Polyaspartic acid, an eco-friendly regulator for the improvement of coking coal flotation: applications and mechanism

ABSTRACT

In this study, a novel approach is to apply polyaspartic acid (PASP) as an eco-friendly regulator for the flotation of coking coal, which is different from the conventional use of oil collectors only. Flotation trails showed that adding PASP contributes to a two-way improvement in the yield and ash content of clean coal. SEM-EDS observations directly revealed that adding PASP significantly reduces the coating of high-ash fine slimes on the surface of low-ash coal particles. Contact angle detections and zeta potential analysis presented that the preferential adsorption of PASP hardly affects the adsorption of sodium oleate (NaOL) on the surface of low-ash coal particles but significantly weakens the adsorption of NaOL on the surface of high-ash fine slimes, leading to a remarkably hydrophobic difference. Particle interaction energy calculations verified that adding PASP enlarges the energy barrier between low-ash coal particle and high-ash fine slime. Hence, it can be arrived that the preferential adsorption of PASP affects the adsorption of NaOL on the surface of high-ash fine slime, widens the hydrophobic difference, enlarges the energy barrier between low-ash coal particle and high-ash fine slime, reduces the high-ash fine slime coating, therefore leading to a better flotation performance of lean coal.

KEYWORDS:

• Lean coal flotation
• polyaspartic acid
• slime coating
• flotation perfect index

Acknowledgements

This research was supported by the National Natural Science Foundation of China [No. 52204284] and the Natural Science Foundation of Shaanxi Province [No. 2022JQ-353].

Disclosure statement

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

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [52204284].