Abstract:The alkaline leaching method has been widely applied for the extraction and recovery of valuable resources such as vanadium and tungsten from spent denitration catalysts. However, due to the similar chemical properties of vanadium and arsenic, during the alkaline leaching process, arsenic is dissolved into the leachate along with vanadium, resulting in difficulties in subsequent vanadium recovery and the generation of toxic wastewater, posing risks to environmental safety. In this study, a novel integrated process of calcium precipitation, acid dissolution, iron salt arsenic removal, and calcium salt vanadium precipitation was proposed. During the calcium precipitation step, vanadium and arsenic are converted into insoluble calcium vanadate and calcium arsenate, achieving efficient precipitation of vanadium and arsenic and enabling the recovery of alkaline leachate. After acid dissolution, effective separation of vanadium and arsenic in the acidic solution was achieved using ferrous sulfate precipitation, with arsenic fixed in the precipitate as iron arsenate. The optimized process conditions include pre-oxidation time of 30 minutes with H2O2, initial pH value of 3, reaction temperature of 30 ℃, and reaction time of three hours. The precipitation rate of arsenic is 97.26%, with loss rate of vanadium of 1.84%. Calcium vanadate is obtained by adding calcium hydroxide to the vanadium-containing filtrate. This process achieves efficient separation of vanadium and arsenic from the alkaline leachate of spent SCR denitration catalysts and the recovery of high alkalinity solution.