Assemblies and methods for processing zinc-bearing materials

Abstract

A process for separating and recovering a desired metal as metal oxide from raw material is provided. The process includes placing the raw material and a reductant in a container to form a reducing microclimate within the container. A housing having an oxidizing atmosphere is heated to maintain a temperature zone within the housing at a heating temperature sufficient to expose the raw material in the container to a reaction temperature. The container containing the raw material is conveyed through the temperature zone in the housing to expose the raw material and the reductant to the reaction temperature wherein the metal oxide is reduced to a gaseous metal that exits the container. Once outside the container, the gaseous metal is exposed to the oxidizing atmosphere of the temperature zone wherein the desired metal is oxidized to metal oxide and the metal oxide is collected. In preferred embodiments, the raw material is EAF dust and the desired metal is zinc. In one specific embodiment, the process also includes maintaining a second temperature zone in the housing at a metal halide vaporization temperature, which is lower than the heating temperature. A flow of air is applied through the housing in a direction that is opposite to a direction of travel of the container during the conveying step, whereby a metal halide in the raw material is volatilized to a volatilized metal halide when the container is conveyed through the second heating zone. The volatilized metal halide is then collected.