ORALS

The high content of chromium in the ilmenite concentrate makes it difficult to process further into titanium-containing slag, titanium tetrachloride and titanium sponge. The most wide-spread industrial application is obtained by methods based on preliminary carbon-thermal reduction of ilmenite concentrates at 900-1200 °C with the subsequent separation of reduced iron and chromium from them by electromagnetic separation, and the nonmagnetic titanium chromium fraction is sent to hydrochemical treatment for purification from chromium and other impurities.<br />It has been established that solid-phase selective reduction of chromium-containing ilmenite concentrate should be carried out at a temperature of 1250 °C and an retention time of 2 hours. The addition of 8% in the charge of sodium chloride accelerates the process of reducing iron from ilmenite. In this case, recovery of reduced iron in the magnetic fraction is 76.1%, chromium 55.8%, titanium 15.3%. To separate titanium compounds from chromium, the titanium-chromium fraction is sintered with a calculated amount of soda at 850 °C for 2 hours and leached with hot water (S:L ratio = 1: 4) at a temperature of 95-100 °C and stirred for 120 minutes. The recovery into the chromium solution is 83.6%.

References:
ilmenite concentrate, high chromium content, reductive roasting, magnetic separation, soda, sodium chloride, leaching