Abstract: A blank suitable for minting to form a coin or similarly disc-shaped article has an appropriately disc-shaped steel core completely encased by a copper coating electroplated thereof. The blank is produced by electroplating a copper coating onto an appropriately disc-shaped steel core such that the copper coating completely encases the steel core.

Abstract: A process for the recovery of uranium values from uranium-bearing material by sulphuric acid leaching when the material also contains siliceous matter which is at least partly soluble in sulphuric acid. The process comprises leaching the material with sulphuric acid in an aqueous slurry under oxidizing conditions at a temperature within the range of from about 65.degree. C. to about 200.degree. C. and at elevated pressure, with sulphuric acid being present in a quantity only slightly in excess of the amount required to dissolve the uranium and any other element whose dissolution is desired, to produce an insoluble residue containing siliceous matter and a leach solution containing dissolved values of uranium and any other desired element.

Abstract: A blank suitable for minting to form a coin or similarly disc-shaped article has an appropriately disc-shaped steel core completely encased by a copper coating electroplated thereof. The blank is produced by electroplating a copper coating onto an appropriately disc-shaped steel core such that the copper coating completely encases the steel core.

Abstract: A process for purifying copper sulfate solution by converting contained hexavalent selenium to tetravalent selenium which is amenable to removal from solution by heating and maintaining the solution at a temperature in the range of about 135.degree. to 220.degree. C. under a non-oxidizing atmosphere in the presence of bivalent iron. The converted selenium is removed from the solution either by co-precipitation with ferrous iron oxidized and hydrolyzed to ferric oxide at a temperature in the range of 135.degree. to 220.degree. C. and under an oxygen pressure of about 140 to 450 kPa or by cementation with a metal powder at a temperature in the range of about 25.degree. to 85.degree. C. at about ambient pressure under a non-oxidizing atmosphere.

Abstract: A process for thermal activation of chalcopyrite-pyrite ore concentrates for activation of iron values in both chalcopyrite and pyrite constituents whereby said iron values can be selectively removed in a subsequent acid leach. Controlled oxidizing conditions are maintained in an oxidizing heating zone for removal of up to about 90% of total sulfur to be removed for conversion of pyrite and chalcopyrite to their acid-leachable forms, measured by a preferable oxidation of 10 to 15% of iron in the concentrate to ferromagnetic oxides, whereby remaining total sulfur to be removed is removed in a reducing zone with the assistance of a low H.sub.2 S/(H.sub.2 +H.sub.2 S) ratio by scavenging of H.sub.2 S by said oxides.

Abstract: A process for precipitation of iron as a jarosite compound from sulfate solution in which said solution fed sequentially through a plurality of reaction zones for oxidation and hydrolysis of ferrous sulfate in the presence of alkali-metal or ammonium ions for jarosite precipitation and simultaneous generation of sulfuric acid is subjected to a "reverse temperature profile", i.e., higher temperature in the last reaction zone than in the first reaction zone, by injection of steam to the last reaction zone.

Abstract: The process of the invention is for the separate recovery of elemental sulfur and residual sulfides and metal salt solution from reaction slurries obtained from leaching of metal sulfides in ores and concentrates.

Abstract: A cathode has a hollow body with opposed, spaced sheet-like parallel walls with outer faces on which metal is deposited during use of the cathode. The body has outer surfaces between the outer faces of the walls upon which substantially no metal is deposited during use of the cathode, so that metal is deposited as two separate sheets, one sheet on each wall. The hollow body is connectable to a source of reduced air pressure and the sheet-like walls are resiliently deformable to enable the walls to be inwardly bowed towards one another by reduced air pressure, after metal has been deposited on the walls, so as to effect separation of the deposited metal sheets from the walls.

Abstract: A process for the production of coin blanks suitable for minting into coins, includes providing metal coin core pieces of disc-like shape each having opposed faces from about 14 mm to about 40 mm in diameter and a face to face thickness of from about 0.5 mm to about 2.6 mm. A charge of core pieces is loaded into a non-conducting perforated container with a diameter of from about 15 cm to about 50 cm, the number of core pieces in the container being such that the core pieces occupy from about 1/4 to 1/2 of the container volume. The container is placed in an electroplating bath, and a metallic cladding is plated on the core pieces, while moving the container angularly about a horizontal axis, at a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m.sup.2 to about 1400 A/m.sup.2 based on the exposed area of the charge, until a plating thickness of from about 0.03 mm to about 0.

Abstract: Ammonium jarosite is converted to hematite or magnetite and ammonium sulphate. The invention can be used for removing iron from a feed solution containing dissolved ferrous sulphate. The feed solution is treated with ammonium sulphate and oxygen to precipitate ammonium jarosite which is then separated from the treated solution to produce an ammonium jarosite slurry and a separated solution containing sulphate ions. The ammonium jarosite slurry is treated with ammonia to convert the ammonium jarosite to hematite or magnetite and ammonium sulphate solution. The ammonium sulphate solution is separated from the hematite or magnetite, and a portion of the separated ammonium sulphate solution is recycled to the ammonium jarosite precipitation step, the remaining portion of the separated ammonium sulphate solution being recovered.

Abstract: A process for recovering nickel from an impure nickel compound which contains a major proportion of nickel values and a minor proportion of other metal values which are relatively soluble in ammoniacal ammonium sulphate solution, and a minor proportion of nickel values and other metal values which are relatively insoluble in the solution. The impure nickel compound is treated with ammoniacal ammonium sulphate solution so that the relatively soluble nickel and other metal values are dissolved in the solution with the relatively soluble nickel values being dissolved substantially as nickel diammine sulphate, and so that the relatively insoluble nickel and other metal values form an undissolved residue.

Abstract: Silver is precipitated from an aqueous sulphate solution containing dissolved silver and other metals at a temperature between about 60.degree. C. and about 125.degree. C. by hydrogen gas at a partial pressure between about 2 and about 5 kg/cm.sup.2.

Abstract: A process for separately recovering nickel and cobalt from solution includes adjusting the pH of the solution to a value between about 3 and about 6, and then contacting the solution with a chelating ion exchange resin having aminocarboxylic acid functional groups to selectively load nickel onto the resin to produce a nickel loaded resin and a nickel depleted cobalt containing solution. The process is also applicable to the separate recovery of copper and zinc from solution.

Abstract: A process for recovering metallic cobalt from an aqueous ammoniacal solution containing dissolved cobalt and other metals as ammine sulphates with substantially all the dissolved cobalt being in cobaltic form. The process includes contacting the solution with a water immiscible liquid ion exchange reagent dissolved in an inert organic diluent to selectively substantially completely extract the other metals from the solution and produce an organic extractant loaded with the other metals and an aqueous cobalt bearing raffinate substantially free of the other metals. The cobalt bearing raffinate is separated from the loaded organic extractant and the loaded organic extractant is washed to remove substantially all ammonia therefrom. The other metals are stripped from the washed organic extractant which is then recycled to treat further solution. Cobalt is recovered from the raffinate.

Abstract: A process for the selective extraction of copper chlorides from aqueous solutions by forming a solid addition compound of cuprous chloride with an unsaturated aliphatic hydrocarbon having from 2 to 6 carbon atoms, separating and decomposing the addition compound and recovering solid cuprous chloride. The process can also be used for the separation of copper chlorides from silver-chloride. The process may be applied to the recovery of copper from hydrometallurgical process solutions.

Abstract: A hydrometallurgical process for the separate recovery of non-ferrous, ferrous, and precious metal values and sulfur from metal sulfide ore concentrates by leaching of metal sulfides with a lixiviant containing ferric chloride, cupric chloride and chlorine, precipitating cuprous chloride from the leach solution with butadiene, separating and decomposing the formed addition compound to recover the cuprous chloride, oxidizing and hydrolyzing the cuprous chloride to precipitate cupric oxychloride, converting the cupric oxychloride to cupric oxide, and reducing the cupric oxide with hydrogen for the recovery of copper. The leach residue is treated for the recovery of elemental sulfur and gold. Brine solution resulting from the conversion of cupric oxychloride to cupric oxide is electrolyzed for the production of sodium hydroxide for the cupric oxychloride conversion, hydrogen for the cupric oxide reduction and chlorine, which is partly used in the recovery of gold and partly recycled to the concentrate leach.

Abstract: A process for producing ultrafine cobalt powder includes providing an aqueous solution of cobalt ammine carbonate, with the concentration of cobalt ions being in the range of from about 1 to about 20 grams per liter (gpl). The solution is heated to drive off ammonia and carbon dioxide and precipitate ultrafine cobalt oxide. The cobalt oxide precipitate is then separated from the solution and heated in a reducing atmosphere to reduce the cobalt oxide to ultrafine cobalt powder.

Abstract: A process for the production of coin blanks suitable for minting into coins includes providing metallic core pieces, each core piece having opposed, substantially planar faces and a common side edge. The core pieces are loaded into a perforated container which is placed in an electroplating bath. A metallic cladding is placed on the core pieces, while moving the container angularly about a horizontal axis, until the metallic cladding has a thickness of at least about 0.05 mm on each face of each core piece and a thickness of at least 2 to 4 times the face thickness on the side edge of each core.

Abstract: A process for recovering zinc and manganese dioxide from material containing zinc and manganese compounds, includes leaching the material to provide an aqueous solution containing manganese and zinc ions, electrolyzing the solution in one electrolytic cell with conditions inhibiting the formation of manganese dioxide and favoring the deposition of zinc, and electrolyzing the solution in another electrolytic cell with conditions favoring the formation of manganese dioxide. Zinc is removed from the one electrolytic cell and manganese dioxide is removed from the other electrolytic cell.

Abstract: Gold, as well as copper, is recovered from copper bearing sulphidic material containing gold. The copper bearing sulphidic material is subjected to a main leach to provide a copper containing main leach liquor and a main residue. A secondary leach with ammonium thiosulphate solution is carried out on the copper bearing sulphidic material before the main leach, or on the residue from the main leach, to provide a gold containing secondary leach liquor and a secondary residue. Copper and gold are recovered from the respective leach liquors. Silver may also be recovered in addition to the gold.