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碱熔盐体系中钒钛磁铁矿还原过程物相转变规律
史丽羽
Subtype硕士
Thesis Advisor齐涛
2018-07
Degree Grantor中国科学院研究生院
Degree Name硕士
Degree Discipline化学工程
Keyword钒钛磁铁矿,碱熔盐,渣铁分离,还原动力学,熔渣粘度
Abstract

钒钛磁铁矿是国家重大特色战略资源,高效综合回收钒、钛和铁具有重要的意义。还原–钠化–熔分工艺在一步高温冶炼中同时实现铁的还原熔分及钒的氧化钠化,为实现钒钛磁铁矿多组分综合利用提供了一个新的方法。本文以辽西地区钒钛磁铁矿精矿为原料,开展了对碱熔盐体系中钒钛磁铁矿还原过程的物相转变的研究,取得到了以下成果:(1)考察了还原–钠化–熔分耦合过程的最佳工艺条件,并对还原温度、添加剂用量、还原剂用量和反应时间对铁的还原熔分和钒的钠化的影响进行系统研究。结果表明还原温度、添加剂用量及还原时间的增加均能强化铁的熔分过程,而还原剂用量的增加先强化后抑制了铁的还原熔分。还原温度的降低、添加剂用量的增加、还原剂用量的减少、还原时间的减少有助于钒的氧化钠化行为,增大了渣相的钒含量;确定了最佳反应工艺条件,在优化工艺条件下可实现铁与渣的高效分离以及钒在渣相中的富集。(2)系统研究了还原产物渣的物相组成,并确定了添加剂用量对渣相性质的影响。结果表明:最佳条件下产生的渣相主要有CaTiO3、Na16Ti10O28、NaAlSiO4和Na1.45Al1.45Si0.55O4物相,钒主要赋存于钛酸钙和铝硅酸钠物相中;添加剂的加入不仅可促进钒的钠化转化,有效抑制钒向金属铁相的迁移,同时也降低了产物渣相的粘度,增强了铁与渣相的分离效果。(3)使用红外气体分析仪对实时产生的还原性气体的浓度进行在线检测,进行钒钛磁铁矿在碱熔盐体系中的还原动力学研究。结果表明,钒钛磁铁矿在碱熔盐体系中的还原反应先是界面化学反应控速(R3),后是扩散控速(D4),其化学反应活化能分别为E1=?55904J/mol,E2=?78538J/mol;同时温度升高、添加剂用量降低及还原剂用量增加可增大化学反应速率常数,促进反应进行。;Vanadium-bearing titanomagnetite is a major strategic mineral resource in China. The comprehensive utilization of V, Ti and Fe is of great significance. The selective reduction- sodium modification- smelting separation coupled process can simultaneously achieve smelting separation of iron and sodium modification of vanadium in one-step high-temperature smelting process, providing a new method for the economical and efficient utilization of the resource. In this study, the vanadium-bearing titanomagnetite in Liaoxi region was used to study the phase transitions during the reduction in alkaline molten salt. The main results of are as follows:(1)The reaction conditions for the sodium modification-selective reduction-smelting separation coupled process were studied. It is indicated that the separation status of iron can be enhanced with the increase of the temperature, the additive amount and the roasting time. The increase of the coal addition can enhance separation effect at first, and then restrain the separation effect when the C/Fe ratios were lager than 2.8. The percentage of V2O5 in the slag increased as decreasing the reaction temperature, the coal addition, the reaction time, and increased as increasing the additive amount. The optimal condition was determined. Under this condition, the separation of iron can be achieved efficiently as well as the enrichment of vanadium in the slag.(2)The phase composition of the slag and the effect of the additive on the properties of slag were studied. The results showed that the slag phase mainly consisted of CaTiO3, Na16Ti10O28, NaAlSiO4 and Na1.45Al1.45Si0.55O4. Under optimal condition, vanadium existeds in calcium titanate and sodium aluminosilicate phases. The addition of additive not only promotes the sodium modification of vanadium and inhibits the vanadium enrichment in metal phase, but also reduces the viscosity of slag and enhances the separation between the iron and the slag.(3)The reduction kinetics of the vanadium-bearing titanomagnetite in alkali molten salt was studied by using the infrared gas analyzer to detect the concentration of reducing gas. The results showed that the reduction reaction was firstly controlled by interface chemical reaction rate (R3), and then followed by the diffusion rate (D4). The activation energy of chemical reaction is E1=?55904J/mol, E2=?78538J/mol, respectively. At the same time, increasing reaction temperature, reducing agent and decreasing additive amount can increase the rate constant of chemical reaction and promote the reaction. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/26847
Collection中国科学院过程工程研究所
研究所(批量导入)
Recommended Citation
GB/T 7714
史丽羽. 碱熔盐体系中钒钛磁铁矿还原过程物相转变规律[D]. 中国科学院研究生院,2018.
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