Investigation on the liberation and flotation behaviors of coking middlings

ABSTRACT

In this paper, size distribution, density composition, contact angle, and mineral dissemination characteristics were analyzed to determine the liberation behaviors of the ground coking middlings, and flotation test was performed to evaluate the flotation behavior. Results showed that the organic component in the coking middlings was preferentially dissociated, and the hydrophobicity of the ground products was improved by mild grinding, while non-liberated minerals and organic components can still be found in the coarsely ground product. On the contrary, the minerals were significantly liberated from organic components by deep grinding, leading to higher flotation concentration yield. However, the deeply ground product behaved more hydrophilic and high-ash slime generated by deep grinding worsened the flotation selectivity. This was the reason why increasing grinding time from 2 min to 32 min, the yield of required clean coal only had a 3% increase.

KEYWORDS:

• Coking middlings
• hydrophobicity
• SEM-EDS
• liberation
• flotation

Conflicts of interest

The authors declare no conflict of interest.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51374079 and 51504053].