Solid material comminution or disintegration – Processes – Selective or differential comminution of mixed or bonded solids
Patent
1996-05-20
1997-11-04
Rosenbaum, Mark
Solid material comminution or disintegration
Processes
Selective or differential comminution of mixed or bonded solids
241 23, 241 2414, 241 29, 241DIG37, 241DIG38, B02C 1912
Patent
active
056830408
ABSTRACT:
The invention relates to a method for recycling electronic waste in the form of disassembled printed circuit boards from electronic devices, from which the components have not been removed, known as printed circuit boards. After removal of the batteries, mercury switches and PCB-containing capacitors, the printed circuit boards are mechanically precomminuted and the particles are cryogenically embrittled with liquid nitrogen and comminuted in a hammermill. In order to obtain a higher purity of the recovered metal concentrates and, conversely, a lower metal content of the concentrated residue materials as well as less emission during recycling and a simpler process, the cryogenically embrittled particles are selectively comminuted batchwise in a hammermill, wherein the ground material is divided into a fine fraction, emerging from a sieve at the bottom of the grinding chamber, and a coarser metallic fraction, which can be discharged batchwise and from which iron particles can subsequently be magnetically removed. The fine fraction is sorted into several narrow-band size classes with a particle size of about 1:1.6 per size class. Each individual size class of particles can be separately separated with corona-roller separators into residue material particles and metal particles. The latter can then be divided into different metal classes.
REFERENCES:
patent: 4020992 (1977-05-01), Binger et al.
patent: 5139203 (1992-08-01), Alavi
patent: 5217171 (1993-06-01), Feldman
patent: 5456738 (1995-10-01), Gil
Jakob Ralf
Melchiorre Michele
Daimler-Benz AG
Rosenbaum Mark
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