Dispersion of antimony from oxidizing ore deposits

The solubilities of brandholzite, [Mg(H 2O) 6][Sb(OH) 6] 2, and bottinoite, [Ni(H 2O) 6][Sb(OH) 6] 2, at 25 °C in water have been measured. Solubilities are 1.95(4) × 10 -3 and 3.42(11) × 10 -4 mol dm -3, respectively. The incongruent dissolution of romeite, Ca 2Sb 2O 7, and bindheimite, Pb 2Sb 2O 7, at 25 °C in 0.100 mol dm -3 aqueous HNO 3 was also investigated. Equilibrium dissolved Sb concentrations were 3.3 ± 1.0 × 10 -7 and 7.7 ± 2.1 × 10 -8 mol dm -3, respectively. These values have been used to re-evaluate the geochemical mobility of Sb in the supergene environment. It is concluded that the element is geochemically immobile in solution and in soils. This was in part validated by an orientation soil geochem-ical survey over the Bayley Park prospect near Annidale, New South Wales, Australia. Anomalous soil Sb levels are confined to within 100 m of known stibnite mineralization.