Abstract: This invention relates to refining platinum group metal concentrate and the separation therefrom of silver and the majority of base metals which are present in them. In more detail, the process comprises the steps of:A. contacting a solid particulate mixture of base, silver and precious metal components, any of which may be in metallic or in chemically combined form, with substantially anhydrous sulphuric acid at a temperature which is sufficiently high for most of the base metal and silver components to form water soluble sulphates andB. separating the said water soluble sulphates from the solid precious metal-containing components by contacting the product from step (a) with a dilute aqueous solution or water and dissolving therein the said water soluble sulphates formed in step (a).

Abstract: A method for selectively dissolving non-ferrous metals contained in pyritic ores by the steps of crushing the ores, introducing the crushed ore at a temperature above the ambient temperature into a reaction vessel containing a solution of chlorides of a metal having two valance states, and injecting gaseous chlorine into the reaction vessel at a rate such that the oxido-reduction potential of the solution of chlorides remains between 400 and 700 mv during the operation.

Abstract: The improvement in the process for recovering zinc from ferrites which includes treating electrolytic zinc plants residues with a sulfuric acid solution to dissolve the zinc and metals, a solution resulting which contains sulphates of zinc and the other dissolved metals. The undissolved residue is separated in a certain manner from the solution. The solids-free solution is neutralized in a second step with calcine or another neutralizing agent containing zinc until a certain acidity is reached so that the iron remaining in solution separates therefrom in the form of its complex basic sulfate. The solids are settled out and then sent to a neutralization step, which is part of the residue separation scheme, where they are used as seeds of crystals of complex basic sulfate of iron which helps to remove iron in the first neutralization step. This final solution is added to the normal circuit or process flow path of electrolytic zinc plants. Any Fe.sup.+.sup.

Abstract: Complex sulfide ores or concentrates are decomposed by treatment with a combination of chlorine and oxygen, the amount of chlorine being limited to that necessary to convert sulfides of the desired metals, such as zinc, lead, copper, cadmium, silver, nickel and cobalt to chlorides.

Abstract: A method is disclosed for oxidation of finely-divided sulphide ores or mattes containing iron, with one or more of the elements nickel, copper, cobalt, zinc and lead as constituents, in the presence of iron chloride in an oxygen-containing atmosphere at a temperature of 220.degree.-400.degree. C, to convert the mixture of iron chlorides and sulphides to water-insoluble iron oxide, the nickel, copper, cobalt and zinc being converted to water-soluble chlorides and sulphates, and the lead to a sulphate which may be leached away from the residual iron oxide by special solvents for lead sulphate. The initial iron chloride is preferably obtained by adding aqueous hydrochloric acid to the concentrate, if iron sulphide is present in a susceptible form, to drive off a portion of the sulphide sulphur as hydrogen sulphide gas, and to convert the corresponding iron sulphide to iron chloride. Temperatures may rise as high as 450.degree. C during the roasting phase if special conditions are observed while cooling.

Abstract: Sulfur monochloride is reacted with an ore containing iron, sulfur and a metal which forms a water soluble ammine complex or an ammonium-containing double salt, to yield metal chlorides and sulfur. The metal sought is solubilized with an aqueous solution containing ammonium ions to produce an aqueous solution of metal ammine complex or double salt and thereby separate such complex or salt from the iron and sulfur. The solution containing the sought metal values can then be subjected to electrowinning to recover the metal, or the metal can be precipitated as the metal oxide by the addition of sodium hydroxide. Sulfur and chlorine are recovered during the process and used to regenerate sulfur monochloride.

Abstract: Carbon black is recovered from vulcanized waste rubber such as automobile tires or other articles by reacting pieces of the rubber with an aromatic oil solvent in a stirred reactor at 500.degree.-700.degree.F temperature and about 25-100 psig pressure for 0.5-2 hours residence time. The resulting solids-liquid mixture is processed to remove solids, and the resulting solid product is then dried, screened and chemically treated to recover the carbon black in dry powder form. The remaining solvent oil is also recovered and a portion reused in the process.

Abstract: A process for the treatment of zinc plant residue formed on leaching zinc calcine with sulphuric acid in which the residue is leached in a first leaching step with a sulphuric acid solution at atmospheric pressure, and a temperature above about 60.degree.C, in the presence of excess zinc sulphide reductant whereby ferric iron in the residue is reduced to the ferrous state, thereby forming a zinc sulphate solution containing excess acid, ferrous iron and other dissolved impurities such as germanium, indium, gallium, antimony and arsenic nd a mixture of solids containing undigested zinc residue, lead residue, and unreacted zinc sulphide. Clarified solution is separated, preferably by thickening, from the mixture of solids. The mixture of solids is leached in a second residue leaching step at atmospheric pressure and at a temperature above about 60.degree.

Abstract: A pollution-free process for the recovery of high purity zinc from zinc containing material including sulfide ores which provides for maximum conservation and re-use of reagents, the process consisting of chlorinating the materials either with ferric chloride or chlorine gas followed by selective removal of metals other than zinc by standard procedures, such as, lead chloride crystallization, cementation, etc. to produce a solution containing essentially only zinc chloride and ferrous chloride. To enhance the purity of the zinc end product zinc chloride is separated from the ferrous chloride solution with a zinc selective extraction agent from which the zinc chloride is stripped with sodium chloride solution in a sodium chloride stripping circuit followed by precipitation of zinc as the carbonate.

Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree.C (300.degree.F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.

Abstract: A hydrometallurgical process for treating iron containing metal sulfides for rendering iron and non-ferrous metal values active and amenable for selective extraction and separate recovery. Sulfur values can be controllably produced as elemental sulfur or as sulfuric acid to supply acid requirements of the process, while substantially obviating the discharge of sulfur-containing gases to the atmosphere. Ores and concentrates of the sulfides are thermally activated by sequentially heating and reducing said sulfides in a countercurrent flow of heating and reducing gases respectively in a reactor whereby the reaction products of the reducing gas and sulfides, together with liberated labile sulfur, are controllably combusted with oxygen to satisfy heat requirements of the thermal activation process and to convert sulfur values to SO.sub.2 gas. The activated sulfides are subjected to an acid leach in aqueous sulfuric acid for production of ferrous sulfate and evolution of H.sub.

Abstract: A hydrometallurgical method of recovering zinc, copper and cadmium from their ferrites so that the ferrites are treated under atmospheric conditions in sulphuric acid bearing solution in the presence of potassium-, sodium- or ammonium-ions, is disclosed, in which the treatment takes place in one stage under such conditions that the non-ferrous metals, zinc, copper and cadmium, contained in the ferrites are transferred as sulphates to the solution and the iron is converted in the same stage to a solid basic iron salt by adjusting the sulphuric acid or ferric sulphate addition to be equivalent with regard to the ferrite amount fed into this stage and by adjusting the temperature to 80.degree. - 105.degree.C, preferably to 95.degree. - 105.degree.

Abstract: An improvement in the process of leaching metal sulfide minerals with an oxidative leaching solution is obtained by adding to the leaching solution over only a portion of the leaching cycle aqueous hydrogen peroxide in an amount ranging from about 2 to about 25 percent by weight of the quantity of hydrogen peroxide required to bring the metal value of the mineral into solution if hydrogen peroxide were used as the sole oxidizing agent.

Abstract: In a process for the treatment of a material containing zinc and soluble silica by dilute aqueous solutions of sulphuric acid at a temperature below its boiling point under atmospheric pressure, the acid is progressively added to the zinc containing material over a period of at least 3 hours, in such a quantity that the final acidity of the solution will be 1.5 to 15 g/l, while carefully maintaining the temperature at 70.degree. to 90.degree.C, thereby inducing the lixiviation of the material and simultaneously the reprecipitation of silica in a crystalline form which can readily be eliminated by filtration.

Abstract: Naphthenohydroxamic acid is prepared by reaction at 25.degree.C to 30.degree.C, equimolar quantities ofA. an ester of naphthenic acid,B. hydroxylamine dissolved in an alcohol/water/alkali metal sulfate slurry wherein the water content of the slurry is insufficient to hydrolyze the ester during conversion to naphthenohydroxamic acid, andC. an alkali metal hydroxide dissolved in alcohol.Naphthenohydroxamic acid is useful as a chelating agent in hydrometallurgy to recover metal values from dilute solution.

Abstract: Process for receovering copper values (and zinc, if present) from copper bearing materials, optionally in admixture with iron. The feed material is leached with a mixture of nitric and sulphuric acids, after which the dissolved copper is cemented from solution by contact with iron. The solution, containing dissolved iron (and zinc, if present in the feed material) salts is reacted with ZnO to precipitate iron as ferric oxide, which is separated, leaving zinc sulfate in solution. Solid zinc sulfate is recovered from the solution by evaporation, and then calcined to produce SO.sub.2, which is recovered and recycled as H.sub.2 SO.sub.4, and ZnO, which is reused in the process, any excess being recovered as a product.