低碳铝镇静钢 LF 炉精炼渣优化研究

摘要

CaO-Al2 O3 refining slag system is used by the low carbon aluminum-killed steel LF furnace in our com-pany .By means of chemical composition analysis and X-ray diffraction analysis , it is found out that the calcium alumi-nate is mainly in the form of existing in the original slag system .This composition has the low absorption capacity for inclusions , which is the main cause of the high oxide inclusions content in the steel ingot .In order to make the calcium aluminate in the 3CaO· Al2 O3 slag system exist in the form of low melting point phase 12CaO· 7Al2 O3 , the amount of adding fluorite has been reduced , and the Al2 O3 content has been increase to optimize the slag system , the Mol ratio of CaO/Al2 O3 has been about 1.7.The application of the optimized slag system in the field shows that calcium aluminate in the slag mostly exist in the form of 12CaO· 7Al2 O3 , and the oxide inclusions content in the ingot has been greatly reduced .In the meantime , due to the decrease in adding fluorite , furnace lining erosion has been mitigated , and has avoided occurrence of the magnesia alumina spinel inclusions .%我公司冶炼低碳铝镇静钢LF炉采用CaO-Al2 O3渣系。通过化学成分及X射线衍射分析发现原用渣系中铝酸钙主要以3CaO· Al2 O3形式存在。该组成对夹杂物吸收能力弱，是造成钢锭中氧化物夹杂含量高的重要原因。为使CaO-Al2 O3渣系中铝酸钙以低熔点相12CaO·7Al2 O3形式存在，通过降低萤石加入量，提高Al2 O3量优化渣系，使CaO/Al2 O3的摩尔比为1．7左右。优化渣系的现场应用结果表明，渣中铝酸钙大多以12CaO·7Al2 O3形式存在，钢锭中氧化物夹杂明显减少。同时由于减少了萤石的加入，炉衬冲刷减轻，避免了钢锭中镁铝尖晶石夹杂物的出现。