Abstract: A process for separating precious metals from a roaster calcine leach residue from a process wherein copper or zinc sulfides are roasted to produce a copper or zinc calcine; the calcine is leached with an aqueous sulfuric acid leaching solution to produce a copper or zinc-containing leaching solution and a roaster calcine leach residue and the copper or zinc-containing leaching solution is separated from the roaster calcine leach residue wherein the process comprises:(a) intimately contacting the roaster calcine leach residue with an aqueous sulfuric acid leach solution containing from about 5 to about 200 grams per liter of sulfuric acid to produce a slurry of leach solution and roaster calcine leach residue and to dissolve precious metal from roaster calcine leach residue;(b) adding copper or zinc sulfide solids to the mixture of leach solution and said roaster calcine each residue;(c) agitating the copper or zinc sulfide solids in intimate contact with the mixture of leach solution and roaster calcine leac

Abstract: A process for separately recovering platinum group metal values, nickel values and copper from nickel-copper-iron sulphidic matte containing platinum group metals includes leaching ground matte at atmospheric pressure in acidic nickel-copper sulphate solution at a temperature in the range of from about 75.degree. to about 105.degree. C. and at a pH below about 4 initially under oxidizing conditions and subsequently under neutral or non-oxidizing conditions to cause dissolution of nickel and iron, precipitation of copper as a copper sulphide and precipitation of dissolved platinum group metals. The copper, nickel and platinum group metal containing solids are separated from the nickel and iron containing sulphate solution and are leached in acidic nickel-copper sulphate solution under pressurized oxidizing conditions at a temperature of from about 120.degree. to about 180.degree. C. to cause dissolution of nickel and copper with minor dissolution of platinum group metals.

Abstract: A process for recovering gold from refractory auriferous iron-containing concentrate includes feeding the concentrate as an aqueous slurry to an acidic pretreatment step and treating the concentrate in the acidic pretreatment step with aqueous sulphuric acid solution to decompose carbonate and other acid consuming gangue compounds. The treated slurry is oxidized in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C. under a pressurized oxidizing atmosphere while maintaining a free acid concentration of from about 5 to about 40 g/L sulphuric acid to cause dissolution of iron, formation of sulphuric acid and oxidation of substantially all oxidizable sulphide compounds to sulphate form with less than about 20% of oxidized sulphur being present as elemental sulphur during the oxidation step.

Abstract: A process for recovering gold from refractory auriferous iron-containing sulphidic ore which comprises feeding ground ore as an aqueous slurry to an acidic pretreatment step. The ground ore in the acidic pretreatment step is treated with aqueous sulphuric acid solution to decompose carbonate and acid consuming gangue compounds, and subjecting the treated slurry to a first liquid-solids separation step to produce a sulphate solution and separated solids. Water is added to the separated solids in a first repulping step to form a slurry having a pulp density in the range of from about 25 to about 60% by weight solids. The first repulped slurry is oxidized in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C.

Abstract: In the hydrometallurgical treatment of metal-bearing ores and particularly the beneficiation of iron-containing titaniferous ores wherein the ore is subjected to leaching with a dilute aqueous acid solution in a digestion zone, there is provided an improvement which comprises initiating and maintaining the mixture of ore and acid in a state of boiling. Initiation and maintenance of the mixture in a state of boiling is accomplished through the venting of the digestion zone to remove process vapors substantially in the form of water vapor. Initiation of the boiling of the mixture of ore and acid solution in the digestion zone is commenced when the temperature of the mixture and consumption of the free acid solution in said mixture have reached predetermined values. The initiation and maintenance of the mixture in a state of boiling results in an increased rate of dissolution of the contaminant values in the metal-bearing ore.

Abstract: In the extraction of certain non-ferrous metals from their sulfide ores by a process where these sulfides are converted to water soluble sulfates by roasting, alkali metal carbonate or bicarbonate, especially sodium carbonate, is added to the roaster feed to promote the sulfatization reaction. Ores containing copper, nickel, cobalt or zinc sulfides are concentrated by froth flotation, the concentrate mixed with carbonate or bicarbonate and roasted. The roasted product is mixed with water to separate these metals as soluble sulfates from iron compounds and other solid residue. The sulfate solution is filtered from the solids and the non ferrous metals recovered by precipitation or electrolysis.

Abstract: Process for treating oxidized ores with a manganiferous matrix to recover the small quantities of copper, nickel and cobalt, which consists of attacking the aforementioned ore by means of an aqueous solution of H.sub.2 SO.sub.4 with the simultaneous injection of sulfur dioxide, at a temperature which does not exceed boiling point of the medium, at a pH less than 1.5; introducing an alkaline sulfide to precipitate the copper, nickel and cobalt sulfides in the suspension resulting from the attack; and separating by sulfides and the residue by flotation. The process is applicable to attacks on manganiferous nodules obtained from ocean beds as well as to attacks on land manganiferous matrix oxidized ores.

Abstract: A process for recovering non-ferrous metal values from their ores, minerals, concentrates, oxidic roasting products, or slags by sulphating said starting material using a mixture comprising iron (III) sulphate and alkali metal- or ammonium sulphate as a reagent.

Abstract: Metal values are recovered from ore concentrates by forming a sulfide matte, grindng the matte, leaching with sulfuric acid at elevated temperature to selectively extract nickel and iron, and roasting and leaching the residue with dilute sulfuric acid to selectively extract copper. The residue contains a high concentration of platinum, palladium and gold.

Abstract: The specification discloses a method for recovering non-ferrous metals such as zinc or copper iron from their concentrates, ores or any other metal containing materials into a solution containing these non-ferrous metals as sulphates and a minimal amount of dissolved iron. The resultant solution is suited without or with minimum pre-purification treatment for conventional electrowinning processes to recover such non-ferrous metals with less difficulties than the previous methods involving complex iron-removal processing. There is disclosed a method for recovering at least one non-ferrous metal soluble in sulphuric acid from a strong sulphuric acid solution containing said metal and iron as sulphates, said method comprising the following consecutive steps:subjecting said solution in a sub-divided form to thermal decomposition in a fluidized bed reactor at a temperature of from 600.degree. to 750.degree. C.

Abstract: The specification discloses a method for recovering non-ferrous metals such as zinc or copper from their concentrates, ores or any other metal containing materials into a solution containing these non-ferrous metals as sulphates and a minimal amount of dissolved iron. The resultant solution is suited without or with minimum pre-purification treatment for conventional electrowinning processes to recover such non-ferrous metals with less difficulties than the previous methods involving complex iron-removal processing. There is disclosed a method for recovering at least one non-ferrous metal soluble in sulphuric acid from a strong sulphuric acid solution containing said metal and iron as sulphates, said method comprising the following consecutive steps:subjecting said solution in a sub-divided form to thermal decomposition in a fluidized bed reactor at a temperature of from 600.degree. to 750.degree. C.

Abstract: Anode slimes from an electrorefining operation are fed, together with sulfuric acid, into a heated pelletizer wherein a sulfation reaction occurs, simultaneously with pellet formation, to solubilize copper, nickel and tellurium contained in the slimes.

Abstract: A process for treating zinc plant leach residues for the recovery of the lead, silver, and tin values contained therein is disclosed. The process includes the treatment of the zinc plant residue with concentrated sulphuric acid followed by water leaching and other hydrometallurgical steps to separately recover the lead, silver and tin.

Abstract: The specification discloses a method for recovering non-ferrous metals such as zinc or copper from their concentrates, ores or any other metal containing materials into a solution containing these non-ferrous metals as sulphates and a minimal amount of dissolved iron. The resultant solution is suited without or with minimum pre-purification treatment for conventional electrowinning processes to recover such non-ferrous metals with less difficulties than the previous methods involving complex iron-removal processing. There is disclosed a method for recovering at least one non-ferrous metal soluble in sulphuric acid from a strong sulphuric acid solution containing said metal and iron as sulphates, said method comprising the following consecutive steps:subjecting said solution in a sub-divided form to thermal decomposition in a fluidized bed reactor at a temperature of from 600.degree. to 750.degree. C.

Abstract: An improved process for preparing a metallic sulphate in a reaction zone from mixing of the corresponding metallic sulphide concentrates with ammonium sulphate and heating. Heating preferably includes directly contacting the mixture with products of combustion of a heating fuel at temperatures between about 150.degree. C and about 480.degree. C. The products of combustion may be diluted with a gas, and the metallic sulphate of the corresponding metallic sulphide may be initially mixed with the mixture to inhibit the development of semi-fluid conditions in the reaction of the metallic sulphide concentrates with ammonium sulphate.

Abstract: Process for quantitatively converting non-ferrous metals chosen from the group consisting of copper, nickel, cobalt, vanadium, and manganese in an ore concentrate to soluble sulfates and simultaneously convert the ferrous values in the ore to insoluble oxides. The process comprises roasting finely divided ore particles at a temperature in excess of 650.degree. C. in the presence of a roaster gas comprising at least a stoichiometric amount of oxygen and at least 1% SO.sub.2. The roasting is performed in the presence of a sufficient amount of a mixture of salts to allow the formation of a liquid coating on the ore particles. In a preferred embodiment, the mixed salt which forms the liquid coating comprises Na.sub.2 SO.sub.4 and K.sub.2 SO.sub.4 with the ratio of sodium to potassium being between 1.0 and 2.0.

Abstract: A process for the treatment of nickel-copper concentrates comprises the steps of leaching nickel selectively with a dilute hydrochloric acid solution, separating the leach solution from the residue, roasting the residue at a temperature sufficient to form at least about the stoichiometric quantity of sulphate to convert all the nickel present in the residue to nickel sulphate, leaching the roasted residue with water and precipitating any dissolved copper from the aqueous leach solution thus obtained.

Abstract: Process for control of SO.sub.x emissions from copper smelter operations involving pyrometallurgical reduction of copper ores to elemental copper in which the gases from reverberatory furnaces, roasters, and/or converters are scrubbed with a sodium alkali sorbent to produce sodium sulfate and sulfite wastes. The cleaned flue gases are exhausted to the atmosphere. The waste sodium sulfate/sulfite material is then reacted with excess acid from the smelter acid plant and ferrous ion-rich barren solution from the associated cement copper operations to produce co-precipitated double salts of sodium ferric hydroxy-disulfates and/or sulfites (SFH), having low water solubility and being suitable for landfill type disposal without posing serious water pollution problems. This disposes of the sodium sulfite/sulfate waste materials from the air pollution control process and also strips the barren solution of iron prior to its recycle to heap or dump leaching operations.

Abstract: Non-ferrous metals are recovered from metal bearing ores or other metal sources in substantially quantitative yields by treating a finely divided metal bearing material with an aqueous inorganic acid to form a slurry and baking the slurry at atmospheric pressure and at a temperature of about 350.degree. to 800.degree.C. or higher under quiescent conditions for a period of time sufficient to convert the non-ferrous metals into soluble salts. The fumes from the baking process are scrubbed with a dilute acid solution to extract volatile metal salts. The residue is leached with an appropriate solution or solutions to recover the soluble metal salts which are then recovered from the solution by conventional techniques.