Recovery of niobium and titanium from ilmenorutile by NaOH roasting-H2SO4 leaching process

Niobium has a wide range of application in various industries such as materials, alloy, and electronic industry. To improve the use of ilmenorutile in China's Bayan Obo deposit, a novel process of extracting niobium, titanium, and iron from ilmenorutile by NaOH roasting-H2SO4 leaching process (NRHLP) was proposed. The influences of roasting and leaching temperature, roasting and leaching time, molar ratio of NaOH-to-ilmenorutile, leaching mass ratio of liquid-to-solid, and the H2SO4 concentration on the extraction of niobium were systematically investigated. The results demonstrate that this process is efficient. The optimized reaction parameters were as follows: roasting temperature, 550 °C; molar ratio of NaOH-to-ilmenorutile, 2.6; roasting time, 120 min; leaching mass ratio of liquid-to-solid, 4.0; leaching temperature, 90 °C; the H2SO4 concentration, 60 wt.%; leaching time, 2 h. Under these optimum circumstances, the maximum niobium and titanium recovery can reach 96.68%. In addition, a new phase containing niobium and titanium is confirmed and proved.