Precious metals Ruthenium Silver

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. 

Bruevich TS, Bogomolets NN, Berezovskii AD. 1980. [Sensitizing action of precious metal compounds Gold, platinum, ruthenium, rhodium and silver]. Gig Tr Prof Zabol 42-44. (Russian). 

Rhodium is considered to be a precious metal. A precious metal is one that is rare and valued. Other precious metals are gold, silver, and platinum. Rhodium is also classified as a member of the platinum group of metals. The platinum group includes five other metals that often occur together in nature ruthenium, palladium, osmium, iridium, and platinum. 

Base metal Any metal that is not one of the precious metals. The term base means inferior or impure. Historically, gold and silver were the only precious metals people recognized, but today the elements silver, gold, platinum, palladium, iridium, gallium, rhodium, osmium, and ruthenium are all considered precious metals by the U.S. National Institute for Standards and Technology. 

Precious Metals a term that refers to gold, silver, and the platinum group metals — platinum, palladium, rhodium, iridium, ruthenium and osmium. 

The DOE Oak Ridge Operations Office is responsible for maintaining the DOE supply of precious metals. These metals are platinum, palladium, iridium, osmium, rhodium, ruthenium, gold, and silver. 

Fire assay describes a group of separation methods in which precious metals (PMs) are separated from other species by dissolution in other molten metals, usually lead, nickel, or tin. Fire assay has been and continues to be fundamental to the determination of PMs. These are defined as gold (Au), silver (Ag), and the platinum group metals (PGMs) platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). In the context of fire assaying other elements are referred to as base elements or metals. 

For example, on Nov. 1, 2000, the following prices (per troy ounce) for precious metal industrial bullion were listed by Engelhard (www.engelhard.com) silver 4.77, gold 266, platinum 589, palladium 779, rhodium 1750, iridium 415, ruthenium 165, rhenium 550, and osmium 400. 

THE NOBLE METALS, or precious metals, consist of gold, silver, and the platinum group metals (PGM)— platinum, palladium, iridium, rhodium, osmium, and ruthenium. These metals are known for their stability in corrosive environments, physical beauty, and unique physical and chemical properties. They command a premium price because of their low abundance in nature. The noble metals are used in many applications with great success and often with few, if any, substitutable materials. 

Ruthenium is produced mainly from an anode slime yielded when crude copper or crude nickel, obtained from nickel sulfide ores, is electrolytically refined. The anode slime contains precious metal elements. It is treated with hot aqua regia and platinum, palladium and gold are separated as their chloro complexes. Then, by nitric acid treatment, fusion treatment with NaHS04, and fusion treatment with Na202, silver, rhodium and iridium are separated. The residual ruthenium and osmium salts are dissolved in water, and the osmium is separated by treatment with chlorine, hydrochloric acid and nitric acid. The ruthenium salt is treated with ammonium chloride to afford a ruthenium salt ((NH4)3RuCl6), and the reduction with hydrogen yields ruthenium powder [1,4-6]. 

The third group of chemical elements reviewed in this chapter comprises two precious metals, silver and gold, plus the sextet of Pt metals ruthenium, rhodium, palladium, osmium, iridium and platinum. Considered will be also some less frequent heavy metals, i.e. antimony, bismuth, indium, tin (by some authors... 

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