Thermal decomposition of oxidised and sulphide ores in the Ozernoye deposit

This study seeks to obtain new information on the behaviour of oxidised and sulphide ores in the Ozernoye deposit during their thermal decomposition. Lead and zinc are produced from complex polymetallic lead-zinc ores containing other valuable components, such as copper and silver. The market demand for zinc and lead remains high both in Russia and globally. In this regard, the development of the Ozernoye polymetallic deposit (Republic of Buryatia, Russia) is of particular importance, since its resources can cover the domestic deficit in zinc and other non-ferrous metals. However, in terms of mineral and phase composition, the ores in this deposit are heterogeneous and complex, containing an increased fraction of refractory ores with finely disseminated sulphide minerals and a high content of oxidised forms. The required efficiency of processing finely disseminated sulphide and oxidised lead-zinc ores can be achieved by a new method on the basis of steam-gas technologies allowing the selective decomposing and activation of complex mineral assemblages in a single technological step. A differential thermal analysis was performed using a Netzsch STA 449 F1 Jupiter instrument. Thermogramms were recorded in a platinum crucible under argon atmosphere and linear heating to 850оС. The conducted thermal analysis of technological ore samples from the Ozernoye deposit showed that, in terms of weight loss, the thermal decomposition of oxidised ores consists of two stages - goethite dehydration at 246-318оС and carbonate and plumbojarosite decomposition at 360оС and higher. However, the decomposition of sulphide ores undergoes three stages, i.e. a sequential decomposition of various carbonates and thermal dissociation of pyrite followed by the formation of magnetite and the reduction of sulphur. The thermal effects of the reactions and the temperature decomposition ranges of the main compounds in the studied samples were determined.

complex polymetallic lead-zinc ores, Ozernoye field, thermal analysis, sphalerite, galena, lead