Zinc production technology 1801-1950: a review

• Autores: J.K. Almond
• Localización: 2000 years of zinc and brass / coord. por Paul T. Craddock, D. Hook, Justine Bayley, S. La Niece, 1990, ISBN 0-86159-124-0, págs. 159-228
• Idioma: inglés
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• Resumen

  • The conditions necessary to yield zinc from its minerals are stated. Close to 1801 these conditions were met in four districts of Europe: in Britain, and in Carinthia, Silesia and Belgium. In the years between 1801 and 1950 wordl production of metallic zinc grew from less than 1 x 10 tonnes to more than 2,000 x 10 tonnes annually. For each of the several steps involved in progressing from ore to refined metal the technololy that emerged in the 150-yeaar period to 1950 is reviewed and, where possible, the sources of the technology are indicated. In dressing, because of the unfavourable specific gravities of the minerals, separations by gravity were supplemented by those based on magnetic and electrostatic behaviour, prior to the introdution and develpment of flotation. The preliminary high-temperature treatments of calcination, roasting and sintering are considered, tracing the evolution of reasting technology for the zinc industry.The high-temperature reduction-and-distillation step is examined under the headings: choice of reductant; generation of the necessary high temperatures; charge treatment without access to air; and condensation. Within these subdivisions the features of horizontal batch retorting, vertical continuous retorting, and electrothermic distillation are discussed. Metal refining by various means is outlined, as is zinc-oxide production by hydrometallurgy and electrolysis is summarised, and practice around 1950 is exemplified by notes on the method used by the Rhodesia Broken Hill Development Company. Estimated figures are given for metal production by various processes. One hundred sources are listed.