Johnson, J & Accioly, A 2017, 'Feedwell is the heart of a thickener', in A Wu & R Jewell (eds), Paste 2017: Proceedings of the 20th International Seminar on Paste and Thickened Tailings, University of Science and Technology Beijing, Beijing, pp. 23-28, https://doi.org/10.36487/ACG_rep/1752_03_Johnson
(https://papers.acg.uwa.edu.au/p/1752_03_Johnson/)
Abstract: Thickeners that produce non-Newtonian underflow suspensions use the same feedwells as with other thickener types. The functions of converting the horizontal momentum of the feed to a vertical flow and the promoting flocculation of the suspended solids are the same for any thickener. The industry has correctly addressed the feedwell design in recent years. The effectiveness of the feedwell design to accomplish these functions has generally been poor in the industry. Short circuiting flows carry the solids into the thickener prematurely before all the suspended solids have been captured. Also these flows generate such force that solids are carried to the overflow launder before settling can occur. Paste thickeners are oftentimes used as the final dewatering stage of the tailings and the main source for process water return. Clarity of the process water is often regulated if discharged and poor clarity recirculates solids that cause a burden on the system. The patented EvenfloTM feedwell has been installed in all types of thickener in China and around the world with significant improvements to overflow clarity and overall thickener operation. This paper provides case study results of clarity and elimination of short circuiting.