WO1987003222A1

WO1987003222A1 - Collector compositions for the froth flotation of mineral values

Info

Publication number: WO1987003222A1
Application number: PCT/US1986/000342
Authority: WO
Inventors: Richard R. Klimpel; Robert D. Hansen
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1985-11-29
Filing date: 1986-02-18
Publication date: 1987-06-04
Anticipated expiration: 1988-05-29
Also published as: SE461768B; ZA861170B; YU23086A; MX173645B; SE8702987D0; CN86101495A; ES8706045A1; CN1014247B; JPS62129160A; BR8607004A; FI82395B; AU588579B2; ZW4186A1; PH23458A; ZM1586A1; CA1268565A; ES552033A0; FI873288L; RU1839638C; RO100034B1

Abstract

A collector composition, useful for the recovery of metal-containing sulfide minerals, sulfidized metal-containing oxide minerals, metals-containing oxide minerals and metals occuring in the metallic state from ores in a froth flotation process, comprises two collectors. One collector is an organic compound containing at least 4 carbon atoms and one or more monosulfide units, wherein the carbon atoms to which the sulfur atoms are bound are aliphatic or cycloaliphatic carbons. The other collector is preferably an omega-(hydrocarbylthio)alkylamine, S-(omega-aminoalkyl)-hydrocarbyl thioate, N-(hydrocarbyl)-alpha, omega-alkane-diamine, (omega-aminoalkyl)hydrocarbon amide, omega-(hydrocarbyloxy)alkylamine, omega-aminoalkyl hydrocarbonoate, omega-(hydrocarbylthio)-alkylamide or mixture thereof.

Description

COLLECTOR COMPOSITIONS FOR

THE FROTH FLOTATION OF

MINERAL VALUES

This invention concerns novel collectors for the recovery of metal-containing sulfide minerals, sulfidized metal-containing oxide minerals, metal-containing oxide minerals and metals occurring in the metallic state, all four mineral groups referred to herein as metal-containing 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 particles 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. Accordingly, 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. These agents are classed according to the function to be performed: collectors, such as xanthates, thionocarbamates and the like; frothers, which facilitate the forming of a stable froth, e.g., natural oils such as pine oil and eucalyptus 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, e.g., lime and soda ash, to produce optimum metallurgical results; and the like.

An understanding of the phenomena which makes flotation a particularly valuable industrial operation is not essential to the practice of this invention. The phenomena which render flotation a particularly valuable industrial operation appear 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 specific additives used in a flotation operation are selected according to the nature of the ore, the mineral(s) sought to be recovered and the other additives which are to be used in combination therewith.

Flotation is employed in a number of mineral separation processes including the selective separation of such metal-containing minerals as those containing copper, zinc, lead, nickel, molybdenum, and other metals from iron-containing sulfide minerals, e.g. pyrite and pyrrhotite.

Among collectors commonly used for the recovery of metal-containing sulfide minerals or sulfidized metal-containing oxide minerals are xanthates, dithiophosphates, and thionocarbamates. Other collectors commonly recognized as useful in the recovery of metal- -containing minerals or sulfidized metal-containing oxide minerals are mercaptans, disulfides (R-SS-R) and polysulfides [R-(S)_n-R], wherein n is 3 or greater.

The conversion of metal-containing sulfide minerals or sulfidized metal-containing oxide minerals to the more useful pure metal state, is often achieved by smelting processes. Such smelting processes can result in the formation of volatile sulfur compounds. 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-containing oxide minerals are found naturally in the presence of iron-containing sulfide minerals, such as pyrite and pyrrhotite. When the iron-containing sulfide minerals are recovered in flotation processes along with the nonferrous metalcontaining sulfide minerals and sulfidized metalcontaining oxide minerals, there is excess sulfur present which is released in the smelting processes. What is needed is a process for selectively recovering the nonferrous metal-containing sulfide minerals and sulfidized metal-containing oxide minerals without recovering the iron-containing sulfide minerals such as pyrite and pyrrhotite.

Of the commercial collectors, the xanthates, thionocarbamates, and dithiophosphates do not selectively- 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. The mercaptan collectors have an environmentally undesirable order and are very slow kinetically in the flotation of metal-containing sulfide minerals. The disulfides and polysulfides, when used as collectors, give low recoveries with slow kinetics. Therefore, the mercaptans, disulfides, and polysulfides are not generally used commercially. Furthermore, the mercaptans, disulfides and polysulfides do not selectively recover nonferrous metal-containing sulfide minerals in the present of iron-containing sulfide minerals.

In view of the foregoing, what is needed is a flotation collector which will selectively recover, at relatively good recovery rates, a broad range of metal-containing minerals in the presence of iron-containing sulfide minerals such as pyrite and pyrrhotite.

Accordingly, in one aspect, the present invention is a collector composition for the floatation of metal-containing minerals which comprises: (a) a compound of the formula:

R¹-X-(R)_n-Q

wherein Q is

-N(R²)_a(H)_b where a + b equals 2,

-N=Y where Y is S, O, a hydrocarbylene radical or a substituted hydrocarbylene radical,

≡ N, or

ring where the cyclic ring is saturated or unsaturated and may contain additional hetero atoms, but must contain the N atom;

R¹ and R² are independently a C_1-22 hydrocarbyl radical, a C_1-22 substituted hydrocarbyl radical, or a saturated or unsaturated heterocyclic ring;

wherein y + p + m = n, where n is an integer from 1 to 6, and y, p and m are independently 0 or an integer from 1 to 6, and each moiety can occur in a random sequence;

where R³ is hydrogen, a C_1-22 hydrocarbyl radical or a C_1-22 sukstituted hydrocarbyl radical; and

(b) hydrocarbons containing monosulfide units of the formula

R⁵-S-R⁶

VIII wherein

R⁵ and R⁶ are independently a hydrocarbyl radical or a hydrocarbyl radical substituted with one or more hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moieties;

wherein

R⁵ and R⁶ may combi.ne 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 interface.

The invention also concerns a process for recovering metal-containing 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 under conditions such that the metal-containing minerals are recovered in the froth. The collector compositions of this invention are capable of floating a broad range of metal-containing minerals. Furthermore, such collector compositions also give good recoveries and selectivity towards the desired metal-containing minerals.

In a preferred process of the present invention, the described collector composition is employed in a process for recovering metal-containing sulfide minerals or sulfidized metal-containing oxide minerals from an ore, which method comprises subjecting the ore, in the form of an aqueous pulp, to a froth flotation process in the presence of a flotating amount of the collector composition at conditions sufficient to cause the metal-containing sulfide mineral or sulfidized metal-containing oxide mineral particles to be driven to the air/bubble interface and recovered in the froth.

The collector composition of this invention results in a surprisingly high recovery of nonferrous metal-containing minerals and a high selectivity toward such nonferrous metal-containing minerals when such metal- -containing minerals are found in the presence of iron- -containing sulfide minerals.

Component (a) of the collector composition of this invention is a component of formula (I) above. Although not specifically set forth in formula (I), it should be understood that in aqueous medium of lower pH, preferably acidic, component (a) can exist in the form of a salt. In this formula, R is advantageously -(CH₂)-_p

or mixtures thereof, where p + m + y = n, where n is an integer from 1 to 6, preferably 2 or 3. R¹ and each R² is advantageously a C₁_₂₂ hydrocarbyl radical or a C_1-22 hydrocarbyl radical substituted with one or more hydroxy, amino, phosphonyl, alkoxy, imino, carbamyl, carbonyl, thiocarbonyl, cyano, halo, ether, carboxyl, hydrocarbylthio, hydrocarbyloxy, hydrocarbylamino or hydrocarbylimmo groups. If substituted, R¹ and R² are advantageously substituted with one or more hydroxy, halo, amino, phosphonyl or alkoxy moieties. Q is preferably -N(R²)_a(H)_b where a + b = 2.

More advantageously, the carbon atoms in R¹ and R² total 6 or more with R¹ preferably being a C_2-14 hydrocarbyl or a C_2-14 hydrocarbyl substituted with one or more hydroxy, amino, phosphonyl or alkoxy groups, more preferably a C_4-11 hydrocarbyl; and R² preferably being a C_1-6 alkyl, C_1-6 alkylcarbonyl or C_1-6-substituted alkyl or alkylcarbonyl, more preferably a C_1-4 alkyl or C_1-4 alkylcarbonyl or a C_1-6 alkyl or C_1-6 alkylcarbonyl substituted with an amino, hydroxy or phosphonyl group, and most preferably a C_1-2 alkyl or C_1-2 alkylcarbonyl. In addition, R is preferably

-(CH₂)_p- or

more preferably -(CH₂)_p-; n is preferably an integer from 1 to 4, most preferably 2 or 3; X is prefer¬

ably -S-, or -O-, more preferably -S- or

-N-R³, most preferably -S-; and R³ is preferably hydrogen or C_1-14 hydrocarbyl, more preferably hydrogen or C_1-11 hydrocarbyl, most preferably hydrogen.

As described, the component (a) includes compounds such as the S-(omega-aminoalkyl) hydrocarbon thioates:

II the omega-(hydrocarbylthio)alkylamines and omega- (hydrocarbylthio)alkylamides:

III the N-(hydrocarbyl)-alpha,omega-alkanediamines:

IV the N-(omega-aminoalkyl) hydrocarbon amides:

V the omega-(hydrocarbyloxy-)alkylamines:

VI and the omega-aminoalkyl hydrocarbonoates:

VII

wherein R¹, R², R³, a, b and n are as hereinbefore defined. In formulas II-VII, when X is -S- or

R¹ is preferably a C_4-10 hydrocarbyl; when X is

the total carbon content of the groups R¹ and R³ is preferably between about 1 and 23, more preferably 2 and 16, and most preferably 4 and 15; and when X is

R¹ is most preferably C_6-11 hydrocarbyl

Of the foregoing, the preferred component (a) compound includes omega-(hydrocarbylthio)alkylamine, N-(hydrocarbyl)-alpha,omega-alkanediamine, N-(omega- -aminoalkyl)hydrocarbon amides, omega-(hydrocarbyloxy-)alkylamine, omega-(hydrocarbylthio)alkylamides, or a mixture thereof. More preferred component (a) compounds include omega-(hydrocarbylthio)alkylamines, omega-(hydrocarbylthio)alkylamides, N-(hydrocarbyl)-

-alpha, omega-alkanediamines, N-(omega-aminoalkyl)hydrocarbon amides, or mixtures thereof. The most preferred classes of component (a) compounds are the omega- (hydrocarbylthio)alkylamines, for example, 2-(hexylthio)ethyl- amine and omega- (hydrocarbylthio)alkylamides, for example, ethyl 2-(hexylthio)ethylamide.

The omega-(hydrocarbylthio)alkylamines of formula III can be prepared by the processes disclosed in Berazosky et al., U.S. Patent 4,086,273; French Patent 1,519,829; and Beilstein, 4, 4th Ed., 4th Supp., 1655 (1979).

The N-(omega-aminoalkyl) hydrocarbon amides of formula V can be prepared by the processes described in Fazio, U.S. Patent 4,326,067 Acta Polon Pharm, 19, 277 (1962); Beilstein, 4, 4th Ed., 3rd Supp., 587 (1962). The omega-(hydrocarbyloxy)alkylamines of formula VI can be prepared by the processes described in British Patent 869,409; and Hobbs, U.S. Patent 3,397,238.

The S-(omega-aminoalkyl) hydrocarbon thioates of formula II can be prepared by the processes described in Faye et al., U.S. Patent 3,328,442; and Beilstein, 4, 4th Ed., 4th Supp., 1657 (1979).

The omega-aminoalkyl hydrocarbonoates of formula VII can be prepared by the process described in J. Am. Chem. Soc, 83, 4835 (1961); Beilstein, 4, 4th Ed., 4th Supp., 1413 (1979) and Beilstein, 4, 4th Ed., 4th Supp., 1785 (1979).

The N-(hydrocarbyl)-alpha,omega-alkanediamines of formula IV can be prepared by the process well-known in the art. One example is the process described in East German Patent 98,510.

Component (b) of the collector composition is an organic compound which contains at least 4 carbon atoms and one or more monosulfide units wherein the sulfur atoms of the sulfide units are bound to nonaromatic carbon atoms, i.e., aliphatic or cycloaliphatic carbon atoms. Monosulfide unit refers herein to a unit wherein each sulfur atom is bound to two carbon atoms of a non-aromatic moiety only, for example to two carbon atoms of a hydrocarbon moiety only. The hydrocarbon compounds can contain one or more monosulfide units, and include such compounds which are substituted with hydroxyl, cyano, halo, ether, hydrocarbyloxy and hydrocarbyl thioether moieties.

Preferred organic compounds containing monosulfide units include those corresponding to the formula

R⁵-S-R⁶

IX wherein R⁵ and R⁶ are independently a hydrocarbyl radical or a hydrocarbyl radical substituted with one or more hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moieties; wherein R⁵ and R⁶ 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 sulfide portion be such that the sulfide portion have sufficient hydrophobic character to cause the metal-containing sulfide mineral particles to be driven to the air/bubble interface.

The specific R⁵ and R⁶ groups most advantageously employed herein are dependent on a variety of factors including the component (a) employed, the specific ore being treated and the like. In general, to provide the required hydrophobic character, the monosulfide compound of formula IX contains at least 4, more preferably 6, and most preferably 8, carbon atoms. The maximum number of carbon atoms in the monosulfide compound is preferably 20, more preferably 16, and most preferably 12. Preferably, R⁵ and R⁶ are independently an aliphatic, cycloaliphatic or aralkyl moiety, unsubstituted or substituted with one or more hydroxy, cyano, halo, -OR⁷ or -SR⁷ moieties, wherein R⁷ is a hydrocarbyl radical; R⁵ and R⁶ may combine to form a heterocyclic ring with S. R⁵ and R⁶ are more preferably an aliphatic or cycloaliphatic moiety, unsubstituted or substituted with one or more cyano, halo, hydroxy, OR⁷ or SR⁷ moieties, wherein R⁷ is a hydrocarbyl radical; wherein R⁵ and R⁶ may combine to form a heterocyclic ring with

S. In a more preferred embodiment, R⁵ and R⁶ do not combine to form a heterocyclic ring with S and R⁵ and

R⁶ are independently alkyl, alkenyl, alkynyl, cycloalkyl or cycloalkenyl, unsubstituted or substituted with one or more hydroxy, halo, cyano, O R⁷ or S R⁷ moieties, wherein R⁷ is aliphatic or cycloaliphatic. In the most preferred embodiment, R⁵ and R⁶ are not the same hydrocarbon moiety, that is, the monosulfide is asymmetrical.

R⁷ preferably being aliphatic or cycloaliphatic. R⁷ is more preferably alkyl, alkenyl, cycloalkyl or cycloalkenyl. In a most preferred embodiment, R⁵ and R⁶ are independently alkyl or alkenyl, particularly R⁵ is methyl or ethyl and R⁶ is a C_6-11 alkyl or C_6-11 alkenyl group, for example, ethyl octyl sulfide.

Examples of cyclic compounds which can be employed as the monosulfide compound of formula IX include the following structures:

wherein R⁸ is independently hydrogen, an aryl, alkaryl, aralkyl, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, hydroxy, cyano, halo, OR⁷ or SR⁷ group, wherein the aryl, alkaryl, aralkyl, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl group may optionally be substituted with a hydroxy, cyano, halo, OR⁷ or SR⁷ group, and the like; wherein R⁷ is a hydrocarbyl group, preferably aliphatic or cycloaliphatic, more preferably alkyl, alkenyl, cycloalkyl or cycloalkenyl; and R⁹ is a straight- or branched- alkylene or -alkenylene or

-alkynylene, unsubstituted or substituted with a hydroxy, cyano, halo, OR⁷ or SR⁷ group.

A preferred compound useful as component (b) in this invention corresponds to the formula:

(R⁴)_3-nC(H)_n-S-C(H)_n(R⁴)_3-n

X wherein

R⁴ is independently hydrocarbyl, or hydrocarbyl substituted with a hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moiety; wherein two R⁴ 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 particles to be driven to the air/bubble interface.

In the foregoing formula, R⁴ is preferably an aliphatic, cycloaliphatic, aryl, alkaryl or aralkyl group, unsubstituted or substituted with a cyano, halo, hydroxy, OR⁷ or SR⁷ group, wherein R⁷ is as herembefore defined. More preferably, R⁴ is an aliphatic or cycloaliphatic group, unsubstituted or substituted with a hydroxy, cyano, halo, aliphatic ether, cycloaliphatic ether, aliphatic thioether or cycloaliphatic thioether group. Even more preferably, R⁴ is an alkyl, alkenyl, cycloalkyl or cycloalkenyl moiety. Most preferably, one -C(H)_n(R⁴)_3-n is a methyl or ethyl group, and the other is a C_6-11 alkyl or C_6-11 alkenyl group. Preferably, n is 1, 2 or 3, and more preferably 2 or 3.

The preferred hydrocarbon containing monosulfide units of the formula R⁵-S- R⁶, wherein R⁵ and R⁶ are defined as above, are prepared by standard methods known in the art, e.g. reacting R⁶-H with R⁵-SH, where

R⁵ and R⁶ are defined as above.

Examples of compounds within the scope of this invention include methylbutyl sulfide, methylpentyl sulfide, methylhexyl sulfide, methylheptyl sulfide, methyloctyl sulfide, methylnonyl sulfide, methyldecyl sulfide, methylundecyl sulfide, methyldodecyl sulfide, methylcyclopentyl sulfide, methylcyclohexyl sulfide, methylcycloheptyl sulfide, methylcyclooctyl sulfide, ethylbutyl sulfide, ethylpentyl 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, butyldecyl sulfide, butylundecyl- sulfide, butyldodecyl sulfide, butylcyclopentyl sulfide, butylcyclohexyl sulfide, butylcycloheptyl sulfide, butylcyclooctyl sulfide, dipentyl sulfide, pentylhexyl sulfide, pentyl- heptyl sulfide, pentyloctyl sulfide, pentylnonyl sulfide, pentyldecyl sulfide, pentylundecyl sulfide, pentyldodecyl sulfide, pentylcyclopentyl sulfide, pentylcyclohexyl sulfide, pentylcycloheptyl sulfide, pentylcyclooctyl sulfide, dihexyl sulfide, hexylheptyl sulfide, hexyloctyl sulfide, hexylnonyl sulfide, hexyl- decyl sulfide, hexylundecyl sulfide, hexyldodecyl sulfide, hexyleye1opentyl 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 sulfide, octylcyclohexyl sulfide, octylcycloheptyl sulfide, octylcyclooctyl sulfide, dinonyl sulfide, nonyl- decyl sulfide, nonylundecyl sulfide, nonyldodecyl sulfide, nonylcyclopentyl sulfide, nonylcyclohexyl sulfide, nonylcycloheptyl sulfide, nonylcylcooctyl sulfide, didecyl sulfide, decylundecyl sulfide, decyldodecyl sulfide, decylcyclopentyl sulfide, decylcyclohexyl sulfide, decyl- cycloheptyl sulfide, and decylcyclooctyl sulfide. More preferred sulfides include methylhexyl sulfide, methyl- heptyl sulfide, methyloctyl sulfide, methylnonyl sulfide, methyldecyl sulfide, ethylhexyl sulfide, ethylheptyl sulfide, ethyloctyl sulfide, ethylnonyl sulfide, ethyldecyl sulfide, dibutyl sulfide, dipentyl sulfide, dihexyl sulfide, diheptyl sulfide, and dioctyl sulfide.

Hydrocarbon means herein an organic compound containing carbon and hydrogen atoms. The term hydrocarbon includes the following organic compounds: 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, hydro carbon compounds, that is, alkanes, alkenes or alkynes. Cycloaliphatic refers herein to saturated and unsaturated cyclic hydrocarbons, that is, cycloalkenes and cycloalkanes.

Cycloalkane refers to an alkane containing one, two, three or more cyclic rings. Cycloalkene 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 hydrocarbyl 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 hereinbefore. Aralkyl means herein an alkyl group, wherein aryl is as defined hereinbefore.

C_1-20 alkyl 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.

Hydrocarbylene means herein an organic radical- -containing carbon and hydrogen atoms which must be attached to the nitrogen atom by a double bond. The term hydrocarbylene includes the following organic radicals alkenyl, cycloalkenyl and aralkylene where aryl is defined as before.

A heterocyclic ring means herein both saturated and unsaturated heterocyclic rings including an -N-cyclic ring. The heterocyclic ring may include one or more N, O or S atoms. Examples of suitable heterocyclic rings are pyridine, pyrazole, furan, thiophene, indole, benzofuran, benzothiophene, quinoline, isoquinoline, coumarin, carbazole, acridine, imidazole, oxazole, thiazole, pyridazine, pyrimidine, pyrazine, purine, ethylenimine, oxirane, azetidine, oxetane, thietane, pyrrole, pyrrolidine, tetrahydrofuran, isoxazole, piperidine, azepine and others. The composition of the present invention is prepared using sufficient amounts of component (a) and component (b) to prepare an effective collector for metal-containing minerals from ores in a froth flotation process. The amounts of each component most advantageously employed in preparing the composition will vary depending on the specific components (a) and (b) employed, the specific ore being treated and the desired rates of recovery and selectivity. The composition preferably comprises from about 10 to about 90, more preferably from 20 to 80, percent by weight, of component (a), and from about 10 to about 90, more preferably from 20 to 80, percent by weight, of component (b). The composition of this invention even more preferably comprises from about 30 to about 70 percent by weight of component (a) and from about 30 to about 70 percent by weight of component (b).

The process of this invention is useful for the recovery by froth flotation of metal-containing minerals from ores. An ore refers herein to the 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 little or no value and needs to be separated from the desired metal-containing minerals.

The collector composition of this invention is preferably employed in the recovery, in a froth flotation process, of metal-containing minerals. In a more preferred embodiment of this invention minerals containing copper, nickel, lead, zinc, or molybdenum are recovered. In an even more preferred embodiment, minerals containing copper are recovered. Also preferred metal-containing sulfide minerals are those which have high natural hydrophobicity in the unoxidized state. The term "hydrophobicity in the unoxidized 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 compounds 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 process of this invention include copper-bearing minerals such as, for example, covellite (CuS), chalcocite (Cu₂S), chalco- pyrite (CuFeS₂), valleriite (Cu₂Fe₄S₇ or Cu₃Fe₄S₇) , bornite (Cu₅FeS₄), cubanite (Cu₂SFe₄S₅), enargite [Cu₃(As₁Sb)S₄], tetrahedrite (Cu₃SbS₂), tennantite (Cu₁₂As₄S₁₃), brochantite [Cu₄(OH)₆SO₄], antlerite [Cu₃SO₄(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, stephanite (Ag₅SbS₄) and argentite (Ag₂S); chromium-bearing minerals such as, for example, daubreelite (FeSCrS₃); nickel-bearing minerals such as, for example, pentlandite [(FeNi)₉S₈]; molybdenum-bearing minerals such as, for example, molybdenite (MoS₂); and platinum- and palladium-bearing minerals such as, for example, cooperite [Pt(AsS)₂]. Preferred metal-containing sulfide minerals include molybdenite (MoS₂), chalcopyrite (CuFeS₂), galena (PbS), sphalerite (ZnS), bornite (Cu₅FeS₄), and pentlandite ([(FeNi)₉S₈].

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 mineral 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 metal-containing oxide minerals and oxide minerals for which this process is useful include oxide minerals containing copper, aluminum, iron, titanium, magnesium, chromium, tungsten, molybdenum, 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 (CluO), tenorite (CuO), malachite [Cu-(OH)₂CO₃], azurite [Cu-(OH)₂(CO₃)₂], atacamite [Cu₂Cl(OH)₃], chrysocolla (CuSiO₃); aluminum-bearing minerals such as corundum; zinc-containing minerals, such as zincite (ZnO) and smithsonite (ZnCO₃); tungsten-bearing minerals such as wolframite [(Fe, Mn)WO₄]; nickel-bearing minerals such as bunsenite (NiO); molybdenum-bearing minerals such as wulfenite (PbMoO₄) and powellite

(CaMoO₄); iron-containing minerals, such as hematite and magnetite; chromium-containing minerals, such as chromite (FeOCr₂O₃); iron- and titanium-containing minerals, such as ilmenite; magnesium- and aluminum- -containing minerals, such as spinel; iron-chromium- -containing minerals, such as chromite; titanium-con- taining 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 minerals, such as, for example, pitchblende [U₂O₅(U₃O₈)] and gummite (UO₃nH₂O).

Other metal-containing minerals for which this process is useful include gold-bearing minerals, such as sylvanite (AuAgTe₂) and calaverite (AuTe); platinum- and palladium-bearing minerals, such as sperrylite (PtAs₂); and silver-bearing minerals, such as hessite (AgTe₂). Also included are metals which occur in a metallic state, e.g. gold, silver and copper.

The collector composition of this invention can be used in any concentration which gives the desired recovery of the desired minerals. In particular, the concentration 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 collector composition of this invention is used in a concentration of 5 grams (g) to 1000 g per metric ton of ore, more preferably between about 10 g and 200 g of collector per metric ton of ore to be subjected to froth flotation. In general, to obtain optimum syner- gistic behavior, it is most advantageous to begin at low dosage levels and increase the levels until the desired effect is achieved. 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.

During the froth flotation process of this invention, the use of frothers is preferred. Frothers are well-known in the art and reference is made thereto for the purposes of this invention. Any frother which results in the recovery of the desired metal-containing 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 C_5-8 alcohols, pine oils, cresols, C_1-4 alkyl ethers of polypropylene glycols, dihydroxylates of polypropylene glycols, glycols, fatty acids, soaps, alkylaryl sulfonates, 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.

In addition, in the process of this invention it is contemplated that the collector combination which makes up the composition of this invention can be used in mixtures with other collectors well-known in the art.

The collector composition of this invention may also be used with an amount of other collectors known in the art, sufficient to give the desired recovery of desired mineral. Examples of such other collectors useful in this invention include dialkyl thioureas, alkyl, dialkyl and trialkyl thiocarbonates, alkyl and dialkyl thionocarbamates, monoalkyl dithiophosphates, dialkyl and diaryl dithiophosphates, dialkyl monothiophosphates, diaryl dithiophosphates, dialkyl and diaryl thiophosphonyl chlorides, dialkyl and diaryl dithiophosphonates, alkyl mercaptans, xanthogen formates, 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 the purposes of illustration only and are not to be construed to limit the scope of the invention. Unless otherwise indicated, all parts and fractions are by weight.

In the examples, the performance of the frothing processes described is shown by giving the fractional amount of recovery at a specified time.

Example 1- Froth Flotation of a Copper/Molybdenum Ore

A series of bags (Sample Nos . 1-8) containing 1200 g of homogeneous copper/molybdenum ore, containing chalcopyrite and molybdenite minerals, from Western Canada were prepared. The ore in each bag was ground using 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. The resulting pulp was transferred to an Agitair 1500 ml flotation cell outfitted with an automated froth removal paddle. The pH of each slurry was adjusted to 10.2 using lime. No further pH adjustments were made during the test. A standard methyl isobutyl carbinol (MIBC) frother and the collectors or collector combinations set forth in Table I were employed to float the copper and molybdenum using a four-stage rougher flotation scheme as set forth below.

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

STAGE 2 Collector 0.0021 kg/ton* MIBC 0.005 kg/ton** condition - 0.5 minute float - collect concentrate for 1.5 minutes

STAGE 3: Collector - 0.0016 kg/ton* MIBC - 0.005 kg/ton**

- condition - 0.5 minute

- float - collect concentrate for 2.0 minutes

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

*kilogram of the collector or collector composition per metric ton of ore being treated **kilogram of the frother per metric ton of ore being treated The results of the froth flotation testing are compiled in Table I.

TABLE I

*Not an example of the present invention

1A = C₆H₁₃S(CH₂)₂NH₂ ²R-7 is the experimental fractional recovery after 7 minutes

³Grade is the fractional content of the specified metal in total weight collected in the froth.

In conducting the froth flotation testing on Sample Nos. 1-8, the collector composition comprises 50 weight percent of each collector. The 95 percent confidence level of statistical error associated with the Cu R-7 value in Table I is ± 0.010. Thus the statistical range of R-7 values for Cu in Table I associated, for example, with collector A is 0.688 ± 0.010 or 0.678 to 0.698.

The statistical error associated with the Mo R-7 values in Table I is ± 0.015.

Clearly, the recoveries of Cu and Mo at 7 minutes with the collector blends of this invention match or exceed the 7 minute recoveries that would be expected from a weighted average effect of the components used alone; synergism has occurred.

Example 2 - Froth Flotation of a Cu/Ni Ore

A series of samples of -10 mesh ore from Eastern Canada were divided into 900 g samples. The ore contained chalcopyrite, pentlandite, and pyrrhotite minerals. All tests were performed using an Agitair 1500 ml cell operated at a speed of 900 rpm with an air flow of 9.0 liters/minute. Before flotation, each sample was ground in a rod mill for 1080 revolutions. Before grinding, 600 ml of water were added along with sufficient lime to adjust the slurry pH to 9.2. After grinding, the ore had a particle size less than 200 mesh (75 microns). The rod mill contents were emptied into the float cell and the pH adjusted to 9.2 (using either lime or sulfuric acid).

A complex nine-stage flotation sequence was performed. The first four stages are referred to as rougher float and stages five through nine as scavenger float. After stage 4, sulfuric acid was added to adjust the pH to 9.2; CuSO₄ was added to stage 5 and stage 7 (0.015 kg/metric ton). The frother used was DOWFROTH^® 250.

The addition rates of frother and collector were as shown in Table IIA.

The samples were dried, weighed and metal assays performed. Standard mass balance formulae were used to calculate recoveries and grades. The results are compiled in Table IIB.

In this example, the lowest pyrrhotite recovery and highest Cu and Ni recoveries possible after 7 minutes are important, as it is at this time point that the major rejection of high sulfur containing mineral occurs. At 17 minutes the Cu and Ni recoveries are to be the highest possible using normal flotation logic. However, Cu recoveries were approaching the theoretical limit of 1.0 at both 7 and 17 minutes, so statistically significant comparisions were not possible.

Clearly, the recovery of Ni at 7 minutes using a collector blend of this invention gave a high value with low pyrrhotite. Also, the Ni recovery at 17 minutes with the blend of this invention is high. The 95 percent confidence level of statistical error associated with Ni at R-7 is ± 0.015 and at R-17 is ± 0.006; pyrrhotite at R-7 is ± 0.012. Ni recovery shows that synergism has occurred with desired lower recovery of pyrrhotite.

Example 3- Froth Flotation of a Complex Pb/Zn/ Cu/Ag Ore

A series of uniform 1000 g samples of a complex Pb/Zn/Cu/Ag ore from Central Canada were prepared. The ore contained galena, sphalerite, chal- copyrite, and argentite minerals. For each flotation run, a sample was added to a rod mill along with 500 ml of tap water and 7.5 ml of SO₂ solution. Six and one-half minutes of mill time were used to prepare the feed such that 90 percent of the ore had a particle size of less than 200 mesh (75 microns). After grinding, the contents were transferred to a cell fitted with an automated paddle for froth removal, and the cell was attached to a standard Denver flotation mechanism. A two-stage flotation was then performed Stage I being a copper/lead/silver rougher float and Stage II being a zinc rougher float. To start the Stage I flotation, 1.5 g/kg of Na₂CO₃ was added (pH of 9 to 9.5), followed by the addition of the 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. A methyl isobutyl carbinol (MIBC) frother was then added (standard dose of 0.015 ml/kg). The 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 CuSO₄ to the cell remains of Stage I. The pH was then adjusted to 10.5 with lime addition. This was followed by a condition period of 5 minutes with agitation only. The pH was then rechecked and adjusted back to 10.5 with lime. At this point, the collector(s) were added, followed by a five-minute condition period with agitation only. A methyl isobutyl carbinol (MIBC) frother was then added (standard dose of 0.020 ml/kg). Concentrate was collected for 5 minutes and labeled as zinc rougher concentrate.

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

The 95 percent confidence levels of statistical error in the 5 minute recovery data of the Cu/Pb flotation (Stage I) are for Ag, ± 0.01; Cu, ± 0.01; and Pb, ± 0.02. Runs 1 and 4 represent the tests where single components were used in each stage.

In Stage I of Run 2, the addition of the two component blend of this invention at less dosage (24% less) as compared to the single component collector of Stage I of Run 1, gave slightly more Ag and Cu recovery and significantly more Pb recovery.

In a similar manner, the collector blends of this invention in Stage I of Run 3 compared to Stage I of either Run 1 or 4, gave higher Ag recovery, slightly higher Cu recovery, and much higher Pb recovery. Note that Ag, Cu or Pb not recovered in Stage I is lost to the process.

The total Zn recovery of Stages I and II in all four runs of Table III is so close to 1.0 (the theoretical limit) that statistical comparisons are not valid.

Claims

1. A collector composition for the flotation of metal-containing minerals which comprises: (a) a compound of the formula:

R¹-X-(R)_n-Q

wherein Q is

-N(R²)_a(H)_b where a + b equals 2,

≡ N, or

ring where the cyclic ring is saturated or unsaturated and may contain additional hetero atoms, but must contain the N;

where y + p + m = n, where n is an integer from 1 to 6, and y, p and m are independently 0 or an interger from 1 to 6, and each moiety can occur in a random sequence;

where R³ is hydrogen, a C_1-22 hydrocarbyl radical or a C_1-22 substituted hydrocarbyl radical; and

(b) hydrocarbons containing monosulfide units of the formula

IX wherein

wherein

R⁵ and R⁶ 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 interface.

2. The collector composition of Claim 1 wherein R¹ and R² are independently a C_1-22 hydrocarbyl radical or a C_1-22 hydrocarbyl radical substituted with one or more hydroxy, amino, phosphonyl, alkoxy, imino, carbamyl, carbonyl, thiocarbonyl, cyano, carboxyl, hydrocarbylthio, hydrocarbyloxy, hydrocarbylamino or hydrocarbylimino groups.

3. The collector of Claim 2 wherein compound (a) corresponds to the formula:

la wherein R¹ is a C_2-14 hydrocarbyl radical or a C_2-14 hydrocarbyl radical substituted with one or more hydroxy, amino, phosphonyl or alkoxy groups;

R² is a C_1-6 alkyl, C_1-6 alkylcarbonyl, or a C_1-6 alkyl or C_1-6 alkylcarbonyl group substituted with an amino, hydroxy or phosphonyl group; a is 0 or 1 and b is 1 or 2 and a + b = 2.

4. The composition of Claim 3 wherein n is 2 or 3.

5. The composition of Claim 3 wherein component (a) is an omega- (hydrocarbylthio)alkyl- amine; S-(omega-aminoalkyl) hydrocakbon thioate; N- -(hydrocarbyl)-alpha,omega-alkanediamine; (omega- -aminoalkyl) hydrocarbon amide; omega-(hydrocarbyloxy)alkylamine; omega-aminoalkyl hydrocarbonoate; omega-(hydrocarbylthio)-alkylamide; or mixture thereof

6. The composition of Claim 1 wherein R⁵ and R⁶ are independently an aliphatic, cycloaliphatic or aralkyl moiety, unsubstituted or substituted with one or more hydroxy, cyano, halo, O R⁷ or S R⁷ moieties; R⁷ is a hydrocarbyl radical and R⁵ and R⁶ may combine to form a heterocyclic ring with S.

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

8. The composition of Claim 7 wherein

R⁵ and R⁶ are independently alkyl, alkenyl, alkynyl, cycloalkyl or cycloalkenyl, unsubstituted or substituted with one or more hydroxy, cyano, halo, O R⁷ or

SR⁷ moieties; R⁷ is aliphatic or cycloaliphatic; and

R⁵ and R⁶ do not combine to form a heterocyclic ring structure.

9. The composition of Claim 5 which comprises:

(a) from about 10 to about 90 percent by weight of omega-(hydrocarbylthio)alkyl- amine, S-(omega-aminoalkyl) hydrocarbon thioate, N-(hydrocarbyl)-alpha,omega-alkanedi- amine, (omega-aminoalkyl) hydrocarbon amide, omega-(hydrocarbyloxy) alkylamine, omega- -aminoalkyl hydrocarbonoate, omega-(hydrocarbylthio)alkylamide, or mixture thereof; and

(b) from about 10 to about 90 percent by weight of the sulfide compound and the sulfide compound corresponds to the formula (R⁴ ) _3-nC (H)_n-S-C (H)_n(R⁴ )_{3 -n}

X wherein R⁴ is independently hydrocarbyl or hydrocarbyl substituted with a hydroxy, cyano, halo, ether, hydrocarbyloxy or hydrocarbyl thioether moiety; wherein the two R⁴ moieties may combine to form a cyclic ring or heterocyclic ring with the sulfur atom; and n is an integer of 0, 1,

2 or 3.

10. The composition of Claim 9 which comprises:

(a) from about 20 to about 80 percent by weight of omega-(hydrocarbylthio)alkyl- amine, S-(omega-aminoalkyl) hydrocarbon thio- ate, N-(hydrocarbyl)-alpha,omega-alkanedi- amine, (omega-aminoalkyl) hydrocarbon amide, omega- (hydrocarbyloxy)alkylamine, omega- -aminoalkyl hydrocarbonoate, omega-(hydrocarbylthio)alkylamide or mixture thereof; and (b) from about 20 to about 80 percent by weight of the sulfide compound.

11. The composition of Claim 10 wherein R is -CH₂- or

R¹ is C_2-14 hydrocarbyl; R² is C_1-6 alkyl or C_1-6 alkylcarbonyl; R³ is hydrogen or C_1-14 hydrocarbyl; R⁵ and R⁶ are independently an alkyl or alkenyl group and the sum of carbon atoms in R⁵ and R⁶ is from 6 to 16; a is the integer 0 or 1; b is the integer 1 or 2; and n is an integer of 1 to 4.

12. The composition of Claim 9 wherein R¹ is C_4-11 hydrocarbyl; R² is C_1-4 alkγl or C_1-4 alkylcarbonyl;

R³ is hydrogen or C_1-11 hydrocarbyl; R⁵ is C_1-2 alkyl;

R⁶ is a C_6-11 alkyl or alkenyl group; X is -S-,

or -O-; and n is the integer 2 or 3.

13. The composition of Claim 13 wherein X is -S-.

14. The composition of Claim 5 wherein R⁵ and R⁶ 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. The composition of Claim 1 or 5 wherein component (a) is 2-(hexylthio)ethylamine or ethyl

2-(hexylthio)ethylamide.

17. The composition of Claim 1 or [6 wherein component (b) is ethyl octyl sulfide.

18. A process for recovering metal-con- taining 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 the flotation collector composition of any one of Claims 1 to 17.

19. The process of Claim 18 wherein a metal- -containing mineral is recovered in the froth.

20. The process of Claim 19 wherein the metal-containing mineral recovered in the froth contains copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium, or mixtures thereof.

21. The process of Claim 20 wherein the metal-containing sulfide mineral recovered in the froth is molybdenite, chalcopyrite, galena, sphalerite, bornite, or pentlandite.

22. The process of Claim 21 wherein the collector composition is present in a concentration of from 0.001 to 1.0 kg of collector/metric ton of ore to be subjected to froth flotation.