Effects of rotary triboelectrification technology on macerals separation for low-rank coal

ABSTRACT

In this study, the rotary triboelectrification separation technology is applied to the separation of macerals for low rank coal, which has not been studied by previous researchers. The effects of air humidity and temperature on permittivity and specific-charge were tested to ensure that vitrinite and inertinite were effectively separated under obvious electrical differences. The best separation index of macerals was determined by single factor test, including airflow rate, feed rate, friction wheel speed, and plate voltage. The test results of specific-charge and permittivity showed that the difference is most reasonable when the air humidity is 20% and the temperature is 40°C. Single factor test showed that the optimal conditions are the feed rate of 1.5 g/s, the friction wheel speed of 3000 r/min, the plate voltage of 20 kV and the air flow rate of 6 m/s. Finally, this study obtained the best maceral separation indexes are vitrinite content of 72.03 vol%, vitrinite recovery of 67.86% and benefication ratio of 1.33. Comparison with other maceral separation technologies, the rotary triboelectrification technology is a clean dry and economical process technology, it has inherent advantages in the separation of macerals for low rank coal.

KEYWORDS:

• Maceral
• low rank coal
• rotary triboelectrification separation
• specific-charge
• permittivity

Acknowledgments

This work was supported by the Fundamental Research Funds for the Central Universities (No. 2019XKQYMS45).

Declaration Of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities [2019XKQYMS45].