Separation performance of mechanical flotation cell and cyclonic microbubble flotation column: in terms of the beneficiation of high-ash coal fines

ABSTRACT

Separation performance of mechanical flotation cell and cyclonic microbubble flotation column (FCMC) was compared in terms of the beneficiation of high-ash coal fines that has the characteristics of the content of <0.045 mm accounting for more than 50% of the flotation feed and the ash content of <0.045 mm being more than 50%. The optimal experimental results of the mechanical flotation were determined as the flotation perfection index η of 47.37%, the clean coal yield of 39.19% and the clean coal ash content of 10.78% at the feed pulp concentration of 40 g/L through twice explorative flotation experiments and the orthogonal experiment. It was found that the ash content of the clean coal had a strong dependence on the feed concentration. In contrast, the yield of the concentrate of the column flotation was increased to 43.26% with the lower ash content of 9.47% and the higher η of 54.51% even at higher feed concentration of 60 g/L. The remarkable separation efficient of the FCMC flotation column for the difficult-to-float coal slime that has the characteristics of high content of fine particles with high ash was attributed to the presence of the centrifugal force field, more microbubbles generated by hydrodynamic cavitation, the form of countercurrent mineralization, and thicker froth layer.

KEYWORDS:

• Flotation
• high ash
• coal fines
• separation performance
• microbubble

Acknowledgments

This work was supported by “the Fundamental Research Funds for the Central Universities (Grants No. 2018BSCXB09)”and Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grants No. KYCX18_1935).

Supplementary material

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Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities [Grants No. 2018BSCXB09];Postgraduate Research & Practice Innovation Program of Jiangsu Province [Grants No. KYCX18_1935].