Gold reclamation

Recovered copper in electronic scrap (old) is small in comparison representing about 14,000 t/yr of copper from 68,000 t/yr of waste (25). Electronic scrap accounts for iron (27,000 t), tin (14,000 t), nickel, lead, and aluminum (6,800 t each), and zinc (3,500 t). Precious metal value, which is the primary economic reason for the reclamation of electronic waste, accounts for 345 t of gold, twice that in silver, and some palladium. 

Precious metals reclamation Precious metals reclamation is the recycling and recovery of precious metals (i.e., gold, silver, platinum, palladium, iridium, osmium, rhodium, and ruthenium) from hazardous waste. Because U.S. EPA found that these materials will be handled protectively as valuable commodities with significant economic value, generators, transporters, and storers of such recyclable materials are subject to reduced requirements. 

Precious Metals Recovery Metal recovery units engaged in precious metals recovery are also conditionally exempt from Part 266, Subpart H. Precious metal recovery is defined as the reclamation of economically significant amounts of gold, silver, platinum, palladium, iridium, osmium, rhodium, ruthenium, or any combination of these metals. Provided the owner/operator complies with the alternative requirements, the unit would be exempt from all BIF requirements except for the regulations concerning the management of residues. 

Uses. Extraction of gold and silver electroplating hardening of metals coppering zincing bronzing manufacture of mirrors reclamation of silver from photographic film pesticides... 

Metallic mercury is mostly a problem in confined spaces or where it is handled in industrial processes or in laboratories. It is not generally an environmental problem, more likely an industrial hazard. However, metallic mercury does occur naturally (it was mined in Spain and Slovenia, for example) and the use of mercury for metal reclamation is a potential environmental hazard in countries such as Brazil where miners use it to extract gold from river sediments. Inorganic and organic mercury may be produced from the metallic mercury during its use and subsequent release into the environment. 

Many component terminations are either plated or dipped into molten tin-lead solder to preserve their solderability, providing yet another source of lead. This is the normal procedure for component terminations that are difficult to solder, such as nickel-iron or nickel plating. Alternative lead-free finishes for components include palladium (Pd), and gold (Au) applied by electroless plating over nickel (Ni), and hot-dipped coatings of Sn-Ag, Sn-Cu, or Sn-Ag-Cu alloy. Some component metallizations are coated with Pd-Ag, Pd-Au, or Pd-Ni. These coating alternatives for tin-lead add new materials to the electronics waste stream, and potentially make recycling or reclamation of metals in electronic products more difficult and costly due to the increased number of separations required. 

Beyond reuse, the next best option is recycling to derive a partial benefit from some components, parts, or reclamation of materials for use in new or refurbished computers, monitors, printers, scanners, and other electronic products. Among the materials that can be reclaimed in electronic products are plastics, glass, steel, aluminum, copper, nickel, and precious metals including gold, silver, and palladium. 

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