The invention relates to the field of comprehensive recovery of valuable elements such as bromine, base metal and precious metal from incineration ash, especially relates to a method for enriching precious metals from printed circuit board incineration ash by bath smelting-chlorination circulation process. The process mainly comprises pretreatment of the printed circuit board Incineration ash and circulation-chlorination enrichment process for precious metals. The crude copper, crude zinc sulfate, bromine, lead chloride and precious metal enriched slag are obtained. Compared with the traditional process, it realizes the cycle enrichment of precious metals as well as avoids the loss of valuable metals and secondary pollution caused by tail liquid discharge.

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209 C.) aerated NaKZn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.

A method for recovery of precious metals from copper anode slime may include leaching a leach liquor out of the copper anode slime by mixing the copper anode slime with a mixture of nitric acid and sulfuric acid, separating silver from the leach liquor by forming a silver chloride precipitate in the leach liquor by mixing a supersaturated sodium chloride solution with the leach liquor at room temperature and obtaining a first filtrate by filtering the silver chloride precipitate out of the leach liquor. Copper may be separated from the first filtrate by forming a copper hydroxide precipitate in the first filtrate by adjusting pH of the first filtrate at 9 and obtaining a second filtrate by filtering the copper hydroxide precipitate out of the first filtrate. Metallic selenium may be recovered from the second filtrate by reducing the metallic selenium via a chemical reduction utilizing L-ascorbic acid (LAA) as a reducing agent.

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209 C.) aerated NaKZn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.

Process for removing inorganically and/or organically-bound carbon from a precious metal-containing composition inside an oven chamber comprising at least one direct burner and at least one exhaust gas conduit, characterised by the sequence of steps of: a) providing a precious metal-containing composition comprising fractions of inorganically and/or organically-bound carbon inside the oven chamber; b) closing the oven chamber; c) heating the content of the oven chamber by means of at least one direct burner in order to establish a temperature T1 in the range of 450 C. to 1,000 C. and maintaining temperature T1 for 5 min-48 h; whereby, once the oven chamber is closed, any gas exchange between the oven chamber and the surroundings can take place only via the at least one direct burner and the at least one exhaust gas conduit.

Suggested is a method for recovering precious metals from secondary resources comprising or consisting of the following steps: (a) providing a source of solid waste material comprising precious metals in an amount of at least 0.0001% b.w.; (b) bringing said waste material into contact with heterotrophic micro-organisms capable of producing and releasing hydrocyanic acid; (c) adding a solvent or an aqueous nutrient solution capable of serving as a nutrient source for said micro-organisms to the mixture; (d) depleting said waste materials from the precious metals contained therein by complexation of the metals with said hydrocyanic acid released by said micro-organisms; (e) separating the depleted solid waste material from the liquid containing the metal-cyano complexes; (f) recovering the precious metals from their cyano-complexes in known manner.

Described is a method of recovering a metal from a substrate having a metal sulphide, metal oxide, or combination thereof, by contacting the substrate with an aqueous oxidant to oxidize the metal sulphide to elemental sulphur and oxidized metal or convert the complex metal oxide to a metal salt, contacting the oxidized metal or simple metal oxide with ammonium hydroxide to form soluble a ammine complex of the metal to obtain a leachate and residual solids; separating the leachate from the residual solids; and recovering the metal.

A method for recovering metals, such as noble metals or copper, from secondary materials and other materials having organic constituents, wherein the organic components are extracted from the secondary materials and other material by thermal treatment in a process chamber and the secondary materials and other materials having organic constituents are prepared for the recovery process.

A process for digestion of fine iridium includes (a) alkaline oxidative digestion of 1 part by weight fine iridium and 3 to 20 parts by weight of a combination comprising 40 to 70 parts by weight sodium hydroxide, 15 to 30 parts by weight sodium nitrate, and 10 to 40 parts by weight sodium peroxide in the melt, whereby the sum of the weight fractions equals 100 parts by weight; (b) cooling the digestion material formed in step (a) to 20 to 70 C.; (c) dissolving the acid-soluble fractions of the cooled digestion material in water/halogen hydracid until an acidic aqueous solution with a pH value of 1 to +1 is obtained; and (d) boiling the acidic aqueous solution obtained in step (c) until the formation of nitrous gases is completed. Insoluble ingredients can be separated from the acidic aqueous solution before or after step (d), if needed.

The present invention relates to a process for the selective and ecoefficient recovery of lead and silver jointly as a concentrate product from hydrometallurgical residues.