Abstract: Disclosed is a method for removal of an unburned carbon contained in a fly ash material. The method comprises the steps of adding water to the fly ash to prepare a fly ash slurry; shearing the fly ash slurry using an agitating blade that can rotate at a high speed to generate an active energy on the surface of an unburned carbon by the shearing force, thereby imparting lipophilicity to the unburned carbon; and adding a collecting agent and a foaming agent to the slurry containing the lipophylized unburned carbon to cause the attachment of the collecting agent to the lipophylized unburned carbon, and at the same time, causing the attachment of the unburned carbon having the collecting agent attached thereto an air bubble to separate the unburned carbon by flotation.

Abstract: Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectos for the flotation of phosphate minerals are disclosed.

Abstract: Methods and compositions for separating materials are provided. The present invention provides a method of separating a first material from a second material such as mixing the first material and the second material in a slurry with a beneficiation composition. The beneficiation composition can comprise methyl isobutyl carbinol mixture derived from a methyl isobutyl ketone and/or methyl isobutyl carbinol manufacturing process. Additionally air bubbles can be provided in the slurry to form bubble-particle aggregates with the first material and the bubble-particle aggregates can be allowed to be separated from the second material.

Abstract: A metal or mineral compound collector for use in a froth flotation process so as to recover one or more desired minerals or metals; the collector comprising a functional group attached to a carbon chain; the functional group being a nitrile and the said chain having (11) or more carbon atoms. In a further form there is provided a method of recovering a metal or mineral compound from an ore comprising the steps of: wet grinding the ore to a desired particle size; adding water chemicals such as frothers or slurry-modifiers to the ground ore so as to prepare a slurry; adding an effective proportion of a collector comprising a functional group which has a carbon chain with a nitrile attached, said chain having (11) or more carbon atoms; supplying a gas stream to the slurry so as to generate a froth; and recovering the desired metal, mineral and/or sulphide thereof in the froth.

Abstract: This invention is directed to the use of non-sulfur containing compounds as collectors in the froth flotation of certain mineral sulfide and metallic compounds. These non-sulfur-containing compounds may be from natural sources, such as vegetable oils, or synthesized commercial sources. These non-sulfide collectors can be used singularly, in combinations, and in mixtures with known commercial sulfur containing collectors. These non-sulfur-containing collectors are compatible with common frothers.

Abstract: An energy efficient method and system for producing micron-sized particles and transforming and sequestering carbon dioxide into mineral carbonates is described, along with uses for the mineral carbonates produced in the process.

Abstract: This invention relates to the pH modifier in alkaline froth flotation processes to treat oxide and semi-soluble salt ores, such as phosphates, sulfates, carbonates and halides, to increase the recovery while generally maintaining or improving selectivity, thus the grade of desired minerals. The invented pH modifier is used to replace traditional alkaline pH modifiers—hydroxides, carbonates and bicarbonates, such as sodium hydroxide, sodium carbonate, lime and ammonia in anionic flotation processes. The pH modifier is aqueous solution, comprised of combinations of sodium hydroxide, sodium carbonate, and sodium silicate, along with sulfonated surfactant products, such as sulfonated petroleum oil, fatty acids, alkylates, ethoxylated alcohol ethers, and also sulfosuccinamates; and anionic polymers. The pH modifier is also used as a promoter for anionic collectors and as a depressant for gangue minerals.

Abstract: Froth flotation collectors comprising dithiocarbamates of the Formula (I) as described herein are useful for the beneficiation and recovery of metals from mineral ores.

Abstract: A mineral beneficiating reagent containing an alkyl hydroxamic acid or salt thereof and a nonionic surfactant. The alkyl hydroxamic acid or a salt thereof is represented by the formula: R—C(?O)N(R?)—OM, wherein R is linear or branched C2-C18 alkyl, linear or branched C2-C18 alkenyl, C6-C20 aryl or substituted aryl, C7-C26 aralkyl or substituted aralkyl; R? is H, C1-C12 alkyl or aralkyl; M is hydrogen, an alkali metal, or an ammonium cation represented by N+(A,B,C,D) wherein each of A,B,C,D, respectively, are H or C1-C6 alkyl or benzyl radicals. The nonionic surfactant can be any known nonionic surfactant, including but not limited ethoxylated alcohols, esters, ethoxylated acids, ethoxylated (alkyl) phenols, alcanolamides, polyethylene oxide copolymers and mixtures thereof.

Abstract: A method of recovering a valuable component from a feed slurry in minerals processing plant for a mined material is disclosed. The method includes separating the feed slurry on the basis of particle size into at least two streams, of which one stream is a fines stream. The pH of the fines stream is then adjusted to be within a range in which contaminants on the surface of the fines are soluble so that contaminants dissolve from the surface of the fines. Thereafter, the valuable component is floated from the pH adjusted fines stream.

Abstract: A method and apparatus are presented for determining the quantity of liquid and solid content in a removal stream of a froth created from a suspension that is generated during a froth flotation operation. Specifically, electrodes are immersed in the froth generated from a suspension having a known quantity of fiber particles, and the conductance of the froth is measured to establish a relationship between the measured conductance and the quantity of fiber particles. The electrodes are then submerged in a froth generated from a suspension having an unknown quantity of fiber particles, and the froth conductance is measured. The quantity of fiber particles in the froth can then be determined from the pre-established relationship between conductance and solid particle content.

Abstract: The present invention provides a method to improve the cleaner froth flotation process for the selective separation of ore values including, for example, copper, zinc, molybdenum, iron and mixtures there of, in existing flotation plants comprising the step of adding one or more acrylic acid polymers and copolymers to the cleaner froth flotation step in a standard multistep flotation process.

Abstract: The present invention relates to a gravity/flotation circuit where a mineral stream, such as a flotation rougher or cleaner concentrate, undergoes a two stage size separation wherein: i) the screen of the first stage provides a coarse stream of particles greater than 110 microns and a fines stream of particles less than 110 microns; and ii) the fines stream of less than 110 microns is subjected to the second stage separation whereupon a cyclone provides an ultrafine/slimes stream of p80 less than about 25 microns and a middlings stream of p80 greater than around 25 microns. The middlings stream is subjected to flotation to recover nickel sulphide which is sent to final concentrate, and reject or depress magnesia which undergoes gravity separation to concentrate the MgO. It has been discovered that a large proportion of the MgO minerals in the concentrate are contained in the 30 to 100 micron size fraction and that they are well liberated making physical separation possible.

Abstract: The present invention relates to a froth flotation process in which silicates are separated from an iron ore in the presence of a collector containing a quaternary ammonium compound having the formula R1R1N+R3R4 1/z Xz? (I), in which the groups R1 independently are hydrocarbon groups, preferably aliphatic groups containing 6-14 carbon atoms and/or the group R2—(OR7)m—OR8—, where the groups R2 independently are acyl groups containing 6-14 carbon atoms, the groups R7 independently are alkylene groups containing 2-4 carbon atoms, the groups R8 independently are alkylene groups containing 2-3 carbon atoms and m is a number from 0-5, R3 and R4 independently are alkyl groups containing 1-4 carbon atoms or groups (R5O)pH, where the groups R5 independently are alkylene groups having 2-4 carbon atoms and p is a number from 1-4, X is an anionic group, and z is the charge of the anion X.

Abstract: The present invention provides a ammoniated collector (amine, azepine, etc.) alone or in combination with other thiol-type collecting reactants, as well as sodium, iron, magnesium, and/or manganese sulfates, sulfurs, oxides, and hydroxides, acrylic acid polymers and copolymers or other spreading agents, in the process of grinding and floating mineral ores, in order to allow to set new floating operational conditions in existing mineral ore processing plants; to obtain substantial improvements in metallurgic productivity by improving the kinetics of the floating process, which allows to increase recovery of molybdenum, decrease recovery of iron, increase copper grade in copper concentrate, at least keep or improve copper recovery, among others, through the addition of a collecting reactant implying savings of up to 100% of consumption of modifying agents, such as lime, currently used.

Abstract: An environmentally safe composition of matter for use as a promoter chemical in flotation separation of carbonates from industrial sand is disclosed. The promoter chemical replaces the standard petroleum sulfonate, glycol ether and nonphenol used in promoter chemicals with biodegradable substitutes permitting the waste from flotation separation to be disposed without fear of contamination of ground water. The biodegradable promoter is technically sound and causes little change to the flotation process.

Abstract: A method of flotation processing ores and other mineral materials containing soluble nonferrous base metal and sulfide minerals involves dissolving the soluble nonferrous base metal and precipitating the soluble nonferrous base metal in the form of a floatable precipitate that is collected as part of a sulfide concentrate. The use of an oxygen-deficient flotation gas, such as nitrogen gas, promotes the precipitation of the floatable precipitate. A method for removing dissolved nonferrous base metal from solution involves contacting the solution with a particulate containing sulfide minerals under conditions promoting precipitation of the nonferrous base metal onto the sulfide mineral.

Abstract: A concentration process of zinc silicated minerals, particularly willemite and calamine concentration, by single operations, or conventional steps of ore treatment, some of which include the following: Preparation of stockpiles of different mineralogical and contents compositions, crushing, screening, storage, dense separation, washing, homogenization, magnetic separation, grinding, classification, rubbing, conditioning, flotation, thickening, filtering, calcination, storage and waste deposition.

Abstract: A new reagent for the application in the preparation of mineral raw materials, mainly sulphide and oxyde mono- and polymetallic ores of non-ferrous metals, which are used as a corrosion inhibitor of the equipment and grinding bodies and as a selective collector of the wanted metal, is described. The new reagent is a composition of water, mercaptobenzothiazole salts and its derivatives in the quantity of 0–50%, by weight, sodium metasilicates in the quantity of 0.1–10%, by weight, amines in the quantity of 1–5%, by weight, and dithiophosphates in the quantity of 0.5–20%, by weight. Also, it discloses the methods for the application of that new reagent for the preparations of the copper, zinc and lead concentrates from the sulphide and oxyde ores, for the purpose of further metallurgic processing. In those methods the new reagent is added fully, or in part, in the phase of wet grinding, and in part, as needed, in the flotation phase, in the quantity of 20–300 g of the reagent per ton of ore.

Abstract: The use of ozone during certain stages of metal separation by flotation degrades certain collectors that are absorbed on the particle surface, as well as the collectors and frothers in the liquid slurry. As a result, the mineral particle has a fresh surface and new chemical reagent(s) can be added in the subsequent flotation step(s). Also since ozone oxidizes the iron sulfide particles faster than the other mineral particles, depending upon the duration of treatment, the ozone concentration, and the kg O3/ton consumed by the treated ore, the surface of the iron sulfide particles may be partially or even totally oxidized, thus allowing better separation. As a consequence, the iron content is decreased, and the grade of the mineral value such as zinc, copper, and nickel increases. Also, sulfide emissions during heat treatment or further processing of the minerals are decreased due to decrease iron sulfide content.

Abstract: A method of recovering a target mineral from an ore containing the target mineral and an iron sulphide mineral comprising the steps of: a) grinding the ore to liberate target mineral from the iron sulphide mineral; b) forming a pulp of said ore; c) selecting a collector having the structure as follows: X—R—Y where R is a branched or straight chain hydrophobic hydrocarbon or polyether chain, and X and Y represent metal coordinating functional groups, d) add the collector to the pulp at a concentration at which the target mineral is able to be floated in preference to the iron sulphide mineral; and e) subjecting the pulp to froth flotation. The metal coordinating sulphur based functional groups may be identical or different.

Abstract: A method for the flotation of sulfide ores is disclosed. The method comprises contacting the sulfide ores with a composition comprising at least one compound of the formula where R1, R2 and R3 independently of one another are alkyl groups having 1 to 18 carbon atoms, alkenyl groups having 2 to 18 carbon atoms, aryl groups having 6 to 10 carbon atoms, or alkylaryl groups having 7 to 10 carbon atoms.

Abstract: The present invention relates to a flotation reagent and a process for the flotation of sulfidic ores. The process comprises contacting the sulfidic ores with a combination of thionocarbamates and mercaptobenzothiazoles to improve the flotation of sulfidic ores, particularly the flotation of copper ore when the copper ore is associated with molybdenum and/or gold. The flotation reagent comprises a combination of compounds of formula (1) and formula (2) where R1 and R2 independently of one another are alkyl groups having 1 to 18 carbon atoms, and R3 and R4 independently of one another are hydrogen or C1–C6-alkyl, and M is hydrogen or an alkali metal, and (1) and (2) are in a weight ratio of (1):(2) of 95:5 to 75:25.

Abstract: The present invention relates generally to a process for flotation of sulphide minerals where a flotation pulp is separated into a coarse stream and a fine stream, preferably containing particles coarser than about 30 micron and particles finer than about 30 micron, respectively. Typically, alkali and depressant are added to the coarse flotation stream only and acid and activator are added to the fine flotation stream only. During flotation of the fine stream, acid and/or activator may be added at the conditioning, cleaning, re-cleaning, cleaner-scavenging or third cleaning stage. During flotation of the coarse stream, alkali and/or depressant may be added at the conditioning or cleaning stage.

Abstract: Composition intended for the flotation of ores, comprising: from 70 to 95% of a combination (A) of n-dodecyl mercaptan (or NDM) and of tert-dodecyl mercaptan (or TDM), the NDM/TDM ratio by weight of which is between 0.5 and 1.5, and from 5 to 30% of a product (B) composed of one or more aromatic or aliphatic compounds comprising from 4 to 100 carbon atoms, preferably from 5 to 40, and having one or two —OH groups. Process for the recovery by flotation of metal compounds of value present in ores employing it.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising an N-butoxycarbonyl-O-alkylthionocarbamate selected from the group consisting of N-butoxycarbonyl-O-methylthionocarbamate, N-butoxycarbonyl-O-ethylthionocarbamate, N-butoxycarbonyl-O-propylthiononocarbamate, N-butoxycarbonyl-O-butylthionocarbamate, N-butoxycarbonyl-O-pentylthionocarbamate, and N-butoxycarbonyl-O-hexylthionocarbamate.

Abstract: The invention relates to a hydroxamate composition for collection of minerals by froth flotation, the composition including an aqueous mixture of hydroxamate wherein the pH of the composition is at least 11 and a method of collecting mineral values from an aqueous ore slurry by froth flotation.

Abstract: A mineral separation process includes wet-grinding the ore to liberation of minerals, oxidizing the slurry using air, hydrogen peroxide or other oxidants and floating the valuable minerals at a pH between about 9.0 and 10.0 with a xanthate as collector, and a combination of a polyamine and a sulfur containing species as depressants for arsenide minerals. This depressant suite effectively depresses the flotation of arsenide minerals with no effect on the flotation of the valuable minerals.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising N-butoxycarbonyl-O-butylthionocarbamate.

Abstract: The present invention provides for a reactive oily bubble carrier comprising: (a) a gas bubble having an oil-coating; and (b) a collector dissolved within the oil-coating. The present invention also provides for the use a reactive oily bubble carrier in a flotation target particle separation process. The present invention also provides for a flotation target particle separation process using the reactive oily bubble carriers disclosed herein.

Abstract: The present invention relates generally to a process and an apparatus for flotation of sulphide minerals, such as sulphide minerals hosted in ores rich in magnesium minerals. The process involves grinding of the nickel ore rich in magnesium minerals and thereafter separation of the ground material into a coarse and fine stream of particles coarser than about 30 microns and finer than about 30 microns, respectively. Optionally, the fines stream may be further separated into a slimes fraction. The coarse and fine flotation streams are then fit to separate parallel flotation circuits. Acid and/or activator is added during flotation of the coarse stream only. Significantly improved recoveries and grades were obtained with reduced acid consumption.

Abstract: A method for decontaminating soil containing inorganic contaminants having a degree of liberation of at least 60%, comprising the steps of removing from a coarse fraction at least a portion of inorganic contaminants in particulate form contained therein with a jig to produce a treated coarse fraction, removing from an intermediate fraction at least a portion of inorganic contaminants in particulate form contained therein with a separator selected from the group consisting of a spiral and a classifier to produce a treated intermediate fraction, removing from a fine fraction at least a portion of inorganic contaminants in particulate form contained therein with a separator selected from the group consisting of a flotation cell and a multi-gravity separator to produce a treated fine fraction, whereby the combined treated coarse, intermediate and fine fractions are impoverished in inorganic contaminants.

Abstract: The present invention relates to a process for improving the recovery of valuable sulphide minerals. The process involves determining an Eh range within which the valuable sulphide mineral may be recovered by flotation without the need of a collector. The slurry is then subjected to flotation in a pneumatic cell (50) at such a speed that the slurry remains within the Eh range during flotation. The process substantially reduces or totally eliminates the need for collector. For mixed ores such as chalcopyrite/chalcocite chalcopyrite is recovered without collector, while some non xanthate collector may be required to recover chalcocite.

Abstract: The present invention provides a process for the recovery of bastnaesite and other minerals containing rate earth oxide from complex, weathered ores containing barite, borite, fluorites and/or barite, fluorites, silicates and iron oxides, and comprises reverse barite flotation using a barite collector containing the following individual reagents: 1. Petroleum sulphonate 30-40% by weight 2. Sulphosuccinate 30-40% by weight 3.

Abstract: Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectors for the flotation of phosphate minerals are disclosed.

Abstract: A process of separating a desired constituent from a mixture of particulate matter including the steps of: conditioning a liquid mixture of particulate matter with a frothing agent to create a pulp; aerating the pulp to generate a float fraction of froth supported on the surface of a non-float fraction of pulp; separating a portion of froth from the float fraction; draining the separated froth; washing the separated froth with a liquid to dislodge particles comprising one or more of non-selectively attached, entrained, and entrapped particles; and recovering the washed froth, is disclosed herein. Also disclosed herein are a froth cleaning apparatus and a froth flotation apparatus for separating a desired constituent from a mixture of particulate matter.

Abstract: This invention is directed to the use of non-sulfur containing compounds as collectors in the froth flotation of certain mineral sulfide and metallic compounds. These non-sulfur-containing compounds may be from natural sources, such as vegetable oils, or synthesized commercial sources. These non-sulfide collectors can be used singularly, in combinations, and in mixtures with known commercial sulfur containing collectors. These non-sulfur-containing collectors are compatible with common frothers.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising an N-butoxycarbonyl-O-alkylthionocarbamate selected from the group consisting of N-butoxycarbonyl-O-methylthionocarbamate, N-butoxycarbonyl-O-ethylthionocarbamate, N-butoxycarbonyl-O-propylthiononocarbamate, N-butoxycarbonyl-O-butylthionocarbamate, N-butoxycarbonyl-O-pentylthionocarbamate, and N-butoxycarbonyl-O-hexylthionocarbamate.

Abstract: A method of recovering a target mineral from an ore containing the target mineral and an iron sulphide mineral comprising the steps of: a) grinding the ore to liberate target mineral from the iron sulphide mineral; b) forming a pulp of said ore; c) selecting a collector having the structure as follows: X-R-Y where R is a branched or straight chain hydrophobic hydrocarbon or polyether chain, and X and Y represent metal coordinating functional groups, d) add the collector to the pulp at a concentration at which the target mineral is able to be floated in preference to the iron sulphide mineral; and e) subjecting the pulp to froth flotation. The metal coordinating sulphur based functional groups may be identical or different.

Abstract: Methods of increasing the rate of separating hydrophobic and hydrophilic particles by flotation have been developed. They are based on using appropriate reagents to enhance the hydrophobicity of the particles to be floated, so that they can be more readily collected by the air bubbles used in flotation. The hydrophobicity-enhancing reagents include low HLB surfactants, naturally occurring lipids, modified lipids, and hydrophobic polymers. These methods can greatly increase the rate of flotation for the particles that are usually difficult to float, such as ultrafine particles, coarse particles, middlings, and the particles that do not readily float in the water containing large amounts of ions derived from the particles. In addition, new collectos for the flotation of phosphate minerals are disclosed.

Abstract: A method of recovering a valuable component from a feed slurry in minerals processing plant for a mined material is disclosed. The method includes separating the feed slurry on the basis of particle size into at least two streams, of which one stream is a fines stream. The pH of the fines stream is then adjusted to be within a range in which contaminants on the surface of the fines are soluble so that contaminants dissolve from the surface of the fines. Thereafter, the valuable component is floated from the pH adjusted fines stream.

Abstract: The invention uses machine-vision to improve the performance of a flotation operation to provide a substitute for conventional human vision and problem-solving abilities. The invention redirects the conventional approach of “characterizing the froth” to “measuring the froth characteristic.” The invention provides a method of monitoring and controlling a mineral mixture flow in a froth flotation cell of a flotation plant which includes the steps of obtaining a series of digital images extracted of froth characteristics from a flotation cell. The digital images are transmitted to a computer for processing thereof into parameter signals of digital parameter froth characteristics.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising N-butoxycarbonyl-O-butylthionocarbamate.

Abstract: Collector compositions of a mixture of a C6 to C22 fatty hydroxamic acid and an oil for use in a method the removal of impurities from mineral ores by the froth flotation method. The collectors are prepared by reacting an ester of a C6 to C22 fatty acid with a hydroxylamine salt and a base in the presence of an oil and water to produce an alkyl hydroxamate salt; acidifying the alkyl hydroxamate salt, forming an organic layer and an aqueous layer, wherein the organic layer contains a C6 to C22 fatty hydroxamic acid substantially free of starting esters and hydrolysis and transesterification products of the ester; and separating the organic layer from the aqueous layer to provide a collector composition of the C6 to C22 fatty hydroxamic acid and the oil.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising N-butoxycarbonyl-O-butylthionocarbamate.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising N-butoxycarbonyl-O-butylthionocarbamate.

Abstract: Froth flotation processes, useful for beneficiating base metal mineral values from metal sulfide ore, utilize a collector comprising an N-butoxycarbonyl-O-alkylthionocarbamate selected from the group consisting of N-butoxycarbonyl-O-methylthionocarbamate, N-butoxycarbonyl-O-ethylthionocarbamate, N-butoxycarbonyl-O-propylthiononocarbamate, N-butoxycarbonyl-O-butylthionocarbamate, N-butoxycarbonyl-O-pentylthionocarbamate, and N-butoxycarbonyl-O-hexylthionocarbamate.

Abstract: The invention relates to a flotation agent for phosphate ore, comprising a fatty acid as collector and alkoxylated alkylphenols as dispersing agents, characterized in that the alkylphenols are composed of a) 8 to 20% by weight of one or more dialkylphenols having alkyl radicals from 8 to 12 carbon atoms b) 80 to 92% by weight of one or more monoalkylphenols having alkyl radicals from 8 to 12 carbon atoms, which have been alkoxylated with 2 to 6 mol of ethylene oxide.

Abstract: The present invention relates to a phosphate ore beneficiation process, which includes a method to float inadequately de-oiled phosphate particles prior to silica flotation. It is emphasized that this abstract is being provided to comply with the rule requiring an abstract that will allow examiners and searchers to quickly ascertain the subject matter of the technical disclosures. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, as promised by the Patent Office's Rule 1.72(b) for abstracts.

Abstract: Provided is a method involving flotation of a feed of platinum group metal ore material to prepare a platinum group metal concentrate during mineral processing operations. Prior to and/or during the flotation, a lead-containing activator reagent and a xanthate collector reagent are added to the slurry and during the flotation, an oxygen-deficient flotation gas, such as nitrogen gas, is used.