一套红外池测定精四氯化钛中二氯氧钛的含量

钛材质量控制的关键是控制精TiCl₄中杂质含量。精TiCl₄是海绵钛生产的关键环节，海绵钛中杂质与精TiCl₄中杂质含量成4倍富集关系。需要分析氧杂质的来源，对精TiCl₄中氧杂质进行严格控制。精TiCl₄中TiOCl₂含量的测定具有重要意义。TiOCl₂具有红外吸收谱线，因而能够利用红外光谱实现测定，然而精TiCl₄与空气中水气接触极易发生水解反应，生成强腐蚀性的盐酸烟雾，不能使用常规的红外吸收池进行测定。根据Lambert-Beer定律，被测组分浓度(c_x)与吸光度(A)～样品光程(L)曲线的斜率成正比，利用波长范围7 800～440 cm-1的硒化锌窗片(10×1 mm)和玻璃池体(22，12，7和4 mm光程)组装成一套红外吸收池，采用加标法测定精TiCl₄中TiOCl₂杂质含量。实验得出TiOCl₂的检出限为17.8 mg·kg-1，样品回归方程Y=1.0118X，相关系数r为0.996 3，加标TiOCl₂样品的回归方程Y=1.940 0X，相关系数r为0.997 0，线性关系较好。测定精TiCl₄中TiOCl₂含量为833.8 mg·kg-1，标准偏差(SD)为40.0 mg·kg-1，方法精密度相对标准偏差(RSD)在0.95～1.94之间，加标回收率在88.5%～93.1%之间。此红外吸收池安全简便、容易拆洗、可重复使用，通过一次加标样品定量分析精TiCl₄中TiOCl₂含量，可满足精TiCl₄中TiOCl₂分析的要求。

A Set of Infrared Cells for the Determination of Titanium Oxychloride in Refined Titanium Tetrachloride

The content control of the impurities in refined TiCl₄ becomes the key part for the quality control of titanium material. Refined TiCl₄ is the key procedure in producing titanium sponge. Besides, the content of the impurities in titanium sponge and that of the impurities in refined TiCl₄ presents the 4-times enrichment relationship. Therefore, control the content of the oxygen, there is the need to analyze the source of oxygen impurities so that strict control can be conducted over the impurities of refined TiCl₄. Determination of TiOCl₂ in refined TiCl₄ was significant for analysis of its impurities. TiOCl₂ could be determined by infrared spectroscopy due to its infrared characteristic spectrum line. However, normal infrared absorption cell was not fit for the sample analysis, because TiCl₄ easily reacted with moisture in the air and immediately was hydrolyzed to form highly corrosive hydrochloric acid smoke. According to Lambert-Beer Law, which means the concentration (c_x) and absorbance(A)～length (L) curve’s slope have direct ratio. The infrared absorption cell with the window film of ZnSe (10×1 mm, wavenumers: 7 800～440 cm-1) and the glass cell (optical path: 22, 12, 7 and 4 mm) was assembled and utilized in determination of the TiOCl₂ in refined TiCl₄ by standard addition method. The detection limit of TiOCl₂ was 17.8 mg·kg-1, the regression equation was Y=1.011 8X, R=0.996 3; With standard addition method, the regression equation of TiOCl₂ was Y=1.940 0X, R=0.997 0, it’s good in linearity relation, the TiOCl₂ content in refined TiCl₄ is determined to be 833.8 mg·kg-1 and SD up to 40.0 mg·kg-1. RSD of the method precision is between 0.95%～1.94%, while recovery rate is between 88.5%～93.1%. This infrared absorption device was safe, simple and convenient, easily removable and washable, and re-useable. The method could conduct the quantitative analysis over the TiOCl₂ content in refined TiCl₄ through adding standard sample for one time, it could meet the requirement of determination of TiOCl₂ in refined TiCl₄.