| Most of gold mines in China have lower grade at present. And there is much tailings discharged in the process of beneficiation. Compared with developed countries, the recovery of gold mine in China is very low. There are 30 tons gold metals still remained in more than 20 million tons gold tailings. The degree of comprehensive utilization and treatment of tailings has become a standard that can measure a country's scientific and technological level and economic development degree in industrialized countries.Because of complex components in tailings and different production areas, valuable components and content are in great differences. Presently, the comprehensive utilization degree of tailings is only 7% in our country. The comprehensive utilization of tailings mainly includes recovering valuable components from tailings, being used as building materials, producting fertilizer and filling gob area in mine.The study has researched the comprehensive utilization of resource which is from cyanide-leaching tailings in Wulonggou gold mine, Qinghai. That is recovering gold metal from cyanide-leaching tailings. The natural environment of mineral beneficiation in the area is different from that in other places, as low temperature, not enough oxygen and higher salinity in water of which the alkalinity is similar to that of sea water. So the concentrate indexes are restricted by these poor conditions. Thus, the intent of this study is to make best use of secondary resource applying new beneficiation techniques, new flotation reagents and new processing technologies, making selectabilized assessment for the mentioned tailings resource in unconventional environment.Through the study on processing mineralogy of minerals, it is known that the gold mineral mainly exists in the packed form of sulfide mineral at a content of 91.32%. The natural gold has very fine grain size (the main grain size is less than 0.005mm), very difficult to be recovered. The main gold-carrier minerals are pyrite and arsenopyrite.The gold tailings used in the test were undergone the cyanide-leaching process, and its disseminated size is extremely fine. So the nice beneficiation index is hardly received by gravity separation. A series conditional experiments are carried out basing on the characteristics of local environment and the properties of minerals, to determine the best reagent system. Finally the flotation method is determined to be the best to concentrate gold mineral.The results of experiments demonstrate that in the unconventional mineral processing environment, water quality, low temperature and insufficient oxygen content restrict improved flotation indexes. And through the experiment it is known that the NaCl has no significant effect on the other flotation reagents, but has potential impact on lead nitrate. In order to avoid the bad impact, copper sulfate is used as the activator instead of lead nitrate, and the flotation performance is better. The weak alkalinity of water has an effect on the process of flotation in a certain place, and sulphuric acid is used as pH regulator. The low temperature is the factor which limits the improved index of the beneficiation. On condition that ore characteristics, flotation temperature and flotation equipment are constant, a good result has received by changing regime of agents and strengthening absorption action. On condition that the oxygen is insufficient, under theoretically analysis which a certain extent affects the action of the agents, but it is good for selective action of xanthate. In all, it can get a better flotation index.A better result in the study is obtained. Finally a gold concentrate which contains 19.56g/t Au at a recovery of 90.78%, is producted. |
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