废弃SCR催化剂中钒和钨的浸出及回收

采用NaOH溶液一次性浸出废弃SCR催化剂中的钒和钨,并用硫酸对浸出液进行除杂,再利用NH4Cl和硫酸分步对浸出液中的钒和钨进行沉淀回收。在NaOH质量分数40%、液固比8、浸出时间4 h、浸出温度90℃的最佳碱浸条件下,钒和钨的浸出率分别达到90.44%和84.49%。除杂过程的铝去除率达到100%,硅去除率达到77.56%。在沉钒pH为8.0、n(NH_4~+)∶n(V)为4的最佳沉钒条件下,钒回收率达到82.79%。在n(SO_4~(2-))∶n(W)为2的最佳沉钨条件下,钨回收率达到76.41%。

Leaching and recovery of vanadium and tungsten from spent SCR catalyst

V and W were leached from the spent SCR catalyst by one-step process with sodium hydrate solution,and then sulfuric acid was added to remove impurities in leached solution. V and W in the leached solution were recovered by precipitation method with NH₄Cl and sulfuric acid step by step. The leaching rate of V and W reached 90.44% and 84.49% respectively under the optimum alkaline leaching conditions of NaOH mass fraction 40%,liquid to solid ratio 8,leaching time 4 h and leaching temperature 90 ℃. The removal rate of Al and Si in the impurities-removing process reached 100% and 77.56%,respectively. Under the optimum conditions for V precipitation of V precipitation pH 8.0 and n（NH₄⁺）∶n（V）=4,the V recovery reached 82.79%. Under the optimum conditions for W precipitation of n（SO₄^2-）∶n（W）=2,the W recovery reached 76.41%.