Abstract: A method of treating value bearing material comprising oxidized or surface oxidized mineral values includes the steps of crushing the value bearing material, contacting the crushed material! with a sulfide solution to sulfide the oxidized or surface oxidized mineral values, and adding ions of a selected base metal to the crushed value bearing material. The value bearing material may comprise oxidized or surface oxidized base metal or precious metal minerals. The crushed value bearing material is prepared as a slurry or pulp comprising from 15% to 40% solids and the remainder comprising water. The sulfide solution preferably comprises a soluble sulfidiser such as sodium hydrosulfide and the base-metal ion solution preferably comprises metal salt of base metals like copper or iron.

Abstract: A microwave source is used in conjunction with a waveguide and microwave window aperture to direct controlled microwave energy into the housing of a filter. The microwave energy will heat and vaporize any fluid present on the filter material, preventing the filter from “wetting” and becoming unusable.

Abstract: Disclosed are surfactant compounds and compositions that are antimicrobial. Also provided are polymeric compositions incorporating the surfactant compounds. The polymeric compositions may be used to form antibacterial coatings on surfaces.

Abstract: The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

Abstract: Methods and systems for heavy metal separation and recovery from heavy metal-containing sludge or wastes. The method utilizes ultrasonic treatment assisted acid leaching process to separate and recover different heavy metals from multi metals-containing sludge. The technique can be cost effectively implemented for heavy metal separation and purification processes in the real world at industrial scales.

Abstract: Disclosed are surfactant compounds and compositions that are antimicrobial. Also provided are polymeric compositions incorporating the surfactant compounds. The polymeric compositions may be used to form antibacterial coatings on surfaces.

Abstract: The present invention is directed to a precious metal recovery process in which basic ferric sulphates and/or jarosites are controlled by hot curing of the autoclave discharge slurry followed by decomposition of argentojarosite using strong acid consumers.

Abstract: A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below 600 mV (vs. SHE) to cause dissolution of the copper sulphide.

Abstract: An aqueous precipitation process for the preparation of particles comprising primarily silver sulfate, comprising reacting an aqueous soluble silver salt and an aqueous soluble source of inorganic sulfate ion in an agitated precipitation reactor vessel and precipitating particles comprising primarily silver sulfate, wherein the reaction and precipitation are performed in the presence of an aqueous soluble carboxylic acid additive or salt thereof, the amount of additive being a minor molar percentage, relative to the molar amount of silver sulfate precipitated, and effective to result in precipitation of particles comprising primarily silver sulfate having a mean grain-size of less than 70 micrometers.

Abstract: An aqueous precipitation process for the preparation of particles comprising primarily silver sulfate, comprising reacting an aqueous soluble silver salt and an aqueous soluble source of inorganic sulfate ion in an agitated precipitation reactor vessel and precipitating particles comprising primarily silver sulfate, wherein the reaction and precipitation are performed in the presence of an aqueous soluble inorganic additive compound containing a cation capable of forming a sulfate salt that is less soluble than silver sulfate or a halide anion or an oxyanion capable of forming a silver salt that is less soluble than silver sulfate, the amount of additive being a minor molar percentage, relative to the molar amount of silver sulfate precipitated, and effective to result in precipitation of particles comprising primarily silver sulfate having a mean grain-size of less than 70 micrometers.

Abstract: A hydrometallurgical process for the treatment of complex silver-bearing sulfide ores and concentrates that recovers substantially all silver, lead, antimony, zinc, copper and sulfur, along with the chemical reagents utilized during the process. Finely ground ores and concentrates are leached under heat and pressure with water, sulfuric acid, nitric acid, oxygen, and a catalyst, and are further treated to recover silver in the form of silver chloride; iron in the form of iron hydroxide; copper and all traces of soluble toxic metals as sulfides; zinc as zinc ammonium sulfate and specifically nitric acid, sulfuric acid, oxygen, ammonia, and ammonium compounds as valuable fertilizer products.

Abstract: A method of treating value bearing material comprising oxidised or surface oxidised mineral values includes the steps of crushing the value bearing material, contacting the crushed material! with a sulfide solution to sulfide the oxidised or surface oxidised mineral values, and adding ions of a selected base metal to the crushed value bearing material. The value bearing material may comprise oxidised or surface oxidised base metal or precious metal minerals. The crushed value bearing material is prepared as a slurry or pulp comprising from 15% to 40% solids and the remainder comprising water. The sulfide solution preferably comprises a soluble sulfidiser such as sodium hydrosulfide and the base-metal ion solution preferably comprises metal salt of base metals like copper or iron.

Abstract: A chemical process to leach copper concentrates in the presence of a concentrated solution of sulfates and chlorides. The process includes forming a high reactivity chemical paste containing a high concentration of ions in the liquid phase of the paste which react with copper ores and forms a series of soluble salts. The salts are extracted by a simple wash. Mixing equipment for handling high viscosity liquids is used. The total mixing time is about 5 minutes, after which the paste is poured into a rectangular mold, of several hundred meters per side, and is left to settle and breathe. During settling, water and sulfuric acid are added at intervals to replace that consumed by the reactions taking place during the aeration, until the reactions have virtually end. This treatment results in a dry, very resistant mass, containing the copper extracted in form of chlorine salts, and sulfate.

Abstract: The present invention is directed to the microwave treatment of a class of selected metal ores and concentrates, particularly those known as chalcopyrite, in a fluidized bed reactor. The end product is commonly a mixture of copper oxide and copper sulfate, both of which are liquid soluble and directly recoverable by known techniques. The ratio of the oxide-sulfate mixture end product may be controlled by suitable control of microwave parameters.

Abstract: An aqueous precipitation process for the preparation of particles comprising primarily silver sulfate, comprising reacting an aqueous soluble silver salt and an aqueous soluble source of inorganic sulfate ion in an agitated precipitation reactor vessel and precipitating particles comprising primarily silver sulfate, wherein the reaction and precipitation are performed in the presence of an aqueous soluble organo-sulfate or organo-sulfonate additive compound, the amount of additive being a minor molar percentage, relative to the molar amount of silver sulfate precipitated, and effective to result in precipitation of particles comprising primarily silver sulfate having a mean grain size of less than 50 micrometers.

Abstract: Spent, acidic solutions comprising cupric chloride and hyrdrochloric acid from the copper etching process are regenerated by a process in which the acid is subjected to distillation with sulfuric acid. In one embodiment, the process comprises (a) providing a spent etchant comprising at least about 10% by weight chloride and at least about 5% dissolved copper; (b) adding at least about 2 moles of sulfuric acid per mole of dissolved copper to the spent etching solution, thereby converting copper chloride into hydrochloric acid and precipitated copper sulfate; (c) distilling the mixture from step (b) to vaporize at least a portion of the hydrochloric acid; (d) condensing at least a portion of the vaporized hydrochloric acid; (e) separating at least a portion of the precipitated copper sulfate from the residual liquid, wherein said residual liquid comprises sulfuric acid; and (f) reusing at least a portion of the residual liquid as a sulfuric acid source in step (b).

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reducing “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: A method for recovering catalytic metals from compositions containing catalytic metal colloids. Compositions such as rinse solutions or dragout baths containing catalytic metal colloids are passed through a filter that entraps catalytic metal colloids from the solutions. The catalytic metal colloid has a high affinity for the filter in contrast to other components of the solutions. The other components of the solution pass through the filter concentrating the catalytic colloid on the filter. The filter containing the catalytic metal colloid is rinsed with an acid solution to remove the catalytic metal from the filter. The catalytic metal is collected in a suitable container or on an adsorbent such as a resin. The method is economically efficient and environmentally friendly.

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reduce “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: A process for the extraction of copper from a sulphide ore or concentrate comprises the steps of subjecting the ore or concentrate to pressure oxidation in the presence of oxygen and an acidic solution containing halide and sulphate ions to obtain a resulting pressure oxidation slurry. The slurry is subjected to a liquid/solid separation step to obtain a resulting pressure oxidation filtrate and a solid residue containing an insoluble basic metal sulphate salt. The basic metal sulphate salt is leached in a second leaching with an acidic sulphate solution to dissolve the basic metal salt to produce a leach liquor containing a metal sulphate, e.g. copper sulphate, in solution and a resulting solid residue. The leach liquor is separated from the solid residue and subjected to a solvent extraction process to produce metal concentrate solution and a metal depleted raffinate. At least a portion of the raffinate is recycled to the pressure oxidation after being subjected to evaporation.

Abstract: The ore which contains gold and at least one of the metals silver, copper, nickel, zinc or iron is calcined at temperatures in the range from 500.degree. to 900.degree. C. with the addition of oxygen-containing gas, thereby producing a metal-oxide-containing solids mixture and a SO.sub.2 -containing exhaust gas. The SO.sub.2 containing exhaust gas is brought in contact with aqueous solution, thereby producing a sulfite-containing solution. The solids mixture from the calcination is cooled to temperatures in the range from 50.degree. to 300.degree. C. and is stirred up with the sulfite-containing solution. Metal oxides are dissolved, and a sulfate-containing solution os formed. In a first separating zone, the sulfate-containing solution is separated from the solids, and either the solids are supplied to a gold leaching or the sulfate-containing solution is subjected to a further treatment for the separation of nonferrous metals.

Abstract: The ore which contains gold and/or silver and as accompanying metal at least iron is calcined at temperatures in the range from 500.degree. to 900.degree. C. with the addition of oxygen-containing gas. There is obtained a metal-oxide-containing solids mixture and a SO.sub.2 -containing exhaust gas. The solids mixture from the calcination is cooled, the temperature being reduced by at least 50.degree. C. The cooled solids mixture is added to a fluidized-bed reactor, and SO.sub.2 -containing exhaust gas is introduced into the fluidized-bed reactor. In the reactor, metal sulfate is produced in the solids mixture, so that at least 10% of the sulfur content are bound in the exhaust gas. Solids mixture containing metal sulfate is withdrawn from the fluidized-bed reactor, is stirred up with an aqueous acid solution, thereby dissolving metal sulfate. The remaining solids are supplied to a recovery of gold and/or silver.

Abstract: A method for the recovery of copper from copper-containing materials, for example, scrap, ores or dust. An aqueous cupric tetrammine sulfate lixiviant is contacted with the copper-containing material to produce a leachate containing cuprous, nickel, and zinc ions, ammonium sulfate and free ammonia. Copper can be recovered from the leachate by electrolysis. Nickel and zinc can be precipitated from the resulting spent electrolyte by oxidizing substantially all of the cuprous ions in the copper ammine sulfate solution to cupric ions and lowering the pH of the solution to a range from about pH 7.5 to about pH 8.0 in order to form a precipitate. Alternatively, copper sulfate can be added to the cupric ammine sulfate-containing solution in order to form nickel and/or zinc containing precipitate.

Abstract: A method for producing copper sulfate from waste copper-containing liquid including the steps of recovery of acidic and basic copper-containing liquid, and neutralization of the liquid to form crystalline copper sulfate, wherein the ratio of acidic to basic copper-containing liquid, temperature, pH value and the concentration of copper ion in the resultant solution of each step is being controlled such that the solid copper sulfate is obtained in high yield and purity and will have a larger particle size, and at the same time, the filtrate will contain copper ion in a concentration below 0.3 ppm before being expelled to the surroundings.

Abstract: Aqueous effluent solutions containing metal cations may be treated with an extractant comprising an organophosphinic acid, a di-2-ethylhexyl phosphoric acid and/or an aliphatic amine to selectively separate chromium, nickel, cobalt, copper and lead cations from the aqueous solution. Typical extraction techniques include liquid-liquid extraction employing either mixer settlers or columns, liquid membrane extraction and selective supported membrane extraction.

Abstract: The invention relates to a process for recovery of metals from metal/plastic waste using used etching and washing solutions from the electronics industry, with the following process steps:(a) heating of the metal/plastic waste in a heating bath in order to separate the metal from the plastic;(b) dissolution of the metal component in the optionally regenerated etching and washing solutions;(c) conversion of the dissolved metal component into the sulfate through treatment with ion exchanger;(d) electrolytic deposition and, if appropriate, selective separation of the metal component into the individual metals, and(e) regeneration of the ion exchanger with reformation of the reusable etching solution.

Abstract: A process is described for leaching ores or concentrates containing one or more metallic sulphides .with a circulating liquor so as to solubilize desired metal values therefrom, if said metal values are capable of dissolution in an acidic ferric sulphate solution (e.g. copper), or so as to render the desired metal values (e.g. gold) more accessible to subsequent processing, in each case by effecting metallic sulphide dissolution from the ore or concentrate.

Abstract: A process for the hydrometallurgical recovery of gold and silver by direct oxidizing sulphuric acid-digestion of arsenopyrite-concentrates (FeAsS.sub.2) containing carbonaceous materials with a silicate gangue, and/or a silicate and pyrite gangue whereby arsenic and iron are fully solubilized and the noble metals are quantitatively enriched in the silicate-residue. The concentrate is subjected to mechano-chemical stress to produce structural deformations before being digested in the presence of oxygen. After decarbonization of the residue, gold and silver can be recovered by cyanide leaching without losses due to adsorption. A bulk process for preparing gold and silver rich concentrates is also disclosed.

Abstract: A method is provided for recovering gold and silver from precious metal bearing materials including ores, leaching residues, flue dust, electronic scrap, jewelry scrap, etc. In the method, the gold and silver are extracted from the precious metal bearing materials with a thiourea solution to form a thiourea leach, and the thiourea leach is contacted with carbon to adsorb the gold and silver and provide loaded carbon. The method is characterized by the step of contacting an alkaline solution of thiousulfate ion with the loaded carbon thereby desorbing the precious metals form the carbon. In one modification of the method, an additional step includes adding a salt to the aqueous thiousulfate solution. When needed, the method includes the step of protecting the thiousulfate ion from oxidizing agents. This is done by adding a reducing agent such as sodium sulfite to the thiousulfate solution.

Abstract: A process for treating a first metal, manganese-containing ore comprising contacting the manganese-containing ore with an aqueous, acidic composition and a material containing at least one metal sulfide at conditions effective to (1) chemically reduce at least a portion of the manganese, (2) solubilize at least a portion of the metal from the metal sulfide, and (3) at least partially liberate the first metal from the ore; and recovering the first metal from the ore. The use of Thiobacillus ferrooxidans and/or added ferric ion in the contacting step are also disclosed.

Abstract: A process for recovering at least one first metal from a metal sulfide-containing ore comprising contacting the ore with an aqueous, acidic composition and at least one reducible manganese-containing material at conditions effective (1) to chemically reduce the manganese, (2) solubilize at least a portion of the metal from the sulfide, and (3) at least partially liberate the first metal from the ore; and recovering the first metal from the ore. The use of added ferric ion and/or Thiobacillus ferrooxidans bacteria in the above-noted contacting is also disclosed.

Abstract: An aqueous solution containing a water soluble polyvalent metal sulphate, an alkali metal silicate and an alkali metal metabisulphite is described which is added to a slurry of a copper mineral bearing ore to be subjected to a froth flotation step for obtaining a copper concentrate. The aqueous solution is added to enhance the selectivity of conventional flotation collectors and depressants when the valuable minerals are finally disseminated in the host ore, which is then required to be ground to very small particle sizes to achieve the desired liberation. Other valuable minerals such as those bearing zinc and lead, may be recovered from the tailing.

Abstract: Low-grade refractory gold ores, which may also contain silver and other metal values are treated by partial roasting of concentrate to remove controlled amounts of sulfur and carbon, then oxygen pressure leached to oxidize further amounts of sulfur and carbon and to dissolve base metals and a portion of any silver present, and the residue is then cyanided to dissolve gold and remaining silver which are then recovered.

Abstract: The purpose of the method is to remove chlorides and fluorides from a valuable metal raw material by leaching the raw material into sulphuric acid solution and by crystallizing the valuable metal sulphate selectively out of the solution. The valuable metal sulphate crystals are washed in sulphuric acid solution, and the recovered dechlorinated and defluorinated crystals are leached into water and conducted into electrolysis. The sulphuric acid solution employed in the raw material leaching and in the crystal washing is preferably the same as the return acid of the electrolysis. Chlorides and fluorides are removed from the mother liquor of crystallization in the bleed.

Abstract: This is a method for the complete leaching of the valuable metals in a metal sulphide material which contains copper, zinc, lead, silver and iron by the use of a solution which essentially contains cupric chloride/sulphates. After the valuable metals have been recovered, the solution is regenerated whereby ferrous chloride and cuprous chloride/sulphate is oxidized to a ferric hydroxide solid and a cupric chloride solution respectively. The regenerated solution is split into two part-solutions and returned to the process.One part-solution goes to a metathesis stage where the fresh metal sulphide material is added in large excess with respect to the part-solutions's content of copper. The result is that only the valuable metals like zinc, lead and silver are leached while copper and iron remain in the residue.The other part-solution goes to a leach stage where the residue from the metathesis stage is added.

Abstract: A process for the recovery of gold from a precious metal bearing sludge concentrate is disclosed. The process comprises the steps of leaching the sludge with hydrochloric acid and hydrogen peroxide to solubilize at least gold, palladium and platinum, removing silver from the leach slurry as insoluble silver chloride and selectively precipitating gold from the leach solution remaining after removal of silver by reduction with SO.sub.2 in the presence of sodium ions.

Abstract: This invention provides processes for selectively recovering silver and gold values from feed materials containing both precious metals, and comprises leaching the feed material with a hot ferric chloride-acid brine leach solution for a time sufficient to dissolve the silver, but wherein the gold is not dissolved and remains with the solid residue. The silver-containing ferric chloride-acid brine leachate is separated from the solid residue containing the gold. The leach solution is then cooled to precipitate the silver as silver chloride. The solid residue containing the gold is then leached with hypochlorous acid to dissolve the gold, and after separating the solids form the gold-containing hypochlorous acid leach solution, the gold is precipitated by contacting the solution with sulfur dioxide. The silver chloride may be further processed in a fused salt electrolysis step at or above the melting point of silver to produce a substantially pure silver and chlorine gas.

Abstract: A process for the recovery of silver from a residue essentially free of elemental sulphur obtained by acidic pressure oxidation leaching or iron-containing sulphidic material which comprises forming a slurry of the residue with lime at a temperature of at least about 80.degree. C. to raise the pH of the slurry to at least about 9. The slurry is maintained at this temperature for from about 0.5 to about 4 hours, and the resultant slurry is subjected to silver recovery treatment.

Abstract: Metal is removed from particlized metal bearing refractory ores in an efficient manner utilizing pressure metallurgy with heat recovery. The particlized ore is mixed with a heated liquid, and preferably a flocculant and fibers, to form a slurry. The ore in the slurry is oxidized at superatmospheric pressure, and elevated temperatures (e.g. around 300.degree. F.). The oxidized ore is washed to remove acids, and like products of oxidation, and the washed ore is subsequently subjected to conventional leaching processes to effect an actual metal recovery. Heat recovery is practiced by utilizing spent wash water as part of the slurrying liquid, and using two or more liquid-interconnected vessels in effecting the oxidization.

Abstract: A process for the treatment of a complex manganese ore, wherein it comprises the following stages:(a) crushing the ore,(b) subdividing the crushed ore into a first part and a second part,(c) preparing the first pulp from the first part of the crushed ore,(d) reacting the first pulp with a reducing agent to obtain a manganous sulphate solution,(e) separating the liquid phase constituted by the thus obtained manganous sulphate solution from the solid phase of the thus treated first pulp,(f) preparing a second pulp from the second part of the crushed ore,(g) subjecting the second pulp to a solubilization treatment of the nickel, copper and cobalt by reacting it hot with sulphuric acid and the manganous sulphate solution obtained in stage (e),(h) separating the liquid phase and the solid phase of the thus treated second pulp, and(i) recovering the nickel, copper and cobalt from the liquid phase separated in stage (h).

Abstract: This invention relates to the development of a viable metallurgical process capable of treating low grade concentrates, bulk concentrates, dirty concentrates, or ore directly for the recovery of non-ferrous metals such as zinc, lead, copper, and precious metals and accordingly is significant to the development of massive fine grained sulphide ore bodies found throughout the world. The process involves the consecutive steps of sulphatizing roasting in a fluidized bed reactor, a two stage leach, metal recovery from solution by conventional processes such as electrowinning and precipitation, and recycling of residue wash waters and leach liquors containing high concentrations of iron and minor impurity elements to the roaster or a spray dryer for thermal decomposition. Simple and efficient rejection of iron from the circuit to residue as stable hematite is the net result of the recirculation and thermal decomposition.

Abstract: A hydrometallurgical process is provided for separating heavy metal nuisance elements such as As, Sb, Bi, Sn and Pb from precious metals and/or selenium. The process can be used as a step in an overall hydrometallurgical process for treating refinery residues such as anode slimes for the separation and recovery of valuable metal values.

Abstract: A process is disclosed for the hydrometallurgical treatment of finely divided iron-containing steel plant dusts containing zinc, lead and such other metal values as calcium, manganese, silicon, magnesium, aluminum, cadmium, copper, and the like. The process is carried out by forming an aqueous slurry of the flue dust with a mixed lixiviant comprising HCl and H.sub.2 SO.sub.4, the amount of sulfate ion concentration being in excess of the chloride ion concentration and in stoichiometric excess of that required to sulfate substantially all of the lead and calcium present. The amount of chloride ion present as HCl should be sufficient to maintain the pH at about 1 to 4. The leaching is conducted at a temperature ranging from ambient to below the boiling point for a time at least sufficient to effect dissolution of at least zinc and other metal values and form a residue containing iron oxide, calcium sulfate and lead sulfate.

Abstract: A process for lixiviation of concentrates of copper sulphides of tetrahedral type containing high concentration of arsenic and antimony to recover copper and noble metals. The concentrates are repulped into an aqueous ferrous sulphate solution with an established and controlled solid-liquid ratio which is thereafter oxidized by an oxygen containing gas in a reactor, thereby oxidizing the sulphides to sulphates, precipitating iron as ferric arsenates and antimoniates and yielding a lixiviation pulp in which the solid phase contains the iron, antimony and arsenic as well as the insoluble sulphates of the non-ferrous metals, such as lead and noble metals, and the liquid phase containing the copper, free sulphuric acid and the soluble sulphates of non-ferrous metals, as well as zinc, cadmium, cobalt, etc. The metals contained therein are recovered, after solid-liquid separation by conventional method.

Abstract: A process for the pressure oxidation leaching of non-ferrous metal sulphidic material which comprises providing an autoclave assembly which has a series of successive compartments, the first compartment of which being substantially larger in size than each of the remaining compartments. An oxygen partial pressure is provided in the autoclave assembly in the range of from about 50 to about 2000 kPa. An aqueous slurry of the material is fed into the relatively large first compartment with resultant flow of the material through the successive smaller compartments causing the temperature in the first and successive compartments to be sufficient to produce autogeneous oxidation of the sulphidic material. The oxidized slurry from the last compartment of the series is discharged.

Abstract: The invention comprises the treatment of metal oxides and mixed metal oxides and metal sulfides in a vertical tube reactor system having a downcomer section and a riser section in order to oxidize and dissolve the metal values in aqueous slurry primarily in the downcomer section and introducing a reducing agent comprising a formate species and reducing the dissolved metal values in the riser section. The reduced metal values are then separated with the gangue values from the product solution downstream from the vertical tube reactor system. The reduced metal values may then be separated from the gangue material by conventional solid separation techniques, such as flotation.

Abstract: A process for the recovery of gold from refractory auriferous iron-containing sulphidic material which comprises providing an aqueous feed slurry of fresh feed material and oxidized solids from a subsequent pressure oxidation step. The feed slurry has a pulp density in the range of from about 30 to about 60% by weight. The slurry is subjected to pressure oxidation at a temperature of from about 120.degree. to about 250.degree. C. under a total pressure of from about 360 to about 6000 kPa to produce a slurry of oxidized solids. A portion of the oxidized solids is recycled to the feed slurry, and gold is recovered from the remaining oxidized solids.

Abstract: A process for recovering cobalt and nickel values from cobalt and nickel containing sulphidic material also containing iron includes roasting the sulphidic material to produce a calcine containing water soluble cobalt and nickel sulphate, and leaching the calcine in aqueous sulphate solution under oxidizing conditions at an oxygen overpressure in the range of from about 50 kPa to about 1500 kPa and at a temperature in the range of from about 100.degree. to about 180.degree. C. to produce an iron-containing residue and a cobalt and nickel containing solution. The residue is separated from the solution, and cobalt and nickel values are recovered from the solution.

Abstract: A method of recovering copper and nickel from sulphidic minerals containing copper, nickel and iron comprises the steps of roasting the mineral, preferably to provide magnetite; sulphating, for example with sulphuric acid, sulphur trioxide, metal sulphate and/or sulphur dioxide together with oxygen; and a subsequent leaching of the sulphated material and recovery of copper from the leaching solution, for example by electrolysis. All or part of the leaching solution with its nickel content is recycled to the roasting stage, and the nickel content is removed in the form of nickel oxide together with the leaching residue, from which nickel can be recovered.

Abstract: Thiosalts contained in waste streams are oxidized to sulfate ions in the presence of sulfur-bound copper. Air oxidation of the waste stream is effected in a slurry of the copper compound, which may be CuS, Cu.sub.2 S or chalcopyrite, and continuous long term operation is possible without loss of catalytic activity and without catalyst degradation.