Fundamental Research On Silicon-manganese Alloy With High Sulphur

China is rich in manganese ore resources,but the most is low-grade ores with theaverage grade less than30wt.%, and it generally depended on import for the high gradeManganese ores, e.g.,the manganese oreswith high phosphorus and sulfurin Chenkouand Xiushan, it is rich but low grade, which resulted the out of standard sulfur contentin silicomanganese alloys.It dropped down the value of produces and hindered thedevelopment of the local related enterprises.Silicomanganese alloy is generally used as the deoxidizer or alloying addition inthe secondary refining of steelmaking with its low costandeffectivelydeoxidization.However,the steel may bepolluted by the silicomanganese alloys with thehigh sulfur contentwhich would stay insteel material to decline in quality. Therefore, thesulfur content in the silicomanganesealloys must be controlled as low as possible. Inother hands, the further improvement of the silicomanganese alloy desulfurizationtheories is necessary for high sulfur content silicomanganese alloy achieving nationalstandard. It hastheoretical and practical significances.This work focued on the desulfurization of high sulfur contentsilicomanganesealloys.Combined the coexistence theory, it studyed the influences of all components ofthe slag on desulfurization capability, and the conclusions areas follows:①Based onthe Coexistence Theory, we establish the thermodynamic model ofsulfur distribution ratio between quaternary slags (CaO-MgO-BaO-SiO2) and alloyliquid.②BaO hadmuch greater effect on the desulfurization capabilityinthequaternaryslags. So the appropriate BaO content can increase the effect ofdesulfurization capacity, however, when it was excessive the desulfurizationcapacitywould be decline.The slags desulfurization capability was increased first andthen dropped down as the ratio of BaO and CaO wasincreasing.The bestdesulfurizationcapability ratio of BaO and CaO is0.8.③MgO raises the melting point of the slag system, it made the slag melting timelonger and the liquidity more badly. In order to improve the liquidity, the right amountof CaF2was aslo addedwith MgO.The desulfurization capability improved with therising of MgO content, but the MgOconcent only within limits is good fordesulfurization. ④Experiments show that the calculation results of quaternary slags desulfurizationthermodynamic modelare consistent with the desulfurization experiment.