低温镁热还原TiO2制备金属钛粉的热力学研究

Thermodynamics research of titanium powder preparation by a low temperature magnesiothermic reduction of TiO2

摘要:

本文针对TiO₂镁热还原产品氧含量高的问题进行了热力学研究,计算了反应体系的吉布斯自由能和绝热温度,绘制了反应优势区图,结果表明当反应温度高于1681 K时TiO无法被镁还原。针对这一问题,提出添加稀释剂的思路以实现对还原过程温度的抑制,计算了不同NaCl、MgCl₂添加量和初始温度对反应绝热温度的影响,指出了钛氧化物充分还原的热力学条件。最后分别以NaCl和NaCl-MgCl₂共熔盐作为稀释剂进行了实验研究,实现了钛氧化物的充分还原。

Abstract:

The thermodynamics of magnesiothermic reduction of TiO₂ was studied in order to decrease the oxygen content in reduction product. The Gibbs free energy and adiabatic temperature of reaction system were calculated, and the reaction predominance diagram was drawn. The results show that TiO cannot be reduced by magnesium when the reaction temperature is higher than 1681 K. In order to solve this problem, we put forward a new concept to restrain the reaction temperature by adding diluents. The adiabatic temperatures were calculated at different NaCl, MgCl₂ addition amount and initial temperatures, and the thermodynamic condition for complete reduction of titanium oxide was pointed out. Finally, the experiments were carried out by using NaCl and NaCl-MgCl₂ eutectic salt as diluents, and the titanium oxide was reduced completely.