Effect of ultrasound on surface cleaning of silica particles

One substantial benefit of ultrasonics in mineral processing can be the removal of surface coatings of clay and iron oxides from mineral surfaces. This is mainly achieved through the large, but very localised, forces produced by cavitation. The application of sonication to the reduction of iron oxide in a silica sand from 0.025% to less than 0.012% Fe2O3 - the difference between material suitable for clear glass container ware and that suitable for table ware - is presented. The ultimate reduction in iron oxide contamination is dependent on the sonication power, whereas increasing the concentration of Na,CO, in the suspension, up to 0.2%, shortens the sonication time to approach this limit. (C) 2000 Elsevier Science B.V. All rights reserved.