Daimler-benz Ag

Daimler Chrysler Ag

Mercedes-benz Aktiengesellschaft

Michele Melchiorre

Bernd-Uwe Kettemann

Karsten Lohr

Ralf Jakob

Jorg Zurn

Ralph Greiner

Joachim Pfitscher

Bjorn Stuckrad

Joerg Melchinger

Martin Guldenpfennig

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 the recovery of secondary polyols from paint sludge coagulate, formed from paint overspray which has first been dewatered by mass action, by chemical treatment in a manner such that the recovered product can be reused in the manufacture of paints. According to the recovery method, the organic components contained in the paint coagulate are glycolytically split at an elevated temperature into reusable polyols. Preferably, a mixture of different glycols is used, preferably in an amount of about 20 to 50% by weight based on the dewatered paint coagulate. The addition of glycol dilutes the paint coagulate and makes it flowable. The water contained in the paint coagulate is evaporated and removed during the glycolytic splitting because of the increase in temperature. The impurities contained in the paint coagulate, such as pigments, coagulants or flocculants, can be comminuted and finely dispersed by intensive shearing of the paint coagulate. At the end of the process, these impurities can also be filtered out from the polyols formed.

Method for the recovery of secondary polyols from paint sludges

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.

Method for recycling waste from printed circuit board assemblies from

A method and apparatus for the single type recovery of plastic materials from starting pieces of a multiple composite material is disclosed. The starting pieces are firstly comminuted mechanically into particles of a size compatible with the process. These composite materials particularly are separated and a mixture of different materials is produced and, from this material mixture, the individual materials are isolated. For the recovery of starting pieces of prepreg fabric from flexible cutting residues, lined with films on both sides, the following steps are performed in sequence. First, the starting pieces are comminuted by cutting them up into shreds of composite material. Then the shreds of composite material are cooled down to temperatures below room temperature and, in a cold state, are subjected to a mechanical alternating bending stress and/or a shearing stress, the films becoming detached from the prepreg pieces in a scale-like manner to form a mixture. This mixture of film clippings and free prepreg pieces is subjected to a wet, density-selective flotation-like float and sink separation, the films floating and the free prepreg pieces sinking.

Method and apparatus for dividing and separating self-adhesive composite

A process for stripping of used parts or reject parts, in particular of polycarbonate (PC) or of a polycarbonate blend, preferably with polybutylene terephthalate (PBT/PC), for the purpose of recycling the plastic. In this process the plastics parts are first mechanically comminuted to a pourable size and then are circulated together with anhydrous alkalified diethylene glycol or propylene glycol in a mass with mutual abrasion of the plastics chips at elevated temperatures of at least 50.degree. C., preferably from 80.degree. to 100.degree. C., until complete removal of the paint. Thereafter the stripped plastics chips are separated from the stripping agent, flushed and then dried. The quantity of glycol added corresponds to from 1 to 10% of the volume of the mass to be treated, so that the circulated parts are only wetted by the glycol, but with stripping agent being circulated continuously through the treatment space of the mass from a relatively large reservoir. The circulation of the mass of parts is preferably carried out in a closable free-fall or positive mixer or in a rotary tube mixer. During the abrasive circulation the plastics parts are preferably admixed with abrasive particles whose specific apparent density corresponds roughly to the specific apparent density of the plastics parts.

Chemo-mechanical stripping of paint from plastic parts

A process is provided for disintegration and pure-sorted separation of different plastics of composite structural parts to be recycled, which parts consist of a support composed of thicker-walled hard plastic, an intermediate layer applied with firm adhesion to this support and composed of foam material, and a flexible foil adhering firmly to the outside of the intermediate layer and made thinner-walled than the support. The composite structural parts are first comminuted into approximately cuboid particles preferably of a granulation of approximately 20 mm and comprising still different plastics. Subsequently, the particles formed are disintegrated in a dry manner into their individual materials, and these are then separated in a pure-sorted manner. For this purpose, the less break-resistant foam material of the particles is selectively comminuted mechanically by an impact stressing of the particles to form substantially smaller crumbs than the remaining pieces of particles of more break-resistant plastic. The smaller foam crumbs are screened off from the coarser remaining particle pieces. These two operations are advantageously carried out in a batchwise operated hammer mill with an integrated screen plate. To produce cuboid particles, the composite structural parts are first cut into narrow strips in a twin-shaft cutter, and these are subsequently chopped into short parts in a knife mill. Where three-component structural parts are concerned, the initially remaining mixture of thick-walled hard-plastic fragments and of thin-walled foil chips is separated in a pure-sorted manner by a vertical low-turbulence wind sifter.

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Blaustein, Germany

Michele Melchiorre