Study on the Recovery of Vanadium from Waste Catalyst in Coal-fired Power Plants

Spent SCR catalyst contains vanadium(V),tungsten(W),titanium(Ti) and other valuable metals.Direct discard will cause not only environmental pollution but also a waste of resources,so the recovery of valuable metals from the spent catalyst has a great significance. A hydrometallurgical process for recovery of V and W from the spent catalyst was raised in this paper.V and W were firstly leached from the catalyst using NaOH solution,then the leaching solution was precipitated with calcium reagent and the obtained sediment was selectively dissolved by formic acid that V was enriched in the liquor.Undergoing impurities removal for the liquor,V can be recycled as ammonium metavanadate by adding ammonium water into the liquor for precipitation. W in the formic acid-leached sediment was extracted by hydrochloric acid to form tungstic acid and finally transformed into tungsten trioxide after calcination. The optimum parameters for NaOH leaching and formic acid selective leaching were determined by the experiments.