选择氯化钛铁矿制取人造金红石

Preparation of synthetic rutile by selective chlorination of ilmenite

研究了选择氯化钛铁矿制取人造金红石反应的Ｆｅ－Ｔｉ－Ｃ－Ｏ２－Ｃｌ２系平衡图，计算了氧与某些氯化物相互作用的自由能变化，采用“通氧一步选择氯化法”，在钛铁矿原料中配加适量的碳，并往炉内通入相应量的氧气或空气，可以解决选择氯化“自热”反应持续进行的技术关键．对反应参数，如温度、配碳量、物料粒度、氯化时间和通氧量等均进行了实验室、半工业和工业化生产试验研究．研究证明，选择氯化过程的动力学模型是“固体颗粒粒度保持不变的缩核反应模型”，动力学区的活化能为３４．３３ｋＪ／ｍｏｌ；扩散区的活化能为０．８０ｋＪ／ｍｏｌ．试验结果表明，这种选择氯化新工艺具有流程短、产能大、产品质量好、成本低、操作简单等优点．研究开发的无筛板沸腾氯化炉可以长期稳定地连续运转，生产出的人造金红石品位为９２．１０％．经摇床和磁选，品位达到９５％，钛的回收率和氯的利用率都大于９５％，床层单位炉产能达１２．４ｔ／ｍ２ｄ．该工艺和设备已成功地应用于工业生产．

In this paper, the equilibrium diagram of Fe-Ti-C-O2-Cl2 system is studied for the preparation of synthetic rutile by selective chlorination of ilmenite, and the changes of free energy are calculated in the reactions between O2 and certain chlorides. A process--'oxygen- induction one-step selective chlorination' is adopted in which a proper quantity of carbon is added ln the raw material ilmenite, and a correspondent quantity of O2 or air is induted into the reactor, thus the key technical problem is solved which requires a sustainably processed ' self-heating' chlorination. The technical parameters such as temperature, quantity of carbon added, grain size of feed, time of chlorination, quantity of O2 introduced, etc. have been ver- ified by lab-test, pilot test and industrial-scale test. The study has proved that the dynamic model of the selective chlorination process is a 'shrinking core reaction model in which the solids' particle size is kept unchanged', with the activation energy in the dynamic zone being 34. 33 kJ/mol and that in the diffusion zone 0.8 kJ/mol. Test results show that this new se- lective chlorination process is characterized by short flowsheet, high output, good product quality, low costs and simple operation. The fluidized bed chlorinator without the perfora- ted-plate developed in this process can stably and continuously operate in a long period of time. The process and the relevant equipment have been successfully applied in the industrial production, with the grade of resultant synthetic rutile being 92. 1 %, and even up to 95% through the additional table concentration and magnetic separation. Both the recovery of ti- tanium and the utilization ratio of chlorine are over 95%, and the reactor's capacity per bed- layer can reach 12.4 t/m2d.