INDIUM IN MAGMATIC-HYDROTHERMAL SYSTEMS: UNDERSTANDING ITS BEHAVIOR TODAY TO MEET TOMORROW'S DEMAND
We also performed experiments to evaluate the partitioning of indium between a sulfide(pyrrhotite, po) (Fe1-xS) and silicate melt (m). Experiments were performed at 800 °C, 100 MPa, and fO2 ≈ NNO in a vapor-brine-rhyolite melt system for 5 to15 days. Three separate series of experiments were conducted in which each differed by the aqueous solution added: 1) pure water; 2) 1.01 M Cl- solution; and, 3) 0.35 M CuCl2-bearing solution. Changes in starting material produced changes in the composition of the run product po and glass. The partition coefficients D(po/m) from the experiments were on the order of ≈ 10, ≈ 1.5, and ≈ 3, respectively. Although the D varies depending upon the composition of the starting aqueous solution, D is ~ 4 is a reasonable, preliminary, order of magnitude estimate D(po/m). By using reasonable estimates of the mode of po that crystallizes in magmatic systems, the proportion of indium sequestered by po can be evaluated. The results indicate that po sequesters <0.5% indium from a crystallizing silicate melt. Results presented here are consistent with the inability of po alone to limit the capacity of a magmatic-hydrothermal system to yield an indium-rich ore fluid, and we suggest that Fe-, Mg-bearing silicates can play a key role in the mass transfer of indium in magmatic-hydrothermal systems.