Technology for Extracting Manganese from Vanadium Converter Slag After Leaching Vanadium

New technology is developed for preparing pure vanadium pentoxide from vanadium-containing metallurgical slag. As a result of the selective extraction of vanadium from calcined slag, solid residues containing from 7 to 10% of manganese are formed, which are suitable for extraction. A study of the mineralogical composition of solid residues shows that manganese is found in cakes in the form of MnCO3. An aqueous solution of sulfuric acid is adopted as the leaching agent. According to our data, the maximum solubility of manganese sulfate was 484–500 g/dm3 at T = 25 °C, 5 g/dm3 H2SO4. Considering these data, a study is made of leaching Mn from solid residues with aqueous solutions of H2SO4. Extraction of Mn from solid residues into the solution is 75%, and additional extraction of vanadium remaining in cake is up to 50%. The complex solutions obtained by leaching, containing Fe3+, V5+, Al3+, Si4+, are purified by feeding them to a fresh portion of cake at pH 4–4.5 and Mn is precipitated from solution by using (NH4)2CO3 to form MnCO3. The washed and calcined residue contains pure Mn3O4. The main production scheme for comprehensive treatment of vanadium slag with preparation of V2O5, Mn3O4, MgO, (NH4)2SO4 from solution, and complex master alloys from solid residues is presented.