Гидрохимическая очистка золотосодержащих катодных осадков от примесей тяжелых цветных металлов

Abstract

The purpose of this paper is to conduct the research on hydrochloric acid cleaning of gold-containing cathode deposits from the impurities of heavy non-ferrous metals and mathematical processing of the experimental data obtained by the method of dispersion analysis. The atomic absorption method is used to study the chemical composition of the cathode deposits. The method of dispersion analysis is used to process experimental data. The composition of cathode deposit impurities is studied using x-ray spectral microanalysis. The study of the chemical composition of cathode deposits has shown that their main components are gold, silver, copper, lead, as well as non-metallic impurity compounds (CaO, SiO2, etc.). It is found that the optimal concentration of hydrochloric acid for cleaning gold-containing cathode deposits from heavy non-ferrous metals is 371 kg/m3; the degree of copper transition to solution is 69.06%, lead - 93.9%. The calculation of the expected mass fraction of precious metals in the alloyed gold demonstrates an increase in the mass fraction of gold by 14.08%, silver - by 17.46%. The study of the chemical composition of cathode deposits has also revealed that the main impurities that affect their subsequent processing are copper and lead. The latter fall into the ingot of alloyed gold, which is the target product of gold-bearing ore processing and complicate subsequent refining. The dispersion analysis of experimental data shows that solvent concentration significantly affects the transition degree of heavy non-ferrous metals to the solution starting from the value of 20.1 kg/m3. It is shown that the proposed method allows to increase the content of precious metals in the alloyed gold by 31.54%, as well as to perform maximum transition of copper and lead to the solution. The use of acid leaching of impurities from cathode deposits obtained by cyanide-sorption technology is one of the promising directions for improving the quality of gold-containing alloys and hence the reduction of the cost of refining services.