Preparation of Titanium Powder by Reduction of TiO2 at Low Temperature with CaH2
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摘要: 以工业钛白粉和分析纯氢化钙粉为原料, 探索一种在较低温度下热还原制备Ti粉新方法。结合反应热力学理论计算及试验验证, 对氢化钙分解条件及分解产物还原TiO2过程进行了研究。结果表明:真空条件可降低CaH2分解温度, 初始真空度2.5 Pa, 温度890.7 K, 保温1 h, CaH2分解为Ca和H2;分解后的Ca粉对TiO2的还原为逐级还原, 在温度993 K以上、还原时间3 h, TinO2n-1及CaTiO3等中间产物最终被还原为Ti;反应结束时通过蒸馏去除残余Ca可有效降低Ti粉H含量;获得的钛粉颗粒形貌为不规则块体状、中位粒径1.83μm, 成分满足行业标准YS/T 654-2007 TF-2牌号要求。Abstract: A new method for preparing Ti powder by thermal reduction at low temperature was explored with industrial titanium dioxide(TiO2) powder and AR(Analytical Reagent) calcium hydride(CaH2)powder as raw materials.The decomposition conditions of CaH2 and the process for reduction of TiO2 by decomposed CaH2 were studied by reaction thermodynamics calculations and experiments.The results show that vacuum conditions can reduce the decomposition temperature of CaH2,and CaH2 is decomposed into Ca and H2 at 890.7 K for 1 h with 2.5 Pa of initial vacuum degree.TiO2 is stepwise reduced by Ca decomposed from CaH2,and the intermediate products such as TinO2 n-1 and CaTiO3can be finally reduced into Ti at temperatures higher than 993 K for 3 h.H residual in Ti powder can be efficiently removed by distilling the products at reaction terminal.The obtained Ti powder is of irregular block shapes with a median size of 1.83 μm,satisfying the composition requirements for TF-2 grade of Ti powder according to the industrial standard YS/T 654-2007.
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Key words:
- titanium powder /
- titanium dioxide /
- calcium hydride /
- thermal reduction /
- vacuum degree /
- temperature
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