Abstract

This article discusses the issues of sulfur removal in a ladle–furnace unit. The coefficient of sulfur distribution depends on sulfide capacity of slag, the coefficient of sulfur activity, as well as oxidation potential of medium and equilibrium constant. The sulfide capacity of slags C_S is one of the most important properties of refining power of slags used upon extra furnace steel processing. One of the factors influencing on sulfide capacity is temperature. The equation is proposed to determine the sulfide capacity as a function of optical basicity and temperature in the range of 1400–1650°C. At optical basicity Λ not higher than 0.75, the error of the equation does not exceed 6%. The equation for estimation of optical basicity is proposed, which accounts for the influence of basic, acidic oxides and amphoteric oxide Al₂O₃. It is demonstrated that the slags comprised totally of homogeneous phase are characterized by higher optical basicity of aluminum oxide. The heterogeneous slags are characterized by lower optical basicity of Al₂O₃ in comparison with homogeneous slags. Most likely, this can be attributed to the fact that the homogenous slags are characterized by deficit of basic oxide CaO and, under the considered conditions, the compound Al₂O₃ starts to exert more basic properties than acidic ones. Therefore, in homogeneous slags, the optical basicity of aluminum oxide is higher and approaches the optical basicity of the oxide CaO. The estimations performed on real heats demonstrate that its optical basicity decreases upon increase in Al₂O₃ content in slag. A known value of optical basicity allows to determine sulfide capacity of slag, distribution coefficient of sulfur between metal and slag, and, respectively, final content of sulfur in metal. Theoretical estimations carried out for actual heats demonstrate that the sulfide capacity can be reasonably determined by ionic theory of slags.

中文翻译：

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离子理论估算炉渣中的硫化物容量

摘要

本文讨论了钢包炉装置中硫的去除问题。硫的分布系数取决于炉渣的硫化物容量，硫的活度系数，介质的氧化电位和平衡常数。渣的硫化能力C _S是在额外的炉钢加工中使用的炉渣精炼能力的最重要特性之一。影响硫化物容量的因素之一是温度。建议使用该方程式确定硫化物容量与光学碱度和温度（在1400–1650°C范围内）的函数。在光学碱度Λ不大于0.75时，方程式的误差不超过6％。提出了用于估计光学碱度的方程，该方程考虑了碱性，酸性氧化物和两性氧化物Al ₂ O _3的影响。结果表明，完全由均相组成的炉渣具有较高的氧化铝光学碱度。非均质炉渣的特征在于Al ₂ O的光学碱度较低₃与均质炉渣相比。这最有可能归因于这样的事实，即均质炉渣的特征在于碱性氧化物CaO的缺乏，并且在考虑的条件下，化合物Al ₂ O ₃开始发挥比酸性作用更大的碱性。因此，在均质的炉渣中，氧化铝的光学碱度更高并且接近氧化物CaO的光学碱度。对真实热量的估计表明，其光学碱度随Al ₂ O _3的增加而降低炉渣中的含量。已知的光学碱度值可以确定炉渣的硫化能力，硫在金属和炉渣之间的分配系数以及金属中硫的最终含量。对实际热量进行的理论估算表明，可以根据炉渣的离子理论合理确定硫化物的容量。