Gold and platinum group element analysis

Abstract

Throughout history, gold, silver and the platinum group elements have occupied a position of considerable social and economic importance. Indeed, the analytical chemistry of these elements extends back into pre-history, analyses being traditionally performed by fire assay techniques. Such techniques, which still form an important aspect of modern determinations of these elements, involve fusing together a sample and flux at a temperature of about 1000{\textdegree}C. The resultant melt separates into two immiscible liquids. The lighter glassy slag contains the alumino-silicates and base metals and is discarded, whereas the more dense `collector' phase, usually composed of molten lead, sinks to the bottom. The platinum group elements are strongly partitioned into this collector phase from which they may be subsequently separated for analysis.