碳热还原/熔融分离废SCR催化剂中有价金属

Carbon thermal reduction/melting separation of valuable metals from spent SCR catalysts

在热力学计算的基础上,把废SCR催化剂(钒钛系)与碳、铁和石灰等原料混合后装入直流电弧炉中熔化、还原,用SEM、XRD分析渣/铁两相试样的化学成分与物相,研究废SCR催化剂再回收的基础问题,并探讨其碳热还原/熔融分离行为和机理。结果表明,有价金属回收率随n(碳)/n(氧)、温度和碱度等条件而变。在熔池温度为1650℃的条件下,回收废SCR催化剂中二氧化钛、金属的最佳参数为:n(碳)/n(氧)为1.0、碱度为1.0;在此条件下可实现含钒、钨的铁合金与高钛渣的完全分离,铁、钒、钨和二氧化钛的回收率分别达到99%、97%、92%和93.5%。这对于开发废SCR催化剂的回收再利用技术,实现可持续发展具有重大的现实意义和经济价值。

On the basis of thermodynamics calculate,the spent SCR catalyst(V-Ti)was mixed with C,Fe and CaO and then melted and reduced in a DC arc furnace.The chemical composition and phase of slag/iron samples were analyzed by SEM and XRD.The basic problem of spent SCR catalyst recycling was studied,and the behavior and mechanism of carbon thermal reduction/melting separation were discussed.Results showed that the recovery rate of the valuable metal changed with the amount-of-substance ratio of C to O,temperature and basicity etc..Under the condition of molten pool temperature of 1650℃,the optimal parameters of recycling TiO2/metal from spent SCR catalyst were as follows:n(C)/n(O)=1.0 and basicity was 1.0.This can realize the complete separation of ferroalloy containing V and W and high titanium slag.The recovery of Fe,V,W and TiO2 could reach around 99%,97%,92%and 93.5%,respectively.This is of great practical significance and economic value for the development of spent SCR catalyst recycling technology and the realization of sustainable development.