Preparation of V2O5 from converter slag containing vanadium

Preparation of V2O5 from converter slag (CS) was investigated through roasting, leaching, extracting, and precipitating processes. The corresponding roles of the parameters during every procedure were analyzed in detail. (NH4)(2)SO4 and KHSO4 were used as fusing agents to transform compounds containing vanadium into soluble species. Mass ratio of (NH4)(2)SO4 to CS, mass ratio of KHSO4 to CS, and roasting temperature during the roasting process can significantly influence leaching rate of vanadium (LRV). With H2SO4 as leaching agent, 99.2% vanadium in CS can be leached out under the optimum leaching conditions, which mainly refer to liquid-to-solid ratio, H2SO4 concentration, leaching temperature, and leaching time. Extracting and back-extracting processes were introduced to purify the vanadium from the H2SO4 lixivium. Extracting rate of vanadium (ERV) greatly depends on iron powder concentration, pH, diisooctyl phosphate (P-204) content, volume ratio of extractant to H2SO4 lixivium, and extracting time. By adding ammonium hydroxide, 94.0% vanadium in back-extracting solution can be separated in the form of precipitates. The product from the roasted precipitate mainly consists of V2O5, the content of which is higher than 90.0%.