湿法提纯作为冶金法制备太阳能级硅的前处理工序,可以去除大部分金属和硼杂质.研究了以氢氟酸-硫酸混合酸为浸出剂,有机溶剂甲醇作为后处理剂,去除硅粉中硼杂质的方法.采用电感耦合等离子体发射光谱仪(ICP)等对产品进行表征.酸浸过程优化工艺条件:硫酸质量分数为55%,氢氟酸质量分数为7%,酸浸温度为70℃、酸浸时间为4 h、液固质量比为8:1.酸浸后可使硅粉中的硼杂质质量分数Eh 6.893×10-6降至3.867×10-6,去除率为41.9%.在酸浸基础上采用有机溶剂甲醇作为后处理剂,杂质硼质量分数降至3.84×10-6,去除率为44.29%.从硼酸浸后形成的产物入手探索提高硼去除率的方法,实验验证了该方法的可行性,为研究湿法冶金预处理太阳能级硅提供了新的参考.%As a pre-treatment unit for preparing solar-grade silicon (SG -Si) by metallurgic method, wet purification could remove most metallic impurities and non-metallic impurities, such as boron. Experiment researched a new method to remove boron from SG -Si with mixed hydrofluoric acid -sulfuric acid as leaching agent and with organic solvent methanol as post-treatment agent. Samples were characterized by ICP and other analysis methods. When SG - Si powder had been leached at optimized conditions as follows:mass fraction of sulfuric acid was 55％, mass fraction of hydrofluoric acid was 7％ ,reaction temperature was 70 ℃ ,reaction time was 4 h,and liquid - solid mass ratio 8:1 ,it was found that mass fraction of impurity boron in SG - Si was reduced to 3. 867 x 10 -6 from 6. 893 x 10 -6 and the removal rate was 41.9％ after acid leaching;on the basis of the former procedure,mass fraction of impurity boron was reduced to 3.84 x 10-6 and the removal rate was 44.29％ when treated with organic solvent. Experiment proved the feasibility of the method and provided a new reference for researching on the pre-treatment of SG - Si by hydrometallurgy.
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