Use of Lithium Tetraborate in the Fire-Assay Procedure with Nickel Sulphide as the Collector

摘要

The platinum- group metals were determined in chromite materials by a fire-assay procedure in which lithium tetraborate was substituted for sodium tetraborate in the flux mixture. The results show that, while lithium tetraborate improves the dissolution of the chromite grains and is more efficient as a fluxing agent than sodium tetraborate, the values obtained for the platinum- group metals are not significantly different. Nevertheless, lithium tetraborate was found to be the preferred reagent for chromium-rich materials. Stages of the analytical procedure at which loss of the platinum-group metals may occur are identified, and recommendations are made as to how these losses can be reduced. A revised analytical laboratory method is detailed in an appendix.