Hydrothermally Altered Basalt as a Source for Indium in Ore Deposits

Abstract

Indium is an element integral to various emerging technologies. Despite the demand for indium, little is known about its geochemical behavior in hydrothermal systems that generate economic deposits. The aim of this study is to estimate the efficiency with which indium can be removed from basalt during hydrothermal alteration in order to develop better exploration vectors. This can be accomplished by studying how indium partitions between an aqueous solution and the products of hydrothermal alteration. To evaluate the magnitude of this efficiency, two sets of experiments were performed. The first set used a low initial pH, indium+HCl-bearing aqueous solution, whereas the second used a higher initial pH, indium+sulfur-bearing seawater solution. The water/rock mass ratio ranged from 1-10. Experiments were performed at 500°C and 50 MPa for 2-8 weeks. Water/rock was found to have the greatest affect on the partition coefficient of indium between the altered basalt and the aqueous solution.