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| Number | Title | Issue Date |
| 5769925 | Process for the elution of precious metals absorbed on active carbon 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.... | 06/23/1998 |
| 5580905 | Process for recycling polyesters 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 polyes... | 12/03/1996 |
| 5439503 | Process for treatment of volcanic igneous rocks to recover gold, silver and platinum 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 ... | 08/08/1995 |
| 5395858 | Process for recycling polyester 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... | 03/07/1995 |
| 5364444 | Metal leaching and recovery process 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 ap... | 11/15/1994 |
| 5221325 | Process for recovering silver oxide and metals from spent silver oxide button cells 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 s... | 06/22/1993 |
| 5074909 | Gold and silver recovery method 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° C. Thereafter... | 12/24/1991 |
| 5004500 | Chlorination process for recovering gold values from gold alloys 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 degr... | 04/02/1991 |
| 4915730 | Process and apparatus for recovery of flue dust A process and apparatus for the recovery of metals such as silver from phosphate flue dust. The process includes the steps of blending chloride salt and the flue dust to produce a blended material, roasting the blended material in an oxygen bearing atmosp... | 04/10/1990 |
| 4857107 | Gold inquartation process A method of refining a precious metal comprising the steps of inquarting the material containing the precious metal into an alloy, with a known quantity of a base metal to form an alloy of a known concentration of the precious metal, and dissolving the ba... | 08/15/1989 |
| 4440569 | Recovery of zinc from zinc-containing sulphidic material A process for recovering zinc from zinc containing sulphidic material which also contains iron together with lead and/or silver includes leaching the material under oxidizing conditions at a temperature in the range of from about 130° to about 170° C. i... | 04/03/1984 |
| 4372782 | Recovery of lead and silver from minerals and process residues Residues containing lead as lead sulphate and silver in the form of native silver or silver chloride, sulfide or sulphate, as well as silver complexes with other metals, and resulting from the roasting and leaching of sulfide concentrates containing lead,... | 02/08/1983 |
| 4331472 | Metal removal apparatus and method A first metal is removed from solutions such as polluted water by contacting the solution with a metallic exchange medium. The metallic exchange medium comprises a plurality of buoyant elements, each comprising a substrate coated with a second metal suffi... | 05/25/1982 |
| 4168969 | Recovery of silver, copper, zinc and lead from partially roasted pyrite concentrate by acid chloride leaching A process for treating a pyrite concentrate containing silver, copper, lead and zinc to recover the metals contained therein is disclosed. The process includes the partial roasting of the concentrate to open the pyrite matrix to solution penetration follo... | 09/25/1979 |
| 4086084 | Refining of metals This invention relates to refining platinum group metal concentrates and the separation therefrom of silver and of the majority of base metals with which they naturally occur. In more detail the process comprises the steps of: (a) contacting a solid parti... | 04/25/1978 |
| 3964901 | Production of copper and sulfur from copper-iron sulfides A hydrometallurgical process for treating iron containing metal sulfides for rendering iron and non-ferrous metal values active and amenable for selective extraction and separate recovery. Sulfur values can be controllably produced as elemental sulfur or ... | 06/22/1976 |
| 3961941 | Method of producing metallic lead and silver from their sulfides A process for producing metallic lead and silver from materials such as ores and concentrates containing the corresponding sulfides and particularly a mixture of minerals such as galena and tetrahedrite in which process the minerals are initially roasted ... | 06/08/1976 |
