氧压浸出提纯冶金级硅过程中添加剂对除杂效果的影响(英文)

Effect of Additives on Purification of Metallurgical Grade Silicon by Oxygen Pressure Leaching

研究了氧压浸出提纯冶金级硅过程中添加剂(硫酸铵)及原料粒度对去除金属杂质Fe、Al、Ca、Ti的影响.研究结果表明,添加剂硫酸铵的加入能够有效提高冶金硅中主要金属杂质的去除率,低压(无氧)条件下浸出,金属杂质Fe、Al、Ca、Ti的去除率比常压浸出分别高出4.6%、17.3%、16.6%及0.5%;氧压浸出又比低压(无氧)浸出的去除率分别高出22.2%、34.9%、19.5%及0.6%,且随着氧分压的升高,除Ti外Fe、Al、Ca的去除率明显提高;氧压条件下加入添加剂硫酸铵后,金属杂质Fe、Al、Ca、Ti的去除效果更为显著,分别达到85.1%、80.6%、95.4%和16.3%.硅粉粒径<75μm后对金属杂质的去除率的影响不明显.此外,对比浸出前后的SEM-EDS结果发现,常压浸出时硅中的Si-Fe-Ti杂质相难以去除,在氧压浸出并加入添加剂时,可部分去除.

The effect of additives viz. ammonium sulfate and particle size on the purification of metallurgical grade silicon （ MG - Si） by pressure leaching is investigated. It is found that the addition of ammonium sulfate can promote the removal efficiency of major impurities obviously; low pressure leaching is a little more effective than atmospheric leaching. The removal efficiency of Fe, AI, Ca and Ti are increased by 4. 6%, 17. 3% , 16.6% and 0. 5% respectively. Compared with low pressure leaching, the oxygen pressure leaching can increase the removal efficiency by 22. 2% , 34.9% , 19.5% and 0. 6% respectively. Moreover, with the increase of oxy- gen pressure, the extraction of Fe, A1 and Ca are improved except for Ti. In the presence ammonium sulfate, the removal efficiency increases obviously which reaches to 85.1% , 80. 6% , 95.4% and 16.3% respectively. The particle size has no effect on the extraction of Fe, A1, Ca and Ti when it is less than 75 μm. Furthermore, it is found by comparing the SEM - EDS results before and after acid leaching that the Si - Fe - Ti phase in MG - Si cannot be removed by hydrochloric acid under atmospheric pressure. With the addition of additive, Si - Fe - Ti phase may be removed to a certain extent under oxygen leaching.