Synthesis of titanium dioxide precursor by the hydrolysis of titanium oxychloride solution

This communication focuses on the development of an approach to improve the synthesis of [Ti8O12(H2O)24]Cl8.HCl.7H2O crystals which is one of the precursor for titanium dioxide TiO2 particles. This study provides a significant improvement in crystallization kinetics with a production rate increased by a factor nineteen by intensifying heat and mass transfers compared to the process in a close vessel. This enhancement was made possible by the development of a new reactor to control the heat and mass transfers involved. In parallel with the experimental set-up, a numerical model representative of the transfer phenomena was initiated. The first numerical results are encouraging and present a good agreement with the measurements. Keywords: Heat and mass transfer; Co-desorption, Modelling, Experiment

Resource utilization of titanium-containing slurry by selective extraction and leaching

Resource utilization of titanium-containing slurry was realized by selective extraction and leaching. The results from the experiment confirmed that thistechnology was effective for recycling titanium and niobium from the slurry. During selective extraction, the extract solution with titanium content of 159.40 g/L was obtained after 3 stage-counter current extractions, and the titanium content of extracted residue could be reduced to 1.85 wt% which was much lower than the titanium content of titanium-containing slurry. The results of evaporation experiments indicated that CH2Cl2 in extracted residue could be separated and recovered effectively by evaporation and high temperature is beneficial for the whole process. Meanwhile, the titanium oxide and titanium oxychloride in extracted residue could also be transformed into TiCl4 and recovered by evaporation as the evaporation of dichloromethane in extracted residue. The beneficiation of niobium could be achieved when the evaporated residue was leached with diluted hydrochloric acid, the results of leaching test showed that more than 97% of the aluminum in evaporation residue was dissolved, while, only 1.3% of the niobium was leached. Finally, niobium concentrate with Nb2O5 content of 76.39% was obtained by washing the leaching residue with dilute ammonia water.

Determination of Titanium Oxychloride in Refined Titanium Tetrachloride by Infrared Spectroscopy

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. The infrared absorption cell with the window film of ZnSe ( Ф10×1mm, wavenumbers: 7800cm-1~440cm-1) and the glass cell (optical path: 22mm, 12mm, 7mm and 4mm) was assembled and utilized in determination of the TiOCl2 in refined TiCl4 by standard addition method. The detection limit of TiOCl2 was 26.5mg•kg-1, the regression equation was Y=1.0118X, R2=0.9926; With standard addition method, the regression equation of TiOCl2 was Y=1.9400X, R2=0.9940,This infrared absorption device was safe, simple and convenient, easily removable and washable, and re-useable. This method could meet the requirement of determination of TiOCl2 in refined TiCl4.