Abstract: Recovering gold from gold-loaded fine carbon by application of thermo-kinetic chemical activation regime at a low temperature, while preventing vitrification of imputies found in the gold-loaded fine carbon.

Abstract: The invention involves a method for recovering gold from a gold concentrate comprising: dissolving gold from the concentrate in an aqueous liquor to provide a gold liquor; subjecting the gold liquor to electrolysis in an electrowinning cell to provide cathode-associated gold material; leaching the cathode associated gold material in an aqueous liquor under reducing conditions to provide a treated solid residue; and smelting the treated solid residue to recover gold.

Abstract: Disclosed herein is a method for concentrating gold contained in a leach residue obtained in a copper hydrometallurgical process for recovering copper from a copper sulfide mineral to efficiently separate and recover gold from the leach residue: a gold-bearing copper sulfide mineral is subjected to pressure leaching with sulfuric acid at a temperature higher than 102° C. and 112° C. or lower to obtain a leach residue, and the leach residue is subjected to flotation to separate it into a float fraction and a sink fraction; the float fraction obtained by flotation is desulfurized to obtain a desulfurized product; the desulfurized product is subjected to oxidative roasting to obtain an oxidatively-roasted product; the oxidatively-roasted product is dissolved in a sulfuric acid solution to obtain a copper solution, and a gold-bearing residue is separated and recovered from the copper solution.

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: The present invention provides a new and useful method for bringing about a metallurgical effect in a metal-containing ore or concentrate comprising treating said ore in a resonant microwave cavity while maximizing electric field strength in the area of said ore in said cavity.

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 extracting precious metal from volcanic ore includes the steps of crushing the ore, heating the ore in a hydrogen atmosphere to soften oxide mineral encapsulating the precious metal, cooling the ore, grinding the ore, and processing the ore to extract precious metal.

Abstract: A process for extracting iron, copper, and nickel from a solution containing iron, copper, nickel, and at least one contaminent selected from the group comprising magnesium, aluminum, calcium and sodium, wherein each of said solutes is present at its respective chloride. In the process, calcium oxide or calcium hydroxide are added as a precipitating agent in incremental steps to cause incremental increases in the pH of the solution. At each increasing pH, one of the aforesaid metals will precipitate as the corresponding metal hydroxide while leaving the remaining metals in solution. The metal hydroxide precipitate is separated from the remaining solution prior to the subsequent addition of the precipitating agent.

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: Refractory gold ores are roasted at temperatures from 500.degree. to 650.degree. C. in an oxidizing atmosphere in a fluidized bed, which is supplied with a carbonaceous additional fuel. To effect a substantially complete combustion of the additional fuel to form CO.sub.2 and H.sub.2 O, methanol is added as a carbonaceous fuel.

Abstract: Complex ores of the precious metals which also contain iron spinels and similar compounds are assayed and their precious metals content is extracted by subjecting the ores or concentrates thereof together with an iron-embrittling agent to a pyrometallurgical process which reduces at least a major portion of the iron compounds to liquid metallic iron. The liquid iron serves as a collector metal for the precious metals and, after cooling, the iron is brittle and easily comminuted and can be separated from the precious metals through use of either an electrolytic process or a selective chemical dissolution of the iron and other base metals leaving the precious metals available for analysis and recovery.

Abstract: Recovery of a precious metal value from refractory carbonaceous and sulfidic ores, concentrates or tailings which also include arsenic-containing components is improved by roasting the ore or ore concentrate in an oxygen-enriched gaseous atmosphere having an initial oxygen content from about 25 percent (by volume) to about 65 percent (by volume) while maintaining a reaction temperature of less than about 600 degrees Celsius during the roasting and while maintaining a minimum amount of iron to react with arsenic and for forming ferricarsenate; thereafter recovering a thus-roasted ore as calcine, whereby the calcine is amenable to recovery of precious metal values in it; gold ores are preferred candidate ores.

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.

Abstract: Gold-containing ores, having refractory sulfidic matter or a combination of refractory sulfidic matter and refractory carbonaceous matter, are processed to recover their gold values. The process uses an ore roasting procedure that utilizes a two-state, fluidized bed roaster. The process also employs a pure oxygen atmosphere during roasting. A carbon-in-leach step is desirably used to extract gold values from the roasted ore.