Experimental testing of technologies for processing refractory gold-bearing raw materials

Abstract

Primary deposits of gold-bearing ores are characterized by a variety of chemical and mineralogical composition. The search for a cost-effective method for processing gold-bearing ores is inextricably linked with a set of preliminary studies aimed at studying the composition of the ore, the forms of finding useful components, as well as assessing the effect of impurity elements and physical characteristics of the ore on the process of direct extraction of gold or ore dressing. In addition to preliminary gravity and flotation enrichment, technologies for preliminary preparation of raw materials before cyanidation, including ultrafine grinding, oxidative roasting, bacterial and autoclave oxidation, as well as various combinations of these operations, have found active use in industry. To evaluate the effectiveness of various methods of preparing raw materials before cyanidation, a refractory gold-bearing flotation concentrate obtained from pyrite-arsenopyrite ore was considered as the subject of research. The results of a number of studies on the search for rational parameters of flotation concentrate cyanidation made it possible to achieve gold recovery from the concentrate at the level of 45%. Further studies on pre-treatment of the flotation concentrate and subsequent cyanidation made it possible to achieve the following gold recovery rates:– 44.95% — during cyanidation of flotation concentrate of initial size;– 56% — during cyanidation of flotation concentrate after ultrafine grinding;– up to 85% — using oxidative firing;– 92.8–94.5% using autoclaved oxidative leaching (POX).The gold recovery indicator is the main, but not the only criterion for choosing the technology for processing gold ores and concentrates. It is necessary to take into account operating and capital costs, stocks of raw materials, the geography of the area, the availability of developed infrastructure and qualified personnel. For each specific gold deposit, it is necessary to conduct technological studies and provide a feasibility study for the developed technology.