Effect of ultrasound on surface cleaning of silica particles

One substantial benefit of ultrasonics in mineral processing can be the rem oval of surface coatings of clay and iron oxides from mineral surfaces. Thi s is mainly achieved through the large, but very localised, forces produced by cavitation. The application of sonication to the reduction of iron oxid e in a silica sand from 0.025% to less than 0.012% Fe2O3 - the difference b etween material suitable for clear glass container ware and that suitable f or table ware - is presented. The ultimate reduction in iron oxide contamin ation is dependent on the sonication power, whereas increasing the concentr ation 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 .