高铬型钒钛磁铁精矿选择性直接还原过程钒铬钛迁移机理和调控规律研究

Vanadium, chromium and titanium are the world recognized scarce resources and strategic materials with wide applications. The high-chromium V-bearing titanomagnetite of Hongge District in Panzhihua-Xichang region is a giant iron-polymetallic deposit associated with vanadium, chromium, titanium, etc. Therefore, the comprehensive utilization of the resource is of great significance. The vanadium and titanium recovery rates are low in the existing BF-BOF process that unable to effectively extract chromium, resulting in serious waste and environmental problems. In the project, selected direct reduction-magnetic separation method is used to process high-chromium titanomagnetite concentrates. The key scientific problem is to understand the phase transfer mechanism and the separation regulation rules of the valuable components in the key process. Then by strengthening and controlling the valuable components migration, the process can realize the mineral phase reconstruction, efficient enrichment and further effective separation of the valuable components. Using the methods of the theoretical analysis and the experimental research combined, we study the phase structure changes of the valuable components in the selective direct reduction-magnetic separation process, the V/ Cr/ Ti migration mechanism, the reduction kinetics rules, the phase separation regulation rules, and the selected direct reduction-magnetic separation technology. The project will obtain the transfer mechanism and the separation method of the selective direct reduction-magnetic separation process, achieving the effective separation of V/Cr/Ti with Fe. The results will not only improve the theoretical system of the direct reduction, but also lay the theoretical foundation for the large-scale application of high-chromium V-bearing titanomagnetite.

钒、铬、钛是世界公认的紧缺资源和重要战略物资，应用领域广泛。攀西红格地区大宗特色高铬型钒钛磁铁矿为铁、钒、钛、铬等典型多金属共伴生矿产资源，资源开发利用意义重大。现有高炉流程钒、钛回收率低，无法有效提取铬，资源环境问题突出。本项目采用选择性直接还原-磁选工艺处理高铬型钒钛磁铁精矿，围绕关键冶炼-分离过程中矿物有价组元相间迁移传递及分离调控的关键科学问题，通过强化和调控有价组元的迁移，实现矿相重构、高效富集和进一步的高效分离。采用理论分析、实验研究相结合的方法，开展选择性直接还原反应-磁选过程中有价组元相结构变化规律、钒铬钛组元相际迁移的动力学规律及迁移机理、各组元相分离调控规律和选择性直接还原-磁选工艺研究。本项目的实施，将获取选择性直接还原-磁选过程组元迁移机理和分离调控方法，实现钒、铬、钛与铁的高效分离，不仅完善了直接还原的理论体系，也为高铬型钒钛磁铁矿的大规模应用奠定理论基础。

攀西红格地区大宗特色高铬型钒钛磁铁矿为铁、钒、钛、铬等典型多金属共伴生矿产资源，资源开发利用意义重大。现有高炉流程钒、钛回收率低，无法有效提取铬，资源环境问题突出。本项目围绕钒钛磁铁矿关键冶炼-分离过程中矿物有价组元相间迁移传递及分离调控的关键科学问题，提出选择性直接还原-磁选分离铁与钒/钛的思路，探明强化和调控有价组元的迁移的方法，揭示了选择性直接还原过程中钛、钒迁移调控机制，获得钛\钒与铁的分离方法，实现矿相重构和高效富集。研究结果表明，C/Fe摩尔比对还原过程钒的还原有着决定性的影响：在低C/Fe摩尔比（=0.8）下，钒难以被还原进入金属铁相中；当C/Fe摩尔比高于1.0，钒开始被还原为碳化物，并固溶于金属铁相中。同时，在低C/Fe摩尔比（=0.8）下，还原温度（1100~1250 ºC）对钒的还原影响甚微；但在高C/Fe摩尔比（≥1.0）下，大量钒被还原为碳化物，从而导致了金属铁相中钒含量的升高。因此，通过有效调控还原过程参数，成功的选择性迁移钒至非磁性钛渣相，与金属铁相有效分离。采用选择性直接还原-磁选工艺处理钒钛磁铁矿，可获得总铁含量94%的铁精粉，渣相为主要由钛磁铁矿（(Fe2.5Ti0.5)1.04O4）、钛铁矿（FeTiO3）和亚铁假板钛矿（(Fe,Mg)Ti2O5）等组成，且钒在此含钒钛渣中富集。在强化钛、钒有效迁移的同时，通过加入低熔点物质有效控制铁晶粒长大，获得了钛、钒组元相际迁移机理和各组元相分离调控规律，完善了直接还原法处理钒钛磁铁矿的理论体系。