Fire Assay Fusion

PPB-level Detection for Exploration Samples
Zarazma analyses mineral samples for Au, Pt and Pt by fire-assay. This well-proven technique involves fusion of the samples at high temperature (1,100°C), during which precious metals are separated from gangue materials and collected in molten lead. Lead is then removed by cupellation, again at high temperature, resulting in a prill of silver, gold and precious metals. The prill is dissolved in acids before the metal values are determined by ICP-OES or AAS.


Fire-assay is essentially a total-recovery technique., and is generally used as the reference technique when calculating ore reserves.

Very high base metal concentrations can interfere with the technique, and require particular care. Zarazma’s proprietary assay flux mix is designed to provide optimum recoveries from the widest range of rock types possible.

The highest quality assay consumables (flux, crucibles and cupels) are sourced from around the world, to ensure that assay integrity is guaranteed.

Zarazma’s standard assay charge is 25g.