Amethod has been elaborated for the determination of the content of gold and
silver in geological samples by atomic absorption spectrophotometry (AAS) in
combination with the fire assay method. The weight of sample used for
analysis was 10 g. Sulphur present as sulphide, which is an undesirable
element in smelting, was removed by the addition of iron to the charge. The
sample was smelted with fluxes and lead oxide to replace the silver and gold
by lead and to transfer non-precious elements to slag. Lead was separated
from precious metals by cupellation. The separated silver and gold alloy was
dissolved with aqua regia with addition of hydrochloric acid in excess.
Silver and gold were determined from the same solution. For determination of
the silver content, the AAS method with an air-acetylene flamewas used.
Goldwas determined in a graphite furnace with the addition of a matrix
modifier in an argon current, at an atomization temperature of t = 2200 ?C.
The lower determination limit for silver was 0.05 g/t and for gold 0.005
g/t. The results of the analysis for silver and gold obtained with the
proposed method showed good agreement with the results of the analysis of
the same samples with the fire assay method.
The determination of the content of gold and silver in geological samples