Zinc solvent extraction in the process industries

Abstract

The global zinc industry is currently experiencing unprecedented interest in new developments and expansions. While most of the new projects and plant upgrades remain committed to traditional processing technologies, recent advances in zinc solvent extraction have created opportunities for new process routes in the treatment of both primary ore and secondary materials. The production of special high-grade zinc from the complex Skorpion ore, previously considered untreatable, will be the first commercial application of zinc solvent extraction for the mainstream processing of primary ore. This mine-to-metal project promises to become one of the lowest-cost zinc producers. Solvent extraction is also under consideration for several other oxide and sulfide projects in various stages of feasibility. With respect to the processing of secondary materials, new applications of zinc solvent extraction have proved advantageous for the treatment of zinc residues and furnace dust. In contrast to the zinc industry itself, zinc solvent extraction is well established in the refining of other base metals, providing an efficient means of eliminating zinc as an impurity element. Many applications have been for cobalt and nickel refinery operations. More recently, larger-scale applications have been for primary operations, where refined copper, cobalt, and nickel are produced at the mine site. Previously regarded as a waste product in such operations, interest is now being shown in recovering zinc as a valuable by-product in selected flowsheets. The industrial application of zinc solvent extraction is reviewed in this paper. The reagents used for the selective extraction of zinc are discussed to provide the basic rationale for the choice of this separation technique. An historical perspective is given by brief discussions of some early applications. The review then focuses on recent installations and projects under development where zinc solvent extraction features as the key separation step.

Keywords:

• Solvent Extraction
• Zinc
• Review
• Di(2-ethylhexyl)phosphoric Acid