Paper Title
Cyanide and Cyanide-Free Leaching of Refractory Oxidized and Primary Gold-Copper Porphyriticore

Abstract
The porphyry copper Malmyzh deposit is situated in the Russian Federation (Khabarovskiy kray). Dioriteporphyritic ores of the oxidation zone of the Malmyzh deposit have low copper content from the production and economic point of view of (less than 0.3%) and the increased content of gold (0.1-1.2 ppm). Cyanide-free leaching of refractory gold oxidized and primary gold-copper porphyritic ore were carried out. Cyanide tests were comparative. Sodium bicarbonate and chloride leach solution were activated with electrolysis and UV-radiation. Theoretical aspects of formation of active oxidizers as a result of electro and photo-activation are stated in the article. Sulfuric acid was applied for the sulphatization and formation of a Fe2(SО4)3 surface layer. Surface passivation of iron reduces the detrimental precipitation of goldcontaining complexes. NaCN (0.7 %) and sulfate-chloride lixiviants demonstrate best results and provide for 93 % gold recovery. Low-concentrated NaCN solution (0.05 %) provide for 65 % gold recovery, similar to the direct chloride leaching results (64 % gold recovery). Equal results are demonstrated by cyanide-carbonate schemes with sulfate (80 % gold recovery) and ammonium hydrate (81 % gold recovery) addition. Two-stage leaching of primary Malmyzh ore provided 91 % gold recovery. First stage was electrochemical oxidation of sulphide minerals and the second was cyanidation. The analysis of the methods applied for the processing of this type of ores is carried out. Heap leaching is the optimal processing method from the economic and technological point of view. Keywords - Gold-Copper Recovery Methods, Malmyzh Deposit, Photo-Electro Activated Leaching, Cyanide, Sulfuric- Carbonate Preparation.