Extraction of Vanadium from LD Converter Slag by Pressure Leaching Process with Titanium White Waste Acid

The process of extraction vanadium from LD converter slag by pressure leaching with titanium white waste acid was investigated. The mineralogy analysis indicates that several kinds of spinel containing Fe, V, Ti, Mn and Cr, mainly exist in the converter slag. Potential-pH diagrams of V-Fe-H2O, V-Ti-H2O, V-Mn-H2O, V-Cr-H2O system have been calculated at elevated temperature condition (150 °C). The thermodynamics diagrams show that soluble ions of V and Fe2+, Fe3+, Mn2+, Cr2+ and Cr3+ can be extracted by the acidic leachate during the pressure leaching process. The results of orthogonal experiment reveal that the impacts of temperature and initial acid concentration on the vanadium extraction process are effective. The effect of temperature on the leaching process was further investigated with a increased temperature from 100 °C to 160 °C, and the results indicate that the content of titanium in the residue is 4.56% to about 12.0%, while other elements tend to be enriched in the leaching solution. Under the optimization condition (temperature 140 °C, liquid-solid ratio 10:1, concentration of acid at 200 g·L−1, stirring speed 500 r/min and the reaction time of 90 min), the leaching rate of vanadium is 96.85%.