Ultrasound-assisted Extraction of Fe(III) from Wet-process Phosphoric Acid

An ultrasound-assisted extraction (UAE) method was developed for the extraction of Fe (III) from wet-process phosphoric acid with di (2-ethylhexyl) phosphoric acid (D2EHPA). The influences of UAE parameters, including ultrasonic power, extraction time, concentration of D2EHPA and extraction temperature, were systematically studied. The response surface methodology, a statistical technique, was used to obtain the optimal conditions and evaluate the significance of variables affecting the extraction efficiency of the UAE. It was found that ultrasound could markedly improve the extraction rate of Fe (III) with D2EHPA, the largest improvement is up to 7 times compared with the traditional solvent extraction method. However, the extraction equilibrium of the extraction system was not affected by ultrasound. It is believed that the cavitation effect of ultrasound, along with the increased interfacial surface area, contribute to the enhancement of the extraction rate.