(1. 龍巖學院 化學與材料學院，龍巖 364012；
2. 福州大學 紫金礦業(yè)學院，福州 350108；
3. 中南大學 冶金與環(huán)境學院，長沙 410083)
摘 要: 某礦山選銅尾礦經浮選獲得的高品位明礬石精礦富含Al、K和Ga等有價金屬。為了實現(xiàn)明礬石中有價金屬的綜合回收，首先采用“焙燒-梯級浸出”工藝選擇性浸出Al、K和Ga，再通過冷卻結晶與蒸發(fā)結晶工藝梯級回收明礬與硫酸鋁，最后采用中和法實現(xiàn)Ga富集。結果表明：明礬石精礦經焙燒一段酸浸后，Al、K的浸出率分別為80.31%和87.49%，Ga幾乎不浸出；浸出渣經二段酸浸后，Al、Ga和K的浸出率分別為65.67%、86.17%和94.54%。一段酸浸液經冷卻結晶后可獲得食品級鉀明礬純度達99.65%，結晶后液經蒸發(fā)結晶可獲得Al2O3含量為15.95%的一級硫酸鋁產品；利用NaOH控制二段酸浸液的pH為2.5~2.6時，浸出液中Ga沉淀率達98%以上，沉淀物中Ga含量達4100 g/t。XRD分析結果表明，沉淀物經焙燒后，Ga主要以KGa(SO4)2的形式存在。
關鍵字: 明礬石；焙燒-酸浸；硫酸鋁；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
