Mechanochemical milling-induced reactions between gases and sulfide minerals:: II.: Reactions of CO2 with arsenopyrite, pyrrhotite and pyrite

X-ray diffractometry, scanning electron microscopy and mass spectrometry have been utilised to study mechanochemical milling of arsenopyrite. pyrite and pyrrhotite, separately, in the presence CO2 gas. Arsenopyrite alters to the iron arsenide phase, westerveldite, through an intermediate arsenopyrite-type phase and pyrite decomposes to pyrrhotite, which appears to be stable in CO2, although it does undergo a phase transformation to the hexagonal form. (C) 2001 Elsevier Science B.V. All rights reserved.