National University of Science and Technology “Moscow Institute of Steel and Alloys” (MISIS), Moscow, Russia:

L. S. Strizhko, Professor of a Chair of Non-Ferrous Metals and Gold, e-mail: sls_2007.47@mail.ru

I. R. Boboev, Post-Graduate Student, Chair of Non-Ferrous Metals and Gold

Joint Enterprise “Zarafshon”, Pаnjakent, Tadjikistan Republic:

B. Bobokhonov, First Deputy Chief Executive Officer

This work is concerned with research and development of technology for gold recovery from copper-arsenic-bearing oxidized ores, which is one of the most important tasks of economic development in the industry of the Republic of Tajikistan. Also, there are concidered the following tasks: requiring of the development of scientific-based recommendations for the design of efficient and environmentally friendly methods of gold extraction in order to increase the volume of gold production in the country. In the article there are compared gold dissolution in cyanide and ammonia-cyanide solutions with dependence on time and concentration of cyanide. Recovery of gold from oxidized copper-arsenic bearing ores is higher in the ammonia cyanide solutions than in the cyanide solutions by 77% and 67% respectively. It is shown that the conducted study did not give the satisfactory results for gold recovery by direct leaching of the ores in cyanide solutions and in ammonia-cyanide solutions. Aimed at increasing of the gold recovery, there are cited the results of experimental studies, which are undertaken with Nitrox pre-treatment of the ores. The second stage is subsequent recovery of the gold from undissolved residue by dissolution in ammonia-cyanide solutions, which is effectively used in the processing of ores with high contents of arsenic. There are presented the following results: preliminary oxidizing of the ores roasting, followed by dissolution of the residue in the ammonia-cyanide solution, during which could be attained the disclosure of finely dispersed gold; the removal of carbonaceous substances and arsenic in their oxide forms and collection of arsenic oxides sublimates the application of wet scrubber with subsequent disposal in the form of calcium arsenate — that is one of the major problems of similar processing of ores.

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