Zinc production

The exploration, evaluation, and development of zinc and lead ore bodies in North and Central America are discussed in Ref. 12. A survey of world zinc production in Ref. 13 gives all operating mines and mills, and their methods, production, and chemical analysis of the products zinc smelters are included. 

Open-pit zinc mining is not common, since most mines ate below the surface. The Kidd Creek Mine in Ontario, Canada, is a combination open-pit—underground mine. It is one of the richest deposits in the world with an estimated 62.5 x 10 t grading 7.08% zinc, 1.33% copper, and 151 g silver (14). Underground mining methods include room-and-pdlar, shrinkage, cut-and-fill, and square set. In the United States, ca 20 mines account for more than 98% of zinc production. 

Tabic 13. Slab-Zinc Production in the United States by Various Reduction Methods, 10001... 

Table 14. World Mine Production and Slab-Zinc Production, 10001...

The level of natural versus man-made emissions to the environment are of a similar magnitude. SoH erosion is the major contributor of natural emissions with zinc mining, zinc production facHities, iron and steel production, corrosion of galvanized stmctures, coal and fuel combustion, waste disposal and incineration, and the use of zinc fertilizers and pesticides being the principal anthropogenic contributors. 

Rolled Zinc. RoUed-zinc products constitute ca 2—3% of slab zinc consumed in the United States over the past ten years. The U.S. production has declined by ca 50% since 1965 (65) and in 1996 only two companies rolling zinc products were left. 

RoUed-zinc products in the form of strip, sheet, wire, and rod have many and varied commercial appUcations. Strip is formed into dry-ceU battery cans, mason jar covers, organ pipes, grommets, eyelets, and many other objects, some of which are subsequentiy brass or chromium plated (jewelry, medaUions, bathroom accessories, etc) (132). The zinc—carbon dry-ceU appUcation accounts for about one half the roUed-zinc consumption in the United States (see Batteries). Sheet zinc is used in photoengraving and also in the constmction of roofing and other architectural uses. Special high grade zinc with a... 

Systems for evaluating electrolytes for metal electrowinning have been developed and are being used commercially in zinc production (96). Computerized mathematical models of zinc electrowinning cells have been developed and vaUdated by comparison with experimental data taken from pilot-plant cells (97). 

The production of secondary zinc requires only 20-25% of the energy required for primary zinc production. Only one-fourth of the total zinc produced is the secondary metal. The reason for such limited recycling is that the major application of zinc is in castings rather than in parts. 

Secondary metal production is advantageous not only with respect to energy consumption but also to environmental impact as compared to primary metal production. The important environmental problems pertain to the formation of dioxins during thermal processing and the generation of dusts of the oxides of zinc, lead, and other metals in secondary steel, copper, and zinc production. 

For the most part, the zinc materials recovered from secondary materials such as slab zinc, alloys, dusts, and compounds are comparable in quality to primary products. Zinc in brass is the principal form of secondary recovery, although secondary slab zinc has risen substantially over the last few years because it has been the principal zinc product of electric arc furnace (EAF) dust recycling. Impure zinc oxide products and zinc-bearing slags are sometimes used as trace element additives in fertilizers and animal feeds. About 10% of the domestic requirement for zinc is satisfied by old scrap. 

Zhou, W. (1996), Chinese traditional zinc smelting technology and the history of zinc production in China, Bull. Metals Museum 25, 36-47. 

Figure 7 An outline of the flowsheet for zinc production by the conventional roast/neutral-leach/electro-...

The use or safe disposal of the iron residues from zinc production (see Figure 7) presents a major technical problem.204 The use of chelating aminomethylene phosphonic acid extractants such as (28) and (29) to recover iron from these residues has been proposed.205 These give much higher FenI/Znn selectivity than D2EHPA but are more difficult to strip. A reductive-stripping process is proposed.187,205... 

Martin, D. Diaz, G. Garcia, M. A. Sanchez, F. Extending zinc production possibilities through solvent extraction. International Solvent Extraction Conference, Cape Town, South Africa, Mar. 17-21, 2002, 1045-1051. 

World production of zinc increased from 0.5 million metric tons in 1900 to 6.1 million tons in 1978 (Elinder 1986) to 7.1 million tons in 1987 (USPHS 1989). The principal ores of zinc are sulfides, such as sphalerite and wurtzite (Elinder 1986). The major world producers include Canada, the former Soviet Union, and Japan — which collectively account for about half the production — and, secondly, the United States, Australasia, Mexico, and Peru (Weatherley et al. 1980 Elinder 1986). Zinc is now available as ingots, lumps, sheets, wire, shot, strips, granules, and powder (USPHS 1989). The United States produced 240,000 tons of zinc in 1987 — mostly from Tennessee, Mississippi, and New York, but also 16 other states — and imported an additional 774,000 metric tons, thus consuming 14% of world zinc production while producing 3.4% (USPHS 1989). 

Rose (2) A process for extracting gold from the residues from zinc production. The residues are fused with a mixture of borax and silica, and air blown through. The base metals oxidize and pass into the slag. 

Occurrence. Germanium is widely dispersed, but only a few minerals have been isolated. Germanite Cu3(Ge,Fe)S4 and renierite (Cu,Fe,Ge,Zn,As)S were in the past the principal sources of germanium. Actually germanium is recovered as by-product of the zinc production. 

K067 Electrolytic sludge from zinc production... 

Alloys of zinc were used for brass production as early as in the ancient times. Trials of zinc production were conducted in Europe in the 6th century, however it had been produced earlier in China and India. Zinc is widely applied, i.e., in metallurgy, electrotechnics, printing, rubber production, production of articles of daily use, paints, drugs, disinfectants, and impregnates, as well as in microfertilizers and pesticides. 

In the United States, germanium is obtained as a by-product of zinc production from zinc blende ores. The ore is concentrated by the flotation process. Concentrated ore is then roasted, converting zinc and the impurity metals to their oxides. Heating the crude oxides with sodium chloride and coal converts germanium and other impurity metal oxides into their volatile chlorides. The chloride vapors are condensed and germanium chloride, GeCh, is separated from the condensate by fractional distillation. 

Air pollution problems and labor costs have led to the closing of older pyrometallurgical plants, and to increased electrolytic production. On a worldwide basis, 77% of total zinc production in 1985 was by the electrolytic process (4). In electrolytic zinc plants, the calcined material is dissolved in aqueous sulfuric acid, usually spent electrolyte from the electrolytic cells. Residual solids are generally separated from the leach solution by decantation and the clarified solution is then treated with zinc dust to remove cadmium and other impurities. 

Poll, Gerard H., Jr. April 1987. "The Case for Alkaline Non-Cyanide Zinc." Products Finishing. Gardner Publications, Inc., Cincinnati, Ohio. 

The consumption of zinc oxide in Western Europe in 1990 was estimated to be 160000 t. Annual world consumption is in the region of 500000 t, representing ca. 10% of the total world zinc production. The rubber industry consumes ca. 45% of the total and the remainder is divided among a large number of industries. 

As of the early 1980s. zinc production throughout the world is based almost exclusively on two processes ... 

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