(1. 龙岩学院 化学与材料学院，龙岩 364012；
2. 福州大学 紫金矿业学院，福州 350108；
3. 中南大学 冶金与环境学院，长沙 410083)
摘 要: 某矿山选铜尾矿经浮选获得的高品位明矾石精矿富含Al、K和Ga等有价金属。为了实现明矾石中有价金属的综合回收，首先采用“焙烧-梯级浸出”工艺选择性浸出Al、K和Ga，再通过冷却结晶与蒸发结晶工艺梯级回收明矾与硫酸铝，最后采用中和法实现Ga富集。结果表明：明矾石精矿经焙烧一段酸浸后，Al、K的浸出率分别为80.31%和87.49%，Ga几乎不浸出；浸出渣经二段酸浸后，Al、Ga和K的浸出率分别为65.67%、86.17%和94.54%。一段酸浸液经冷却结晶后可获得食品级钾明矾纯度达99.65%，结晶后液经蒸发结晶可获得Al2O3含量为15.95%的一级硫酸铝产品；利用NaOH控制二段酸浸液的pH为2.5~2.6时，浸出液中Ga沉淀率达98%以上，沉淀物中Ga含量达4100 g/t。XRD分析结果表明，沉淀物经焙烧后，Ga主要以KGa(SO4)2的形式存在。
关键字: 明矾石；焙烧-酸浸；硫酸铝；Ga
（1. School of Chemistry and Materials, Longyan University, Longyan 364012, China;
2. College of Zijin Mining, Fuzhou University, Fuzhou 350108, China;
3. School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:An alunite concentrate is obtained by flotation of copper mine tailings, which is rich in Al, K and Ga and other valuable metals. In order to utilize alunite concentrate comprehensively, firstly a “calcination-cascade leaching” process was proposed to selective leaching of Al, K and Ga. Then, the combination of cooling crystallization and evaporative crystallization processes were adopted to extract alum and aluminum sulfate. Finally, the gallium was enriched by neutralization method. After roasting and one-stage acid leaching, the leaching rates of Al and K after calcining alum stone concentrate are 80.31% and 87.49%, respectively, and gallium can hardly been leached out. At the second-stage acid leaching process, the leaching rates of Al, Ga and K are 65.67%, 86.17% and 94.54%, respectively. After cooling crystallization and evaporative crystallization, a food-grade alum with purity of 99.65% and a firsts aluminum sulfate with Al2O3 content of 15.95% are sequently obtained from one-stage livixium. Ga concentrate with content of 1500 g/t is obtained by controlling the pH value of 2.5-2.6 at second-stage lixivium with NaOH, and the precipitation rate of Ga is 98%. XRD analysis results show that the occurrence state of Ga in the sediment after calcination is KGa(SO4)2.
Key words: alunite; roasting-leaching; aluminum sulfate; gallium
