Multi-component mineral-fluid equilibria in ore forming systems: rapid scoping calculations making use of non-conventional standard states

摘要

The adoption of suitable non-conventional (sensu lato) standard states enables redox and pH dependent mineral-fluid equilibria calculations facilitated by the PHOX code (Polya, 1998a) to be extended to multi-component chemical systems, which more meaningfully represent natural ore forming systems. Using this approach, PHOX Version 2.0 enables ore and gangue mineral solubilities, relative mineral stabilities and aqueous species predominance fields to be determined in 8 component chemical systems of the type C_1-C_2-C_3-C_4-C_5-O_2-H~+-H_2O where two of the five components C_1-C_5 may be speciated. For systems with more than 8 significant chemical components and where suitable data exist, the calculations are necessarily less accurate than codes which (i) explicitly consider all these components and (ii) include appropriate activity coefficient calculations, neverthless the ease of operation of the PHOX program indicates its utility for rapid, scoping calculations as illustrated by calculations of jarosite stability in the system Fe-S-Cl-K-C-O_2-H~+-H_2O.