AU576422B2

AU576422B2 - Novel collector composition for froth flotation

Info

Publication number: AU576422B2
Application number: AU55497/86A
Authority: AU
Inventors: Robert D. Hansen; Richard R. Klimpel
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1985-07-12
Filing date: 1986-02-18
Publication date: 1988-08-25
Anticipated expiration: 2006-02-18
Also published as: CN1011945B; PL257992A1; RU1831373C; ZW3986A1; SE461256B; BR8606770A; PL148165B1; YU23186A; YU45767B; CA1267979A; ES8706046A1; SE8701018D0; FI81975C; CN86101646A; ZM1386A1; PH22952A; WO1987000451A1; ES552028A0; MX165319B; ZA861172B

Description

NOVEL COLLECTOR COMPOSITION FOR FROTH FLOTATION

This invention concerns a novel collector composition useful for the recovery of metal-containing sulfide minerals and sulfidized metal-containing oxide minerals from ores by froth flotation.

Flotation is a process of treating a mixture of finely divided mineral solids,- e.g., a pulverulent ore, suspended in a liquid whereby a portion of such solids is separated from other finely divided solids, e.g., clays and other like materials present in the ore, by introducing a gas (or providing a gas in situ) in the liquid to produce a frothy mass containing certain of the solids on the top of the liquid, and leaving suspended (unfrothed) other solid components of the ore. Flotation is based on the principle that introducing a gas into a liquid containing solid par¬ ticles of different materials suspended therein causes adherence of some gas to certain suspended solids and not to others and makes the particles having the gas thus adhered thereto lighter than the liquid. Accord_ ingly, these particles rise to the top of the liquid to form a froth. Various flotation agents have been admixed with the suspension to improve the frothing process. Such added agents are classed according to the function to be performed: collectors, for sulfide minerals including xanthates, thionocarbamates and the like; frothers which impart the property of forming a stable froth, e.g., natural oils such as pine oil and euca¬ lyptus oil; modifiers such as activators to induce flotation in the presence of a collector, e.g., copper sulfate; depressants, e.g., sodium cyanide, which tend to prevent a collector from functioning as such on a mineral which it is desired to retain in the liquid, and thereby discourage a substance from being carried up and forming a part of the froth; pH regulators to produce optimum metallurgical results, e.g., lime, soda ash and the like.

It is of importance to bear in mind that additives of the hereinbefore described types are selected for use according to the nature of the ore, the mineral(s) sought to be recovered, and the other additaments which are to be used in combination there¬ with.

An understanding of the phenomena which make flotation a particularly valuable industrial operation is not essential to the practice of the present inven¬ tion. The phenomena appear, however, to be largely associated with selective affinity of the surface of particulated solids, suspended in a liquid containing entrapped gas, for the liquid on the one hand, the gas on the other. The flotation principle is applied in a number of mineral separation processes among which is the selective separation of such metal sulfide minerals as those containing copper, zinc, lead, nickel, molyb- denum, and other metals from iron-containing sulfide minerals such as pyrite and pyrrhotite.

Among collectors commonly used for the recov¬ ery of metal-containing sulfide minerals or sulfidized metal-containing oxide minerals are xanthates, dithio- phosphates, and thionocarbamates. These volatile

^• sulfur compounds are often released to the atmosphere through smokestacks, or are removed from such smoke¬ stacks by expensive and elaborate scrubbing equipment. Many nonferrous metal-containing sulfide minerals or metal-containig oxide minerals are found naturally in ores which also consist of iron-containing sulfide minerals. When the iron-containing sulfide minerals are recovered in flotation processes along with the nonferrous metal-containing sulfide minerals and sul- fidized metal-containing oxide minerals, there is excess sulfur present which is released in the smelting processes resulting in an undesirably high amount of sulfur present during the smelting operations. What is needed is a collector composition useful for selectively recovering the nonferrous metal-containing sulfide minerals and sulfidized metal-containing oxide minerals, without recovering the iron-containing sulfide minerals.

Of the commercial collectors, the xanthates, thionocarbamates, and dithiophosphates do not selec- tively recover nonferrous metal-containing sulfide minerals in the presence of iron-containing sulfide minerals. On the contrary, such collectors collect and recover all metal-containing sulfide minerals. What is needed is a flotation collector composition which will selectively recover the non¬ ferrous metal-containing sulfide minerals or sulfidized metal-containing oxide minerals in the presence of ferrous sulfides.

This invention concerns a novel composition which is useful as a collector for the recovery of nonferrous metal-containig sulfide minerals and sulfid¬ ized metal-containing oxide minerals from ores in a froth flotation process. The novel composition com¬ prises:

(a) a hydrocarbon containing one or more monosulfide units, wherein the carbon atoms to-which the sulfur atom(s) are bound are aliphatic or cycloali- phatic carbon atoms, and the total carbon content of the hydrocarbon portion is such that the hydrocarbon has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal- -containing oxide mineral particles to be driven to an air/bubble interface; and

(b) an alkyl thiocarbonate, a thionocarba¬ mate, a thiophosphate, or mixtures thereof.

The novel collectors of this invention result in surprisingly high recovery of nonferrous metal-con- taining sulfide minerals or sulfidized metal-containing oxide minerals and good selectivity toward such non¬ ferrous metal-containing sulfide minerals and sulfi¬ dized metal-containing oxide minerals when such metal- containing sulfide minerals or sulfidized metal-con- taining oxide minerals are found in the presence of iron-containing sulfide minerals. These collectors demonstrate good recovery and good kinetics. One component of the novel collector compo¬ sition of this invention is a hydrocarbon which con¬ tains one or more monosulfide units wherein the sulfur atoms of the sulfide units are bound to non-aromatic carbon atoms, i.e., aliphatic or cycloaliphatic carbon atoms. Monosulfide unit refers herein to a unit wherein a sulfur atom is bound to two carbon atoms of a hydro¬ carbon moiety only. Such hydrocarbon compounds con¬ taining one or more monosulfide units, as used herein, include such compounds which are substituted with hydroxy, cyano, halo, ether, hydrocarbyloxy and hydro- carbyl thioether moieties.- Non-aromatic carbon atom refers herein to a carbon atom which is not part of an aromatic ring.

"Preferred hydrocarbons containing monosulfide units include^' those corresponding to the formula

wherein

R 1 and R2 are independently a hydrocarbyl radical or a hydrocarbyl radical substituted with one or more hydroxy, cyano, halo, ether, hydro¬ carbyloxy or hydrocarbyl thioether moieties;

wherein

R 1 and R2 may combine to form a heterocyclic ring structure with S; with the proviso that S is bound to an aliphatic or cycloaliphatic carbon atom; with the further proviso that the total carbon content of the hydrocarbon sulfide be such that it has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral particles to be driven to an air/bubble inter¬ face.

Preferably, R 1 and R2 are independently an aliphatic, cycloaliphatic or aralkyl moiety, unsubsti- tuted or substituted with one or more hydroxy, cyano, halo, OR 3, or SR3 moieties, wherein R3 is a hydrocarbyl radical, wherein R 1 and R2 may combine to form a hetero- cyclic ring with S. R 1 and R2 are more preferably an aliphatic or cycloaliphatic moiety, unsubstituted or

3 substituted with one or more hydroxy, cyano, halo, OR , or SR 3 moieties; wherein R1 and R2 may combine to form a heterocyclic ring with S. In a more preferred embodi- ment, R 1 and R2 do not combi.ne to form a heterocyclic ring with sulfur and R 1 and R2 are alkyl, alkenyl, alkynyl, cycloalkyl ^'or cycloakenyl, unsubstituted or

. . . 3 substituted with one or more hydroxy, halo, cyano, OR

3 . . . 3 . . . .

SR moieties, wherein R is aliphatic or cycloaliphatic. In a most preferred embodiment, R is methyl or ethyl.

R 2 i•s a C, ,.. alkyl or alkenyl group. In the most preferred embodiment, R 1 and R2 are not the same hydro¬ carbon moiety, that is, the monosulfide is asymmetrical. R 3 i.s preferably ali.phatic or cycloaliphati.c. R3 i.s more preferably alkyl, alkenyl, cycloalkyl or cyclo- alkenyl.

The total carbon content of the hydrocarbon portion of the hydrocarbon monosulfide must be such that the hydrocarbon sulfide has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral particles to be driven to the air/bubble interface. Preferably, the total carbon content of the hydrocarbon mono¬ sulfide is such that the minimum carbon number is 4, more preferably 6, and most preferably 8. The maximum carbon content is preferably 20, more prefer-ably 16, and most preferably 12.

Examples of cyclic compounds which are hydro¬ carbon sulfides of this invention include the following structures.

- la lb wherein R is independently aryl, alkaryl, .aralkyl, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, hydroxy, cyano, halo, OR 3, SR3, wherein the aryl, alkaryl, -aralkyl, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl may optionally be substituted with a hydroxy, cyano, halo, OR 3 or SR3 moiety, and the like; and R is a straight- or branched-alkylene, -alkenylene, or -alkynylene, unsubstituted or substituted with a hydroxy, cyano, halo, OR 3 or SR3 moiety.

In another preferred embodiment of this invention, the hydrocarbon sulfides useful in this invention correspond to the formula

<^R5>3-n <^H>n-^s-^c<^H>n<^R6>3-n Ic

wherein

R is independently hydrocarbyl, or hydro¬ carbyl substituted with a hydroxy, cyano, halo,

-.:^~-^~ hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moiety; wherein two R moieties may combine to form a cyclic ring or heterocyclic ring with the sulfur atom; n is an integer of 0, 1, 2 or 3; with the proviso that the total carbon content of the hydrocarbon portion of the collector is such that the collector has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral par¬ ticles to be driven to the air/bubble interface.

Preferably, R is aliphatic, cycloaliphatic, aryl, alkaryl or aralkyl, unsubstituted or substituted with a cyano, hydroxy, halo, OR 3 or SR3 moi.ety, wherein . R is as hereinbefore defined. More preferably, R is an aliphatic or cycloaliphatic moiety, unsubstituted or substituted with a hydroxy, cyano, aliphatic ether, cycloaliphatic ether, aLiphatic thioether or cycloali- c. phatic thioether moiety. Even more preferably, R is an alkyl, alkenyl, cycloalkyl or cycloalkenyl moiety.

Most preferably, one -C(H) (R )₃__n is a methyl or ethyl moiety, and the other is a ^~c __-, -, alkyl or alkenyl moiety. Preferably, n is 1, 2 or 3, and more prefer- ably 2 or 3.

Examples of hydrocarbon sulfides within the scope of this invention include methylbutyl sulfide, methylpentyl sulfide, methylhexyl sulfide, methylheptyl sulfide, methyloctyl sulfide, methylnonyl sulfide, methyldecyl sulfide, methylundecyl sulfide, methyl- dodecyl sulfide, methylcyclopentyl sulfide, methyl- cyclohexyl sulfide, methylcycloheptyl sulfide, methyl- cyclooctyl sulfide, ethylbutyl sulfide, ethylpentyl

• j . ^, ly-πii r- ' sulfide, ethylhexyl sulfide, ethylheptyl sulfide, ethyloctyl sulfide, ethylnonyl sulfide, ethyldecyl sulfide, ethylundecyl sulfide, ethyldodecyl sulfide, ethylcyclopentyl sulfide, ethylcyclohexyl sulfide, ethylcycloheptyl sulfide, ethylcyclooctyl sulfide, propylbutyl sulfide, propylpentyl sulfide, propylhexyl sulfide,. propylheptyl sulfide, propyloctyl sulfide, propylnonyl sulfide, propyldecyl sulfide, propylundecyl sulfide, propyldodecyl sulfide, propylcyclopentyl sulfide, propylcyclohexyl sulfide, propylcycloheptyl sulfide, propylcyclooctyl sulfide, dibutyl sulfide, butylpentyl sulfide, butylhexyl sulfide, butylheptyl sulfide, butyloctyl sulfide, butylnonyl sulfide, butyl- decyl sulfide, butylundecyl sulfide, butyldodecyl sulfide, butylcyclopentyl sulfide, butylcyclohexyl sulfide, butylcycloheptyl sulfide, butylcyclooctyl sulfide, dipentyl sulfide, pentylhexyl sulfide, pentyl- heptyl sulfide, pentyloctyl sulfide, pentylnonyl sul¬ fide, pentyldecyl sulfide, pentylundecyl sulfide, pentyldodecyl sulfide, pentylcyclopentyl sulfide, pentylcyclohexyl sulfide, pentylcycloheptyl sulfide, pentylcyclooctyl sulfide, dihexyl sulfide, hexylheptyl sulfide, hexyloetyl sulfide, hexylnonyl sulfide, hexyl- decyl sulfide, hexylundecyl sulfide, hexyldodecyl sulfide, hexylcyclopentyl sulfide, hexylcyclohexyl sulfide, hexylcycloheptyl sulfide, hexylcyclooctyl sulfide, diheptyl sulfide, heptyloctyl sulfide, heptylnonyl sulfide, heptyldecyl sulfide, heptylundecyl sulfide, heptyldodecyl sulfide, heptylcyclopentyl sulfide, heptylcyclohexyl sulfide, heptylcycloheptyl sulfide, heptylcyclooctyl sulfide, dioctyl sulfide, octylnonyl sulfide, octyldecyl sulfide, octylundecyl sulfide, octyldodecyl sulfide, octylcyclopentyl sul¬ fide, octylcyclohexyl sulfide, octylcycloheptyl sul¬ fide, octylcyclooctyl sulfide, octylcyclodecyl sulfide, dinonyl sulfide, nonyldecyl sulfide, nonylundecyl sulfide, nonyldodecyl sulfide, nonylcyclopentyl sul¬ fide, nonylcyclohexyl sulfide, nonylcycloheptyl sul¬ fide, nonylcyclooctyl sulfide, didecyl sulfide, decyl- undecyl sulfide, decyldodecyl sulfide, decylcyclopentyl sulfide, decylcyclohexyl sulfide, decylcycloheptyl sulfide, and decylcyclooctyl sulfide. More preferred sulfides include methylhexyl sulfide, methylheptyl sulfide, methyloctyl sulfide, methylnonyl sulfide, methyldecyl sulfide, ethylhexyl sulfide, ethylheptyl sulfide, ethyloctyl sulfide, ethylnonyl sulfide, ethyl- decyl sulfide, dibutyl sulfide, dipentyl sulfide, dihexyl sulfide, diheptyl sulfide, and dioctyl sulfide.

The second component of the novel collector composition of this invention is an alkyl thiocarbon¬ ate, a thionocarbamate, a thiophosphate, or mixtures thereof. Alkyl thiocarbonates refer herein to those compounds which contain a thiocarbonate moiety and at least one alkyl moiety wherein the alkyl moiety has sufficient hydrophobic character so as to cause a metal-containing sulfide mineral or sulfidized metal- containing oxide mineral particles associated therewith to be driven to an air/bubble interface. Preferred alkyl thiocarbonates correspond to the formula

X R -X-C-S M ^{l l} wherein

R 7 is a C-, _2Q alkyl group;

X is independently in each occurrence

S or O; M is an alkali metal cation.

Preferred alkyl thiocarbonates include alkyl monothiocarbonates, alkyl dithiocarbonates, or alkyl trithiocarbonates.

Preferred alkyl monothiocarbonates cor- respond to the formula

7 " - + R -O-C-S M Ha

wherein R 7 and M are as defined hereinbefore.

Examples of preferred alkyl monothio¬ carbonates include sodium ethyl monothiocarbonate, sodium isopropyl monothiocarbonate, sodium iso- butyl monothiocarbonate, sodium amyl monothiocar¬ bonate, potassium ethyl monothiocarbonate, potas- sium isopropyl monothiocarbonate, potassium iso- butyl monothiocarbonate, and potassium amyl mono¬ thiocarbonate.

Alkyl dithiocarbonates are commonly referred to as xanthates. Preferred alkyl di- thiocarbonates correspond to the formula 7 » - + R -O-C-S M Ha

7 wherein R and M are as hereinbefore defined.

Preferred alkyl dithiocarbonates include potassium ethyl dithiocarbonate, sodium ethyl dithiocarbonate, potassium -amyl dithiocar¬ bonate, sodium amyl dithiocarbonate, potassium isopropyl dithiocarbonate, sodium isopropyl di- thiocarbonate, sodium sec-butyl dithiocarbonate, potassium sec-butyl dithiocarbonate, sodium iso¬ butyl dithiocarbonate, potassium isobutyl dithio¬ carbonate, and the like.

Preferred alkyl trithiocarbonates cor- respond to the formula

7 " - + R -S-C-S M He

7 wherein R and M are as hereinbefore defined.

Examples of alkyl trithiocarbonates include sodium isobutyl trithiocarbonate and potassium isobutyl trithiocarbonate.

Preferred thionocarbamates correspond to the formula S

Q II

(R°) -N-C-Y III ^a !

(H)v

wherein p

R is independently in each occurrence a C, ,_n alkyl group;

- + 9 9 .

Y is -S M or -OR , wherein R is a ^Cl-10 ^^Y¹ group; a is the integer 1 or 2; and b is the integer 0 or 1, wherein a+b must equal 2.

Preferred thionocarbamates include dialkyl dithiocarbamates and alkyl thionocarba¬ mates. Preferred dialkyl dithiocarbamates cor¬ respond to the formula

R® S

^ ^■• - + TTTa N-C-S M

«8

o wherein M is as hereinbefore defined; and R is independently a C, ,_Q alkyl group.

Examples of preferred dialkyl dithio- carbamates include methyl butyl dithiocarbamate, methyl isobutyl dithiocarbamate, methyl sec-butyl dithiocarbamate, methyl propyl dithiocarbamate, methyl isopropyl dithiocarbamate, ethyl butyl dithiocarbamate, ethyl isobutyl dithiocarbamate, ethyl sec-butyl dithiocarbamate, ethyl propyl dithiocarbamate, and ethyl isopropyl dithiocar¬ bamate.

Preferred alkyl thionocarbamates cor¬ respond to the formula

S

Q ii q R -NH-C-OIT 11lb

wherein R 8 is as hereinbefore defined and R9 is a C, ₁₀ alkyl group.

Examples of preferred alkyl thionocar¬ bamates include N-methyl butyl thionocarbamate, N-methyl isobutyl thionocarbamate, N-methyl sec- -butyl thionocarbamate, N-methyl propyl thiono¬ carbamate, N-methyl isopropyl thionocarbamate, N-ethyl butyl thionocarbamate, N-ethyl isobutyl thionocarbamate, N-ethyl sec-butyl thionocarba¬ mate, N-ethyl propyl thionocarbamate, and N-ethyl isopropyl thionocarbamate. More preferred thiono¬ carbamates include N-ethyl isopropyl thionocarba¬ mate and N-ethyl isobutyl thionocarbamate.

Preferred thiophosphates generally cor¬ respond to the formula

R¹⁰O S

^XP-X-M^{+ IV}

R¹⁰θ' wherein

R is independently hydrogen, a C₁_₁₀ alkyl group or an aryl group; X is oxygen or sulfur; and M is an alkali metal cation.

Preferred thiophosphates include monoalkyl dithiophosphate, dialkyl dithiophosphate, diaryl dithio¬ phosphate, and dialkyl monothiophosphate. Preferred monoalkyl dithiophosphates correspond to the formula

wherein R and M are as hereinbefore defined.

Examples of preferred monoalkyl dithio¬ phosphates include ethyl dithiophosphate, propyl dithiophosphate, isopropyl dithiophosphate, butyl dithiophosphate, sec-butyl dithiophosphate, and isobutyl dithiophosphate.

Preferred dialkyl and diaryl dithiophos¬ phates correspond to the formula

wherein R and M are as hereinbefore defined.

Examples of dialkyl and diaryl dithiophos¬ phates include sodium diethyl dithiophosphate, sodium di-sec-butyl dithiophosphate, sodium diisobutyl dithio- phosphate, sodium diisoamyl dithiophosphate, and sodium dicresyl dithiophosphate.

Preferred dialkyl monothiophosphates cor¬ respond to the formula

wherein R and M are as hereinbefore defined.

Preferred monothiophosphates include sodium diethyl monothiophosphate, sodium di-sec-butyl mono¬ thiophosphate, sodium diisobutyl monothiophosphate, and sodium diisoamyl monothiophosphate.

7 R is preferably C₂_₁₆ alkyl, more preferably

^C ₃-₁₂ ^alkyl. R is preferably C, . alkyl and most preferably C-,_₃ alkyl. R is preferably C₂ ,_Q alkyl, more preferably C₂_₆ alkyl and most preferably C₃_₄ alkyl. R is preferably C₂ „ alkyl or cresyl.

Preferably, the composition of this invention comprises: (a) the hydrocarbon sulfide of formula I to (b) the alkyl thiocarbonate of formula II, thionocar¬ bamate of formula III, thiophosphate of formula IV, or mixture thereof, in a ratio such that the composition is an effective collector for metal-containing sulfide minerals and sulfidized metal-containing oxide minerals in a froth flotation process.

The composition of this invention preferably comprises: (a) between about 10 and about 90 percent by weight of hydrocarbon sulfide of formula I; and (b) between about 10 and about 90 percent by weight of an alkyl thiocarbonate of formula II, thionocarbamate of formula III, thiophosphate of formula IV, or mixtures thereof.

The composition of this invention more pre¬ ferably comprises: (a) between about 20 and about 80 percent by weight of a hydrocarbon sulfide of formula I; and (b) between about 20 and about 80 percent by weight of an alkyl thiocarbonate of formula II, thio¬ nocarbamate of formula III, thiophosphate of formula IV . or mixtures thereof.

The composition of this invention even more preferably comprises: (a) between about 30 and 70 percent by weight of a hydrocarbon sulfide of formula

I; and (b) between about 30 and 70 percent by weight of an alkyl thiocarbonate of formula II, thionocarbamate of formula III, thiophosphate of formula IV or mixtures thereof. In its most preferred embodiment, the ratio of hydrocarbon sulfide of formula I to alkyl thiocar¬ bonate of formula II, thionocarbamate of formula III, thiophosphate of formula IV or mixtures thereof is such that the recovery of metal-containing sulfide minerals or sulfidized metal-containing oxide minerals in a froth flotation process is higher than either component alone could recover at the same weight dosage. More preferably, the dosage at which the collector is used, is that dosage at which the component (b) of formula II, III, or IV of the composition when used alone gives a higher recovery than the hydrocarbon sulfide of formula I gives at such level.

The novel collector composition of this invention gives higher recoveries, often with better metal grade(s), than can be achieved with the use of either collector component alone. Grade is defined as the fractional amount of a desired metal contained in the material collected in the froth.

Hydrocarbon means herein an organic compound containing carbon and hydrogen atoms. The term hydrocarbon includes the following organic com- pounds: alkanes, alkenes, alkynes, cycloalkanes, cycloalkenes, cycloalkynes, aromatics, aliphatic and-cycloaliphatic aralkanes and alkyl-substituted aromatics.

Aliphatic refers herein to straight- and branched-chain, and saturated and unsaturated, hydrocarbon compounds, that is, alkanes, alkenes or alkynes. Cycloaliphatic refers herein to satu¬ rated and unsaturated cyclic hydrocarbons, that is, cycloalkenes and cycloalkanes.

Cycloalkane refers to an alkane contain¬ ing one, two, three or more cyclic rings. Cycloal- kene refers to mono-, di- and polycyclic groups containing one or more double bonds. Hydrocarbyl means herein an organic radical containing carbon and hydrogen atoms. The term hydro¬ carbyl includes the following organic radicals: alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aliphatic and cycloaliphatic aralkyl and alkaryl. The term aryl refers herein to biaryl, biphenylyl, phenyl, naphthyl, phenanthrenyl, anthracenyl and two aryl groups bridged by an alkylene group. Alkaryl refers herein to an alkyl-, alkenyl- or alkynyl-substituted aryl substituent, wherein aryl is as- defined hereinbe¬ fore. Aralkyl means herein an alkyl group, wherein aryl is as defined hereinbefore.

^Cl-20 ^alky¹ includes straight- and branched- -chain methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl and eicosyl .groups.

Halo means herein a chloro, bromo or iodo group.

The novel collector compositions of this invention are useful for the recovery by froth flota¬ tion of metal-containing sulfide minerals and sulfi¬ dized metal-containing oxide minerals from ores. An ore refers herein to material as it is taken out of the ground and includes the desired metal-containing minerals in admixture with the gangue. Gangue refers herein to that portion of the material which is of no value and needs to be separated from the desired metal- -containing minerals. In a preferred embodiment, metal-containing sulfide minerals are recovered. In a more preferred embodiment of this invention sulfide minerals contain¬ ing copper, nickel, lead, zinc or molybdenum are recov- ered. In an even more preferred embodiment, sulfide minerals containing copper are recovered. Also pre¬ ferred metal sulfide-containing minerals are those which have high natural hydrophobicity in the unoxi- dized state. The term "hydrophobicity in the unoxi- dized state" applies to a freshly ground mineral or a mineral having a fresh surface which demonstrates a tendency to float without collector addition.

Ores for which these compositions are useful include sulfide mineral ores containing copper, zinc, molybdenum, cobalt, nickel,- lead, arsenic, silver, chromium, gold, platinum, uranium, and mixtures thereof. Examples of metal-containing sulfide minerals which may be concentrated -by froth flotation using the pro¬ cess of this invention include copper-bearing minerals such as, for example, covellite (CuS), chalcocite

(Cu₂S), chalcopyrite (CuFeS₂), valleriite (Cu₂Fe₄S- or Cu₃Fe₄S~), tetrahedrite (Cu₃SbS₂), bornite (Cu.-FeS₄), cubanite (Cu₂SFe₄S₅), enargite [Cu₃(As,Sb)S₄] , ten- nantite (Cu-,₂As₄S,₃), brochantite [Cu₄(0H)₆S0₄] , ant- lerite [Cu₃S0₄(OH)₄] , famatinite [Cu₃(SbAs)S₄] , and bournonite (PbCuSbS₃); lead-bearing minerals such as, for example, galena (PbS); antimony-bearing minerals such as, for example, stibnite (Sb₂S₃); zinc-bearing minerals such as, for example, sphalerite (ZnS); silver-bearing minerals such as, for example, steph- anite (Ag₅SbS₄), and argentite (Ag₂S); chromium-bearing minerals such as, for example, daubreelite (FeSCrS₃); nickel-bearing minerals such as, for example, pent- landite [(FeNi)_QS_ft]; molybdenum-bearing minerals such as, for example, molybdenite (MoS₂); and platinum- and palladium-bearing minerals such as, for example, cooper- ite [Pt(AsS)₂]. Preferred metal-containing sulfide minerals include molybdenite (MoS₂), chalopyrite (CuFeS₂) galena (Pbs), sphalerite (ZnS), bornite (Cu₅FeS₄) and pentlandite [(FeNi)_gS_ft] .

Sulfidized metal-containing oxide minerals are minerals which are treated with a sulfidization chemical, so as to give such minerals sulfide mineral characteristics, so the minerals can be recovered in froth flotation using collectors which recover sulfide minerals. Sulfidization results in oxide minerals having sulfide characteristics. Oxide minerals are sulfidized by contact with compounds which react with the minerals to form a sulfur bond or-affinity. Such methods are well-known in the art. Such compounds include sodium hydrosulfide, sulfuric acid and related sulfur containing salts such as sodium sulfide.

Sulfidized oxide minerals for which this process is useful include oxide minerals containing copper, aluminum, iron, titanium, tungsten, molybdenum, magnesium, chromium, nickel, manganese, tin, uranium, and mixtures thereof. Examples of metal-containing oxide minerals which may be concentrated by froth flotation using the process of this invention include copper-bearing minerals, such as cuprite (Cu₂0), tenor- ite (CuO), malachite [(Cu₂OH)₂C0₃] , azurite [Cu₃(OH)₂- (C0₃)₂], ataca ite [Cu₂Cl(OH)₃] , chrysocolla (CuSi0₃); aluminum-bearing minerals, such as corundum; zinc-con¬ taining minerals, such as zincite (ZnO), and smithsonite (ZnC0₃); tungsten-bearing minerals such as, for example, wolframite [(Fe,Mn)W0₄] ; nickel-bearing minerals such as, for example, bunsenite (NiO); molybdenum-bearing minerals such as, for example, wulfenite (PbMo0₄) and powellite (CaMo0₄); iron-containing minerals, such as hematite and magnetite; chromium-containing minerals, such as chromite (FeOCr₂0₃); iron- and titanium-con¬ taining minerals, such as ilmenite; magnesium- and aluminum-containing minerals, such as spinel; iron- chromium-containing minerals, such as chromite; tita¬ nium-containing minerals, such as rutile; manganese- containing minerals, such as pyrolusite; tin-containing minerals, such as cassiterite; and uranium-containing minerals, such as uraninite; and uranium-bearing miner- als such as, for example, pitchblende [U₂0₅(U₃0g)] and gummite (U0₃hH₂0).

The collectors of this invention can be used in any concentration which gives the- desired recovery of the desired minerals. In particular, the concen- tration used is dependent upon the particular minerals to be recovered, the grade of the ore to be subjected to the froth flotation process, the desired quality of the mineral to be recovered, and the particular mineral which is being recovered. Preferably, the collectors of this invention are used in concentrations of 0.001 to 1.0 kg per metric ton of ore, more preferably between 0.010 and 0.2 kg of collector per metric ton of ore to be subjected to froth flotation.

Frothers are preferably used in the froth flotation process of this invention. Any frother well-known in the art, which results in the recovery of the desired mineral is suitable. Frothers useful in this invention include any frothers known in the art which give the recovery of the desired mineral. Examples of such frothers include C₅__Q alcohols, pine oils, cresols, C., ₄ alkyl ethers of polypropylene glycols, dihydroxylates of polypropylene glycols, glycols, fatty acids, soaps, alkylaryl sulfo- nates, and the like. Furthermore, blends of such frothers may also be used. All frothers which are suitable for beneficiation of ores by froth flotation can be used in this invention.

Further, in the process of this invention it is contemplated that collectors of this invention can be used in mixtures with other collectors well-known in the art. Collectors, known in the art, which may be used in admixture with the collectors of this invention are those which will give the desired recovery of the desired mineral: Examples of collectors useful in this invention include- dialkyl thioureas, dialkyl and diaryl thiophosphonyl chlorides, dialkyl and diaryl dithio- phosphonates, alkyl mercaptans, xanthogen formates, xanthate esters, mercapto benzothiazoles, fatty acids and salts of fatty acids, alkyl sulfuric acids and salts thereof, alkyl and alkaryl sulfonic acids and salts thereof, alkyl phosphoric acids and salts thereof, alkyl and aryl phosphoric acids and salts thereof, sulfosuccinates, sulfosuccinamates, primary amines, secondary amines, tertiary amines, quaternary ammonium salts, alkyl pyridinium salts, guanidine, and alkyl propylene diamines.

Specific Embodiments

The following examples are included for illustration and are not intended to limit the scope of the invention. Unless otherwise indicated, all parts and fractions are by weight. Synergism is defined herein as when the measured result of a blend of two or more components exceeds the weighted average results of each component when used alone. This term also implies that the results are compared under the condition that the total weight of the collector used is the same for each experiment.

Example 1 - Froth Flotation of a Copper/Molybdenum Ore from Western Canada

Bags of homogeneous ore containing chal- copyrite and molybdenite minerals were prepared with each bag containing 1200 g. The rougher flotation procedure was to grind a 1200 g charge with 800 ml of tap water for 14 minutes in a ball mill having a mixed ball charge (to produce approximately a 13 percent plus 100 mesh grind). This pulp was transferred to an Agitair 1500 ml flotation cell outfitted with an auto¬ mated paddle removal system. The slurry pH was adjusted to 10.2 using lime. - No further pH adjustments were made during the test. The standard frother was methyl isobutyl carbinol (MIBC). A four-stage rougher flo¬ tation scheme was then followed.

STAGE 1: Collector 0.0042 kg/metric ton MIBC 0.015 kg/metric ton condition - 1 minute float - collect concentrate for 1 minute

STAGE 2: Collector 0.0021 kg/metric ton MIBC 0.005 kg/metric ton condition - 0.5 minute float - collect concentrate for 1.5 minutes STAGE 3 Collector 0.0016 kg/metric ton MIBC 0.005 kg/metric ton condition - 0.5 minute float - collect concentrate for 2.0 minutes

STAGE 4: Collector 0.0033 kg/metric ton MIBC 0.005 kg/metric ton condition - 0.5 minute float - collect concentrate for 2.5 minutes

The results are compiled in Table I

TABLE I

Cu Moly Cu Mo

Collector R-7² R-7² Grade³ Grade³ potassium amyl 0.776 0.725 0.056 0.00181 xanthate¹

1,2-epithiooctane¹ 0.710 ^' 0.691 0.093 0.00325

50/50 blend of potas¬ 0.794 0.766 0.054 0.00177 sium amyl xanthate and 1,2-epithiooctane methyl hexyl sulfide¹ 0.699 0.697 0.107 0.00386

50/50 blend of potas¬ 0.790 0.793 0.056 0.00169 sium amyl xanthate and methyl hexyl sulfide

^-Not an example of the invention

²R-7 is the experimental fractional recovery after

7 minutes ³Grade is the fractional content of specific metal contained in total weight collected in the froth

The 95 percent confidence region of statistical error associated with the Cu R-7 experimental values in Table I is ± 0.010. Thus the statistical range of R-7 value for Cu in Table I associated with potassium amyl xanthate is 0.776 ± 0.010 or 0.766 to 0.786. The statistical error associated with the Mo R-7 experi¬ mental values in Table I is ± 0.015. Applying these limits clearly indicates the recoveries of Cu and Mo at 7 minutes with the collector blends of this invention exceed the 7-minute recoveries that would be expected from a weighted average effect of the individual compo¬ nent used alone; synergism has occurred.

Example 2 - Froth Flotation of a Copper/Nickel Ore from Eastern Canada

A copper/nickel ore containing chalcopyrite, pentlandite, and pyrrhotite minerals was floated using 0.0028 kg/metric ton of DOWFROTH® 1263 frother and a collector dosage of 0.28 kg/metric ton. A. series of samples were drawn fro the feeders to plant rougher bank and placed in buckets to give approximately 1200 g of solid. The contents of each bucket were then used to perform a time-recovery profile on a Denver cell using an automated paddle and constant pulp level device with individual concentrates selected at 1.0, 3.0, 6.0 and 12.0 minutes. The chemicals were added with a condition time of one minute before froth removal was started. There was no stage addition of reagents. Individual concentrates were dried, weighed, ground and statistically representative samples pre¬ pared for assay. The results are compiled in Table II.

TABLE II

Pyrrho-

Cu Ni tite

Collector R-12² R-12² R-12² sodium amyl xanthate¹ 0.930 0.839 0.358

1,2-epithiooctane¹ 0.927 0.751 0.247 dibutyl sulfide¹ 0.928 0.630 0.190

50/50 blend of 1,2-epi- 0.927 0.844 0.344 thiooctane and sodium amyl xanthate

50/50 blend of dibutyl 0 . 931 0.824 0.245 sulfide and sodium amyl xanthate

¹Not an example of the invention

²R-12 is the experimental fractional recovery after 12 minutes

The recoveries of Cu at 12 minutes are all so high in Table II (approaching the theoretical limit of 1.0) that the use of statistical confidence limits does not apply. The 95 percent confidence level of the

R-12 values for Ni in Table II is ± 0.012. It is clear that the collector blends of this invention give Ni recoveries that significantly exceed those recoveries that would be expected from a weighted average of each component used alone; synergism has occurred.

Example 3 - Froth Flotation of a complex Pb/Zn/Cu/Ag Ore from Central Canada

Uniform 1000 g samples of ore, containing galena, sphalerite, chalcopyrite, and argentite, are prepared. For each flotation run, a sample was added to a rod mill along with 500 ml of tap water and 7.5 ml of S0₂ solution. Six and one-half minutes of mill time were used to prepare a feed of 90 percent less than 200 mesh (75 microns). After grinding, contents were transferred to a cell fitted with an automated paddle for froth removal, and the cell attached to a standard Denver flotation mechanism.

A two-stage flotation was then performed. In Stage I a copper/lead/silver rougher was used, and in Stage II a zinc rougher was used. To start the Stage I flotation, 1.5 g/kg Na₂C0₃ was added (pH of 9 to 9.5), followed by the addition of collector(s) . The pulp was then conditioned for 5 minutes with air and agitation. This was followed by a 2-minute condition period with agitation only. MIBC frother was then added (standard dose of 0.015 ml/kg). Concentrate was collected for 5 minutes of flotation and labeled as copper/lead rougher concentrate.

The Stage II flotation consisted of adding 0.5 kg/metric ton of CuS0₄ to the cell remains of Stage I. The pH was than adjusted to 10.5 with lime addition. This was followed by a condition period of 5 minutes with agitation only. pH was then rechecked and adjusted back to 10.5 with lime. At this point, the collector(s) were added, followed by a 5-minute condition period with agitation only. MIBC frother was then added

(standard dose of 0.020 ml/kg). Concentrate was col¬ lected for 5 minutes and labeled as zinc rougher con¬ centrate.

Concentrate samples were dried, weighed, and appropriate samples prepared for assay using X-ray techniques. Using the assay data, fractional recover¬ ies and grades were calculated using standard mass balance formulae. The results are compiled in Table III.

TABLE III

Stage Col- Dosage ii Cu Pb Zn Run (Rougher) lector (g/met. t) pH R-5² Grade³ R-52 Grade³ R-5² Grade³ R-5² Grade³

0.886 .0.275 0.941 0.107 0.794 0.050 0.220

0.052 0.030 0.077 0.762 0.48 .5 9.5 0.778 0.312 0.893 0.136 0.662 0.057 0.145

10.5 0.103 0.048 0.145 0.812 0.497

D 5 rCu/Pb 0.891 0.272 0.942 0.110 0.795 0.052 0.218 B 7.5 9.5

3

_Zn D 35 10.5 0.030 0.018 0.045 0.570 0.532

A - sodium ethyl xanthate

B - dithiophosphate

C - thionocarbamate

D - dihexyl sulfide ^xNot an example of the invention

²R-5 is the actual recovery after 5 minutes

³Grade is the fractional content of specific metal- contained in total weight collected in the froth

In Table III, then are two test conditions which logically allow comparision of the recoveries associated with the collector blends of this invention to those recoveries achievable with a component col- lector used alone.

Comparing the Cu/Pb flotation (Stage I) Run 2 with collector D used alone verses the Cu/Pb flotation (Stage I) of Run 3 using the collector blend D + B, the results illustrate the greater Ag, Cu, Pb recoveries achieved with the collector blends of this invention. The 95 percent confidence level of statistical error is for Ag, ± 0.01, for Cu, ± 0.01, and for Pb ± 0.02.

The Zn flotation (Stage II) of Run 3 compared to the Zn flotation (Stage II) of Run 2 also illustrates the obvious increase in the Zn recovery associated with the blend versus that of the component used alone. The 95 percent confidence level of statistical error for Zn is ± 0.01.

Other runs using single components in various stages are not reported in Table III as many of the single components when used alone simply do not perform adquately enough to collect meaningful data for comparison. For example, collector B used alone in Stage I for Cu and Pb gives less than 0.500 recovery.

Example 4- Froth Flotation of a Complex Cu/Mo Ore from South America A 500 g quantity of a Cu/Mo ore, containing several copper containing sulfide minerals and moly¬ bdenite, was placed in a rod mill having one-inch (2.5 cm) rods along with 257 g of deionized water and a quantity of lime. Then the mixture was ground for 360 revolutions at a speed of 60 rpm to produce a size distribution of suitable fineness. The ground slurry was transferred to a Agitar 1500 ml flotation cell outfit¬ ted with an automated paddle removal system. The slurry was agitated at 1150 rpm and the pH adjusted to the appropriate value (shown in Table IV) with either more lime or hydrochloric acid

At this point, the collector(s) were added to the float cell (45 g/metric ton), followed by a condi- tioning time of one minute, at which time the frother, DOWFROTH 250 was added (34.4 g/metric ton). After an additional conditioning^' time of one minute, the air to ^• the float cell was turned on at a rate of 4.5 liters/- minute and the automatic froth removal paddle was started. Samples of the froth were collected at 0.5, 1.5, 3.0, 5.0, and 8.0 minutes.

The samples were dried overnight in an oven along with the flotation tailings. The dried samples were weighed, pulverized to a suitable degree of fineness for dissolution, and dissolved in acid for analysis on a DC Plasma Spectrograph. The results are compiled in Table IV. TABLE IV

Dosage Cu Mo

Run Collectors (g/metric ton) PiL R-8² R-8²

Isopropyl ethyl thionocarbamate¹ 22.7 10.5 0.891 0.742

Sodium isopropyl xanthate¹ 22.7

Ethyl octyl sulfide¹ 45.4 10.5 0.854 0.791

Isopropyl ethyl

J thionocarbamate 11 .4 10.5 0.893 0.808

Sodium isopropyl xanthate 11 4

Ethyl octyl sulfide 22 7

^' Isopropyl ethyl thionocarbamate¹ 22 7 8.0 0.912 0. 780

Sodium isopropyl xanthate¹ 22 7

Ethyl octyl sulfide¹ 45.4 8.0 0.887 0.822

Isopropyl ethyl thionocarbamate 11.4 8.0 0.901 0.831

Sodium isopropyl xanthate 11.4

Ethyl octyl sulfide 22.7 ^xNot a example of this invention

²R-8 is the experimental fractional recovery after 8 minutes

The recoveries of Cu at 8 minutes are all so high in Table IV (approaching) the theoretical limit of 1.0) that the use of statistical confidence limits does not apply.

THe 95 percent condifience level of statistical error for Mo recovery at 8 minutes is ± 0.012. Clearly, the collector blends of this invention provide Mo recoveries that significantly exceed those recoveries that would be expected from the individual components used alone. For example, the Mo recovery of Run 3 clearly exceeds that expected from the weighted average of Runs 1 and 2. Synergism has occurred.

Claims

1. A novel composition which comprises:

(a) a hydrocarbon containing one or more monosulfide units, wherein the carbon atoms to which the sulfur atom(s) are bound are aliphatic or cycloaliphatic carbon atoms and the total carbon content of the hydrocarbon portion is such that the hydrocarbon has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral particles to be driven to an air/bubble interface; and

(b) an alkyl thiocarbonate, a thionocar¬ bamate, a thiophosphate, or mixtures thereof.

2. The composition of Claim 1 wherein the ratio of (a) hydrocarbon sulfide to (b) the alkyl thio¬ carbonate, thionocarbamate, thiophosphate, or mixtures thereof, is such that the composition is an effective collector for metal-containing sulfide minerals and sulfidized metal-containing oxide minerals in a froth flotation process.

3. The composition of Claim 1 or 2 wherein the hydrocarbon sulfide corresponds to the formula

1 2 R -S-R

I the thiocarbonates correspond to the formula

X

7 ^» - + R -X-C-S M

II the thionocarbamates correspond to the formula

S (R⁸) -N-C-Y

(^H>b

III and the thiophosphates correspond to the formula

R¹⁰O S P-X-M

R¹⁰O'

IV wherein

R 1 and R2 are independently a hydrocarbyl radical or hydrocarbyl radical substituted with one or more hydroxy, cyano, halo, ether, hydro- carbyloxy or hydrocarbyl thioether moieties; wwhheerreeiinn RR 1 1 aanndd RR22 mmaayy ccoommbbiinnee to form a hetero- cyclic ring structure with S; with the proviso that S is bound to an aliphatic or cycloaliphatic carbon atom; with the further proviso that the total carbon content of the hydrocarbon sulfide be such that it has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral particles to be driven to an air/bubble interface; 7 . R is a C-, ₂₀ alkyl group;

R is independently a C, ,_Q alkyl group;

R is a C, ,_n alkyl group;

10 -iu R is independently hydrogen, a

^'C, ₁₀ alkyl group or an aryl group;

M is an alkali metal cation;

X is independently in each occurrence S or 0;

Y is -S^"M⁺ or OR⁹;

.a is the integer 1 or 2; and

^■ b is the integer 0 or 1, wherein a+b=2.

4. The composition of Claim 3 which com¬ prises:

(a) between about 10 and about 90 percent by weight of hydrocarbon sulfide; and

(b) between about 10 and about 90 per¬ cent by weight of an alkyl thiocarbonate, thionocarbamate, thiophosphate, or mixtures thereof.

5. The composition of Claim 4 which comprises: ta) between about 20 and about 80 per¬ cent by weight of a hydrocarbon sulfide; and

(b) between about 20 and about 80 per¬ cent by weight of an alkyl thiocarbonate, thionocarbamate, thiophosphate, or mixtures thereof.

6. The composition of Claim 3 or 5 wherein R 1 and R2 are independently an aliphatic, cyclo¬ aliphatic or aralkyl moiety, unsubstituted or substituted with one or more hydroxy, cyano, halo, OR 3 or SR3 moieties;

R 3 is a hydrocarbyl radical;

wherein

R 1 and R2 may combi.ne to form a heterocycli.c ring with S;

7 . R is C₆-16 alkyl;

R is Cm . alkyl;

9 R is C, _ιn alkyl;

10 . -^,'""-^LU R is C» _n alkyl or cresyl; and

M is a sodium or potassium cation.

7. The composition of Claim 6 wherein the total carbon content of the hydrocarbon sulfide is from 4 to 20 carbon atoms.

8. The composition of Claim 7 wherein R 1 and R2 are a cycloaliphatic or aliphatic moiety, unsubstituted or substituted with one or more hydroxy, cyano, halo, OR 3 or SR3 moieties; wherein R1

2 and R may combine to form a heterocyclic ring 7 8 9 with S; R is C₃_₁₂ alkyl; R is C₁_₃ alkyl; R is C₂_₆ alkyl; and R is C₂__g alkyl or cresyl.

9. The composition of Claim 8 wherein the hydrocarbon sulfide has a total carbon content of from 6 to 16 carbon atoms.

10. The composition of Claim 9 wherein R 2 and R are independently alkyl or alkenyl.

11. The composition of Claim 10 wherein R

2 . is methyl or ethyl, and R is C_g^, alkyl ^{or C} _ _]_ alkenyl group.

12. The composition of Claim 3 or 5 wherein the hydrogen sulfide corresponds to the formula

<^R n <^H>n-^S- <^H>n<^R6>3-n ^'

Ic wherein g

R is independently hydrocarbyl, or hydro¬ carbyl substituted with a hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moiety; wherein two R moieties may combine to form a cyclic ring or heterocyclic ring with the sulfur atom;

n is an integer of 0, 1, 2 or 3; with the proviso that the total carbon content of the hydrocarbon portion of the collector is such that the collector has sufficient hydrophobic character to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral par¬ ticles to be driven to the air/bubble interface.

13. The composition of Claim 12 which com¬ prises:

(a) a hydrocarbon sulfide; and

(b) an alkyl thiocarbonate which comprises an alkyl monothiocarbonate, alkyl di hiocarbonate or alkyl trithiocarbonate.

14. The composition of Claim 3 wherein R 2 and R are not the same hydrocarbon moiety.

15. The composition of Claim 1 wherein the metal-containing sulfide minerals are those which have a high natural hydrophobicity in the unoxidized state.

16. A process for recovering metal-con¬ taining sulfide minerals or sulfidized metal-containing oxide minerals from an ore which comprises subjecting the ore, in the form of an aqueous pulp, to a froth flotation process in the presence of a flotating amount of a flotation collector wherein the collector com¬ prises a composition of any one of Claims 1 to 15.

17. The process of Claim 16 wherein a metal- -containing sulfide mineral is recovered in the froth.

18. The process of Claim 17 wherein the metal-containing sulfide mineral recovered in the froth contains copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium, or mixtures thereof.

19. The process of Claim 18 wherein the metal-containing sulfide mineral recovered in the froth is molybdenite, chalcopyrite, galena, sphalerite, bornite, or pentlandite.

20. The process of Claim 19 wherein the sulfide collector is present in a concentration of from 0.001 to 1.0 kg of collector/metric ton of ore to be sugjected to froth flotation.