Process water conditioning to improve slurry dewatering

Portions of this paper were originally published in ‘A strategy for improving water recovery in kimberlitic diamond mines’ as it appeared in the February 2019 Edition of the SAIMM Journal, Volume 119 published by The Southern African Institute of Mining and Metallurgy. Mine site location and the sources from which raw water is drawn are fixed by geology, geography and climate. The colloidal behaviour of the tailings is therefore randomly determined by the tailings mineralogy and the chemical characteristics of the process water circuit. In some fortunate cases, the tailings slurries are non-dispersive and solid/liquid separation, either by gravity thickening or filtration, is easily achieved at low capital and operating cost. In less fortunate cases the tailings are highly dispersive and solid/liquid separation is achieved only at high capital and operating cost. This paper presents a strategy by which difficult-to-treat slurries can be modified by conditioning the process water circuit with a process water conditioner (ClariVie44®) so that gravity thickening and filtration can be enhanced.