The potential for dry processing using a Knelson Concentrator

Centrifugal gravity concentrators currently operate on a wet basis, with slurry feed and fluidising water used to enhance the separation based upon density differences. This work investigated the potential for running a laboratory scale 3″ Knelson Concentrator on a dry basis. Air was used as the fluidising medium in order to separate tungsten from silica in a synthetic ore (1%w/w tungsten), and compared to an optimised wet process. The wet processing attained a mean tungsten recovery of 94.92% (tungsten grade: 30.96%). The dry processing at two different fluidising air pressures attained a recovery of 78.53% (tungsten grade: 6.32%) and 69.90% (tungsten grade: 15.57%) at 2 psi and 3 psi respectively. This preliminary work shows that it is feasible to separate minerals on a dry basis in a Knelson Concentrator.