New Process For Producing High-grade Titanium Dioxide And Experimental Investigation

With the progress of process in producing titanium dioxide, improving the optics and pigment properties become a developing trend of this industry in the world.The sulfate method is still in a leading position in producing titanium dioxide in China. But the production is in a low grade, which is hard to compete with other enterprises in international market. Basing on this method, the hydrolysis process was improved, the operations of salting and heating processes were optimized, and a new technology to produce high purity titanium dioxide was prepared in this paper.An additive A was selected to affect hydrolysis, and the variety of the concentration of titanyl sulfate solution is another factor. After adding A, the mean size of the hydrolysate became smaller, the probable reason of which is the metal ion of A replaced Ti4+ to break the bond between Ti and O. The mean size of the particles became smaller with the increase of the concentration of titanyl sulfate solution. The adding quantity of A and the concentration of titanyl sulfate solution were optimized, and the negative influences by exceeding the optimal values were analyzed.The salting and calcining processes were experimental studied. The best heating temperature and time and the quantities of the salts were investigated separately. In the same condition, the heating temperature of the hydrolysate became higher after adding A to get a same transformation rate. The mean size of the final production was smaller and the shape of it was better ordered, which could improve the pigment properties a lot.A new technology of extracting and recovering the titanyl sulfate solution was developed. Using different distribution coefficients of different metals in organic solvent, Ti4+ and the foreign metal ions were separated. Multi-group orthogonal experiments were designed to optimize the factors which affected the extracting and recovering operations. The concentration of Foreign metal ions such as Fe, Mn, Cr, Mg were reduced observably in the titanyl sulfate solution.