Abstract:Applying H2SO4 instead of HF as leaching reagent to extract niobium from tantalum-niobium concentrate, a new wet treatment process of sulfuric acid roasting and sulfuric acid leaching was proposed to reduce cost and solve pollution issue. The results show that niobium in mineral sample reacts completely and stays in slag in sulfuric acid roasting stage under the conditions including particle size of -74 μm of 90%, mass ratio of concentrated sulfuric acid to ore sample of 80%, roasting temperature of 300 ℃, and roasting time of 1.5 h. In the leaching stage, leaching rate of niobium is 93.4% under the conditions including H2SO4 concentration of 30%, L/S of 3︰1, temperature of 90 ℃, and leaching time of 3 h.