Abstract: This invention relates to the recovery of precious metals and, more particularly, to the recovery of precious metals, such as platinum group metals, gold and rhenium, from various sources using a solution comprising at least one ammonium salt, at least one halogen salt and at least one oxidant.

Abstract: This invention relates to the recovery of platinum group metals and, more particularly, to the recovery of platinum group metals from various sources by roasting the source material with one or more of sulfuric acid, a sulfate and/or a bi-sulfate and with one or more halogen salt. The roasted product is put in contact with a leaching solution to dissolve at least a portion of the platinum group metals, which then may be separated and recovered.

Abstract: This invention relates to the recovery of platinum group metals and, more particularly, to the recovery of platinum group metals from various sources by roasting the source material with one or more of sulfuric acid, a sulfate and/or a bi-sulfate and with one or more halogen salt. The roasted product is put in contact with a leaching solution to dissolve at least a portion of the platinum group metals, which then may be separated and recovered.

Abstract: Copper and nickel are extracted from their elemental state, complex sulfides, ores, and other materials such as scrap by leaching them with a solution containing halogen salts: bromine/bromide, or iodide/iodine, oxygen and sodium or potassium nitrate. The invented process is particularly effective for chalcopyrite and pentlandite in an autoclave at a temperature of 100.degree. C.-150.degree. C.

Abstract: Platinum group metals and rhenium are extracted from their elemental state, complex ores, and other materials such as catalysts by leaching them with a solution containing ammonium halogen salts--iodide and bromide in the presence oxygen and/or sulfuric acid. The invented process is particularly effective for spent catalysts containing precious metals and rhenium in an autoclave at a temperature of 50.degree. C.-300.degree. C.

Abstract: Platinum group metals, gold and silver are extracted from complex ores, automobile scrap, refractory ores and as naturally occurring by leaching the precious metal containing materials with a solution containing halogen salts such as potassium or sodium iodide and bromide in the presence of ammonium ions and oxygen. The precious metal containing materials and reactants are charged into a reaction zone held at high temperatures and pressures to form a slurry containing a precious metal ion solution. The precious metal ion solution is separated from the slurry and subjected to recovering techniques to recover the precious metals.

Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.

Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.