Native Gold In Dilute Nitric Acid Cyclic Oxidation Friction Desulfurization Technology

The extraction of gold has been gradually turned into treating refractory gold bearing-materials with the running decrease in easy processing ores. To recover the gold from refractory materials is a worldwide difficult problem, especially in China, for which can be effectively recovered only after the complex pretreatment which depends on the mineralogical and liberation characteristics of gold. So it is significant to develop new extracting gold mine crafts.The paper puts forward the new craft of the nitric acid pre-oxidizing —friction desulfuration—cyanide leaching through analyzing research of extracting gold mine craft and material photograph of laowangzhai of zhenyuan in Yunnan in the present condition proceeds, and again and again groping and experiment in a year .The accomplished concrete work of whole experiment is following.1 putting forward the research problem by understanding and analyzing the present condition of the crafts of difficult processing ores in abroad and at home.2, The thesis summarized the present condition of craft of extracting of laowangzhai, and analyzed the current existed problem. The traditional baking method produced ]arge quantity's smoke, whose pressure of accepting dust is big. The craft still increased craft of fine grinding and alkali washing, which is complicacy. The fixed sulphur baking produce the water-soluble sulfuric acid calcium, which make against the cyaniding lixiviation. Although bio-oxidization method has advantages of high rate of lixiviation and amity environment, it exists disadvantage of Long time of oxidization, the high early investment and not easily controlling operation. All is not ideal craft of extracting gold of laowangzhai.3 it shows practicable to apply to the friction desulfuration to raise the gold leaching rate through exploring experiment research , comparing and analyzing the experiment data of the crafts of the nitric acid pre-oxidizing—cyanide leaching and the nitric acid pre-oxidizing—friction desulfuration —cyanide leaching .exploring theoretical feasibility and mechanism of the friction desulfuration , comparing the contribute to raising the gold leaching rate between friction desulfuration and grinding function .discussing the affecting elements of the craft and comparing the gold leaching rate between the craft of friction desulfuration and reagent desulfuration after friction desulfuration.4 The craft shorten the schedule because pre-oxidizing and desulfuration occurs in the same reactor at the same time in the craft of nitric acid pre-oxidizing—friction desulfuration—cyanide leaching . The craft achieve the aim of eliminating resultant sulfur pacing the mineral and gold , and raise the oxidizing degree and the leaching rate which , when the rate of original material is 9. 4%, the top rate is 87. 4%. On the other hand it also enhance the reaction velocity , shorten reaction time .realize the cycle use of nitric acid to save the nitric acid.5, According to the theory of the gold resolving speed and the factual conditions of the mineral, the paper chooses the craft parameter of cyanide leaching and discuss the mechanism of cyanide leaching.