Abstract In this paper, a process of selective extraction and separation of vanadium (IV) from acid leaching solution of spent oil hydrotreating catalyst by a solvent extraction method with P204 as an extractant was proposed. Because the leaching solution contained a large amount of elements such as nickel, aluminium and iron, the effects of various conditions on the separation of vanadium from nickel, aluminium and iron were investigated and the optimum conditions were determined. At the same time, the thermodynamic discussion on the extraction process of vanadium in the system was carried out. Using kerosene as a diluent and 20% (v/v) P204 as an extractant, the single-stage maximum extraction ratio of 93.47% for vanadium was obtained under the optimum extraction conditions of O/A ratio of 2, oscillation time of 8 min, extraction temperature of 298 k(25 °C) and pH value of initial aqueous phase of 2. After three stages of countercurrent extraction experiments, the concentration of vanadium, iron, nickel and aluminium in the loaded organic phase were 0.377, 0.001, 0.005 and 0.02 g/L, respectively, and their extraction ratios were determined to be 99.21%, 1.02%, 2.857% and 1.942%, respectively, realizing the selective extraction and separation of vanadium. With 2 mol/L of sulfuric acid as a stripping reagent, the complete removal of vanadium from the loaded organic phase could be achieved at O/A ratio of 2 by three stages of countercurrent experiments of vanadium removal. The thermodynamic calculation showed that the enthalpy change of the vanadium extraction in the system was −20.37 kJ.mol−1. This demonstrated that the extraction of vanadium from acid leaching solution of spent oil hydrotreating catalyst with P204 as the extractant was an exothermic reaction.

中文翻译：

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D2EHPA（P204）溶剂萃取法从废油加氢处理催化剂酸浸液中回收钒

摘要 本文提出了一种以P2O4为萃取剂的溶剂萃取法从废油加氢处理催化剂酸浸液中选择性萃取分离钒(IV)的工艺流程。由于浸出液中含有大量的镍、铝、铁等元素，研究了各种条件对钒与镍、铝、铁分离的影响，确定了最佳条件。同时对体系中钒的提取过程进行了热力学讨论。以煤油为稀释剂，以20% (v/v) P2O4为萃取剂，在O/A比为2、振荡时间为8 min的最佳萃取条件下，钒的单级最大萃取率为93.47% , 萃取温度298k(25℃)，初始水相pH值为2。经过三个阶段的逆流萃取实验，负载的有机相中钒、铁、镍和铝的浓度分别为0.377、0.001、0.005和0.005。 0.02 g/L，其萃取率分别为99.21%、1.02%、2.857%和1.942%，实现了钒的选择性萃取分离。以2 mol/L的硫酸为汽提剂,通过三段逆流脱钒实验,在O/A比为2的条件下,可实现负载有机相中钒的完全脱除。热力学计算表明，体系中钒提取的焓变为-20.37 kJ.mol-1。