Evaluation of cold filter cake leaching using green deepeutectic solvent choline chloride-malonic acid

Nickel and cadmium are removed as cold filter cake (CFC) by zinc powder in the zinchydrometallurgical process. Besides environmental issues, this filter cake also has economic value, andsome research has been conducted to recycle metals through leaching using aqueous solutions. On theother hand, deep eutectic solvents (DESs) are a class of new solvents with good compatibility andbiodegradability that have been used for dissolving various metals. In this study, the ability of cholinechloride-malonic acid DES was investigated for leaching CFC. The used filter cake contained ۲۳.۸%zinc, ۷.۷% nickel, and ۱۱.۸% cadmium. Choline chloride-malonic acid had high dissolution for all threeelements: zinc, nickel, and cadmium, and almost all of them completely dissolved. Therefore, thissolvent can be suitable for the cumulative dissolution of zinc, nickel, and cadmium metals with adissolution efficiency of over ۹۰% in a DES to CFC ratio of ۵۰. There is no considerable change in Zn,Ni, and Cd leaching efficiencies when the DES to CFC ratio is decreased from ۵۰ to ۵. However, as theDES to CFC ratio decreased to ۲.۵, the dissolution of elements decreased significantly. It can beconcluded that ChCl-Ma DES can act as a suitable solvent for the cumulative leaching of Zn, Ni, andCd from CFC

Keywords:

Deep eutectic solvents , Cold filter cake , Choline chloride , Malonic acid.