Recovery Leaching of Niobium from Metallurgical Residues

Niobium was recovered by acid-alkaline leaching from metallurgial residues. The experimental results indicate that effects of different leaching system and leaching conditions on the Nb recovery were different. Separation of niobium and impurities such as iron, manganese, calcium and silicon is essential for Nb recovery. Acid leaching distributed metals between the solid and solution. While about 98%Nb remains in the leached mud when alkaline sintering–leaching processed. According to the investigation of comprehensive process of acid-base, tungsten residue was leached with a double excess of 15%HCl at 60°C for 90mins,and leached mud was mixed with soda as W(soda)/W(residue) =0.37，then Sintered at 850°C for 90mins，gained concentrated material with 2.74%Nb2O5after leaching at 95°C for 60mins. 86.8%Nb remain in the mud. Product containing 15.8% Nb2O5was gained via decomposition by HF+H2SO4system and solvent extraction with MIBK. Wasted residue from alkali leaching of tin metallurgical slag were deal with the same conditions and concentrate containing 17.02% Nb2O5was gained.