Supported Liquid Membrane Separation of Aluminum From Copper Leaching Liquors

The Bureau of Mines, US Department of the Interior, investigated the separation of Al from Cu dump leaching liquors using a supported liquid membrane. Aluminum was selectively transported through porous polypropylene impregnated with di(2-ethylhexyl) phosphoric acid in an aliphatic diluent. The effects of variables, such as solution composition, temperature, and extractant concentrations, were measured using a three-level fractional factorial experimental design. Experimental results were used to derive equations for predicting transport rates for Al, Fe, and Cu. The major variables influencing Al transport were solution temperature, feed solution pH, Al concentration in the feed solution, and extractant concentration. Copper and Fe transport rates were almost zero when Al transport rates were high. Measured Al transport rates under the best conditions of 55 deg C, pH 3.0, 16 g/l Al exp 3+ and 65% extractant solution confirmed the predicted value of 210 mu g/(cm exp 2 h). Transport rates for Fe and Cu were < 5 mu g/(cm exp 2 h) under these conditions. 7 ref.--AA(US).