Application of ultrasound in extractive metallurgy: Sonochemical extraction of nickel

The importance of ultrasound in solvent extraction was examined by studying solvent extraction of nickel with Lix 65N and Lix 70 extractants. The studied parameters were ultrasonic energy and frequency, pH, temperature, and organic and aqueous solution composition. The stability of extractants under the influence of ultrasound was also examined. It was found that ultrasound had a significant importance, because it increased the extraction rates four- to sevenfold. The effect of ultrasound was physical,i.e., to increase the surface area. Ultrasonic energy consumption was also evaluated. The consumption was high, but it can be significantly reduced by the appropriate method of application. A novel solvent extraction method, extraction-in-pipe, was also proposed.