Preparation of V2O5 from converter slag containing vanadium

Abstract

Preparation of V 2 O 5 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. (NH 4 ) 2 SO 4 and KHSO 4 were used as fusing agents to transform compounds containing vanadium into soluble species. Mass ratio of (NH 4 ) 2 SO 4 to CS, mass ratio of KHSO 4 to CS, and roasting temperature during the roasting process can significantly influence leaching rate of vanadium (LRV). With H 2 SO 4 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, H 2 SO 4 concentration, leaching temperature, and leaching time. Extracting and back-extracting processes were introduced to purify the vanadium from the H 2 SO 4 lixivium. Extracting rate of vanadium (ERV) greatly depends on iron powder concentration, pH, diisooctyl phosphate (P 204 ) content, volume ratio of extractant to H 2 SO 4 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 V 2 O 5 , the content of which is higher than 90.0 %.