Product Carbon Footprinting and Life Cycle Assessment
Acid Rock Drainage prediction CPD course
MSc Project title A pre-pilot feasibility study on the use of froth flotation for coal recovery and sulphur removal from fine coal waste
(Duration: 2014 to 2015)
Currently the coal mining industry produces approximately 12 million tonnes of coal ultrafine wastes each year, most of which is dumped in tailing slurry dams. These slurry dams have the potential to cause prolonged pollution of local water resources through the generation of acid rock drainage (ARD) over the long-term. Pre-disposal removal of sulfide sulfur by means of froth flotation is aimed at effectively removing the ARD risk associated with sulfide bearing wastes, such as those produced from coal processing. In the two stage process developed at the University of Cape Town, froth flotation is used to both recover coal (stage 1) and remove pyritic sulfur (stage 2) from fine (-150 micron) coal waste, resulting in three outputs streams: a saleable coal product, a small volume pyrite-rich stream, and a large volume sulfide lean tailings stream.
The technical feasibility of this process has been demonstrated for a number of coal waste types on a laboratory-scale, with results indicating that it is possible to recover large quantities of useable coal (up to 86%), whilst generating a tailings waste stream with a reduced sulfur content (down to 0.2%) and negligible ARD risk. On the basis of this testwork, an order of magnitude financial model for a conceptual plant has been developed, and applied to demonstrate the economic viability for selected case studies. Studies are also currently in progress to identify downstream management options for the pyrite-rich and benign tailings fractions, with a view to both maximising resource productivity and minimising waste burden.
This project will be focused on conducting an environmental assessment of the two-stage flotation process for the treatment of fine coal waste, by making use of current in-house research studies, literature sources and by conducting mass and energy balances. More specifically the environmental performance assessment will address aspects such as resource utilisation and recovery, waste burden and material consumption. Ultimately, this study aims to inform the development of a comprehensive value proposition for this process, with a view to establishing the business case for scale-up and implementation.
Fundikwa, B., Broadhurst, J.L., Harrison, S.T.L. and Franzidis, J.-P. 2014. A pre-pilot feasibility study on the use of froth flotation for coal recovery and sulfur removal from fine coal waste. Poster presented at the at the 32nd annual SAIMM Mineral Processing Conference, 7-8 August, Cape Town.