镁热法制备海绵钛蒸馏工艺优化研究

Optimization Research on Vacuum Distillation Process for Titanium Sponge Preparation by Magnesium Thermal Reduction

针对镁热法制备海绵钛时蒸馏中间通道堵塞、海绵钛氯离子超标的现象进行分析,就蒸馏系统的压力、蒸馏温度和时间开展蒸馏过程工艺优化试验研究。热力学分析结果表明：当蒸馏温度为900~1 000℃时,Mg和MgCl2对Ti的相对挥发度大于2.21×1011。蒸馏过程优化试验研究表明：真空蒸馏过程较优的系统压力应小于4Pa、预热温度为750~800℃、前期预热时间应控制在1~2.5 h、蒸馏初期喷淋水连续喷淋时间控制在30~36 h。蒸馏工艺优化后海绵钛产品品级率明显提升,0级以上品级海绵钛平均提高16.54个百分点,等外钛比例降低6.4个百分点。

According to the technology problems of the intermediate channels blockage in distillation process and the over standard of chloridion in products during the titanium sponge production by magnesium thermal reduction,the optimizations of system pressure,temperature and time in distillation process were conducted.Thermodynamic analysis results show that the relative volatility of Mg and MgCl2to Ti is more than 2. 21 x 1011when the distillation temperature is 900 ~1 000 ℃. Distillation process optimization experiments show that the favorable system pressure of vacuum distillation process is not more than 4 Pa,and the preheating temperature is 750 ~800 ℃,the early stage of the preheating time 1 ~2. 5 h and continuous water spray time in the initial distillation process 30 ~36 h. After the optimizations,the product grade rate of titanium sponge improves significantly,and the titanium sponge above grade 0 increases by 16. 54% on average while the ratio of substandard titanium decreases by 6. 4%.