【作者】 赵和明；

【导师】 谢兵；

【作者基本信息】 重庆大学 ， 钢铁冶金， 2003， 硕士

【摘要】 铝钙渣系是近年发展起来的新型合成精炼渣，主要用于LF炉钢水脱硫、去除夹杂物，以达到净化钢液的目的。预熔型精炼渣是目前国内外冶金工作者研究的重要对象之一，而根据不同的钢种选择合适的精炼渣剂及配方就成了目前研究精炼渣的突出问题。本研究的目的在于探索7Al₂O₃·12CaO型合成渣系的熔化特性、吸收夹杂能力、脱硫能力等物化性能，为实际应用及生产预熔型CaO-Al₂O₃渣提供理论依据。 本文对预熔型铝钙渣的发展历史和研究现状作了简要的概述，分析了预熔型铝钙渣在还原条件下精炼脱硫和去除Al₂O₃夹杂的原理、热力学及动力学条件。运用二次正交回归方法设计出以CaO-Al₂O₃为基体，MgO、CaF₂、SrO为辅料的预熔铝钙型精炼渣，其中各组分的范围为：Al₂O₃/CaO=0.8～1.2，CaF₂=3％～9％，MgO=4％～10％，SrO=0～10％。 本课题首次研究了SrO在精炼渣中的作用；开发研制出Al₂O₃圆柱体在渣中旋转动力学实验研究的控制设备，并测定了Al₂O₃在1#和8#渣中的溶解速度方程和溶解速度常数；应用炉渣的共存理论首次建立了CaO-Al₂O₃-MgO-SrO-CaF₂-SiO₂六元渣系作用浓度模型，将17组渣代入模型进行计算的结果与实验数据存在一致性，该模型可用于预测渣的脱硫性能；通过测定渣高温物理性能和进行脱硫实验，对比分析了预熔渣与混合渣的熔化温度差异性，回归出组分与粘度、熔化温度和硫分配比之间的数学模型，讨论了组分对精炼渣高温性能和硫分配比的影响；采用光学碱度理论计算每组渣样的硫容量，经实验验证，计算结果可用于比较渣的脱硫性能优劣；利用正交直观分析法研究和优化组分含量，得到诸因素影响熔化温度、粘度和表面张力的主次关系；利用矿相显微镜观察了预熔渣的熔化均匀性。 研究中得出的精炼渣中组分重量百分比与硫分配比、熔化温度和粘度之间的数学模型具有很高的置信度，实验数据与所采用的二次回归模型是比较符合的。对脱硫性能而言：Al₂O₃/CaO值越大，则渣的硫容量越低，硫分配比越小；SrO与MgO可使渣的硫分配比提高，但提高幅度有限；对熔化温度和粘度而言：MgO含量为5％时，精炼渣的粘度存在一个最低值，MgO对渣的熔化温度影响不大；Al₂O₃/CaO对渣高温性能的影响呈抛物线形状；CaF₂能增加渣的粘度，但对降低渣的熔点作用不大；熔点与SrO含量近似成线性关系，SrO含量为6％时粘度出现波谷值。综合考虑各种因素，得出本研究条件下各组分的最佳含量为：7％MgO、5％SrO、6％CaF₂、Al₂O₃/CaO=0.8。 动力学研究得出，在渣组分含量的范围内，当Al₂O₃/CaO=0.7～0.9时，精炼渣吸收Al₂O₃夹杂的能力很强，渣中初始Al₂O₃含量影响不大；重庆大学硕士学位论文当A12o3/cao二0.9一1.2时，降低熔渣粘度和减少渣中初始A1203含量，以及减少熔渣与A1203夹杂之间的界面张力均有利于改善熔渣吸收A1203夹杂的能力。更多还原

【Abstract】 In recent years, 7Al2O3·12CaO refining slag is being used to purify molten steel, desulfurize and remove inclusions in the processing of LF. Pre-molten refining slag is one of main research objects concerned by metallurgist currently, and the focused problem is how to choose proper refining slag in accordance to different steel grade. In order to understand the CaO-Al2O3 refining slag deeply, and establish theory base for application and production of the refining slag , the physicochemical properties such as melting temperature, viscosity and desulfurization capacity of the slag were studied in this paper.Literatures about the history and research situation of pre-molten CaO- Al2O3 slag have been reviewed, the thermodynamics and kinetics of desulfurization and removal Al2O3 inclusion in the condition of reducing atmosphere have been discussed. The CaO- Al2Os base slags containing MgO, CaF2, SrO as auxiliary components are designd by quadratic orthogonal regression method. Composition range of the designed slags is Al2O3/CaO=0.8~ 1.2, CaF2=3%~9%, MgO=4%~10%, SrO=0~10%.Effect of SrO on properties of refining slag was innovatively studied. Control devices of kinetics study was developed, and The solution of A12O3 in refining slag (1# and 8#) was experimentally studied. In accordance with the coexistence theory of slag structure, the model of mass action concentration for slag system of CaO-Al2O3-MgO-SrO-CaF2-SiO2 is established firstly. Calculated results had good consistency with experimental data. Based on the experimental results, mathematical models between composition and properties were established, and the effects of composition on molten properties and sulfur distribution were discussed. Optimized composition was obtained by orthogonal direct-visual method. Optical basicity was used to calculate sulfur capacity. Melting uniformity of pre-molten refining slags were observed through microscope, and melting temperatures of pre-molten slag and mixing slag were compared.The confirming test shown that the mathematical models was highly reliable. For desulfurization, while the value of Al2O3/CaO is bigger, the sulfur capacity is lesser, sulfur distribution is also lesser; viscosity of samples has a minimum value when MgO is reached 5%, while MgO has a little influence on molten temperature of samples. The effect of Al2O3/CaO on high temperature properties of refining slag behaved as thefeature of parabola; Viscosity of slag increases with the increasing of CaF2, but molten temperature changes slightly. There is a linear relationship between SrO and molten temperature; viscosity of slag has a minimum value when SrO is reached 6%. By comprehensive consideration of physicochemical properties of slag in the study, the optimized composition of refining slag ought to be 7%SiO2, 7%MgO, 5%SrO, 6%CaF2 and %Al2O3/%CaO=0.8.At the condition of the study, when %Al2O3/%CaO is between 0.7-0.9, the slag has high capacity of adsorbing Al2O3 inclusion, the original content of Al2O3 has little effect on property; when %Al2O3/%CaO is more than 0.9, that adsorption of Al2O3 in refining slag would be improved with decreasing of original Al2O3 content, enhancing of saturated concentration of Al2O3, decreasing of viscosity of slag and interface tension between slag and Al2O3 inclusion.更多还原