Development and implementation of decanter centrifuge technology for continuous improvement in the precious metals industry

摘要

With the recent global economic down turn resulting in a sharp decrease in commodity prices and therefore decrease in profits, emphasis was taken from capital expansion projects and placed on optimization and continuous improvement projects. One such project for the Lonmin Base Metals Refinery in South Africa was to reduce the Metals in Process (MIP) on the plant which effectively lock-up revenue for the company. Stock takes identified thickeners as equipment associated with a large MIP for which alternative technology could be implemented. Finding alternative solid-liquid separation technology, however, is challenging as the BMR environment is highly corrosive and is at elevated temperature, whilst the particles are extremely small with typical d50 values as small as 6 μm. Centrifuge technology was ultimately selected through a literature study, lab- and pilot scale test work, NPV calculations and industry benchmarking visits. Understanding of the technology as well as the process requirements through the above mentioned steps assisted in the designing of the centrifuge circuit and ultimately led to a highly successful project.