| With the increasingly exhausting of easily leachable gold ores, refractory gold ores have attracted extensive attention around the world. In China, the resource of refractory gold ores containing high arsenic is very abundant and extensively distributed. Therefore, it is practically meaningful to explore better use of refractory gold ores at the present and in the future of China. Guigang of Guangxi has rich refractory gold ores containing high arsenic, which are currently explored as flotation concentrate for sale. To make better use of the gold resource in Guigang for more extra value, the thesis presented the experimental study of cyanide leaching of the refractory ore focusing on the methods of the pretreatment of the gold concentrate.Generally the refractory gold ores of high arsenic can not be effectively leached because micro-granular gold is inserted in the cracks of arsenopyrite and pyrite, or precipitated on the interplanars of sulfides, in addition, some gold may have formed in unsolvable form in sulfides. Therefore, the pretreatment prior to gold leaching must be conducted, so that pyrite and arsenopyrite bundling gold are destroyed and gold is exposed to be leached easily. Based on the characteristics of the refractory gold concentrate of interest, our research looked into several process methods for the pretreatment and cyanide leaching of the concentrate. They are: 1) Traditional leaching process, in which the effects of NaCN dose, leaching time and solid concentration were discussed. 2) Microwave heating pretreatment /cyanide leaching, in which the effects of microwave heating on mineral microstructure, and those ofmicrowave power, heating time and adding alkaline material during microwave heating on leaching efficiency were studied. 3) Alkaline leaching pretreatment/ cyanide leaching, which detailed the effects of different conditions on the efficiency of alkaline leaching of arsenic and that of cyanide leaching of gold. Conjunction process of fine grinding with alkaline leaching was also investigated as the pretreatment of the cyanide leaching of the gold concentrate.A lot of conclusions were achieved from our experimental research as follows. Guigang gold concentrate is exactly a kind of typical refractory ore to which the traditional cyanide leaching was of very low efficiency, the highest gold leaching recovery being 12.4% and in most cases even no gold leaching taking place. Microwave pretreatment showed improvement of cyanide leaching, which was related to microwave power, heating time and addition of alkaline matters during microwave heating. The process of alkaline leaching pretreatment/cyanide leaching was verified to be the most effective process for gold extraction of Guigang gold concentrate. Meanwhile, the gold leaching recovery was directly related to arsenic removal level, and better result can be achieved by using some oxidizing agent during cyanide leaching after alkaline leaching pretreatment. Combination of fine grinding and alkaline leaching of arsenic could raise the gold leaching recovery to some extent, but the improvement was not very obvious. All these research results will provide a very meaningful instruction for the plant development of Guigang gold concentrate with cyanide leaching.
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