The use of acoustic fields as a filtration and dewatering aid

An experimental rig has been developed to study the effects of electric and acoustic held combinations on the filtration rate of titanium dioxide susp ensions. Ultrasound energy is applied tangentially to the filter medium. El ectric held strengths, suspension characteristics and process parameters ca n all be varied independently. Results from an experimental programme demon strate that the use of ultrasound across the cake surface can decrease the specific cake flow resistance and increase the filtration rates of low-conc entration rutile suspensions (0.1% v/v). Changes in the conductivity induce d by ultrasonic irradiation affect the suspension such that the application of an electrical field is enhanced, giving an equivalent electric field st rength higher than that applied. (C) 2000 Elsevier Science B.V. All rights reserved.