The effect of crusher type on printed circuit board assemblies’ liberation and dust generation from waste mobile phones

Exploring the comminution process of waste printed circuit boards in recycling: a review

“…The selectivity of impact fragmentation achieves a high level of comminution and becomes the primary factor in the mechanical enrichment of target metals from WPCBs [79]. However, Bachér et al [70] reported that while impact crushing achieved good liberation, it also produced a substantially large amount of fines. This underscores the critical trade-offs that must be weighed between liberation efficacy and overgrinding.…”

“…The impact of crushing mechanisms on WPCB liberation was the focus of a study by Bachér et al [70]. This study introduced an insightful comparison between two distinct types of comminution machinery: a high-speed hammer mill and a low-speed rotary cutter.…”

“…Further exploring the hammer mill, Bachér et al [70] investigated the impact of agitation speed on the WPCB grade and recovery rates. High agitation rates (84 m/s tip speed) were found to provide sufficient energy to achieve a WPCB grade above 86%.…”

“…However, an important consideration raised by Menad et al [90] involved the limited applicability of the manual dismantling and classification methods used in these foundational studies to automated, industrial-scale recycling processes. Additionally, as Bachér et al [70] noted, pursuing maximal liberation by minimizing particle size can increase fine generation, creating an economic trade-off between recovery efficiency and material losses. Therefore, the optimal liberation degree likely depends on specific process objectives and equipment constraints within an industrial context.…”

“…However, this strategy has its own set of limitations. Flotation, shaking, and electrostatic separation, often employed for beneficiation, exhibit diminished efficiency for particle sizes less than 0.074 mm, translating to substantial metal losses [70]. Owing to their large surface energy, fine particles face the added challenge of nonselective agglomeration.…”