Dubenko A. Intensification of the leaching process of ilmenite concentrates of Malyshevske deposit in the production of the titanium dioxide pigment.

Pigment titanium dioxide is one of the most common products of inorganic synthesis. In Ukraine, pigment titanium dioxide is produced by the sulfate acid leaching method, and the most common raw material for the production of pigment TiO2 is ilmenite concentrates. The main reserves of ilmenite are presented in the form of ore of Malyshevske and Irshanske deposits. The ilmenite concentrates obtained from these deposits differ in its mineralogical composition and, accordingly, in its chemical properties. For example, processing of ilmenite concentrates of the Malyshevske deposit by sulfate acid leaching method, even when using the "hardest" conditions of sulfatization (200ºС, 96 wt.% sulfuric acid), does not allow to process the source ore material completely (a titanium leaching degree does not exceed 50-60%). This result, in turn, leads to relatively low the using degree of raw materials, accumulation of industrial sludge and reduced overall production efficiency. The main reason for the low degree of ilmenite processing from the Malyshevske deposit is considered to be the high degree of its alteration. The change in the chemical composition of ilmenites makes them less suitable for the sulfuric acid method of titanium dioxide production. Obviously, identifying the causes of low reactivity of altered ilmenite, as well as identifying the possible ways to intensify the process of its chemical decomposition are actual tasks. The solution to these tasks will lead to increase the using degree of raw materials, reduce production costs, and industrial waste (due to sludge processing). The dissertation is devoted to the theoretical and experimental substantiation of regularities of the sulfuric acid leaching process of titanium from ilmenite concentrates from Malyshevske deposit and the founding of technologically expedient conditions of process intensification of its chemical decomposition in the production of pigment titanium dioxide. As is known, intensification methods of chemical-technological processes can be divided into physical and chemical. The kinetics of the sulfatization process of altered ilmenite and the possibility of its intensification by such physical methods as mechanical, thermal and ultrasonic activation are studied. The concentration of sulfuric acid solutions, its plasma-chemical activation and the adding of the activator-reactant into the reaction mixtures were considered as chemical factors influencing the kinetics of the sulfatization process. For the first time, recommendations have been developed to optimal conditions and improvement of the leaching process of altered ilmenite. It is recommended to carry out additional processing of rutile-containing sludge which was got in the sulfatization process of ilmenite concentrate. The developed recommendations on optimal conditions and improvement allowed to increase the leaching degree of titanium in solution to 95% after processing the raw material, which in turn significantly reduces titanium dioxide production waste and reduces its production cost.