Microwave-assisted leaching of vanadium from vanadium slag with sulfuric acid

Microwave irradiation was used to investigate vanadium slag in place of traditional heating.Factors associated with vanadium extraction ratio were studied following the concentration of leaching agent,oxidant dosage,microwave power,microwave irradiation time and mass ratio of liquid to solid.Results indicated that leaching ratio based on microwave leaching at atmospheric pressure can get to 68.48% under the conditions following sulfuric acid concentration 30%,mass ratio of liquid to solid ratio 2∶1,mass ratio of vanadium slag to manganese dioxide dosage 25∶1.4,and microwave power 800W for 3.5 h at 95 ℃.While,leaching ratio based on microwave leaching under pressure was up to 45.79% under the conditions following sulfuric acid concentration 20%,mass ratio of liquid to solid ratio 2∶1,mass ratio of vanadium slag to manganese dioxide dosage 25∶0.9,microwave power 800W for 10 min.Results showed leaching based on microwave irradiation under pressure can shorten time 94.44% in comparison with that at atmospheric pressure,and the leaching extraction can improve about 20%.