Effect of particle size composition on the separation of waste printed circuit boards by vibrated gas-solid fluidized bed

The mechanism of fine particles on the separation of waste printed circuit boards by vibrated fluidized bed is not clear. In this paper, the influence of particle composition on fluidization behavior and separation characteristics of waste printed circuit boards particles was studied. The separation results showed that the increase of fine particles significantly reduced the metal recovery. When the content of fine particles was 20 %, the concentrate yield decreased by 11.26 % and the metal recovery declined by 15.93 %. The analysis of fluidization characteristics proved that the stability of the bed was reduced at higher fine particle content. When the content of fine particles was 20 %, the standard deviation of bed pressure drop was 34.15 Pa higher than that without fine particles. And the microscopic and X-ray fluorescence analysis confirmed that the adhesion behavior of fine particles prevented them from being separated by density. In addition, it was found that the pre-removal of iron and aluminum could effectively improve the separation performance with a fine particle content of 20 %, and the metal recovery increased by 6.29 %. Based on this, our findings will provide important guidance for efficient recovery of valuable metals from waste printed circuit boards.(c) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.