Coal Preparation » Fine Coal
This project evaluated a novel flotation prototype designed to break the conventional grade-recovery trade-off in fine coal processing. The prototype combined oscillatory air supply with low frequency acoustic excitation for improving coal flotation. The concept was based on two complementary mechanisms:
- dynamic stabilisation of the froth phase under low-frequency acoustic excitation and
- reduction of bubble size through oscillatory air supply in place of conventional steady air supply.
The system was implemented in a 0.4-m diameter flotation column fabricated overseas and installed at the participating mine site. Continuous flotation trials were conducted using feed split directly from an operating flotation circuit. Once steady-state operation was achieved, representative samples of feed, concentrate and tailing were collected for performance evaluation.
Although significant fluctuations in feed ash limited the statistical confidence of the full test program, controlled operating periods demonstrated the potential to simultaneously increase combustible recovery while reducing concentrate ash. These results suggest that the combined oscillatory air - acoustic approach can enhance product quality without compromising yield.
Further validation under more stable feed conditions at an alternative operating site is recommended to confirm and quantify these performance benefits.
If confirmed under extended full-scale plant operation, the proposed technology has the potential to deliver dual value through increased plant revenue and reduced (Scope 3) greenhouse gas emissions within the downstream steelmaking value chain.