Improved magnesium sulphate crystallization using ultrasonic horn

Abstract

The current study explored the use of an ultrasonic horn to improve the crystallization of magnesium sulphate, also employing response surface methodology (RSM) for optimizing the parameters governing particle size reduction, striving to attain the smallest possible particle size and a narrow particle size distribution (PSD). The optimal conditions identified using the model fitting included an ultrasonic power of 136 W, an applied ultrasound time of 10 min, a duty cycle of 70 % and stirring at 1110 rpm. Under the optimized ultrasonic conditions, the particle size was reduced to about 72.9 % of that found in conventional samples. The reduction in particle size during sonication was attributed to shear forces induced by cavitation, along with acoustic streaming and microjet effects. The X-ray diffraction analysis revealed that the sonication affected particle size, with minimal perturbations to the crystal lattice. Fourier-transform infrared (FTIR) spectroscopy confirmed that the functional groups remained unchanged after ultrasonic treatment, while SEM images displayed smaller, and fragmented crystals of magnesium sulphate. Overall, the study demonstrated the advantages of ultrasound in achieving smaller crystals with improved morphology, without compromising crystal quality.