ABSTRACT
This chapter discusses the technique of liquid ion exchange as used in hydrometallurgy. Solid-state ion-exchanging resins may be classified as anion exchangers or cation exchangers. Liquid ion-exchange reagents may also be classified as anionic or cationic. The basic difference between the two processes is that in liquid ion exchange the active agent is a liquid, thereby imparting to the process the hydraulic advantages not possible in processes utilizing solid-state resin. The first generation of liquid ion-exchange reagents were the organophosphates of which di-2-ethyl-hexylphosphoric acid has continued to be the most popular. The major factor affecting the economics of the liquid ion-exchange process will usually be the concentration of the desired ion in the aqueous feed solution. For copper extraction, some of the effective reagents are LIX 64N and LIX 70. In addition, this reagent also selectively extracts copper from ammonical solutions, thus forecasting a nonpyrometallurgical process for the recovery of copper from scrap.
