Daimler Chrysler Ag

Daimler-benz Ag

Ralf Jakob

Michele Melchiorre

Joachim Pfitscher

Joerg Melchinger

A device for cooling material chunks or grains, especially material consisting of multiple components, which are subsequently fed to a device for crushing said material, preferably on a selective basis. An example is electronic waste material intended for recycling. According to the invention, the material is placed into a cooling tank in a discontinuous manner and in separate portions. In at least part of the cooling tank, the material is cooled by means of a liquefied gas having a low boiling point and then removed from the cooling tank in a discontinuous manner. The invention notably allows for the targeted setting of the optimal temperature for the selective crushing of the material in question while at the same time optimizing the required quantities of cooling gas and energy and minimizing both manual labor and processing time.

Method for cooling material chunks or grains and device for carrying out said method

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.

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Karlsbad, Germany

Ralf Jakob