NO168408B - COLLECTOR MATERIALS FOR FLOTION OF METALLIC MINERALS, AND PROCEDURES FOR THE EXTRACTION OF SUCH MINERALS - Google Patents

Description

The invention relates to new collectors (collectors) for the extraction of metal-containing sulfide minerals, sulfidized metal-containing oxide minerals, metal-containing oxide minerals and metals that occur in a metallic state, all four mineral groups here referred to as metal-containing minerals,

from ores by froth flotation.

Flotation is a procedure for treating a

mixture of finely divided mineral solids, e.g. a powdered ore, suspended in a liquid by which some of such solids are separated from other finely divided solids, e.g. clay and other similar materials, occurring in the ore, by introducing a gas (or providing a gas in situ) into the liquid to produce a frothy mass containing some of the solids on top of the liquid, and leaving suspended (unfoamed) others solid components in the ore. Flotation is based on the principle that the introduction of a gas into a liquid containing solid particles of various materials suspended therein causes the adherence of some gas to certain suspended solids and not to others, and makes the particles which have the gas thus attached to themselves, lighter than the liquid. Consequently, these particles rise to the top of the liquid and form a foam.

Various flotation agents have been mixed with the suspension to improve the foaming process. These means are classified according to the function to be performed: collectors such as xanthates, thionocarbamates and the like; foam formers, which facilitate the formation of a stable foam, e.g. natural oils, e.g. pine needle oil and eucalyptus oil; modifiers, e.g. activators to induce flotation in the presence of a collector, e.g. copper sulfate; oppressive means, e.g. sodium cyanide, which tends to prevent a collector from functioning as such on a mineral that is desired

preserve in the liquid, thereby keeping a substance from being carried up and forming part of the foam; pH-regulating agents, e.g. lime and sodium carbonate, to produce optimum metallurgical results; and such.

An understanding of the phenomena which make flotation a particularly valuable industrial operation is not essential for carrying out the invention. The phenomena which make flotation a particularly valuable industrial operation appear to be largely associated with the selective affinity of the surface of particulate solids, suspended in a liquid containing trapped gas, for the liquid on the one hand and the gas on the other. The specific additives used in a flotation operation are chosen according to the nature of the ore, the mineral(s) that one seeks to extract and the other additives to be used in combination with these.

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

Among the collectors that are usually used for the extraction of metal-containing sulphide minerals or sulphided metal-containing oxide minerals are xanthates, dithiophosphates and thionocarbamates. Other collectors generally recognized as useful in the recovery of metal-bearing minerals or sulfided metal-bearing oxide minerals are mercaptans, disulfides (R-SS-R) and polysulfides [R-(S)n-R], where n is 3 or more.

The transformation of metal-containing sulfide minerals or sulfided metal-containing oxide minerals into the more usable pure metal state is often carried out by smelting processes.

Such melting processes can result in the formation of volatile sulfur compounds. These volatile sulfur compounds are often released into the atmosphere via chimneys, or are removed from such chimneys using expensive and cumbersome scrubbing equipment.

Many non-ferrous sulphide minerals or metallic oxide minerals occur naturally in the presence of ferrous sulphide minerals, e.g. pyrite and pyrrhotite. When the ferrous sulphide minerals are extracted in flotation processes together with the non-ferrous sulphide minerals and sulphidised metal-containing oxide minerals, there is an excess of sulfur present which is released in the smelting processes. What is needed is a method for selectively extracting the non-ferrous metal-containing sulfide minerals and sulfidized metal-containing oxide minerals without extracting the iron-containing sulfide minerals such as e.g. pyrite and pyrrhotite.

Of the commercial collectors, the xanthates, thionocarbamates, and dithiophosphates do not selectively recover non-ferrous sulfide minerals in the presence of ferrous sulfide minerals. In contrast, such collectors collect and extract all metal-containing sulphide minerals. The mercaptan collectors have an environmentally undesirable order and are very slow kinetically in flotation of metallic sulphide minerals. The disulfides and polysulfides give, when used as collectors, low recoveries with slow kinetics. Therefore, the mercaptans, disulfides and polysulfides are not usually used commercially. Furthermore, the mercaptans, disulfides, and polysulfides do not selectively extract nonferrous sulfide minerals in the presence of ferrous sulfide minerals.

Based on the above, what is needed is a flotation collector which will selectively extract, at relatively good extraction rates, a wide area of metal-containing minerals in the presence of iron-containing sulphide minerals such as e.g. pyrite and pyrrhotite.

Accordingly, the present invention is, in one aspect, a collector material for flotation of metal-containing minerals, and the collector material is characterized in that it comprises:

(a) a compound of formula:

where a + b equals 2,

R<1> and R<2> independently are a C1_22-nydrocarbyl radical"

where y + p = n, where n is an integer from 1-6, and y and p are independently 0 or an integer from 1-6,

X is -S- or -N-R<3>

where R<3> is hydrogen or a C1_22~hydrocarbylrad:>Lkal °9

(b) hydrocarbons containing monosulphide units with

formula

where

R<5> and R<6> are independently a hydrocarbyl radical under the condition that the total carbon content of the hydrocarbon sulfide is such that it has a sufficiently hydrophobic character to cause the metal-containing sulfide mineral or the sulfided metal-containing oxide mineral particles to be expelled into an air/bubble- interface.

The invention also relates to a method for extracting metal-containing minerals from an ore, and the method is characterized in that it comprises subjecting the ore, in the form of an aqueous mass, to a foam flotation process in the presence of a floating amount of flotation collector material according to which any of requirements 1 to 4.

The collector materials according to the invention have the ability to bring a wide range of metal-containing minerals to flow. Furthermore, such collector materials also provide good recovery and selectivity towards the desired metal-containing minerals.

In a preferred method according to the invention, the described collector material is used in a method for extracting metal-containing sulfide minerals or sulfided metal-containing oxide minerals from an ore, and the method comprises subjecting the ore, in the form of an aqueous mass, to a foam flotation process in the presence or a floating quantity of the collector material under conditions sufficient to cause the metal-bearing sulfide mineral or the sulfided metal-bearing oxide mineral particles to be driven to the air/bubble interface and recovered in the foam.

The collector material according to the invention results

in surprisingly high recovery of non-ferrous metal-containing minerals and high selectivity towards such non-ferrous metal-containing minerals when such metal-containing minerals are present in the presence of iron-containing sulfide minerals.

Component (a) in the collector material according to the invention is a component with formula (I) above. Although not specifically stated in formula (I), it should be understood that in aqueous medium with a lower pH value, preferably acidic, component

(a) exist in the form of a salt. In this formula, R is advantageous

-(CH2)-p.

More advantageously, the sum of carbon atoms in R<1> and R<2> is 6 or more, with R<1> preferably being C2-i4~hydrocarbyl or C2-i4-hydrocarbyl substituted with one or more hydroxyl-, amino-, phosphonyl - or alkoxy groups, more preferably C4_11-hydrocarbyl; and R<2> is preferably C1-6-alkylcarbonyl or C1-6-substituted alkyl or alkylcarbonyl, more preferably C1-4-alkyl or -alkylcarbonyl or C1-6-alkyl or C1-5-alkylcarbonyl substituted with an amino, hydroxyl or phosphonyl group, and preferably a C1-2-alkyl or C1-2-alkylcarbonyl. n is preferably an integer from 1 to 4, preferably 2 or 3;

X is preferably -S-; and

R<3> is preferably hydrogen or C1-4-hydrocarbyl, more preferably hydrogen or C1-4-hydrocarbyl, most preferably hydrogen.

Component (a) includes such compounds as the S-(omega-aminoalkyl)hydrocarbonthionates: the omega-(hydrocarbylthio)alkylamines and the omega(hydrocarbylthio)alkylamides:

N-(hydrocarbyl)-a, the omega-alkanediamines:

The N-(omega-aminoalkyl)hydrocarbonamides:

the omega-(hydrocarbyloxy-)alkylamines: and the omega-aminoalkylhydrocarbons:

where R<1>, R<2>, R<3>, a, b and n are as defined previously.

In formulas II-VII, when X is aS-, R<1> is preferably C4_10~ hydrocarbyl; when X is

then the total carbon content in the groups R<1> and R<3> is preferably between 1 and 23, more preferably 2 and 16, and most preferably 4 and 15.

Of the foregoing, the preferred component (a) compound includes omega-(hydrocarbylthio)alkylamine, omega-(hydrocarbylthio)alkylamides, N-(hydrocarbyl)-a, omega-alkanediamine, N-(omega-aminoalkyl)hydrocarbonamides, omega -(hydrocarbyloxy)-alkylamine, omega-(hydrocarbylthio)alkylamides or a mixture thereof. More preferred component (a) compounds include omega-(hydrocarbylthio)alkylamines, omega-(hydrocarbylthio)alkylamides, N-(hydrocarbyl)-a, omega-alkane diamines, N-(omega-aminoalkyl)hydrocarbonamides or mixtures thereof. The most preferred classes of component (a) compounds are the omega-(hydrocarbylthio)alkylamines, e.g. 2-(hexylthio)ethylamine and omega-(hydrocarbylthio)alkylamides, e.g. ethyl 2-(hexylthio)ethylamide.

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

The N-(omega-aminoalkyl)hydrocarbonamides of formula V can be prepared by the methods described by Fazio in US 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 methods described in British Patent 869,409 and by Hobbs in US Patent 3,397,238.

The S-(omega-aminoalkyl)hydrocarbonthionates of formula II can be prepared by the methods described by Faye et al., in US patent 3,328,442 and in Beilstein, 4, 4th ed., 4 Supp., 1657 (1979 ).

The omega-aminoalkyl hydrocarbons of formula VII can be prepared by the methods described in J. Am. Chem. Soc., 83, 4835 (1961); Beilstein, 4, 4th ed., 4 supp., 1785 (1979).

The N-(hydrocarbyl)-α, omega-alkanediamines of formula IV can be prepared by the method well known in the art. One example is the method described in DDR patent document 98,510.

Component (b) in the collector material is an organic compound containing at least 4 carbon atoms and one or more monosulphide units where the sulfur atoms in the sulphide units are bound to non-aromatic carbon atoms, i.e. aliphatic or cycloaliphatic carbon atoms. Monosulphide unit here refers to a unit where each sulfur atom is bonded to two carbon atoms in only one non-aromatic grouping, e.g. to two carbon atoms in only one hydrocarbon grouping. The hydrocarbon compounds may contain one or more monosulfide units and include such compounds which are substituted with hydroxyl, cyano, halogen, ether, hydrocarbyloxy and hydrocarbylthioether groups.

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

where R<5> and R<6> are independently a hydrocarbyl radical or a hydrocarbyl radical substituted with one or more hydroxyl, cyano, halogen, ether, hydrocarbyloxy or hydrocarbylthioether groups; where R<5> and R<6> can be combined to form a heterocyclic ring structure with S; with the proviso that S is attached to an aliphatic or cycloaliphatic carbon atom; with the additional proviso that the total carbon content in the sulphide part is such that the sulphide part has a sufficiently hydrophobic character to cause the metal

containing sulphide mineral particles are driven to the air/bubble interface.

The specific R<5-> and R<6-> groups that are most advantageously used here depend on a number of factors including the component (a) that is used, the specific ore that is 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 monosulphide compound is preferably 20, more preferably 16 and most preferably 12.

Preferably, R<5> and R<6> are independently an aliphatic, cycloaliphatic or aralkyl group, unsubstituted or substituted with one or more hydroxyl-, cyano-, halogen-, -OR<7-> or -SR<7-> groups, wherein R<7> is a hydrocarbyl radical; R<5> and R<6> can be combined to form a heterocyclic ring with S. R<5> and R<6> are more preferably an aliphatic or cycloaliphatic group, unsubstituted or substituted with one or more cyano-, halogen-, hydroxyl, OR<7> or SR<7> groups, where R<7> is a hydrocarbyl radical; where R<5> and R<6> may combine to form a heterocyclic ring with S. In a more preferred embodiment, R<5> and R<6> do not combine to form a heterocyclic ring with S, and R<5> and R<6> is independently alkyl, alkenyl, alkynyl, cycloalkyl or cycloalkenyl, unsubstituted or substituted with one or more hydroxyl, halogen, cyano, OR<7-> or SR<7-> groups, where R<7 > is aliphatic or cycloaliphatic. In the most preferred embodiment, R<5> and R<6> are not the same hydrocarbon moiety, i.e. that the monosulphide is asymmetric. R<7> is preferably aliphatic or cycloaliphatic. R<7> is more preferably alkyl, alkenyl, cycloalkyl or cycloalkenyl. In a most preferred embodiment R<5> and R<6> are independently alkyl or alkenyl, in particular R<5> is methyl or ethyl and R<6> is a C 6-1 alkyl or C 6-1:L-alkenyl group, e.g. ethyl octyl sulfide.

Examples of cyclic compounds used as the monosulfide compound of formula IX include the following

structures:

where R<8> is independently hydrogen, aryl, alkaryl, aralkyl, alkyl, alkenyl, alkynyl,' cycloalkyl, cycloalkenyl, hydroxyl, cyano, halogen, OR<7> or SR<7>, where aryl, alkaryl, aralkyl, alkyl , alkenyl, alkynyl, cycloalkyl, cycloalkenyl may optionally be substituted with hydroxyl, cyano, halogen, OR<7> or SR<7> and the like; where R<7> is a hydrocarbyl group, preferably aliphatic or cycloaliphatic, more preferably alkyl, alkenyl, cycloalkyl or cycloalkenyl; and R<9> is straight or branched alkylene or alkenylene or alkynylene, unsubstituted or substituted with a hydroxyl, cyano, halogen, OR<7-> or SR<7-> group.

A preferred compound which is applicable as component (b) in connection with the invention corresponds to the following formula:

where

R<8> is as defined previously; R<4> is independently hydrocarbyl, or hydrocarbyl substituted with a hydroxyl, cyano, halogen, ether, hydrocarbyloxy or hydrocarbylthioether group; where two R<4->group rings can be combined to form a cyclic ring or heterocyclic ring with the sulfur atom;

n is an integer of 0, 1, 2 or 3, provided that the total carbon content of the hydrocarbon portion of the collector is such that the collector has a sufficiently hydrophobic character to cause the metal-containing sulfide mineral or sulfided metal-containing oxide mineral particles to be driven into air/bubble- the interface.

In the above formula, R<4> is preferably an aliphatic, cycloaliphatic, aryl, alkaryl or aralkyl group, unsubstituted or substituted with a cyano, halogen, hydroxyl, OR<7-> or SR<7-> group , where R<7> is as defined previously. More preferably, R<4> is an aliphatic or cycloaliphatic group, unsubstituted or substituted with a hydroxyl, cyano, halogen, aliphatic ether, cycloaliphatic ether, aliphatic thioether or cycloaliphatic thioether group. Even more preferably, R<4> is an alkyl, alkenyl, cycloalkyl or cycloalkenyl group. Most preferably, one -C(H)n(R<4>)3_n is a methyl or ethyl group and the other is a Cg_n~alkyl-

or C6-11 alkenyl group. Preferably n is equal to 1, 2 or 3 and most preferably 2 or 3.

Preferred hydrocarbon-containing monosulphide units of formula R<5>S-R<6>, where R<5> and R<6> are defined as above, are prepared by standard methods known in the art, e.g. by

react R<6->H with R<5->SH, where R<5> and R<6> are defined as above.

Examples of compounds within the scope of the present invention include methylbutylsulfide, methylpentylsulfide, methylhexylsulfide, methylheptylsulfide, methyloctylsulfide, methylnonylsulfide, methyldecylsulfide, methylundecylsulfide, methyldodecylsulfide, methylcyclopentylsulfide, methylcyclohexylsulfide, methylcycloheptylsulfide, methylcyclooctylsulfide, ethylbutylsulfide, ethylpentylsulfide, ethylhexylsulfide, ethylheptylsulfide, ethyloctylsulfide, ethylnonylsulfide. , ethyldecylsulfide, ethylundecylsulfide, ethyldodecylsulfide, ethylcyclopentylsulfide, ethylcyclohexylsulfide, ethylcycloheptylsulfide, ethylcyclooctylsulfide, propylbutylsulfide, propylpentylsulfide, propylhexylsulfide, propylheptylsulfide, propyloctylsulfide, propylnonylsulfide, propyldecylsulfide, propylundecylsulfide, propyldodecylsulfide, propylcyclopentylsulfide, propylcyclohexylsulfide, propylcyclohexylsulfide, dipropylcyclohexylsulfide, butylsulfide -sulfide, butylhexylsulfide, butylheptylsulfide, butyloctylsulfide, butylnonylsulfide, butyldecylsulfide id, butyl undecyl sulfide, butyl dodecyl sulfide, butyl cyclopentyl sulfide, butyl cyclohexyl sulfide, butyl cycloheptyl sulfide, butyl cyclooctyl sulfide, dipentyl sulfide, pentylhexyl sulfide, pentylheptyl sulfide, pentyloctyl sulfide, pentyl nonyl sulfide, pentyldecyl sulfide, pentyl undecyl sulfide, pentyl dodecyl sulfide, pentyl cyclopentyl sulfide, pentylcyclohexyl sulfide, pentyl cycloheptyl sulfide, pentyl cyclooctyl sulfide, dihexyl sulfide hexyl nonyl sulfide, hexyl decyl sulfide, hexyl undecyl sulfide, hexyl dodecyl sulfide, hexyl cyclopentyl sulfide, hexyl cyclohexyl sulfide, hexyl cycloheptyl sulfide, hexyl cyclooctyl sulfide, diheptyl sulfide, heptyl octyl sulfide, heptyl nonyl sulfide, heptyldecyl sulfide, heptyl undecyl sulfide, heptyl dodecyl sulfide, heptyl cyclopentyl sulfide, heptyl cyclohexyl sulfide, heptyl cycloheptyl sulfide, heptyl cyclooctyl sulfide, octyl nonyl sulfide, octyl nonyl sulfide sulfide, octyl undecyl sulfide, octyl dodecyl sulfide, octyl cyclopentyl sulfide, octyl cyclohexyl sulfide, octyl cyclo heptylsulfide, octylcyclooctylsulfide, dinonylsulfide, nonyldecylsulfide, nonylundecylsulfide, nonyldodecylsulfide, nonylcyclopentylsulfide, nonylcyclohexylsulfide, nonylcycloheptylsulfide, nonylcyclooctylsulfide, didecylsulfide, decylundecylsulfide, decyldodecylsulfide, decylcyclopentylsulfide, decylcyclohexylsulfide, decylcycloheptylsulfide and decylcyclooctylsulfide. More preferred sulfides include methylhexyl sulfide, methylheptyl sulfide, methyloctyl sulfide, methylnonyl sulfide. methyldecylsulfide, ethylhexylsulfide, ethylheptylsulfide, ethyloctylsulfide, ethylnonylsulfide, ethyldecylsulfide, dibutylsulfide, dipentylsulfide, dihexylsulfide, diheptylsulfide and dioctylsulfide.

Hydrocarbon here means 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 here refers to straight chain and branched,

as well as saturated and unsaturated hydrocarbon compounds, i.e. alkanes, alkenes or alkynes. Cycloaliphatic here refers to saturated and unsaturated cyclic hydrocarbons, i.e. 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 here means 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 here to biaryl, biphenylyl, phenyl, naphthyl, phenanthrenyl, anthracenyl and two aryl groups bridged by an alkylene group. Alkaryl here refers to an alkyl-, alkenyl- or alkynyl-substituted aryl substituent, where aryl is as previously defined. Aralkyl here means an alkyl group, where aryl is as defined previously.

C1_20~alkyl includes straight and branched methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl -, hexadecyl, heptadecyl, octadecyl, nonadecyl and eicosyl groups.

Halogen here means a chlorine, bromine or iodine group.

Hydrocarbyl here means organic radical-containing carbon and hydrogen atoms which must be linked to the nitrogen atom by a double bond. The term hydrocarbylene includes the following organic radicals: alkenyl, cycloalkenyl and aralkylene where aryl is as previously defined.

A heterocyclic ring here means 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, ethyleneimine, oxirane, azetidine, oxetane, thietane, pyrrole, pyrrolidine, tetrahydrofuran, isoxazole, piperidine, azepine and others.

The material according to the present invention is produced by using sufficient amounts of component (a) and component (b) by producing an effective collector for metal-containing minerals from ores in a foam flotation process. The amounts of each component most advantageously used in the production of the material will vary depending on the specific components (a) and (b) used, the specific ore being processed and the desired rates of recovery and selectivity. The material preferably comprises from 10 to 90, more preferably from 20 to 80% by weight, of component (a) and from 10 to 90, more preferably from 20 to 80% by weight, of component (b). The material according to the present invention even more preferably comprises from 30 to 70% by weight of component (a) and from 30 to 70% by weight of component (b).

The method according to the invention is used for extraction by froth flotation of metal-containing minerals from ores. An ore here refers to the material that is extracted from the ground and includes the desired metal-bearing minerals mixed with the gangue species. The gangue here refers to the part of the material which is of little or no value and must be separated from the desired metal-bearing minerals.

The collector material according to the invention is preferably used in the extraction, in a foam flotation process, of metal-containing minerals. In a more preferred embodiment of the invention, minerals containing copper, nickel, lead, zinc or molybdenum are extracted. In an even more preferred embodiment, minerals containing copper are mined. Also preferred metal-containing sulphide minerals are those which have a high natural hydrophobicity in the unoxidised state. The term "hydrophobicity in the unoxidized state" refers to a newly crushed mineral or a mineral that has a fresh surface that shows a tendency to flow without collector addition.

Ores to which these compounds are useful include sulphide mineral ores containing copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium and mixtures thereof. Examples of metal-containing sulphide minerals which can be concentrated by foam flotation using the method according to the invention include copper-bearing minerals such as e.g. covellite (CuS), chalcocite (Cu2S), chalcopyrite (CuFeS2). vallerite (Cu2Fe4S7 or Cu3Fe4S7), bornite (Cu5FeS4), cubanite (Cu2<S>Fe4S5), enargite [Cu3 (As^b)S4] , tetrahedrite (Cu3SbS2) , tennantite (Cu12As4S13 ), brochantite [Cu4(OH)6S04] , antlerite [Cu3SO4(OH)4], famatinite [Cu3(SbAs)S4] and bournonite (PbCuSbS3); lead-bearing minerals such as galena (PbS); antimony-bearing minerals such as stibnite (Sb2S3); zinc-bearing minerals such as sphalerite (ZnS); silver-bearing minerals such as stephanite (Ag5SbS4) and argentite (Ag2S); chromium-bearing minerals such as daubreelite (FeSCrS3); nickel-bearing minerals such as pentlandite [(FeNi)9S8]; molybdenum-bearing minerals such as molybdenite (MoS2); and platinum- and palladium-bearing minerals such as cooperite [Pt(AsS)2]. Preferred metal-bearing sulfide minerals include molybdenite (MoS2), chalcopyrite (CuFeS2), galena

(PbS), sphalerite (ZnS), bornite (Cu5FeS4) and pentlandite [(FeNi)9S8].

Sulfidized and metal-bearing oxide minerals are minerals that are treated with a sulfidizing chemical to give such minerals sulfide mineral characteristics so that the minerals can be recovered in foam flotation using collectors that recover sulfide minerals. Sulfidization results in oxide minerals that have sulfide mineral characteristics. Oxide minerals are sulfidized by contact with compounds that react with the minerals so that a sulfur bond or affinity is formed. Such methods are well known in the field. Such compounds include sodium hydrosulphide, sulfuric acid and related sulphurous salts, e.g. sodium sulfide.

Sulfidated metal-bearing oxide minerals and oxide minerals for which this method 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 can be concentrated by foam flotation using the method according to the invention include copper-bearing minerals, e.g. cuprite (Cu2O), tenorite (CuO), malachite [Cu2(OH)2CO3], azurite [Cu3(OH)2(CO3)2], atacamite [Cu2Cl(OH)3], chrysocolla (CuSiO3); aluminium-bearing minerals, e.g. corundum; zinc-containing minerals, e.g. zincite (ZnO) and smithsonite (ZnCO 3 ); tungsten-bearing minerals such as wolframite [(Fe, Mn)W04]; nickel-bearing minerals such as bunsenite (NiO); molybdenum-bearing minerals such as wulfenite (PbMoO 4 ) and powellite (CaMoO 4 ); ferrous minerals, e.g. hematite and magnetite; chromium-containing minerals, e.g. chromite (FeOCr 2 O 3 ); iron and titanium-containing minerals, e.g. ilmenite; magnesium- and aluminium-containing minerals, e.g. spinel; iron-chromium-containing minerals, e.g. chromite; titanium-containing minerals, e.g.

rutile; manganese-containing minerals, e.g. pyrolusite; tin-containing minerals, e.g. cassiterite; and uranium-bearing minerals, e.g. uraninite; and uranium-bearing minerals, e.g. pitchblende [U2<0>5(U308)] and gumite (U03<n>H20).

Other metal-bearing minerals for which this method is applicable include gold-bearing minerals, e.g. sylvanite (AuAgTe2) and calaverite (AuTe); platinum- and palladium-bearing minerals, e.g. sperrylite (PtAs2); and silver-bearing minerals, e.g. hessite (AgTe2). Also included are metals that appear in a metallic state, e.g. gold, silver and copper.

The collector material according to the invention can be used in any concentration that gives the desired extraction of the desired minerals. In particular, the concentration used depends on the particular minerals to be extracted, the quality of the ore to be subjected to the foam flotation process, the desired quality of the mineral to be extracted, as well as the particular mineral being extracted. Preferably, the collector material according to the invention is used in a concentration of 5 grams (g) to 1000 g per metric ton of ore, more preferably between approx. 10 g and 200 g collector per metric ton of ore to be subjected to foam flotation. In general, to achieve optimal synergistic behavior, it is most advantageous to start at low dosage levels and increase the levels until the desired effect is achieved. Synergism is defined here as when the measured result of a mixture of two or more components exceeds the weighted average results for each component when used alone. This expression also implies that the results are compared under the condition that the total weight of the collector used is the same for each test.

During the foam flotation process according to the invention, the use of foam formers is preferred. Foam formers are well known in the art, and reference is made to them for the purposes of the present invention. Any foaming agent that results in recovery of the desired metal-bearing mineral is suitable. Foam formers which are applicable in connection with the invention include any foam formers known in the art which provide extraction of the desired mineral. Examples of such foam formers include C5-8 alcohols, pine needle oils, cresols, C1-4 alkyl ethers of polypropylene glycols, dihydroxylates of polypropylene glycols, glycols, fatty acids, soaps, alkyl aryl sulfonates and the like. Furthermore, mixtures of such foam formers can also be used. All foam formers which are suitable for refining ores by foam flotation can be used in connection with the present invention.

In addition, in the method according to the invention, it is assumed that the collector combination which makes up the material according to the invention can be used in mixtures with other collectors which are well known in the field.

The collector material according to the invention can also be used together with a quantity of other collectors known in the field, sufficient to provide the desired extraction of the desired mineral. Examples of such other collectors which are applicable in connection with the invention include dialkylthioureas, alkyl, dialkyl and trialkylthiocarbonates, alkyl and dialkylthiocarbamates, monoalkyldithiophosphates, dialkyl and diaryldithiophosphates, dialkylmonothiophosphates, diaryldithiophosphates, dialkyl and diarylthiophosphonyl chlorides, dialkyl and diaryldithiophosphonates , alkyl mercaptans, xanthogen formates, mercaptobenzothiazoles, fatty acids and salts of fatty acids, alkyl sulfuric acids and their salts, alkyl and alkaryl sulfonic acids and their salts, alkyl phosphoric acids and their salts, alkyl and aryl phosphoric acids and their salts, sulfosuccinates, sulfosuccinamates, primary amines, secondary amines , tertiary amines, quaternary ammonium salts, alkylpyridinium salts, guanidine and alkylpropylenediamines.

Specific embodiments

The following examples are included for illustrative purposes only and should not be understood as limiting the scope of the invention. Unless otherwise stated, all parts and fractions are by weight.

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

Example 1 - Foaming of a copper/molybdenum ore

A number of bags (Samples No. 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 crushed using 800 ml of tap water for 14 minutes in a ball mill having a mixed ball charge to produce approximately 13% plus 100 mesh crushing. The resulting mass was transferred to an Agitair 1500 ml flotation cell equipped with an automated defoamer 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) foamer and the collectors or collector combinations listed in Table I were used to flocculate the copper and molybdenum using a four-stage coarser flotation core as indicated below.

The results of the foam flotation testing are summarized in table i.

When performing the foam flotation testing on the samples

no. 1-8, the collector material comprises 50% by weight of each collector.

The 95% confidence level of statistical error associated with the Cu R-7 value in Table I is within 0.010. The statistical range for R-7 values for Cu in Table I as e.g. is associated with collector A, is thus 0.688 ± 0.010 or 0.678 - 0.698.

The statistical error associated with the Mo R-7 values

in Table I is ± 0.015.

It is clear that the recoveries of Cu and Mo at 7 min. with the collector compositions according to the 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 - Foaming of a Cu/Ni ore

A sample series of -10 mesh ore from eastern Canada was 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 l/min. Before flotation, each sample was crushed in a rod mill at 1080 rpm. Before crushing, 600 ml of water was added along with sufficient lime to adjust the slurry pH to 9.2. After crushing, the ore had a particle size below 200 mesh (75 pm). The contents of the rod mill were emptied into the flow cell, and the pH value was adjusted to 9.2 (with either lime or sulfuric acid).

A complex 9-step flotation sequence was performed. The first 4 stages are referred to as rougher flow and stages 5 -r 9 as flushing flow. After step 4, sulfuric acid was added to adjust the pH to 9.2; CuSO 4 was added in step 5 and step 7 (0.015 kg/metric ton). The foamer used was "DOWFROTH" 250.

Addition rates for foamer and collector were as shown in Table IIA.

The samples were dried, weighed and metal analyzes carried out. Standard pulp extraction formulas were used to calculate recoveries and qualities. The results are collected in table IIB.

In this example, the lowest pyrrhotite recovery and the highest Cu and Ni recoveries possible after 7 min. important, as it is at this point that the main scrapping of mineral with a high sulfur content occurs. At 17 min. Cu and Ni recoveries are at their highest possible when normal flotation logic is used. However, the Cu recoveries approached the theoretical limit of 1.0 at both 7 and 17 min, so statistically significant comparisons were not possible.

It is clear that the recovery of Ni at 7 min. using a collector mixture according to the invention gave a high value with little pyrrhotite. Also the Ni recovery at 17 min. with the mixture according to the present invention is high. The 95% confidence level of statistical error associated with Ni at R-7 is ± 0.015 and at R-17 it is ± 0.006; pyrrhotite at R-7 is ± 0.012. Ni recovery shows that synergism has occurred with the desired lower recovery of pyrrhotite.

Example 3 - Foaming 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 was prepared. The ore contained galena, sphalerite, chalcopyrite and argentite minerals. For each flotation test, a sample was added to a rod mill together with 500 ml of tap water and 7.5 ml of SO 2 solution. 6.5 min. mill time was used to make the feed so that 90% of the ore had a particle size of less than 200 mesh (75 pm). After crushing, the contents were transferred to a cell equipped with an automatic skimmer paddle, and the cell was attached to a standard Denver flotation mechanism.

A two-stage flotation was then carried out - with stage I being a copper/lead/silver coarser flow and stage II a zinc coarser flow. To start the flotation in stage I, 1.5 g/kg Na 2 CO 3 was added (pH 9-9.5), followed by addition of the collector(s). The mass was then conditioned for 5 min. with air and agitation. This was followed by a 2 min. conditioning period with only agitation. A methyl isobutyl carbinol (MIBC) foaming agent was then added

(standard dose 0.015 ml/kg). The concentrate was collected for 5 min. flotation and labeled as copper/lead coarser concentrate.

The flotation in stage II consisted of the addition of 0.5 kg/metric ton of CuSO 4 to the cell residues from stage I. The pH value was then adjusted to 10.5 by the addition of lime. This was followed by a conditioning period of 5 min. with mere agitation.

The pH value was then checked again and adjusted back to 10.5 with lime. At this point the collector(s) were added, followed by a 5 min. conditioning period with only agitation. A methyl isobutyl carbinol (MIBC) foaming agent was then added (standard dose 0.020 ml/kg). Concentrate was collected for 5 min. and labeled as zinc coarser concentrate.

The concentrate samples were dried, weighed and appropriate samples prepared for analysis using X-ray techniques. When using the analysis data, fractional recoveries and grades were calculated using standard mass balance formulas. The results are summarized in Table III.

The 95% confidence levels with statistical error i

The 5 min recovery data for the Cu/Pb flotation (stage I) are for Ag: ± 0.01; Cu: ± 0.01; and Pb: ± 0.02. Experiments 1 and 4 represent the tests where individual components were used in each step.

In stage I of experiment 2, the addition of the two-component mixture according to the invention at a lower dosage (24% less), compared to the single-component collector in stage I of experiment 1, gave slightly more Ag and Cu extraction and significantly more Pb- extraction.

Similarly, the collector compositions according to the invention in stage I of trial 3 compared to stage I of either trial 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 step I is lost to the process.

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

Claims (9)

1. Collector material for flotation of metal-containing minerals, characterized in that it comprises: (a) a compound with formula: where a + b equals 2, R<1> and R<2> independently are a 2-hydrocarbyl radical, where y + p = n, where n is an integer from 1-6, and y and p are independently 0 or an integer from 1-6, X is -S- or -N-R<3 > wherein R 3 is hydrogen or a C 22 hydrocarbyl radical and (b) hydrocarbons containing monosulphide units of the formula where R5 and R<6> independently is a hydrocarbyl radical under the condition that the total carbon content in the hydrocarbon sulfide is such that it has a sufficiently hydrophobic character to cause the metal-containing sulfide mineral or the sulfided metal-containing oxide mineral particles to be driven out to an air/bubble interface. 2. Material as stated in claim 1, characterized in that the total carbon content in the sulphide compound is from 4 to 20 carbon atoms. 3. Material as stated in claim 1, characterized in that component (a) is 2-(hexyl-thio)-ethylamine or ethyl-2-(hexylthio)-ethylamide. 4. Material as stated in claim 1, characterized in that component (b) is ethyl octyl sulphide. 5. Process for extracting metal-containing minerals from an ore characterized in that it comprises subjecting the ore, in the form of an aqueous mass, to a foam flotation process in the presence of a floating quantity of flotation collector material according to any one of claims 1 to 4. 6. Method as stated in claim 5, characterized in that a metal-containing mineral is extracted in the foam. 7. Method according to claim 6, characterized in that the metal-containing mineral extracted in the foam contains copper, zinc, molybdenum, cobalt, nickel, lead, arsenic, silver, chromium, gold, platinum, uranium or mixtures thereof. 8. Method as stated in claim 7, characterized in that the metal-containing sulphide mineral extracted in the foam is molybdenite, chalcopyrite, galena, sphalerite, bornite or pentlandite. 9. Method as stated in claim 8, characterized in that the collector material is present in a concentration of from 0.001 to 1.0 kg of collector/metric tonne of ore to be subjected to foam flotation.