钢包铸余渣作为转炉脱磷助熔剂理论及实践

针对铝酸钙系精炼钢包铸余渣代替萤石作为转炉助熔剂对脱磷效率的影响，首先利用Factsage热力学软件对比计算分析了Al2O3、CaF2作为转炉炉渣助熔剂，对脱磷产物活度及磷容量的影响规律，并在实验室硅钼炉上对脱磷效率影响规律进行了对比研究。在此基础上，研究了精炼钢包铸余渣代替萤石的替代比例及应用效果。结果表明，分别以Al2O3、CaF2作为转炉脱磷助熔剂时，二者对炉渣碱度的控制要求相当；CaF2的助熔能力明显强于Al2O3，而Al2O3能降低脱磷产物的活度，增加炉渣磷容量，相比CaF2对脱磷反应具有热力学优势；w((Al2O3))为5.0%～9.0%的炉渣达到的脱磷效率，与w((CaF2))为3.0%～6.0%时相当；用武钢铝酸钙系钢包精炼铸余渣代替萤石作为转炉炼钢脱磷助熔剂，其与萤石的替换比例为2.5∶1，冶炼过程炉渣熔化良好，转炉终点钢水脱磷率提高3.0%左右。

Fundamental and application of converter fluxing agent based on ladle casting residue for dephosphorization

The effect of calcium aluminate refining ladle casting residue instead of fluorite used as converter fluxing agent on dephosphorization efficiency was investigated in the current study. Firstly,the effect of Al2O3 and CaF2 used as converter fluxing agent on the activity of dephosphorization products and phosphorus capacity were studied through Fact-sage software,respectively. Then,for futher studies on the substitute proportion and the application effect of refining la-dle casting residue instead of fluorite used as converter fluxing agent,hot experiments were performed by the MoSi2 fur-nace under laboratory conditions. Finally,industrial tests were conducted in Wuhan Steel. The results show that using Al2O3 or CaF2 used as converter fluxing agent,to achieve high dephosphorization rate,the requirement for final slag ba-sicity of both two fluxes was almost the same. Although the fluxing ability of CaF2 was obviously better than that of Al2O3,Al2O3 had a thermodynamic advantage on dephosphrization reaction compared with CaF2. Because Al2O3 in flux could decrease the activity of dephosphorization products and increase the phosphorus capacity of slag. As w((Al2O3)) was from 5.0% to 9.0%,the dephosphorization rate was equal to that of the flux when w((CaF2)) was from 3.0% to 6.0%. When the Wuhan Steel ladle refining casting residue was used as converter fluxing agent,the proportion of substi-tuting casting residue for fluorite was 2.5∶1. Meanwhile the industrial tests show that,by comparison to the slag using fluorite as fluxing agent,the dephosphorization rate of molten steel in converter endpoint was improved by 3.0%.