(331a) Separation of V(V) and Cr(VI) By Primary Amine in Case of Resource Utilization of Industrial Residue Containing Vanadium and Chromium

Solvent extraction of Vanadium(V) and Chromium(VI) by primary amine was firstly applied to high selectively separate V(V) and Cr(VI) from residue containing Vanadium and Chromium to make high value product respectively. Fundamental research work was systematically carried out in lab, then pilot scale and commercial scale experiments were operated in factory, and it is the first commercial application of V-Cr separation by primary amine. The experiments in lab indicated that, kerosene solution of LK-N21 could separate Cr(VI) and V(V) from nearly neutral aqueous solutions with high efficiency: LK-N21 without acidify as extractant could extract >85% V(V) and >90% Cr(VI) left in aqueous phase with operation conditions as material liquors pH=5, phase ratio=1:1, mixing time >5min. The loaded organic phase could be easily stripped in 15-30min under 45℃, nearly 100% V(V) transferred into aqueous phase. The analysis results showed the mechanism of Cr(VI) and V(V) solvent extraction by primary amine from nearly neutral aqueous solutions was solvation with molecular association between primary amine and V(V)/Cr(VI) through hydrogen bonding. The pilot scale and semi-commercial scale experiments also showed V(V) and Cr(VI) could be separated very well in the conditions above: after solvent extraction separation process, liquor containing 28~35g/L V(V) and 0.3~2g/L Cr(VI) was produced with separation factor over 70, more than 98% V(V) was recovered, the loss of extractant less than 0.2%. The purity of Vanadium pentoxide produced by semi-commercial scale process is over 99.5%.