| Fujian Zijinshan Copper Mine is a large copper ore with low copper grade, proven copper ore reserves are about 428 million tons, among which about 125 million tons could be disposed by flotation process. At present, processing capacity of Zijinshan Copper flotation mill was 18000t/d, after flotation of copper and sulphur the amount of ore tailings was about 17000t/d, existing mainly in quartz, alunite and dickite, but also contains a certain quantity of gallium. After the technical research in recent years, Zijin Mining Group has successfully achieved the effective recovery of alunite from the copper flotation tailings, and gained the alunite concentrate in which the grade of alunite and gallium were 69.79% and 55.9g/t respectively, but the alunite concentrate has not been to good use. Therefore, developing a efficiency economic new technology of alunite and gallium comprehensive utilization, not only solve the key scientific and technical problems in high efficiency clean comprehensive utilization of Zijinshan mine tailings, but also has a very important significance in the development of tailings comprehensive utilization technology of our country.Basing on the physico-chemical properties of the alunite concentrate from Zijinshan Copper Flotation Tailings, this paper carry out researches on comprehensive recovery and utilization of potassium and aluminum,and gallium efficient enrichment experiment, the technical route is as follows:alunite concentrate dehydration roasting-clinker acid leaching-first-step neutralization enriching of Ga-gallium rich slag high acid leaching-second-step neutralization enrichment of Ga-alum crystallized.The results show that:dehydration roasting step’s optimum conditions are: temperature 600 ℃, time 2h, clinker high acid leaching:temperature 80 ℃, time 2h, ratio of liquid to solid 6:1, initial acid concentration 115g/L, first-step neutralization enriching:time 2h, temperature 80℃, pH3.35, gallium rich slag high acid leaching: temperature 80 ℃, time 1h, ratio of liquid to solid 5:1, initial acid concentration 120g/L,second-step neutralization enrichment as the same, alum crystalline:K/Al= 1, temperature 30 ℃, time 24h. after two-step enriching gallium content of the slag is 1153.4g/t, gallium enrichment ratio is 18.14, the total recovery rate is 74.16%, potassium and aluminum recovery rate are 97% and 90%; the alum crystallization rate is 79.23%, purity of product alum is 99.69%, and other indexes reached the quality standard of high-class industrial grade alum requirements.The results of the study can be directly applied to the comprehensive utilization of Zijinshan tailings resources, the key technology can be used as technical reference for comprehensive utilization of a large number of domestic similar mine tailing resources, has broad application prospects and popularization value. |
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