화학공학소재연구정보센터
Separation and Purification Technology, Vol.207, 321-328, 2018
Recovery of residual metals from fine nonmetallic fractions of waste printed circuit boards using a vibrated gas-solid fluidized bed
Nonmetallic fractions are essential byproducts of the physical-mechanical recycling process of waste printed circuit boards. Large amounts of metals remain in fine nonmetallic fractions because it is very hard for recycling metals from fine size fraction by traditional technologies. In this study, a vibrated gas-solid fluidized bed was utilized to recover residual metals from fine particles (- 0.25 mm size) of nonmetallic fractions obtained from the corona electrostatic separation process. The basic mineralogical characteristics and properties of nonmetallic fractions with a size of 0.25 mm indicated that a considerable amount of clavate glass fibers existed in these nonmetallic fractions. The content of residual metals in the 0.25 mm nonmetallic fractions was up to 19.84 wt %. The major metallic elements found in the nonmetallic fractions were Fe, Cu, Pb, and Sn. The results indicated that removing glass fibers from nonmetallic fractions by triboelectric separation can strengthen the gravity segregation process between heavy and light particles in fine nonmetallic fractions, resulting in improved metal recovery from 76.39% to 81.41%. Based on this research, an industrial flowsheet for the recovery of metals from fine WPCBs is proposed.