Increased recovery of free fine gold in the leaching process

Abstract

The current state of world mineral resources is characterized by a decrease in the quality of minerals. An increase in production and processing volumes is possible only through the development of new deposits and the involvement of off-balance ores, dumps and tailings, slags and other industrial wastes in the integrated mining process. More increasing the need for involving raw materials of complex composition, refractory, low-grade, with small reserves, technogenic mineral waste. It becomes more and more relevant as the discovery and exploitation of new deposits, allowing to increase the gold reserve of the Republic of Kazakhstan. The article presents the results of sorption leaching of ore in order to extract gold associated with sulfides, the processes of opening gold. A representative sample was taken and the phase composition of an additional explored ore body was studied at one of the deposits in Kazakhstan. The ore sample was prepared for research: three-time mixing by the ring-cone method, in general, three-stage quarting and mixing were performed. It should be noted that the methods for processing gold-bearing ore raw materials depend on many parameters, including the material composition and technological properties. Samples from the last quarting materials were selected for chemical, sieve and phase analyzes. It was found that the test sample contained 6.04 g / t Au and 7.9 g / t Ag, as well as fineness of gold within 0.01-0.25 mm phase analysis. Mineral gold formations can be easily soluble in cyanide solutions (native gold, electrum), partially soluble (maldonite, or practical are insoluble (tellurides). Gold in ores is present in the form of gold-colored sizes and shapes. Both physical (gravity, flotation) and chemical (cyanide, etc.) methods are used to extract it. Rational analysis also found that gold in the ore under study, crushed to a particle size of 90%, class 0.071 mm, gold is free and in intergrowths is 81.46%, gold associated with sulfides is 14.40%, in rock-forming minerals 1.66%. Based on the data obtained, it can be stated that when cyanidating ore, one should expect rather high rates of gold dissolution (80% or more). Gold extraction from ore with a content of 85% fraction -0.071mm-90.2%, with a content of 85% fraction- 0.071mm-98% with oxidative leaching. Full extraction of gold from ore is possible with sorption cyanide leaching with their preliminary oxidation. The paper considers economically feasible existing and promising technologies for gold extraction at the leading factories of Kazakhstan and abroad.