Chromium Control in Ammonium Vanadate Precipitation from Slag-Derived Liquors: A Diagnostic Framework Integrating Speciation, Entrainment, and Mother-Liquor Recycling

Ammonium precipitation is widely used to recover vanadium from slag-derived liquors as ammonium metavanadate or polyvanadate, but chromium control is often evaluated less systematically than vanadium recovery. This focused process-diagnostic review draws on the topic-guided literature identified from academic literature sources, preliminary literature-discovery tools, and reference-list tracing. It presents a diagnostic framework integrating V/Cr speciation, cake entrainment, washing response, soluble-ion tracers (Na+, SO42−, Cl−), and recycle-accumulation assessment to identify whether product chromium originates from retained mother liquor, solid-associated transfer, or recycle accumulation. The analysis shows that high single-pass vanadium precipitation efficiency alone is insufficient; credible process assessment requires product-Cr source diagnosis, Cr(VI) control, purge/salt-recovery planning, and multi-cycle validation.