Визначення умов одержання синтетичного рутилу при вилуговуванні відновленого Самотканського ільменіту розчинами ферум(ІІІ) сульфату

This study investigates the chemical beneficiation processes for Samotkan ilmenite concentrates, reagent regeneration, and the recycling of extracted iron compounds. The task addressed is to devise technology for obtaining synthetic rutile and converting by-product iron compounds into commercially valuable materials. Kinetic parameters of iron leaching from metallized ilmenite obtained by reducing Samotkan ilmenite concentrate with carbon at 1200 ℃ for 4 hours using ferric sulfate solutions were determined. Up to 8 % iron extraction, the kinetics followed the autocatalytic Prout–Tompkins model (kt=ln(a/(1–a)), with apparent activation energy Еapp=62.7 kJ/mol. At higher degrees of iron extraction, the process was consistent with the shrinking core model (kt=1–(1–a)1/3), with apparent activation energy Еapp=47.3 kJ/mol. The reaction order with respect to Fe3+ was found to be close to first order. Additional removal of impurities from the residue of oxidative leaching was achieved by treatment with 15 % H2SO4 solution at 60 ℃ and subsequent calcination at 800 ℃, resulting in the production of synthetic rutile with a ТіО2 content of 92 %. It was established that the regeneration of oxidative leaching solutions could be carried out via catalytic oxidation of FeSO4 solutions using oxygen. At pH 1.1–1.5 and 60 ℃ in the presence of NO, ferrous iron was quantitatively oxidized within 1–3 hours. Efficient mass transfer under high gas content in the gas-liquid mixture allows oxidation to proceed without elevated oxygen pressure or temperature. A portion of the ferric iron was recovered as high-purity crystalline Fe4(OH)10SO4 precipitates, which, upon calcination at 750 ℃, yielded 99.4 % Fe2O3, suitable for pigment production. The low reagent consumption and the conversion of iron into marketable products underscore the potential for industrial-scale implementation of this process