Sulphide Capacity of CaO-Al_2O_3-MgO Slag

近年来，人们开发了多种生产高纯度钢的二次炼钢工艺，其中CaO-Al_2O_3体系已被用作工业助熔剂。因此，CaO-Al_2O_3、CaO-Al_2O_3-MgO（从耐火材料中溶解MgO）和CaO-Al_2O_3-SiO_2渣（通过炼钢带来SiO_2）的硫化物容量不同。研究了炼钢二次渣与液渣中硫的分布比。用Ar-CO-CO_2-SO_2混合气体在1823 ~ 1923 K进行平衡。达到平衡后，试样被淬火和粉碎，通过化学分析来测定成分和硫的含量。本文计算的CaO-Al_20_3渣的硫化物容量与前人的研究结果吻合较好。结果表明，在给定的N_<Al_2O_2>条件下，CaO被MgO或SiO_2取代会降低硫化物容量。当钢中溶铝含量为0.01%时，在饱和氧化钙条件下，1873 K时两种炉渣的硫分布比的评价值均大于1000。

Many kinds of secondary steelmaking process have been developed recently to product highly purified steel, where CaO-Al_2O_3 system has been utilized as industrial flux. Therefore, the sulphide capacities of CaO-Al_2O_3, CaO-Al_2O_3-MgO, where MgO is dissolved from refractories, and CaO-Al_2O_3-SiO_2 slags, where SiO_2 is brought via steelmaking. process, were studied to estimate the sulphur distribution ratio between secondary steelmaking slag and liquid slag.The slag samples were equilibrated with Ar-CO-CO_2-SO_2 gas mixtures at 1823 to 1923 K. After reaching equilibrium, the samples were quenched and crushed to determine the contents of constituents and sulphur by chemical analysis.The present result of sulphide capacity in CaO-Al_20_3 slag agreed well with the previous works. From the obtained results, it was confirmed that substitution of CaO to MgO or SiO_2 at a given N_<Al_2O_2> decreased the sulphide capacities. The evaluated values of sulphur distribution ratio for both slags was higher than 1000 at 1873 K on the condition of CaO-saturation if the dissolved aluminium content in steel was assumed to be 0.01%.