Preparation of low-oxygen titanium powder by magnesiothermic reduction of TiO2 assisted by MgCl_(2)−HoCl_(3) molten salt

To reduce the production cost of titanium,a new method for direct preparation of low-oxygen titanium powder by the magnesiothermic reduction of TiO_(2) with the assistance of a MgCl_(2)−HoCl_(3) molten salt was proposed.Thermodynamic calculations showed that the magnesiothermic reduction of TiO_(2) was feasible.However,hindrance of the reduction reaction by the reduction by-product of MgO resulted in a considerably high O concentration in the titanium powder.The addition of HoCl_(3) to the system significantly reduces the activity of MgO to produce low-oxygen titanium powder.Thermochemical deoxidation and reduction experiments were conducted with MgCl_(2)−HoCl_(3) molten salt in the temperature range of 1023−1273 K.The results showed that titanium powder with oxygen concentration(mass fraction)below 5.00×10^(-4) can be prepared at the Mg−MgCl_(2)−HoOCl−HoCl_(3) equilibrium.

基于MgCl_(2)-HoCl_(3)熔盐镁直接脱除钛废料中固溶氧研究

针对现有钛脱氧方法存在成本高、效率低、金属/熔盐分离困难等问题,本研究提出了一种在MgCl_(2)-HoCl_(3)熔盐中,采用Mg作脱氧剂直接脱除钛中固溶氧的新方法。在1273 K下开展了热力学计算和实验研究,结果表明:在MgCl_(2)-HoCl_(3)熔盐中,借助HoOCl(O(inβ-Ti)+Mg(l)+HoCl_(3)(l)=MgCl_(2)(l)+HoOCl(s))的生成,有效降低了脱氧副产物MgO的活度,促进了镁深度脱氧,钛中氧含量可降低至1000×10^(-6)以下(甚至500×10^(-6)以下)。随着熔盐中HoCl_(3)活度的增加,钛中的氧含量降低,当HoCl_(3)的活度为1.0时,氧含量可降至80×10_(-6)左右。基于以上研究结果,本研究提出了一种新的脱氧工艺,该工艺具备成本低、效率高、金属/熔盐分离简单等优势,有望在未来实现工业化应用。