Recovery of metals from an acid leachate of spent hydrodesulphurization catalyst using molecular recognition technology

Abstract

Acid leaching of spent hydrodesulphurization (HDS) catalysts solubilizes efficiently all metals present in the catalyst; however, this methodology poses subsequent difficulties in achieving metals separation with high purity. In the present work, molecular recognition technology, using SuperLig® 167 resin, was applied to recover Ni, Mo and Al from H2SO4 leachate of spent HDS catalyst.Batch tests showed a good resin affinity to Ni, in acid, with a maximum capacity of 1.35mmol/g. The separation of Al, which was in excess, was efficient, but Mo was also retained by the resin.Column studies, using 6g of resin and performed at three flow rates (1.0, 1.5 and 2.1mL/min), showed that the lower flow rate was better to treat a higher volume of solution. At 1.0mL/min, each gram of resin treated almost 40mL of solution with 97% and 100% of Ni and Mo retention, respectively. Elution with NaOH 0.25mol/L, followed by HNO3 4mol/L, both at 2.1mL/min, led to efficient separation of Mo and Ni.The use of SuperLig® 167 resin to treat the leaching solution enabled an easy and efficient separation of the metals present in the acid leachate into mono-metal solutions (Al in the raffinate, Mo and Ni in the alkaline and acid eluates, respectively) with high yield (99.7%, 100% and 87%, respectively) and purity (99.3%, 99.8% and 98.7%, respectively).