Extracting Ni, Ti, Sc and RE from niobium-enriched slag by CaCl2 Roasing and H2SO4 decomposition method

The niobium enriched slag was decomposed by calcium chloride activator at high temperature. Then the niobium, titanium, scandium and rare earths were leached out by sulfuric acid. Effects of activator volume, activation temperature, activation time, concentration of H2SO4, leaching temperature and time on leaching rate were researched. The results shows that under the conditions of activator volume 60%, roasting temperature 800°C, roasting time 1-2 hrs, concentration of sulfuric acid 6 mol/L and leaching time 3 hrs, the leaching rates of niobium is over 85%, and the leaching rates of scandium, titanium are all over 90%.