It has been known that stripping of Cu extracted with CYANEX 301 is difficult. To overcome this difficulty, the usage of CYANEX 301/LIX® 984N mixture was investigated. It was found that this mixture is effective in Cu stripping, and that less concentrated acid solution is required for stripping. Addition of LEX® 984N to CYANEX 301 showed strong influence on copper stripping with 6 M sulfuric acid solutions. Stripping % increased to 94 % with increase LEX 984N concentration to 0.1708. From the data obtained, synergism has an important role in copper stripping from CYANEX 301 solutions. Of the stripping solutions studied, HNO3 presented the highest Cu stripping "close to 100%" in 120 min at concentrations higher than 4 M. Additionally, when increasing HCl concentration from 2 to 6 M, 90.65% efficiency was attained. In the same manner, temperature has a slight extent on Cu stripping and indicate that copper stripping is an exothermic process. It was found that activation energy using 4 M nitric acid is -86.7 kJ/mol. This means that stripping from CYANEX 301/LIX® 984N loaded solutions is diffusion and chemically controlled |
