基于铝热还原及活化浸出的含钛高炉渣综合利用基础研究

Comprehensive utilization of metallurgical resources is the realistic requirement of sustainable development strategy of China. The titanium-bearing blast furnace slag has the problems of difficult to recycle, cultivated land occupied, serious waste of resources and so on. To solve these problems, the new comprehensive utilization process of aluminothermal reduction of titanium-bearing blast furnace slag to produce titanium-silicon alloy and activation leaching Al2O3 from the residual slag is developed. Based on the metallurgical theory, the following investigations are carried out: the titanium-bearing blast furnace slag reduction by aluminum and heat balance calculation of multiphase system are investigated. Properties of liquid titanium-bearing blast furnace slag and coupling reaction kinetics of multiphase melt is studied. The mechanism of aluminothermal reduction of titanium-bearing blast furnace slag is illuminated and titanium-silicon alloy is produced. Mineral structure of high temperature melt and the mechanism of adjusting component of residual slag are studied. The 12CaO•7Al2O3 slag which is easy to leach Al2O3 is obtained. The experiment of leaching Al2O3 from the residual slag is studied. The product of Al2O3 which can produce aluminum is obtained. The slag after alumina leaching can be used to sinter. This new technology has the advantages of low production cost, short technological process and high product value. The research results can solve the problem of titanium-bearing blast furnace slag which is difficult to comprehensive utilization in the past. It can provided the theoretical guidance and technical support for high value-added utilization of titanium-bearing blast furnace slag.

开展冶金资源综合利用是我国实施可持续发展战略的现实需求。本项目针对含钛高炉渣难以回收利用、堆存占用耕地、资源浪费严重等问题，提出了含钛高炉渣铝热还原生产钛硅铁合金，还原后炉渣提取氧化铝新工艺理论。项目以冶金基础理论为指导，拟开展含钛炉渣铝热还原热力学及多相体系热平衡计算，液态含钛炉渣物化性能及多相熔体耦合反应动力学研究，阐明含钛高炉渣铝热还原制备钛硅铁合金机理，获得优质钛硅铁合金；开展铝热还原后炉渣高温熔体结构及炉渣调质机理研究，获得易于Al2O3浸出的12CaO•7Al2O3炉渣组织结构形态；开展铝酸钙炉渣活化浸出提取氧化铝机理及实验研究，获得可以用于电解铝的Al2O3产品，提铝残渣代替石灰石返回烧结利用。本研究成果能够解决我国大量的含钛高炉渣难以综合利用的问题，为含钛高炉渣的高附加值利用提供理论依据。

钒钛磁铁矿是我国的优势铁矿资源，含钛高炉渣是高炉冶炼钒钛磁铁矿时排出的液态炉渣。由于含钛高炉渣中TiO2含量高，炉渣活性低，难以资源化利用，造成了环境污染和资源浪费。本课题针对含钛高炉渣难以回收利用、堆存占用耕地、资源浪费严重等问题，提出了含钛高炉渣铝热还原生产钛硅铁合金，还原后炉渣提取氧化铝新工艺理论。通过开展含钛炉渣铝热还原热力学及多相体系热平衡计算，含钛高炉渣物化性能及多相熔体耦合反应动力学研究，铝热还原后炉渣高温熔体结构及炉渣调质机理研究和铝酸钙炉渣活化浸出提取氧化铝机理及实验研究。热力学分析揭示了铝热还原反应过程及CaO配加量对铝热还原反应的影响规律。实验研究结果表明含钛高炉渣铝热还原最佳的CaO配加量为炉渣重量的5%，铝粉配加量为炉渣重量的26%，还原温度为1620℃，还原时间为10min，还原完成以后Ti和Si的收得率分别为87.50%和80.23%，获得了较高的还原收得率。铝热还原炉渣调质实验结果表明配加不同CaO，炉渣中稳定存在的物相为钙铝硅镁四元化合物，由于含钛高炉渣中MgO含量太高，抑制了炉渣中12CaO•7Al2O3物相的生成。机械活化及浸出实验结果表明CaO配加量对炉渣中氧化铝的浸出影响较大，随着炉渣中CaO配加量的增大，氧化铝的浸出率成先增大后减小的趋势，在CaO配加量20%时，炉渣中钙铝比1.44，此时炉渣中氧化铝的浸出率最高为67.45%。本课题研究制备得到了优质的硅钛合金，得到了铝酸钙浸出渣，但浸出渣中氧化铝浸出率较低，下一步继续研究还原渣直接制备铝酸钙水泥，拓宽铝热还原浸出渣的利用领域，提高新工艺的经济效益。炉渣铝热还原及活化浸出技术也可以推广应用到钢渣和赤泥，提高钢渣和赤泥的资源化利用水平，实现冶金固废资源的高附加值利用。课题实施期间发表论文4篇，授权专利2项。