Investigation of microwave treatment in kimberlite beneficiation for enhanced separation efficiency and sustainable fine waste reduction

Abstract

Kimberlite beneficiation is constrained by high circulating loads, inefficient liberation, and substantial fine waste generation. This study evaluates the effectiveness of microwave pre-treatment in improving comminution and dense media separation performance by subjecting coarse (16–31.5 mm) and overall (6.7–31.5 mm) feed classes to controlled microwave irradiation using an industrial 2.45 GHz, 15 kW system. Treated samples were subsequently crushed in a single-roll crusher and processed through a laboratory dense media separation workflow to quantify changes in product size distribution, concentrate recovery, circulating load, and waste generation. Microwave pre-treatment produced consistent improvements in downstream performance. At low energy inputs, concentrate mass fraction increased by up to 75% for the coarse feed and 68% for the overall feed, indicating enhanced liberation of dense mineral phases. Circulating load decreased by 6%–10%, reducing the volume of material requiring reprocessing and lowering the potential for diamond damage during repeated crushing. Waste (<1 mm) and fine waste (<0.3 mm) generation declined by 5%–10%, demonstrating that microwave exposure can suppress excessive fines production and support more sustainable tailings management. Overall, the results show that controlled microwave pre-treatment can enhance mineral liberation, improve separation outcomes, and reduce waste generation, representing a promising pathway for increasing the efficiency and sustainability of kimberlite beneficiation.

Keywords

microwave heating / rock pre-treatment / fine waste reduction / circulating load / mineral processing / separation efficiency

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