Particle Separation Systems Technologies (PSST) has developed and patented a new technology that can dewater paste thickener underflow, economically and effectively, to the dryness selected.
The technology accepts the paste thickener underflow, which is introduced onto a woven steel belt (SBF) in a dyke and furrow shape. The paste is subsequently subjected to medium wave infrared radiation (MIR) under vacuum. The symbiosis of both negative pressure (vacuum) and MIR on the SBF provide for evaporation rates whereby 1 kWh power evaporates in excess of 2-3 l of water from a paste. The retention time decides the final paste moisture discarded from the SBF.
Machine capacities are 0.5-1.5 t/m²/h depending on the mineral to be dewatered. Large machines to dewater ultra fine (-45 micron) paste thickener underflow (iron ore) capable of treating 40-45 tph are in design phase.
BHP Billiton has accepted the technology in collaboration with the CSIR to dewater and dry alumina slurry from 50% solids to dry.