Conference Paper

Physical chemistry of roasting and leaching reactions for chromium chemical manufacturing and its impact on the environment - A review

Conference Proceeding cp
TMS Annual Meeting
  • Fecha: 01 January 2013
  • Páginas: 225-236
  • ISBN: 9781118605981
  • Source Type: Conference Proceeding
  • DOI: 10.1007/978-3-319-48197-5_25
  • Document Type: Conference Paper
  • Publisher: Minerals, Metals and Materials Society184 Thorn Hill RoadWarrendalePA 15086
Chromium is mainly used for the production of stainless steel, in electroplating, as pigments and in leather and refractory industries. The natural resource of chromium is the chromite ore, which is a spinel (Fe 2+, Mg)[Cr,Al,Fe3+]2O4, and is often present with gangue minerals such silicates. Traditionally chromium chemical extraction has been carried out with alkali and CaO roasting, which led to major environmental issues due to CaCrO4/head>/Na2CrO 4 release. In this review we examine the physical chemistry of both the low- and high-temperature roasting processes, which oxidizes the Cr 3+ to Cr6+ state. Especially, the influence of silicates and liquid phase on oxygen transport is reviewed for chromite minerals of different origins. The physical chemistry of leaching of water soluble chromate is examined for determining the barrier to the extraction of Cr6+ ions. In this respect the role of spinel is examined. Finally, the precipitation of Cr3+ in oxide/hydroxide forms is also reviewed.

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