Comparison of the Effects of Ultrasonic and Ball Milling on Red Mud Desulfurization

Abstract

Red mud desulfurization is an environmentally friendly desulfurization technology. After desulfurization, the acidity of red mud slurry continues to be neutralized for processing new red mud, and no waste acid is generated. At present, there is a lack of research on desulfurization intensification in external fields, etc. To further enhance red mud desulfurization, this paper used an SO2 detector, X-ray fluorescence spectrometer (XRF), and scanning electron microscope (SEM) to compare and analyze red mud desulfurization under the action of ball mill and ultrasonic external fields. In this study, experiments were conducted using a bubbling and stirring reactor device. The results showed that the suitable red mud slurry concentration was 10 g/L. The raw red mud desulfurization (without external field condition) could reach 100% absorption in the first 25 min, and the desulfurization rate dropped to 81.3% at 80 min. The mechanism of red mud desulfurization was investigated by X-ray diffractometer (XRD), XRF, and infrared spectroscopy. Under the action of the external field of the ball mill, the red mud particles could be refined to prolong the desulfurization time. The red mud after ball milling could reach 100% absorption within 33 min. Under the thermal effect of the ultrasound, 100% absorption could only be achieved within 23 min. From the desulfurization effect and XRF results, it was found that the ball mill was more suitable for promoting red mud desulfurization in the bubbling and stirring reactor.

Analysis of Alkali in Bayer Red Mud: Content and Occurrence State in Different Structures

“…The vibrations of molecules in infrared spectroscopy are divided into two types: stretching vibrations with a changing bond length and bending vibrations with a changing bond angle. Infrared spectroscopy can not only reflect changes in vibration energy levels in molecules but also changes in molecular structure, and changes in molecular structure and chemical bonds can be identified via changes in the infrared spectrum [45,46]. The infrared analysis patterns of the original red mud and the dealkalized red mud are shown in Figure 6.…”