Reducing Pyrometallurgical Selection of Particularly Refractory Ledge Gold Ore

The article is devoted to development of a brand new approach to solution of the issue related to development of efficient technologies aimed at processing of especially refractory and hard to concentrate ledge gold ore types. A new technology of such gold ore Reducing Pyrometallurgical Selection (RPS Process) utilising the direct smelting process avoiding its concentration has been developed for the purpose. Utilisation of high temperatures and liquid phase melting processes allows actually complete processing of refractory gold ores irrespective of the mostly complex resistance to processing types and with simultaneous and efficient performance of the following four process operations: a complete removal of any waste rock in the form of melted slag containing gold not exceeding 0.1‒0.3 g/t; a complete transfer into the gas phase and removal of arsenic and other harmful admixtures with off gases; complete combustion of all the ore carbon containing matter types obtaining additional heat for smelting and reducing gas phase; an actually complete transfer of any precious metals into a sulphide melt, collector matte, with gold recovery of 95‒99%, which yield will amount about 10% of the ledge gold ore weight. Thus, the developed technology ensures a ten-fold decrease of processed ore amounts in the process head. The RPS Process has been developed and tested in laboratories and under workshop conditions on the basis of direct electric smelting of hard to concentrate and refractory ledge gold ore from a number of deposits of Southern, Central and Eastern Kazakhstan. Such tests of the RPS Process revealed the possibility to increase throughout gold recovery by 10‒15% as compared with currently achieved in dices in case of especially refractory ledge ore processing.