Highly efficient separation and recovery of Si, V, and Cr from V-Cr-bearing reducing slag

Abstract

The V-Cr-bearing reducing slag (VCBRS) is solid waste, which cannot be treated at present. This work proposes an effective approach to separately recover its major elements of V, Cr and Si and fully utilize the VCBRS with added-values. Flocculation desiliconization is used to extract Si from the acid solving liquid of VCBRS and Si is recovered as white carbon black with purity of 94.60% and recovery of 93.04%. After desiliconization, V in the solving liquid is selectively oxidized by H2O2 and extracted by microemulsion extraction, which is recovered as V2O5 whose purity is 99.60% with recovery at 96.32% from the stripping liquor of loaded microemulsion. Cr in the raffinate is recovered by alkaline precipitation as final product of Cr2O3 with purity of 98.83% and recovery of 92.68%. The principles are discussed in detail and the operation conditions are optimized systematically. The microemulsion and wastewater are both cyclically utilized, which eliminates the secondary wastes. This work efficiently recovers all valuable elements with increased values from the solid waste, which can not only solve the environmental pollution problem, but also realize the efficient recovery of valuable elements to achieve comprehensive utilization.