Continuous Fuming of Zinc-Bearing Residues: Part I. Model Development

The disposal of zinc-containing residues is an important sustainability issue currently facing the metallurgical industry. These residues can be treated by using zinc slag-fuming processes in which heavy metals are chemically reduced and evaporated from a molten slag bath. Continuous operation of these processes requires high zinc-fuming rates while retaining vessel integrity. To meet these challenges, a new generation of technologies is being developed that depends on the formation of a freeze lining on the internal reactor walls. A general zinc-fuming process model that simultaneously describes the chemical reactions, phase equilibria, and thermal- and heat-transfer outcomes of these processes has been developed using the FactSage thermodynamic databank system and the ChemApp programmer’s library for thermochemical applications. This simultaneous description of these processes allows the model to be used as part of a new approach to the design of freeze linings, namely, the use of slag engineering and composition adjustment to obtain optimum process efficiency and freeze lining behavior.