China Nonferrous Metallurgy

More than 3 million tons of titanium-bearing blast furnace slag are discharged every year in China， and the TiO₂ content of the slag is 10%-25%. At present， the comprehensive utilization of the slag is mainly to prepare building materials. An industrial demonstration production line for the preparation of titanium-rich materials， titanium carbide or titanium carbonitride from titanium-containing blast furnace slag has been built in Panxi area， but there are some limitations. At present， most of the titanium-containing blast furnace slag is disposed by stacking. Some scholars have proposed selective precipitation technology， that is， titanium-containing blast furnace slag is modified by additives to make titanium exist in the form of perovskite， and then perovskite is separated by gravity separation and used as raw material for titanium extraction. The titanium recovery rate of this method is less than 48%. In view of this problem， this study proposes a perovskite crystal transformation technology on this basis， that is， by adding CaO， high titanium slag， and CaTiO₃ to transform the perovskite crystal to improve the recovery rate of gravity separation. The effects of various additives on the recovery rate of titanium were investigated by experiments， and the mechanism of crystal transformation was analyzed according to the characterization results. The following main conclusions were obtained. When the addition amount of CaO， high titanium slag and CaTiO₃ is 20%，25% and 17% respectively， the perovskite is precipitated as equiaxed crystal， and the recovery rate of titanium is 68. 41%. In the subsequent cycle production， the gravity concentrate is used instead of perovskite. The optimum concentrate addition is 50%， and the gravity recovery of titanium is 68. 42%. The main difference between perovskite crystal transformation technology and selective precipitation technology is the crystal form of perovskite. The product of crystal transformation technology is equiaxed crystal， and the product of selective precipitation technology is dendrite. The degree of dissociation of equiaxed perovskite monomer is higher， thus increasing the recovery rate of titanium. The results of this study can provide a reference for the resource recovery and utilization of titanium-containing blast furnace slag.