Thermodynamic and Kinetic of Preparation of TiCl4 from High Ca and Mg Impurities Titanium Concentrate by Boiling Chlorination
Received:January 18, 2024   Revised:January 25, 2024   Accepted:January 29, 2024      Published Online:May 01, 2024
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DOI:doi:10.3969/j.issn.1007-7545.2024.06.006
KeyWord:high Ca and Mg impurities titanium concentrate; boiling chlorination; TiCl4; titanium oxycarbide
                 
AuthorInstitution
ZHU Fuxing 钒钛资源综合利用国家重点实验室
MA Zhanshan 钒钛资源综合利用国家重点实验室
CHEN Aixiang 攀钢集团攀枝花钛金属材料有限公司
LI Liang 钒钛资源综合利用国家重点实验室
HUANG Zhipeng 攀钢集团攀枝花钛金属材料有限公司
PENG Wenxing 钒钛资源综合利用国家重点实验室
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Abstract:
      Aiming at the problems that high Ca and Mg impurities ilmenite concentrate is difficult to meet the boiling chlorination process for preparing TiCl4, the preparation of TiCl4 from high Ca and Mg titanium raw material by carbothermic reduction - boiling chlorination was systematic studied from the perspective of thermodynamics and kinetics. The results show that the high-temperature carbon thermal reduction process of ilmenite concentrate involved the stepwise reduction process: FeTiO3 → TiO2+Fe → TinO2n—1(n=4—9)+Fe → Ti3O5+Fe → Ti2O3+Fe → TiCxO1—x+Fe. The temperature of carbon oxide titanium generation must be higher than 1 400 ℃. However, the impurity elements such as Ca, Mg, Al, Si, Mn in titanium concentrate will not be reduced to corresponding carbides within 1 800 ℃. In the process of carbothermic reduction of high Ca and Mg impurities ilmenite concentrate to prepare titanium oxycarbide, the weight loss rate increases in four stages with the increase of temperature. Among them, Stage 1 and Stage 3 are the rapid weight loss stages of metal Fe and carboxy-titanium controlled by diffusion, while Stage 2 and Stage 4 are the slow weight loss stages of metal Fe and carboxy-titanium nucleation and growth, respectively. The apparent activation energies of the four stages are 49.84, —2.24, 12.82, and —2.53 kJ/mol, respectively. During the boiling chlorination process, Fe, MgO, and CaO in the reduction products are preferentially chlorinated by chlorine gas, but when TiO2 is present, SiO2 and Al2O3 are not easily chlorinated. The most suitable temperature for boiling chlorination is 300—650 ℃. The first 5 min of boiling chlorination is the rapid chlorination stage of titanium oxycarbide in the reduction products, which is mainly controlled by the surface chemical reaction, and the next 5 to 20 min is the slow chlorination stage of Ti2O3, which is mainly affected by the internal diffusion control of the particles.
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