Effect of Preconditioning on the Flotation of Coal

ABSTRACT

Two preconditioning methods, namely, ultrasonication and high-intensity conditioning in an agitated vessel, were compared as a means for improving the flotation of oxidized coal. The use of preconditioning by ultrasound or high-intensity conditioning significantly improved the flotation of the oxidized coal in batch-type laboratory tests, particularly with respect to the flotation rate and the recovery of combustible matter. In addition, the rate and recovery of the smaller size fractions were enhanced considerably. The beneficial effects of preconditioning on the batch flotation of oxidized coal were clearly reflected in smaller bubble size distributions, higher froth loadings, and greater stability of the flotation froths.

Keywords:

• Oxidized coal
• Flotation
• Ultrasound
• High-intensity conditioning
• Image analysis

Acknowledgment

The use of Crusader Systems' Fluxar^® software for digital analysis of the froth images is gratefully acknowledged.

Notes

Standard deviations were less than 0.21%. Statistical significance level was 0.003.

Adjusted multiple regression coefficient: R² = 0.870. Model fit significance level < 0.0005.

^a Dependent variable: R.

Adjusted multiple regression coefficient: R² = 0.870. Model fit significance level < 0.0005.

^a Dependent variable: k.

Adjusted multiple regression coefficient: R² = 0.883. Model fit significance level < 0.0005.

^a Dependent variable: R.

Adjusted multiple regression coefficient: R² = 0.992. Model fit significance level < 0.0005.

^a Dependent variable: k.