Optimisation of rock decomposition conditions for atomic absorption determination of gold
R. A. BURKHANOVA (KHRIPUNOVA)
Ufa Federal Research Centre of the Russian Academy of Sciences, Institute of Geology, Ufa, Russia
Keywords: gold, rocks, atomic absorption spectrometry, decomposition methods, reverse aqua regia
Abstract
The analytical and methodological problems that arise during the preparation of samples for determining the gold content in rocks are described, and possible solutions are suggested. It is determined that the accuracy of the results depends on the method of preliminary decomposition, which should be chosen taking into account the complex composition of the material under study. Decomposition methods are tested on standard samples of rocks with different mineralogical compositions, in particular, the effect of the acid ratio in aqua regia on the efficiency of gold extraction is studied. Special attention is given to atomic absorption analysis as a promising method for determining gold concentration. Treatment of the samples with reverse aqua regia (HСl/HNO3 = 1 : 3) allowed for the most complete extraction of gold. It is shown that gold extraction increases from 62 to 95 % on average with an increase in the relative concentration of nitric acid and a decrease in the concentration of hydrochloric acid.
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