Red mud pressure filtration for the alumina refinery’s bauxite residue tailings disposal

Authors: Avery, Q; Wilson, K Download Paper

DOI https://doi.org/10.36487/ACG_rep/1363_17_Avery

Cite As:
Avery, Q & Wilson, K 2013, 'Red mud pressure filtration for the alumina refinery’s bauxite residue tailings disposal', in R Jewell, AB Fourie, J Caldwell & J Pimenta (eds), Paste 2013: Proceedings of the 16th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 225-238, https://doi.org/10.36487/ACG_rep/1363_17_Avery



Abstract:
Red mud waste residue management has been a consistent issue for review within alumina refinery operations. With 1 to 2.5 tons of red mud residue per ton of Al2O3 produced, the various options must be carefully considered. In light of the 2010 red mud pond dam failure at the Ajka refinery in Hungary, all eyes are on the problem and actions are underway at many producers to implement new strategies. Thickened underflows can be efficiently dewatered into high solids filter press cakes that can be safely stacked in dry storage areas to reduce the volume of waste material. The results of pressure filtration testing demonstrates that, unlike traditional vacuum filters, standard design FLSmidth AFP IV™ filter presses can dewater red mud thickener underflows from initial concentrations of between 30–44 wt% to produce final cakes containing up to 80 wt% solids. We outline the various factors affecting the filtration rate and final cake solids concentration, such as feed solids concentration, slurry temperature, and feed pump delivery rate/pressure relationship, as well as the configuration of the filter plates. This paper will detail the various flow sheets and equipment for efficient red mud disposal. Test results show variations by equipment type, geographic region, and different bauxite ore grades. Details will be presented on the selection criteria for the individual alumina refineries, including the main drivers; safety and environmental concerns, water and caustic recovery, storage volume, and waste area rehabilitation costs.

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