Eliminate tailings risk with solid bowl centrifuges for continuous dewatering
The mining industry is looking for technical solutions to dewater mine tailings to eliminate the risk of tailings dam failures. But while there is growing industry consensus on the Why and possibly the When, the How is not that straight forward. A vast array of mechnical solutions exist that all promise to deliver dry tailings in a cost-effective way. This leaves miners in the difficult position to navigate the often confusing choices of emerging and established technologies, with engineering teams on sites conducting extensive trials to see what works for their operations.
The key evaluation criteria that mining and mineral processing companies consider while selecting tailings dewatering technologies are:
- Consistency of dewatered solids – preferably dry, stackable
- Clarity of filtrate/centrate for recovery and reuse
- Sound operating economy
Solid Bowl Centrifuge (SBC) consists of a horizontal bowl with a scroll conveyor inside it which is together referred to as the rotating assembly. The assembly spins around its own axis at high speed, thereby generating high centrifugal force that enables separation of tailings solids from the liquid. The separated solids are scrolled out by the conveyor in the form of a dry solids cake whereas the clear liquid (centrate) overflows the weir plates located at the opposite end. Although the SBC technology has existed for several decades it is only in the past 8-10 years that design improvements made by Alfa Laval in wear protection of key components, coupled with changes in its geometry and operating philosophy, have enabled the SBC to be utilized to deliver high solids cake concentration, even at high flow rates. Centrifuge technology requires moderate dosage of flocculant in some tailings dewatering applications but has the highest unit capacity per footprint. As well as having a relatively lower CAPEX, the OPEX is favourable due to its high throughput and lower lifecycle costs.