Study of Recovery of Metals from Discarded Printed Circuit Boards Using Water Medium-Varied Diameter Separation Bed

摘要

The dissociation degree of metal and nonmetallic in circuit boards depends on the comminuted grain size. With the metals in circuit board basically dissociated, the discarded printed circuit boards are firstly crushed by wet method, then the crushed products, 1 ~ 0.5 mm, 0.5 ~ 0.25 mm, 0.25 ~ 0.125 mm, 0.125 ~ 0.074 mm, were separated by water mediumvaried diameter separation bed. Experimental results showed that, metal content reduced with decrescent grain size of the crushed circuit board, water medium-varied diameter separation bed could efficiently recover the metal from discarded circuit boards, recovery rates of metals and metal concentrate grade were both over 90 % after separation, total metals and copper had the same enrichment ratio, and both increased with decrescent grain size of the feeding materials. The enrichment ratios of total metals and copper even reached 6.06 and 6.14, copper and most metal components almost had the same migration character in the separation of discarded circuit boards.