A State-of-the-Art Discussion on the Solvent Extraction Reagents Used for the Recovery of Copper from Dilute Sulfuric Acid Leach Solutions

The recovery of copper from dilute sulfuric acid leach solutions has been a commercial reality since 1968 (1), and since then the technology has gained worldwide acceptance. Only one chelating functionality, the hydroxy oxime group, has been used commercially for this task. There are, however, two distinct classes of extractants based on the hydroxy oxime group: the salicylaldoximes, which are very strong copper extractants and the ketoximes, which are mo derate copper extractants. A third class of extractants combines a ketoxime with a salicylaldoxime in about a 1/1 mole ratio and results in some surprising advantages. This paper will discuss each reagent class, showing their advantages and disadvantages and will also introduce two new reagents, LIX¯ 84 and LIX 984, showing their behavior with respect to copper extraction, and discussing where they may be used to advantage.