Fundamentals of zinc recovery from metallurgical wastes in the Enviroplas process

Abstract

The Enviroplas process was developed at Mintek to treat certain metallurgical wastes, such as lead blast furnace slag, electric arc furnace dust, and neutral leach residues from the zinc industry. The process relies on a DC arc furnace and an ISP lead splash condenser for the direct recovery of the contained zinc as prime western grade metal, with the simultaneous production of a disposable slag. This paper outlines certain fundamental issues of the process, including feed preparation and specifications, operating temperatures, coke (coal) requirements, flux addition, and recycling of the fumes and the condenser dross. In addition, the chemical reactions involved and the associated kinetics are presented and discussed, as well as the major factors that influence the condensation process. Selected test results are also included to highlight the significance of the most important factors that affect the process.