Abstract
Coal is the world's most abundant fossil fuel. Coal froth flotation is a widely used cleaning process to separate coal from mineral impurities. Flotation of coarse coal particles, ultrafine coal particles and oxidized coal particles is well known to be difficult and complex. In this paper, the nanobubbles' effects on the flotation of the varying particle size, particle density and floatability coal samples were evaluated using a bank of pilot scale flotation cells, a laboratory scale and a pilot scale specially designed flotation column. The parameters evaluated during this study include the flow rate ratio between the nanobubble generator and the conventional size bubble generator, the superficial air velocity, collector dosage, frother concentration, flotation feed rate, feed solids concentration, feed particle size, and the superficial wash water flow rate, etc. The results show that the use of nanobubbles in a bank of mechanical cells flotation and column flotation increased the flotation recovery by 8∼27 at a given product grade. Nanobubbles increased the flotation rate constants of 600∼355, 355∼180, 180∼75, and 75∼0 microns size coal particles by 98.0, 98.4, 50.0 and 41.6, respectively. The separation selectivity index was increased by up to 34, depending on the flotation feed characteristics and the flotation conditions.
Original language | English |
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Pages (from-to) | 641-671 |
Number of pages | 31 |
Journal | Mining Science and Technology |
Volume | 20 |
Issue number | 5 |
DOIs | |
State | Published - Sep 2010 |
Bibliographical note
Funding Information:The authors gratefully acknowledge the Center for Advanced Separation Technologies (CAST), the Florida Institute of Phosphate Research (FIPR), and the National Natural Science Foundation of China (Nos. 50921002 and 90510002) for the financial support. Special thanks to the Director of CAST, Dr. Roe-Hoan Yoon and the project manager of FIPR, Dr. Patrick Zhang for their valuable advice and support.
Keywords
- cavitation
- coal
- flotation kinetics
- froth flotation
- nanobubble
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Geotechnical Engineering and Engineering Geology
- Energy Engineering and Power Technology
- Geochemistry and Petrology
- Electrical and Electronic Engineering