Mitigating metal loss in waste printed circuit boards reverse flotation: The critical role of particle dispersion

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Abstract

Froth flotation is emerging as a key step in waste printed circuit board recycling (WPCB) recycling, enabling the selective separation of metals from nonmetals. This study investigates the aggregation and dispersion behavior of WPCB particles during pulping and evaluates intense agitation as a pretreatment strategy. The inherent hydrophobicity of WPCB nonmetals drives spontaneous aggregation, which entraps metallic particles and stabilizes persistent foam layers that hinder separation. Intense agitation effectively disrupts these aggregates, releasing entrapped metals and improving dispersion. Under optimized conditions, this pretreatment significantly enhanced flotation performance by mitigating metal losses to the overflow.