Correlation of air recovery with froth stability and separation efficiency in coal flotation

Recent research progress in hard rock mineral flotation shows that froth stability can be represented by air recovery, which is defined as the fraction of air entering a flotation cell that overflows the weir in unburst bubbles, and that air recovery has strong correlation with the separation performance of mineral flotation. Yet no experimental work on air recovery has been devoted to coal flotation. This paper studies air recovery in coal flotation and examines the links between air recovery, froth stability and coal flotation performance. A series of experiments were conducted using a laboratory-scale mechanical flotation cell at various methyl isobutyl carbinol (MIBC) concentrations and aeration rates. It was found that air recovery has a strong correlation with dynamic froth stability determined by measuring the maximum froth height in a non-overflowing froth column. At a fixed aeration rate (hydrodynamic condition) and various MIBC concentrations, a strong correlation between air recovery and coal flotation performance was also observed.