Extracting vanadium from stone-coal by
oxygen pressure acid leaching and solvent extraction
(Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,
Kunming 650093, China)
Kunming 650093, China)
Abstract: Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction. The mineralogy of the stone-coal from Tongren City of Guizhou Province, China, was investigated by various determination methods. The effects of leaching time, leaching temperature, leaching agent concentration, leaching L/S ratio, granularity of material, additive consumption were investigated based on the mineralogy. The results show that under the conditions of leaching time of 3−4 h, temperature of 150 ℃, sulfuric acid consumption of 25%−30%, ratio of liquid to solid of 1.2:1, the granularity less than 0.074 mm, additive consumption of 3%−5%, and oxygen pressure of 1.2 MPa, and the vanadium leaching rate can be more than 92% by the method of two-step pressurized acid leaching. The powdery V2O5 product with 99.52% in V2O5 content is obtained by the flowsheet of acid recovery, removing iron by reduction process, solvent extraction, precipitating vanadium with ammonium water, and pyrolysis from the stone-coal oxygen pressure acid-leaching solution. The total recovery efficiency of vanadium is above 85%, which is more than 20% higher than that obtained in the conventional process. Furthermore, the new process does not cause air pollution since no HCl or Cl2 is released by calcination of the raw material.
Key words: stone-coal; extracting vanadium; oxygen pressure; acid leaching; acid recovery; solvent extraction