Study on Combined Vacuum–Mechanical Defoaming Technology for Flotation Froth and Its Mechanism

Processes

卷:10

Liang Shen¹  Wenzhi Zhao²  Song Yin³  Haibing Jiang³  Duo Yang³  Jiufen Liu⁴  Huaifa Wang⁵  Runquan Yang⁵ 

[1] College of Material Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China;

[2] Harbin Natural Resources Comprehensive Survey Center, China Geological Survey, Harbin 150039, China;

[3] Langfang Natural Resources Comprehensive Survey Center, China Geological Survey, Langfang 065000, China;

[4] Natural Resources Comprehensive Survey Command Center, China Geological Survey, Beijing 100055, China;

[5] School of Mining Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China;

关键词: coal;    flotation froth;    defoaming;    vacuum;   

DOI  :  10.3390/pr10061183

来源: DOAJ

【 摘 要 】

Foam is essential in the flotation process. However, the gas–liquid–solid three-phase froth produced in the flotation process has very strong stability and is difficult to burst spontaneously. The existence of these froths will reduce the transport capacity of the pulp and affect the working efficiency of subsequent processes, such as filtration of the flotation concentrate. In this study, a new defoaming device is designed by combining mechanical impact with depressurized defoaming and its defoaming mechanism is analyzed theoretically. In addition, the liquid level height and pulp overflow method are applied to characterize the defoaming efficiency of the new defoaming device. The effects of impeller structure, pressure drop, impeller rotation frequency, and aeration rate on defoaming efficiency were studied. The results show that when increasing the pressure drop, the defoaming increases, but it will also enhance the generation of bubbles. The efficiency of combined mechanical–vacuum defoaming technology is superior under low-pressure drop using an SC impeller. Under −1 kpa vacuum condition, it only takes 168 s to eliminate 20 cm flotation froth height with combined mechanical impact, while it takes 453 s under ambient pressure, indicating that under vacuum conditions, the mechanical-defoaming method can significantly improve the defoaming efficiency, and the two have a certain synergistic effect.

【 授权许可】

Unknown