Study On Acidithiobacillus Ferrooxidans Cooperating With Dilute Sulfuric Acid Leaching Of Vanadium From Black Shale

Vanadium-bearing shale is one of the most important vanadium mineral resources in China.Reaseraches about extracting vanadium from vanadium-bearing shale are foucs on recovering vanadium by chemical leaching.Compared to the conventional techniques,the biotechnological leaching process offers attractive features for metal extraction from solid materials.It has been proven to be an effective,low-cost and eco-friendly way to process various minerals and wastes.Bioleaching of vanadium from vanadium-bearing shale has the characteristics of simple process and low production cost.There are few studies about bioleaching of vanaidum from shale,and the process and mechanism of vanadium bioleaching need to be improved.Thus,this study investigated bioleaching of vanadium from a vanadium-bearing shale by adapted Acidithiobacillus ferrooxidans.The influence of several parameters on vanadium recovery have been studied.The effect of iron ions on vanadium bioleaching have been discussed.The bioleaching residue was leached by dilute sulfuric acid to recovery vanadium with lower acid consumption and lower energy consumption.The results showed that the best conditions for vanadium extraction were 20 g/L pulp density,5 g/L initial Fe2+ and 10% inoculum percentage under p H 2.0.The vanadium leaching efficiency of 62.39% was achieved in 1.2 days,which was 20% higher than the controls.After bioleaching,most vanadium bounded in silicate and a few vanadium bounded in free oxides remain in residue.To recovery vanadium in the residue,it was leached by 5% sulfuric acid for 1 h at 70 ? with the solid-liquid ratio of 1 m L/g.The vanadium leaching efficiency of bio-chemical leaching was 70.6%,which was 15.24% higher than the chemical leaching.The shale leached at 90 ? by 20% sulfuric acid for 1 h,and 71.28% of vanadium was released.The acid and energy consumption of bio-chemical leaching were lower than the chemical leaching.Thus,bio-chemical leaching can be applied in extracting vanadium from the vanadium-bearing shale.During bioleaching,the vanadium leaching efficience increased in 1.2-day bioleaching.Then,it decreased significantly.The vanadium extraction in 1.2 days was mainly attributed to the dissolution of vanadium in free oxides of shale.Most of V(?)and V(?)in the shale were leached,and V(?)was remained in the residue.The decrease of vanadium leaching efficiency in bioleaching process was caused by both adsorption and co-precipitation with jarosite.And jarosite adsorbed on the shale and inhibited the further dissolution of vanadium.