Effect of different mass proportions of fine slime on the flotation performance of coal

ABSTRACT

The effect of mass proportions of fine slime on the flotation performance of coal was investigated in the present study. Generally, the presence of fine slime showed a negative effect on flotation, i.e. as the mass proportion of fine slime increased, both flotation yield and kinetics decreased, while ash content increased, which was attributed to slime coating and water entrainment. The sedimentation tests, adsorption amount measurements, and Cryo-SEM technique directly indicated the incidence of slime coating, which became more significant with the increase of slime mass proportion. Except for the higher collision efficiency between slime and coal particles, the increased pulp viscosity may also be the reason for the worse slime coating as scrubbing effect of turbulence was weakened. The froth drainage tests showed the occurrence of water entrainment was also correlated to slime mass ratio. However, the water recovery and froth stability showed an increase trend firstly and then a decrease. It may be attributed that high mass proportion of slime increased the pulp viscosity, leading to poor gas dispersion and froth stability.

Graphical abstract

KEYWORDS:

• coal flotation
• slime coating
• water entrainment
• froth stability
• rheology

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Key R&D Program of China (2021YFC2902605), the Jiangsu Natural Science Fund-Youth Fund (BK20210505) and the National Nature Science Foundation of China (Grant no. 52104278, 52174265, U1903207).