Conference Paper

An investigation on the formation of molten salt containing chromium oxide during roasting of chromite ore with sodium and potassium hydroxides

Conference Proceeding cp
Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016
  • Fecha: 01 January 2016
  • Páginas: 71-78
  • ISBN: 9783319486253
  • Source Type: Conference Proceeding
  • DOI: 10.1007/978-3-319-48769-4_7
  • Document Type: Conference Paper
  • Publisher: Springer International Publishing AG
© 2016 by The Minerals, Metals & Materials Society.The extraction of chromium from chromite ore is based on the oxidative alkali roasting of the mineral forming water-soluble alkali chromates. Previous investigations reported the formation of a molten Na2CO3-Na2CrO4 binary mixture during roasting of chromite with sodium carbonate. The physical properties of the Na2CO3-Na2CrO4 liquid phase, which are dependent on temperature, charge and gangue composition, play an important role in the oxidation reaction and may limit the chromium recovery by hindering the oxygen transport to the reaction interface. This investigation focuses on the alkali roasting of chromite ore at 1000°C using NaOH and KOH, and subsequent water leaching. The influence of the alkali ratio on the chromium extraction yield is analysed, and the results obtained with both hydroxides are compared. The formation of molten salt phase under different roasting conditions and its effect on chromium recovery is studied by means of sample characterization and phase diagram analysis.

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