废炼油催化剂酸浸液中钒与铁的共萃取与梯度分离

Co-extraction and gradient separation of V and Fe in acid leaching solution of spent refinery catalyst

以二(2-乙基己基)磷酸(P204)和磷酸三丁酯(TBP)为萃取剂对废炼油催化剂酸浸液中铁、钒进行共萃取,考察了P204体积分数、萃取剂皂化率、萃取相比、萃取时间及萃取级数对钒铁共萃取效果的影响,并考察了以硫酸、草酸作为反萃剂对负载有机相中钒、铁的反萃效果。实验结果表明:采用20%(φ,下同)P204+5%TBP+75%磺化煤油组成的二元萃取体系在萃取剂皂化率为60%、萃取相比为1∶1、萃取时间60 min的条件下,经5级逆流萃取后,铁、钒萃取率分别达98.4%和97.6%;采用150 g/L硫酸作为反萃剂,在相比为6∶1、反萃时间为15 min的条件下对有机相中的钒进行4级逆流反萃,然后采用120 g/L草酸作为反萃剂,在相比4∶1、反萃时间为60 min的条件下对负载有机相中剩余的铁进行4级逆流反萃,钒的总反萃率为100%,铁的总反萃率为98.4%,钒与铁实现了梯度反萃分离。

The co-extraction of V and Fe from the acid leaching solution of spent refinery catalyst was carried out by using bis(2-ethylhexyl)phosphoric acid(P204)and tributyl phosphate(TBP)as the extraction agents.The factors affecting the coextraction effect of V and Fe were investigated,such as:volume fraction of P204,saponification rate of extraction agent,extraction phase ratio,extraction time and extraction stage.The reverse extraction effect of sulfuric acid and oxalic acid to V and Fe in the loaded organic phase was also investigated.The experimental results show that:When the two-phase extraction system composed of 20%P204+5%TBP+75%sulfonated kerosene is used for a 5-stage countercurrent extraction under the conditions of extraction agent saponification ratio 60%,extraction phase ratio 1∶1 and extraction time 60 min,the extraction rates of Fe and V reached 98.4%and 97.6%,respectively;V is extracted from the organic phase by 4-stage countercurrent stripping under the conditions of using 150 g/L sulfuric acid as stripping agent,extraction phase ratio 6∶1 and stripping time 15 min,and then Fe is extracted from the organic phase by 4-stage countercurrent stripping under the conditions of using120 g/L oxalic acid asstripping agent,extraction phase ratio 4∶1 and stripping time 60 min.The gradient stripping separation of V and Fe is achieved with 100%and 98.4%of the total stripping rate,respectively.