在1550℃下将Ca O-Si O2-Al2O3三元渣与Sn-Si合金混合精炼,降温熔析去除工业硅中的杂质B,考察了渣系光学碱度及合金组成对B去除的影响及作用机理.结果表明,渣系光学碱度增大,BO1.5的活度系数降低明显,增加了B的分配系数,即增强了精炼效果.Sn-Si合金中Sn比例从0增至70%时,B在渣相与合金相间的分配系数从3.16提高至13.8,硅中B含量最低为0.89-10-6,最高除硼率为93.3%;当Sn比例大于30%时,合金粘度大幅降低,B的分配系数提高;当Sn比例为70%、合金粘度为0.61 m Pa-s时,渣系Ca O-Si O2-20%Al2O3与Ca O-Si O2-40%Al2O3精炼工业硅所得最大B分配系数分别为10.1和12.3. The CaO-Si O2-Al2O3 ternary slag and Sn-Si alloy were mixed and refined at 1550 ℃, and the impurity B in industrial silicon was removed by cooling down. The effects of slag basicity and alloy composition on the removal of B were investigated. The results show that the optical basicity of slag increases and the activity coefficient of BO1.5 decreases obviously, increasing the partition coefficient of B, which enhances the refining effect.The proportion of Sn in Sn-Si alloy increases from 0 to 70% , The distribution coefficient of B between the slag phase and the alloy phase increased from 3.16 to 13.8, the content of B in silicon was the lowest 0.89-10-6, and the maximum boron removal rate was 93.3%. When the Sn content was more than 30%, the viscosity of the alloy was greatly reduced , And the distribution coefficient of B increased. When the proportion of Sn was 70% and the viscosity of the alloy was 0.61 m Pa-s, the maximum value of industrial grade silicon from slag CaO-Si O2-20% Al2O3 and CaO-Si O2-40% Al2O3 The B distribution coefficients are 10.1 and 12.3, respectively.