Full Plant Fly Ash Magnetite for Dense Medium Separation

This project involved confirming the properties and behaviour of fly ash magnetite (FAM) in full scale plant trials at Oaky Creek and Burton Coal and two pilot plant trials at ACIRL, Maitland. The FAM used in the project was derived from fly ash produced from coal burnt at the Callide “B” Power Station at Biloela. Raw FAM was magnetically recovered from the fly ash, followed by milling, classification and magnetic cleaning.

The full plant trial at Oaky Creek Mine showed that metallurgically FAM was equivalent to natural magnetite. Recovery however was lower than required as expected. The dense medium cyclone pilot plant trial at Maitland demonstrated that good medium stability could be achieved down to very low medium densities (below 1.25), plus efficient separations with coal and density tracers and acceptable medium differentials and D50 offsets.

A pilot plant recovery trial with a new generation Permax wet drum magnetic separator gave FAM recoveries over the drum of better than 99.9%.

The pilot scale low density metallurgical performance and good magnetics recovery were confirmed with a full plant trial at Burton Coal.