中文摘要：

通过热力学计算以及XRD、SEM和EDS等测试手段,研究TiO2钙热还原制备钛粉过程中钛酸钙（CaTiO3）的形成原因。热力学计算表明：当温度高于800 K时,添加剂CaCl2水解产物CaO与TiO2生成CaTiO3的反应以及还原副产物CaO与TiO2生成CaTiO3的反应均满足反应发生的热力学条件。实验研究表明：CaTiO3的生成主要是由添加剂CaCl2水解生成的CaO与TiO2烧结反应所致,CaTiO3的量随着CaCl2添加量的增加而增加,且CaTiO3更容易被还原为金属钛。当CaCl2与TiO2的质量比约为1：4时、在1 273 K下还原时间为6 h时,反应过程中的CaTiO3被完全还原为金属钛粉,该粉末具有不规则外形,颗粒粒径为8~15μm。经EDS分析,金属钛粉中钛的质量分数达到99.55%。

英文摘要：

The formation cause of perovskite calcium titanate（CaTiO3） in calciothermic reduction process of titanium dioxide to prepare the titanium powders was investigated by thermodynamic calculation,XRD,SEM and EDS.Thermodynamic calculations indicate that the reactions of CaO hydrolyzed from the additive of CaCl2 to form CaTiO3 and the reduction by-product of CaO reacted with TiO2 to form CaTiO3 at the temperature beyond 800 K,satisfy the thermodynamic reaction conditions.The experimental results demonstrate that CaO is produced by the hydrolysis of CaCl2,and the large amount of CaTiO3 is generated in the sintering reaction of CaO with TiO2.Furthermore,with increasing the amount of CaCl2,CaTiO3 increases and is easily reduced to titanium.When the mass ratio of CaCl2 to TiO2 is about 1：4,the reduction temperature is 1 273 K and the reduction time is 6 h,CaTiO3 is completely reduced to titanium with irregular shape and particle size of 8-15 μm,and the mass fraction of titanium powder is 99.55% by EDS analysis.