Leili Tafaghodi

This study investigates the efficiency of B and P removal from ferrosilicon alloy via slag refining. Silicon was alloyed with iron and the alloy was subjected to different compositions of CaO-SiO₂-Al₂O₃ ternary slag at 1600 °C. Distributions of B and P between alloy and slag phases were investigated by ICP-OES analysis. Results indicate that oxygen potential and basicity of slag can enhance removal of these impurities from the alloy. However, the partition ratio values decrease when the oxygen potential surpasses a critical value (Pₒ₂, critical). Pₒ₂, critical for B and P was calculated as 9.01 × 10-¹⁸ and 6.29 × 10-¹⁸, respectively. In addition, the highest partition ratios of B and P achieved in this study were 11.25 and 0.11, respectively. The effect of basicity on partition ratio values was also isolated through two parameters called borate (phosphate) capacity and normalized distribution of B (P). Results show that these parameters directly relate to optical basicity of slag.

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