Zinc alloys

Trichloroethanol may be used analogously. The 2,2,2-trichloroethyl (Tee) group is best removed by reduction with copper-zinc alloy in DMF at 30 °C (F. Eckstein, nucleic acid synthesis see section 4.1.1. 

ZINC AND ZINC ALLOYS] (Vol 25) zinc-contaimng [ZINC AND ZINC ALLOYS] (Vol 25)... 

The abundance of indium in the earth s cmst is probably about 0.1 ppm, similat to that of silver. It is found in trace amounts in many minerals, particulady in the sulfide ores of zinc and to a lesser extent in association with sulfides of copper, tin, and lead. Indium follows zinc through flotation concentration, and commercial recovery of the metal is achieved by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting and associated lead (qv) and copper (qv) smelting (see Metallurgy, EXTRACTIVE Zinc and zinc alloys). 

Lead [7439-92-17, Pb, is an essential commodity ia the modem iadusttial world, ranking fifth ia tonnage consumed after iron (qv), copper (qv), aluminum (see Aluminumand aluminum alloys), and 2iac (see Zinc and zinc alloys). In 1993, the United States accounted for 30% of the 4,450,000 metric tons of refined lead consumed by the Western world. Slightly over half of the lead produced ia the world now comes from recycled sources (see Recycling, NONFERROUS LffiTALS). 

Eurther progress was made in the eighteenth and early nineteenth centuries. Many metals were discovered upon the development of experimental chemistry. The modem metallurgical industry was bom with the invention of steelmaking in 1856 (see Steel). Industrial processes for making zinc (see Zinc and zinc alloys), aluminum (see Aluminumand aluminum alloys), and copper followed before the end of the nineteenth century. These processes made possible the industrial revolution and the development of an industrial society relying heavily on the use of metals. 

Volatilization. In this simplest separation process, the impurity or the base metal is removed as a gas. Lead containing small amounts of zinc is refined by batch vacuum distillation of the zinc. Most of the zinc produced by smelting processes contains lead and cadmium. Cmde zinc is refined by a two-step fractional distillation. In the first column, zinc and cadmium are volatilized from the lead residue, and in the second column cadmium is removed from the zinc (see Zinc and zinc alloys). 

Zinc and Zinc Alloys. Zinc metal is highly reactive in acid solutions such as sulfuric, hydrochloric, and nitric dissolving rapidly at acid concentrations normally used to pickle steel and aluminum. Dilute (1—4%) solutions of these acids can be used with caution to remove zinc oxides. 

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