Calcium Aluminate Premelted Slag And Its Application On Converter Wash Heat

Sulphur has large hurmfulness on the steel products.Not only it generate hot brittleness,also it can cause much negative impact on hot-working character, mechanical property,welding performance,resistant character, processability and cold- heading.So desulfurization is one of the study subject by metallurgists at all times.On 100t BOF-130t LF of Handan NO.3 steel works,with LF refining technology alone,for heavy desulfurization mission and long refining cyclic,the phenomenon of increasing silicium and carbon is much serious on refining low carbon steel specially the cold-rolling low carbon steel.The results impact the products'final performance and percent of pass.So applicating wash heat with premelting slag of high desulfurization efficiency and dynamics condition,part of desulfurization mission is completed on tapping process,the sulphur content of molten steel is decreased before entering LF,and the desulfurization mission is relieved on LF.Refining slag,which made of premelting slag must have great desulfurization capability on LF after wash heat.Calcium aluminate premelted slag is prepared for the desulfurization experiment. The result show that this slag's desulfurization effect is better without CaF2. And its best component preparation as:CaO55%,Al2O340%,SiO23%,MgO2%. It has good desulfurization effect,and the desulfurization efficiency reaches 85%.The desulfurization commercial test is proceeded on 100tBOF-130tLF of Handan NO.3 steel works.The premelted slag is bifurcated asâ… andâ…¡.The desulfurization infuence factor of wash heat is analysed combined the delivry data,and the conclusion is obtained as:(1) The carbon content affects the oxygen content in the molten steel of inconverter terminal. The larger the carbon content is, the more advantageous the desulfurization is.(2) Under the identical desulfurization condition,the larger the sulphur content is,the higher the desulfurization efficiency of wash heat is,and the fewer the sulphur content is,the more difficult the desulfurization is.(3) The slag's optical alkalinity and sulphur capability is influenced badly by the CaO content. Compared slagâ… andâ…¡,with the CaO content is increased by 2% ,the average desulfuri- zation efficiency rises from 6.17% to 16.79%.(4) Large quantity of slag is advantageous on increasing desulfurization efficiency of wash heat.(5) Desulfurization of wash heat is influenced by the skimming quality on converter tapping.(6) Desulfurization effect on LF is increased with the high optical alkalinity of exit-station, large sulphur cotent of enter-station and large quantity of refining slag.