Comparison of the adhesion kinetics between air or oily bubble and long flame coal surface in flotation. (1st May 2021)

• Record Type: Journal Article
• Authors: Wang, Shiwei; Tao, Xiuxiang
• Is Part Of: Fuel. Volume 291(2021)
• Publication Date: 2021-05-01
• Subjects: Low-rank coal -- Oily bubble -- Hydrophobic -- Three-phase contact line -- AFM; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.120139
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: TPC formation equation of air or oily bubble on low-rank coal surface was fitted. TPC spreading rate of oily bubbles on low-rank coal surface was higher than that of air bubbles before about 20 ms. Oily bubble surface is more hydrophobic than that of air bubble. Abstract: Flotation is an effective separation technology with a wide range of applications, and oily bubbles have recently been shown to be more effective than air bubbles at separating low-rank coal. However, the differences in the spreading behaviours of oily and air bubbles at the microscale have not yet been clarified. In this study, high-speed camera technology was used to characterise the interaction process of air and oily bubbles with low-rank coal particles. The three-phase contact (TPC) line formation behaviours of air and oily bubbles on the low-rank coal surface were observed in a deionised solution. At 0–20 ms, the oily bubbles spread more quickly on the low-rank coal surface than the air bubbles; the TPC spreading completion percentages of the oily and air bubbles were 97.58% and 70.73%, respectively. At 20–100 ms, the oily bubbles spread more slowly than the air bubbles because they respectively had 2% and 30% of the TPC spreading process to complete. The results indicated that the oily bubble surface was more hydrophobic than the air bubble surface.