Robert P. Cahn

Extraction of Copper by Liquid Membranes

Abstract Important variables governing the permeation of copper ion through liquid membranes and their effects on the separation process are described. These variables are membrane viscosity, treatment ratio (volume ratio of emulsion to feed in mixer), complexing agent concentration, internal droplet size, internal phase leakage, and copper concentration in the internal phase. The information is needed for scaling-up of equipment and further process development. The economic evaluation based on bench-scale pilot plant runs shows this process is 40% cheaper than solvent extraction.

Separations of organic compounds by liquid membrane processes

By allowing a hydrocarbon mixture to permeate through a thin film of a liquid with which it is essentially immiscible, separation of the constituents of this mixture may occur. The phenomenon has been observed with both unsupported and supported liquid films. This paper discusses liquid membrane permeation (LMP) through unsupported liquid films, especially those present when an emulsion of two liquids is dispersed in the form of relatively coarse drops in a third liquid into which permeation is allowed to occur from within the drops. The mechanism underlying the separation phenomenon, differential permeation rates, can be used to formulate an actual separation process. Rate equations can be derived which allow sizing of equipment and comparison of LMP with other separation techniques. Possible improvements involving preferential complexing agents in the membrane phase, as well as potential applications to oil refining and other chemical processes, are discussed.