[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 (Φ10 x 1 mm, wavenumers: 7800-440 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 = 0.9963; 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.