Challenges of using froth features to predict clean coal ash content in coal flotation

ABSTRACT

In coal flotation, clean coal ash content is controlled by adjusting different operating parameters to meet the requirements for products. However, real-time control is strictly restricted by the traditional ash detection method, which is very time-consuming. Froth phase plays an important role in both transporting and upgrading flotation concentrate. The correlation between clean coal ash content and froth property is of great importance to monitor, predict, and control the flotation process. In this review, 14 important froth features related to the concentrate grade are summarized to comprehensively understand the complicated three-phase froth. Foam structure and foam destabilization mechanisms including foam drainage, bubble coalescence, bubble coarsening, and liquid film rupture are introduced, which help us better understand why the froth properties are related to concentrate grade. However, very coarse or highly hydrophobic coal particles could cause inconsistencies in the correlation between concentrate grade and froth properties compared with that in metal ore flotation. The challenges and suggestions in predicting clean coal ash content based on froth characteristics are finally discussed.

KEYWORDS:

• Coal flotation
• froth
• ash content
• prediction

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities [2019QNA25].