AA 85/10/5,800K -do- 89.6 7.2 24.6 64 AMD/DHPM/APS80/10/10, 11.7K 250+60+70 95.0 6.5 47.5 65 AMD/DHPM/VS 80/10/10,7.78K -do- 94.1 7.0 42.9 65A Polymer of Examples 59and 61 in a ratio of 1:1 350+70+80 92.5 10.3 16.8 14 010548

Examples 66-79

Ore 3

This ore has approximately 2.1% Ni and 17% MgO. 1000 Parts of ore is groundin a rod mill to obtain a pulp that has a size of 80% passing 20 mesh. The ground pulpis conditioned for 2 min. with 200 parts/ton of copper sulfate, 2 min. with 100 parts/ton 5 of sodium ethyl xanthate and the required amount of frother, and then for 2 min. withthe desired amount of the depressant. Flotation is then conducted by passing air, anda concentrate is taken. In the second stage, the pulp is conditioned with 40 parts/tonof xanthate and additional amounts of the same depressant, and a second concentrateis taken. A third stage flotation is conducted similarty and a concentrate is taken. Ail 10 of the flotation products are filtered, dried and assayed.

The results for the depressant activity of several of the synthetic copolymer and terpolymer depressants of the présent invention are compared with that of guar gum(at two dosages) in Table 6. These results demonstrate clearly that the depressants.provide metallurgy that is equai or better than that of guar gum at 40 to 70% of the guar 15 gum dosage. In many examples, improved Ni recovery is obtained while maintaininga low MgO recovery indicating gangue silicate minerai dépréssion. 15 010548

Table 6

Feed Assay: Ni 2.06%; MgO 17% - Xanthate Rougher Float

Example Depressant Dose p/t Cum. Wt.% Grade Cum. Rec. % Ni Ni MgO 66C GUAR 200 27.9 6.11 84.6 13.1 67C GUAR 250 27.0 6.31 84.4 12.1 68 AMD/DHPM 90/10, 397K 100 29.4 6.20 86.6 13.5 69 AMD/DHPM 90/10, 397K 140 27.5 6.29 85.6 12.7 70 AMD/DHPM 90/10, 878K 100 28.0 6.45 85.6 12.5 71 AMD/DHPM 90/10, 878K 180 28.3 6.39 84.8 12.8 72 AMD/HEM 90/10, 286K 140 27.9 6.22 85.1 12.8 73 AMD/HEM 90/10, 286K 180 26.7 6.66 84.4 10.9 74 AMD/HEM 90/10, 656K 100 27.9 6.54 85.2 12.1 75 AMD/HEM 90/10, 656K 180 26.6 6.50 83.7 11.2 76 AMD/DHPM/AA 80/10/10,750K 140 28.3 6.15 84.5 12.6 77 AMD/DHPM/AA 80/10/10,750K 180 27.8 6.48 85.4 12.4 78 AMD/HEM/AA 80/10/10,224K 140 28.9 6.18 86.0 13.8 79 AMD/HEM/AA 80/10/10,224K 180 27.4 6.33 84.2 12.5

Examples 80-83

Ore 4

This ore containing approximately 0.6% Ni and about 38% MgO (in the form of Mgsilicates) is ground in a laboratory rod mil! to obtain a puip at a size of 80% -200 mesh.This ground puip is deslimed, conditioned for 20 min. with 120 parts/ton of sodium ethylxanthate and the desired amount of frother. Flotation is then conducted and a concentrateis collected for 4 min. This concentrate is then conditioned for 1 min. with 20 parts/ton ofsodium ethyl xanthate and with the specified amount of the depressant. A cleaner flotation 16 010548 is then carried out for 3.5 min. The concentrate and tails are then filtered, dried andassayed.

The results for the depressant activity of three synthetic polymer depressants arecompared with that of guar gum in Table 7. It is again évident from the results in Table 7that the synthetic depressants of this invention provide metallurgy that is equal to or betterthan guar gum at 40 to 80% of the guar dosage. With two of the depressants the Nirecovery is significantly improved while maintaining low MgO recoveries.

Table 7

Example Depressant Dose (p/t) Cum. Wt.% Grade Cum. Recovery Ni Ni MgO 80C Guar 30 3.8 9.2 62.6 2.3 81 AMD/DHPM 90/10, 397K 15 4.4 9.1 65.8 2.6 82 AMD/DHPM 90/10, 397K 12.5 4.7 7.5 66.2 3.0 83 AMD/HEM/AA 80/10/10,224K 24 3.8 9.0 61.7 2.4

Exemptes 84*96

Ore 5

This ore containing small amounts of NI, Cu and Fe in the form of sulfides, smallamounts of platinum and palladium, and approximately 7.5% MgO (in the form of Mgsilicates) is ground in a laboratory rod mill with 15 parts/ton of potassium amyl xanthate and12.5 parts/ton of diisobutyl dithiophosphate for 10 min. to obtain a pulp at a size of 40% -200 mesh. The ground pulp is then transferred to a flotation cell, and is conditioned for 2min. at the natural pH (-8.2) with the same amounts of collectors as in the grind, followedby conditioning with the specified amount of depressant and an alcohol frother for 2 min.Flotation is then conducted by passing approximately 3.5-5 l/miri. of air and a concentrateis collected. The procedure used in the first stage of flotation is followed in the secondstage and a second concentrate is collected. The flotation products are then filtered, driedand assayed.

The results for the depressant activity of a variety of synthetic polymer depressantsof the présent invention are compared in Table 8 with that of two carboxy methyl cellulosesamples from different sources. The objective here is to obtain high recovery and grades 17 010548 of Pt and Pd in the concentrate. In the absence of any depressant, the recovery of Pt andPd is indeed very high (97.5% and 94-95% respectively), but the concentrate grades areunacceptably low. With the CMC depressants, the Pt and Pd recoveries are 95-96.5% and92-94.6%, respectively, and the grades are 3-3.1 for Pt and 12.7-13 for Pd. It is évidentfrom the results that the synthetic polymer depressants provide Pt and Pd metallurgy thatis equal to or better than that of CMC samples and at significantly lower dosages (60-80%of the CMC dosage). It is also évident that the synthetic polymer depressants providebetter grades for the Pt which is a more important and much higher value métal than Pd.In Example 88, a polymer containing only 0.5 part of the t-butyl acrylamide in addition toDHPM provides Pt metallurgy that is equal to that of CMC(B) but at 80% of the dosage ofCMC.

Table 8

Feed Assay: 5.8 p/t Pt; 22 p/t Pd

Exempte Depreuant p/t Pt Ree. Pt Grade Pd Rec. Pd Grade 84C Non· 0 97,5 1.6 95.0 6.0 8SC Norte 0 97.6 23 94.4 72 86C CMC-A 500 95.2 3.1 92.0 12.7 87C CMC-B 500 96.5 3.0 94.6 13.0 88 AMD/OHPMA-BAMD 89.5/1 σθ.5 400 96.5 3.1 93.1 11.6 89 AMD/DHPM/AA 8010/10, 75OK 400 96.6 2.1 93.2 7.4 90 AMD/DHPM/AA 8010/10, 750K 500 92.9 4.6 88.3 14.7 91 AMD/HEM/AA 8010/10, 224K 370 94.5 3.8 92.1 13.9 92 AMO/HEM/AA 8010/10, 224K 300 95.3 42 91.4 16.4 93 AMO/HEM/AA 801010. 224K 400 96.6 2.7 94.1 10.6 94 AMD/DHPM/AA 85/105 400 96.8 3.2 93.4 11.2 95 AMD/DHPM/VP 801010. 12K 370 96.9 2.8 94.1 10.4 96 AM0/DHPM/MAM0 801010 400 94.8 1.6 91.9 6.5

Examples 97-99

Ore 6

This ore contains 0.85% Ni and 39% MgO. 1000 Parts of the ore are ground in arod mill to give a flotation feed of size 80% passing 200 mesh. The ground pulp isconditioned for 30 min. with the desired amount of a depressant along with 500 parts/tonsodium ethyt xanthate. Rougher flotation is then carried out for 25 min. The rougherconcentrate is then conditioned with the specified amount of depressant and 10 parts/ton 18 010548 of sodium ethyl xanthate and a cleaner flotation is carried out for 15 min. The flotationproducts are filtered, dried and assayed.

The resuits for two synthetic copolymers of AMD/DHPM are compared with that ofCMC in Table 9. These resuits demonstrate that the synthetic depressants providemetallurgy that is equal to or better than that of CMC, but at about 27% of the CMCdosage. In the case of the copolymer with a molecular weight of 878,000, the MgOrecovery in both the regular and cleaner concentrate is significantly lower than that obtainedwith CMC.

Table 9

Feed Assay: Ni 0.85%; MgO 39%

Example Depressant Dose p/t Total Product Grade Ni Cum. Recovery, % Wt Ni MgO 97C CMC 275 1 CIConRoCon 15.44 3.21 3.48 21.17 60.8 76.8 2.3 20.6 98 AMD/DHPM 90/10, 878K 75 1 CIConRoCon 18.01 3.78 2.73 15,92 59.3 72.6 1.5 14.6 99 AMD/DHPM 90/10, 397K 75 1 CIConRoCon 14.48 2.83 3.41 21.96 61.6 77.6 2.1 20.7

Examples 100-109

Ore 7

This ore containing small amounts of Ni, Cu, and Fe in form of sulfides and about17% MgO (in the form of Mg silicates) is ground in a laboratory bail mill for 12 min. toobtain a puip at a size of 40% -200 mesh. The ground pulp is then transferred to a flotationcell, and is conditioned at the natural pK (-7.2) with the specified amount of a depressantfor 3 min., followed with 16 parts/ton of sodium isobutyl xanthate and 34 parts/ton of adithiophosphate and a polyglycol frother for 3 min. Flotation is then conducted by passingair at approximately 3.5 l/min. and two concentrâtes are collected. The flotation productsare then filtered, dried and assayed.

The resuits for the depressant activity of a variety of synthetic polymer depressantsof the présent invention are compared with that of a modified guar in Table 10. Theobjection here is to minimize the recovery of SiO2, CaO, MgO, AI203 - ail of whichrepresent the silicate minerais présent in the sulfide concentrâtes - and to maintain orimprove the recovery of Ni and Cu which constitute the value sulfide minerais. In theabsence of any depressant, the Ni and Cu recoveries are 49.5% and 79%, respectively, but 010548 19 the recovery of the gangue constituents is very high (9.4% for SÏO2, 7,4% for CaO, 10.6%for MgO and 5.8% for AI203). With guar, both the Ni and Cu recoveries are slightlyreduced, perhaps because of dépréssion of some silicate minerais that carry Ni and Cusulfides as minerai locking, but recovery of the gangue constituents is atso reduced. Withali of the synthetic polymer depressants tested, there is a significant réduction in therecovery of the gangue constituents, and with some of them the réduction is far greater thanthat obtained with guar. Ail of the depressants of the présent invention (except one) givehigher copper recoveries than guar; in some cases the copper recoveries are higher thanthat obtained in the absence of the depressant. Also the Ni recoveries obtained with thesynthetic depressants are either equal to or much greater than that obtained with guar. Inthe best case, AMD/HEM 90/10, 10,000 MW, there is more than 50% réduction in SiO2compared to the test with no depressant, and 44% réduction in SiO2 compared to that withguar. Similariy significant réductions are also observed for other gangue constituents.

Table 10

Calculated Head Assays: Cu - 0.07%, Ni - 0.20%; SiO2 - 48.8%; CaO - 5.8%

MgO -17%; AI203 - 9%

Example Depressant p/t Onderot Addn. Copper Nickel Si 02 CaO MgO A12O3 Rec Rec Rec Rec Rec Rec 1OOC Ncne 0 - 79.0 49.5 9.4 7.4 10.6 5.8 101C Guar 60 Depclst 77.2 46.2 7S 5.9 8.6 4.8 102 AMD/HEM 95/5 100k 60 Depr 1st 75.9 46.3 8.5 6.8 9.5 5.6 103 AMO/HEM 9Q/1O 20k 60 Deprlst 78.3 48.6 8.0 6.4 92 52 104 AMD/HEM 90/10 10k 70 Deprlst 81.3 51.0 7.3 5.9 82 4.9 105 AMD/HEM 90/10 10k 70 Reversa 82.4 50.1 42 5.1 7.5 3.9 106 AMD/DHPM 80/20 10k 67 Depr Ist 79.4 46.5 es 4.9 7.4 3.8 107 AMD/DHPM 9CY10 10k 60 Depr ist 79.3 48.2 7.4 5.9 8.5 4.7 108 AMD/DHPM 90/10 10k 60 Reverse 80.2 47.5 6.5 5.0 7S 4.0 109 AMD/DHPM/AA 8010/1010k 60 Depr 1st 78.4 46.3 72 5.9 82 4.9

Example 110

Following the procedure of Example 50 except that the DHPM is replaced by anéquivalent amount of HEA. Similar results are attached.

Example 111

Replacing the HEM of Example 45 with DHPA achieves substantially similar results. 20 010548

Examples 112

Example 53 is again followed but the DHPM is replaced by HPA to achieve similarrecovery.

Example 113

When the HEM of Example 73 is replaced by NHE-AMD similar cumulative recoveryof nickel and magnésium is observed.

Example 114 NBHE-AMD is used to replace DHPM in the Example 88 procedure. The résulte are similar.

Example 115

The DHPM of Example 96 is replaced by NHP-AMD to yield similar platinum andpalladium recoveries.

Example 116 Métal recoveries are similar when the HEM of Example 102 is replaced by NBEP- AMD.

Example 117

Replacement of the AA of Example 22 by SEM résulte in similar % talc flotation.

Example 118

When the VP of Example 55 is replaced by AMPP, similar results are achieved.

Examples 119-127

An ore containing approximately 3.3% Ni and 16.5% MgO (in the form of Mgsilicates) is ground In a laboratory rod miil for 5 minutes to obtain a pulp at a size of 81% -200 mesh. The ground pulp Is then transferred to a flotation cell, and is conditioned at thenatural pH (-8-8.5) with 150 parts/ton of copper sulfate for 2 minutes, 50 to 100 parts/ton ofsodium ethyi xanthate for 2 minutes and then with the desired amount of depressant blendand an aicohol frother for 2 minutes. First stage flotation is then conducted by passing airat approximately 3.5-5 l/min. and a concentrate is collected. In the second stage, the pulpis conditioned with 10 parts/ton of sodium ethyi xanthate, and desired amounts of 21 010548 depressant blend and the frother for 2 minutes and a concentrate is collected. Theconditions used in the second stage are also used in the third stage and a concentrate iscollected. Ail of the flotation products are filtered, dried and assayed.

The depressant activity of a 1:1 blend of AMD/DHPM and guar gum is compared 5 with the individual depressants in Table il. With guar atone the Ni recovery is 93% andMgO recovery is 28.3%. With the synthetic polymer depressant alone, the Ni recovery is84.5% and the MgO recovery is 12.6% which is less than half of that of guar gum, therebyindicating a very strong depressant activity of the synthetic depressant. In the case of theblend, there is a further réduction in MgO recovery and the Ni recovery and grade improve 10 slightly over that of the synthetic depressant. These results demonstrate the greaterdepressant activity obtained with the blend and also suggest that rnuch lower dosages canbe used compared to those of the individuai components.

The depressant activity of a 1:1 blend of AMD/HEM polymer and guar gum iscompared with that of the individuai depressants in Table 2. With guar gum alone, as 15 before, the Ni recovery is 93% and the MgO recovery is 28.3%. With the AMD/HEMcopolymer at the same dosage, the MgO recovery is only 7.7% indicating a very strongdepressant activity; the Ni recovery is also significantly reduced (68.3% vs. 93% for guar).With the blend, however, the Ni recovery improves significantly (82.8%) whilé the MgOrecovery is maintained at the low level of 8.3%. The results also suggest that a 20 considerably lower dosage can be used with the blend to obtain enhanced performance.In fact, when the dosage is lowered to 430 parts/ton, the Ni recovery increases to 86%(from 82.8%) while the MgO recovery increases to 11.5% (from 8.3%). 22 010548

Table II

FEED ASSAY: 3.31% Ni and 17.58% MgO

Example Depressant g/t Ni Rec Ni Grade Mgo Rec. 119C None 0 96.6 4.7 61.4 120C Guar Gum 350+70+80 93.0 7.7 28.3 121C AMD/DHPM 90/10; 397K 300+60+60 84.5 10.5 12.6 122 Guar Gum and AMD/DHPM 1:1 90/10; 397K 350+70+80 85.7 11.0 10.3 123C None 0 96.6 4.7 61.4 124C Guar Gum 350+70+80 93.0 7.7 28.3 125C AMD/HEM 90/10; 656K 350+70+80 68.3 11.4 7.7 126 Guar Gum and AMD/HEM 1:190/10; 656K 300+70+80 82.8 12.2 8.3 127 Guar Gum and AMD/HEM 1:190/10; 656K 30+60+70 86.0 10.3 11.5

Examples 128-143

When the procedures of Examples 119-127 are again followed except that thedepressant components are varied, as are their concentrations, as set forth in Table 12, 20 below, similar results are achieved. 23 010548

Table 12

Example Polymer (PM) Polysaccharide (PS) PM:PS Ratio 128 AMD/MAMD/DHPM 80/10/10; 623K Guar Gum 9:1 129 AMD/DHPM/AA 80/10/10; 7K Starch 1:1 130 -do- 750K CMC 4:1 131 AMD/MAMD/VP 80/10/10; 12K Modified Guar 2:3 132 GPAM (90/10) -do- 1:4 133 AMD/HEM/AA 80/10/10; 9K CMC 1:1 134 AMD/HEM/t-BAMD 89.5/10/0.5 Guar Gum 1:9 135 AMD/DHPM/APS 80/10/10; 11.7K Starch 2:1 136 AMD/DHPM/VS 80/10/10; 7.78K Guar Gum 3:2 137 AMD/HPA 80/20 Guar Gum 1:1 138 AMD/DHPA/AA 80/10/10 Guar Gum 1:1 139 AMD/NHE-AMD 90/10 CMC 1:1 140 AMD/NBHE-AMD/BAMD 89.5/10/0.5 Starch 1:1 141 AMD/NHP-AMD/MAMD 80/10/10 Guar Gum 1:1 142 AMD/NBEP-AMD 95/5 Guar Gum 1:1 143 AMD/HEM/SEM 80/10/10 Guar Gum 1:1

Claims

24 010548 WE CLAIM:

1. A method which comprises beneficiating value sulfide minerais from ores withsélective rejection of non-sulfide silicate gangue minerais by: 5 a. providing an aqueous pulp slurry of finely-divided, liberation-sized ore particles which contain said value sulfide minerais and said non-sulfidesilicate gangue minerais; b. conditioning said puip slurry with an effective amount of non-sulfide silicategangue minerai depressant, a value sulfide minerai collector and a frothing 10 agent, respectively, said depressant comprising either (1) a polymer or a mixture of polymers comprising: 15 20 25 (i) x units of the formula: fx f (ii) y units of the formula w (iii) z units of the formula: w wherein X is the polymerization residue of an acryiamide monomer or mixture of acrylamidemonomers, Y is an hydroxy group containing polymer unit, Z is an anionic group containing 30 polymer unit, x représente a residual mole percent fraction of over about 35%, y is a molepercent fraction ranging from about 1 to about 50% and z is a mole percent fraction rangingfrom about 0 to about 50% or (2) a mixture of said polymer or polymers and apolysaccharide, and c. collecting the value sulfide minerai having a reduced content of non-sulfide 35 silicate gangue minerais by froth flotation. 25 010548
2- A method according to Claim 1 wherein Y has the formula

A I CHH— (CHR1)n- OH 10 wherein A is O or NH, R and R1 are, individualiy, hydrogen or a C, - C4 alkyi group and nis 1-3, inclusive. 15 3. A method according to Claim 1 wherein X is the polymerization residue of acrylamide, Y is the polymerization residue of 1,2-dihydroxypropyl méthacrylate and z is 0.
4. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of 1, 2-dihydroxypropyl méthacrylate, Z is the 20 polymerization residue of acrytic acid and z is a mole percent fraction ranging from about1 to about 50.
5. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of hydroxyethyl méthacrylate and z is 0. 25
6. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of hydroxyethyl méthacrylate, Z is thepolymerization residue of acrylic acid and z is a mole percent fraction ranging from about1 to about 50%. 30
7. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of 1,2-dihydroxypropyt méthacrylate, Z is thepolymerization residue of vinyi sulfonate and z is a mole percent fraction ranging from about1 to about 50%. 35 26 010548 8. -_ A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of 1,2-dihydroxypropyl méthacrylate, Z is thepolymerization residue of vinyl phosphonate and z is a mole percent fraction ranging fromabout 1 to about 50%.
9. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of hydroxyethyl méthacrylate, Z is thepolymerization residue of vinyf sulfonate and z is a mole percent fraction ranging from about1 to about 50%.
10. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of hydroxyethyl méthacrylate, Z is thepolymerization residue of vinyl phosphonate and z is a mole percent fraction ranging fromabout 1 to about 50%.
11. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of 1, 2-dihydroxypropyl méthacrylate, Z is thepolymerization residue of 2-acrylamido-2-methyl propane sulfonic acid and z is a molepercent fraction ranging from about 1 to about 50.
12. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, Y is the polymerization residue of hydroxyethyl méthacrylate, Z is thepolymerization residue of 2-acrylamido-2-methyl propane sulfonic acid and z is a molepercent fraction ranging from about 1 to about 50%.
13. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide and t-butylacrylamlde, Y is the polymerization residue of 1,2-dihydroxypropylméthacrylate and z is 0.
14. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide, and methacrylamide, Y is the polymerization residue of 1,2-dihydroxypropylméthacrylate and z is 0. 27 0 1 054.8
15. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide and methacrylamide, Y is the polymerization residue of hydroxyethylméthacrylate and z is 0. 5 16. A method according to Claim 1 wherein Y represents a glyoxylated acrylamide unit and y is less than about 40.
17. A method according to Claim 1 wherein X is the polymerization residue ofacrylamide and t-butylacrylamide, Y is the polymerization residue of hydroxyethyl 10 méthacrylate and z is O.
18. A method according to Claim 1 wherein the polysaccharide is guar gum.
19. A method according to Claim 1 wherein the polysaccharide is carboxymethyl15 cellulose.
20. A method according to Claim 1 wherein the polysaccharide is starch.