Improvement of methods of chemical preparation of mineral raw materials with low gold content

A method for improving the extraction-atomic-absorption determination of low gold contents in mineral raw materials is proposed. To decompose samples and transfer gold into solution, most techniques use a mixture of concentrated nitric and hydrochloric acids in a ratio of 1:3 when heated. To avoid gold losses at their low contents, the samples were first treated with hydrofluoric acid, and then with a mixture of nitric and hydrochloric acids. With such processing, the silicate matrix that sorbs gold in geological samples is destroyed, and the degree of its extraction increases. It is also necessary to take into account the mineralogical composition of the analyzed samples.