Minerals & Metallurgical Processing

, Volume 33, Issue 3, pp 107–115 | Cite as

Utility of mass-balanced EH-pH diagrams II: Stoichiometry of Cu-As-S-H2O system

  • R. N. Gow
  • H. Huang
  • C. Young


In Part I, Gibbs’ phase rule was applied to mass-balanced EH-pH diagrams for the Cu-As-S-H2O system. The diagrams were generated using the stoichiometry of enargite as a basis. In this study, the calculations were expanded to cover the stoichiometries of three other Cu-As-S minerals — tennantite, sinnerite and lautite — and compared with enargite. Stability regions within the resulting EH-pH diagrams were found to change with stoichiometry such that a particular mineral would predominate if its stoichiometry was used in the calculation. Solution speciation was also found to vary, with thioarsenate being the best example. This stoichiometric effect helps to explain results reported in the literature and would be difficult to realize if it were not for mass-balanced calculations.

Key words

Enargite Arsenic Mass-balanced EH-pH diagrams Equilibrium calculations 


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Copyright information

© The Society for Mining, Metallurgy & Exploration 2016

Authors and Affiliations

  • R. N. Gow
    • 1
  • H. Huang
    • 2
  • C. Young
    • 2
  1. 1.FLSmidth USAMidvaleUSA
  2. 2.Montana Tech of the University of MontanaButteUSA

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