Separation and recovery of V, Ti, Fe and Ca from acidic wastewater and vanadium-bearing steel slag based on a collaborative utilization process

Two typical wastes (acidic wastewater and vanadium-bearing steel slag) produced in the metallurgical process of vanadium-titanium magnetite not only pose a huge threat to the environment, but also waste a lot of resources such as V, Ti, and Fe. In order to effectively treat the two wastes and recover the resources such as V, Ti, Fe and Ca, a collaborative utilization process has been studied. When the O/A ratio of 1.5, the P204 concentration of 20% (v/v), the single-stage extraction rate of titanium was above 96%. After two-stage countercurrent extraction, the extraction rate of Ti can be reached 99.86%, while the co-extraction rate of Fe was less than 3%. The leaching rates of V, Fe, and Mg in the vanadium-bearing steel slag were respectively 98.68%, 99.67% and 99.63% under the condition of a ratio of the volume of the raffinate after titanium extraction to the mass of the vanadium-bearing steel slag at 8:1 (75 min at 60 degrees C). The analysis through XRD proves that the leaching conditions had an effect on the composition of the leaching slag, of which temperature had the greatest impact on it, and the composition of the leaching slag was anhydrite at 90 degrees C. After the leaching solution was pre-reduced with ammonium sulfite, the P507 extractant can separate V and Fe very well, and the V-loaded organic phase was treated by ammonium carbonate stripping and calcination process, the product of V2O5 with a purity of 99.03% can be obtained. Additionally, after the raffinate after vanadium extraction was oxidized with H2O2 solution and neutralized with ammonia solution, the solid product and solution obtained by filtration were respectively processed to obtain a roasted slag containing 72.14% Fe2O3 and a product of 99.09% purity of (NH4)2SO4.