Research On Separation Technology Of Vanadium And Titanium Components From Vanadium-rich Titanium Slag

The resources of vanadium-titanium magnetite are abundant in China, and the vanadium-rich titanium slag is one of the products of solid-state reduction-grinding process based on vanadium-titanium magnetite. Vanadium is one impurity which is difficult to remove when preparing titanium-rich slag with vanadium-rich titanium slag, and this impurity not only has bad effect on the grade of titanium-rich slag and the following titanium-products, but also causes the waste of vanadium resources. At present, more research on the utilization of titanium from vanadium-rich titanium slag has been done, but less research on vanadium recycling.Based on vanadium-rich titanium slag (Prepared by solid-state reduction—grinding process with vanadiferous titanomagnetite as raw material), research on the vanadium extraction through roasting-acid leaching method was carried out, then preparing titanium-rich slag with the titanium slag of vanadium-removed by alkaline leaching combining acid leaching.The mechanism of roasting and leaching of vanadium were investigated, and analysis of thermodynamics determined that leaching of vanadium could be performed at low acidity. The results showed that the vanadium leaching rate reached 53.11%, under the state of particle size of 48～75μm, salt-free roasting, roasting temperature of 900℃, roasting time of 2h, leaching pH of 4～4.5,leaching temperature of 60℃ and leaching time of 15min.The analysis of the E-pH of impurities and water showed that the TiO2 content of vanadium-rich titanium slag can be improved significantly by alkali leaching combining acid leaching method. The optimal alkali leaching conditions:T=95℃, t=2h, CNaOH=10%, L/S=2. The optimal acid leaching conditions:T=30℃, t=30min, CHCl-2.96%, L/S=4. And the titanium-rich material with grade of 72.08% could be obtained finally.Kinetics results of alkaline leaching combining acid leaching showed that the process was in line with the unreacted-core models of constant size spherical particles, and the reaction rate was controlled by product layer diffusion and chemical reaction collectively. The apparent activation energy of process was 27.75kJ/mol.The grade of the titanium slag product could not be improved considerably, because of the particle surface had been covered by the reaction products. While the product layer can be destroyed by the alternate leaching method of alkaline leaching and acid leaching, so multi-stage leaching program was carried out. After four-stage leaching, the grade of titanium-rich slag product reached 86.95%.