Abstract: The present invention is directed to a method for the recovery of one or more trace elements including gold and one or more platinum group elements from coal. More particularly, the present invention may specify parameters for the selection of coal for combustion, the parameters for combustion of the pre-selected coal, the parameters for the preparation and mixing of a charge for a furnace including ash from the combustion of the coal with an inquart and a fluxing agent, the parameters for the heating of the charge and casting of a dore bar and the parameters for the production of an anode slime from the dore bar. The method of the present invention may also specify parameters for the recovery of silver, gold and one or more trace platinum group elements from the anode slimes.

Abstract: A powerful reducing agent such as hydrazine monohydrate is added to the standard eluent solutions such as NsOH-NaCN with or without alcohol. The kinetics of elution of gold or of silver are thus markedly enhanced.

Abstract: A process for recycling polyester contained in waste materials is provided. The polyester is converted into a corresponding acid salt of a polybasic organic acid and a polyol. The process steps generally include first combining materials containing polyester with an alkaline composition to form a mixture. The mixture is heated, causing the polyester to convert to the acid salt and polyol. The polyol is evaporated and separated from the acid salt.

Abstract: The recovery of gold, silver and platinum group metals from volcanic cinders containing iron is achieved by mixing the cinders with a suitable flux, and metallic copper, and smelting the mixture at a sufficiently high temperature to produce a molten mass of metal containing iron and copper, and a molten slag. The molten slag is separated from the molten metal mass by a suitable means. The slag is discarded and the metal mixture is cooled to a solid state. The copper and iron are then dissolved in acid, leaving an undissolved portion which can then be separated from the resulting leach liquor by filtration. Alternatively, the iron and copper bearing metal can be cast into an anode and electrolyzed in a sulfuric acid solution where copper is deposited at the cathode and iron is put into solution as iron sulfate. The insoluble residue at the anode can be recovered from the sulfuric acid solution by filtration.

Abstract: A process for recycling polyester contained in waste materials is provided. The polyester is converted into ethylene glycol and terephthalic acid. The process steps generally include first combining materials containing polyester with an alkaline solution to form a slurry. The slurry is heated, causing ethylene glycol to evaporate which can then be collected. The remaining product stream is then mixed with water and filtered to remove any undissolved impurities. The aqueous filtrate can be acidified causing terephthalic acid to precipitate. Further, if silver is contained within the materials fed to the process, the silver can also be isolated and recovered.

Abstract: A process for extracting metals from a flotation concentrate containing gold, platinum group minerals, copper, nickel and sulfur. The process involves roasting the concentrate in the presence of oxygen to reduce the sulfur content of the concentrate to approximately two percent; leaching the roasted concentrate with an acid solution containing hydrochloric and nitric acids to dissolve substantially all of the metals; and recovering the metals from the solution.

Abstract: A process for recovering silver oxide and metals from a spent silver oxide button cell. The process relates to a physical process which consists of a heating and a cooling process to separate the shell and the content (silver, silver oxide) of the spent silver oxide cell, so that silver oxide, silver and other metals such as zinc, iron and nickel can be recovered and reused.

Abstract: A process for recovering gold and silver from refractory ores containing precious metals locked in sulfide and arsenide minerals including roasting a concentrate of said sulfide and arsenide minerals with lime at a temperature of about 600.degree. C. Thereafter the resultant calcine is ground, leached with cyanide and precious metals are recovered from the cyanide solution.

Abstract: A process for the recovery of precious metal values as essentially pure gold from gold alloys in the form of thin strips 0.05 to 0.25 inch thick having a gold content of up to 80% gold comprising chlorinating the strips at a temperature of 300 to 700 degrees Centigrade to form a metallic gold/metal chloride mixture and removing the metal chlorides from the gold in the mixture using an aqueous wash. When silver is part of the alloying metal, essentially pure silver is recovered by first washing the metallic gold/metal chloride mixture with hydrochloric acid and then with ammonium hydroxide and recovering the silver from the ammonium hydroxide.