Nowicki, K & Hellstrand, A 2013, 'Next generation dewatering for tailings and paste backfill: E-Disc filter with eductor feed system', 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. 393-405, https://doi.org/10.36487/ACG_rep/1363_30_Hellstrand
For many years the traditional continuous vacuum disc filter has experienced great popularity due to its excellent overall design which provides more filtration area per unit of floor space than any other type of continuous vacuum filter. Primarily a dewatering unit, its applications are most numerous in the coal, metallurgical, tailings, and backfill processing industries. FLSmidth has designed, fabricated, and commissioned several thousand Dorr-Oliver and Eimco disc filters and is the leading supplier of disc filters for tailings and paste backfill plants around the world. One primary concern with traditional disc filters, which rely on a paddle agitation system to keep the solids in the slurry suspended, is the higher than acceptable maintenance rate due to leaking stuffing boxes and excessive disc filter tank abrasion wear rates. By adapting feed agitation system technology established in ClariDisc® filters, the agitation energy works to keep the solids in suspension as opposed to centralised energy in the paddle agitation area. Consequently, by removing the paddle agitation and replacing it with an eductor feed system, a lower operational cost is achieved due to less frequent required maintenance as well as lower capital cost for both the disc filter equipment and the plant building. Between 2011 and 2012, the new E-Disc filter with the eductor feed system has successfully been installed and commissioned at five tailings/paste backfill plants throughout Asia, Australia, Europe, and North America; these systems deliver dewatered tails for paste production. Furthermore, an additional six projects using the new eductor feed system are currently underway with planned installation and commissioning in 2013. The installed E-Disc filters that have been in operation for six to 18 months have been able to manage a solids throughput ranging from 300 to 1,200 kg/m2/hr depending on the specific filter feed characteristics such as feed solids weight percentage and particle size distribution, with total moisture content ranging from the mid 10s to low 20s. By controlling the speed of the disc filter, which affects the cake thickness, a specific throughput and moisture content can be targeted to match the desired characteristics for paste production. The method of sizing the E-Disc filters based on laboratory testing with comparison of installed filters is discussed. The paper also discusses some of the challenges experienced during installation, start-up, and commissioning.
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