Kinetics of copper removal from acidic mine drainage by a liquid emulsion membrane

Abstract

Copper was removed from an acidic mine drainage (AMD) using a liquid emulsion membrane contactor. The acidic drainage was a harmful natural acidic solution generated by bioleaching and chemical leaching of copper and iron sulfides, with average pH between 2 and 4. Normally the content of copper in AMD is low, which makes its recovery by SX uneconomical. The kinetics of copper removal in a stirred transfer cell was studied, using a salicylaldoxime as mobile carrier extractant and Span-80 as surfactant. It was found that the initial extraction rate of copper was affected by the carrier concentration in the liquid membrane and by the pH and metal content in the mine water. A minimum content of surfactant in the organic phase was required to stabilize the emulsion. A transport mechanism based on a diffusion model, which includes the extraction chemical reaction between the metal and the carrier extractant is discussed.