Metalliods - Antimony

A. Eh-pH plot of theoretical solubility of the common Sb oxide, valentinite, with superimposed experimental data (red dots) from dissolution of Otago stibnite. The maximum solubilities obtained (37 mg/L Sb) correspond closely with field measurements of Sb solubility in Hillgrove mine waters (55 mg/L).

B. Spatial relationships among stibnite, Sb oxides and dissolved Sb in an oxidised surficial environment with chemical equations linking different Sb species.

C. Graph of dissolved Sb and As concentrations in natural stream water, equilibrated for 32 days at 20°C with stream sediments containing from 7 ppm Sb to 4640 ppm Sb and with Hillgrove stibnite concentrate (66% Sb). Maximum dissolved Sb concentrations attain 5-6 mg/L and are 1-2 orders of magnitude greater than those of As.