Improving zinc processing using computational fluid dynamics modelling – Successes and opportunities

Computational Fluid Dynamics (CFD) models have been developed for many of the unit operations involved in zinc processing, both in the concentrator and in smelting or refining operations. These models are now relatively sophisticated, being capable of accounting for metallurgical effects as well as the underlying multi-phase flow processes, and are therefore powerful tools for optimising process and equipment performance. Examples of unit operation models relevant to the concentrator include flotation, fine grinding and tailings thickeners. Models have also been developed of fluid bed roasters, leach reactors, clarifiers and electrowinning cells as used in a zinc refinery, while smelter processes such as sintering and retorting together with associated equipment such as cyclones and electrostatic precipitators are also amenable to CFD modelling. Although such models exist and have been successfully used in other industries, the application in zinc concentrators and refineries has not so far been widespread. CFD modelling should play an increasingly critical role as operations seek greater gains in recovery because of volatile zinc prices, in energy efficiency because of greenhouse gas issues, and in environmental performance in order to ensure 'license to operate'.