Reducing water consumption at Skorpion Zinc

Bhikha, H; Lewis, A E; Deglon, D A

Reducing water consumption at Skorpion Zinc

Journal Article

2011

Journal Title

Journal of the South African Institute of Mining and Metallurgy

Link to Journal

http://www.saimm.co.za/

Publisher

University of Cape Town

Department

Department of Chemical Engineering

Faculty

Faculty of Engineering and the Built Environment

Abstract

Synopsis: The minerals industry is committed to the principles of sustainability. Reducing water consumption is a priority area, especially for regions of water scarcity. This paper presents a systemic optimization of the water balance of the Skorpion Zinc refinery with the aim of reducing water consumption. An Aspen Plus simulation of the process is used. The validity of the simulation is tested by measuring key output variables and comparing results to plant data. A number of water minimization scenarios are investigated, including unit operation and circuit configuration changes. The scenarios leading to the largest reduction in water consumption are through the full recycle of treated effluent water, which results in water savings of up to 19%. Reducing process water and/or recycling of untreated water is prohibited by the build-up of trace elements, which affect product purity. The Skorpion process already features a highly optimized water balance, with unit operational changes merely resulting in a shift in the water balance. Consequently, the largest area for improvement is through the reuse of effluent water.