摘要:
废弃SCR催化剂中含有V、W和Ti等多种有价金属,直接弃置不仅会造成环境污染,还会造成资源的浪费,因此回收其中的有价金属具有重大意义。提出采用湿法冶金的方法,通过NaOH碱性浸出法一次性浸出废弃催化剂中的V和W,然后对浸出液进行钙化沉淀,通过甲酸选择性浸出钙混合沉淀物中的钒,经过除杂,加入氨水,钒将以偏钒酸铵的形式沉淀出来;甲酸浸出后沉淀物中的钨,加入盐酸转化为钨酸,经过灼烧,最终生成三氧化钨。通过试验确定了NaOH碱性浸出法最佳工艺条件和甲酸选择性浸出最佳反应条件。
Abstract:
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.
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