RU2166376C1 - Method for processing of electronic and cable scrap - Google Patents

Abstract

FIELD: dry processing of scrap, in particular: processing or radioelectronic scrap and playing machines with extraction of metals from them and sorting of plastics. SUBSTANCE: the method consists in crushing, grinding, classification to size and electrostatic separation. Grinding is performed selectively in hammer crushers, in a closed cycle with air classifying and screen sizing. Material particles are brought to size less than 5 mm and directed in a monolayer to a conveyer with a metal belt. Under the action of high-voltage corona electric charges on the belt the material is finally ground and gets charged, separating at the outlet from the conveyer into conducting metal, dielectric fractions and semi-product, which returns to repeated separation. EFFECT: enhanced efficiency of metal separation from the original raw material. 1 dwg

Description

 The invention relates to dry processing of electronic and cable scrap and can be most widely used for the processing of electronic scrap and gaming machines with the extraction of metals and sorting of plastics.

 The organization of recycling industrial and household waste today has stopped the further increase in the extraction of raw materials.

 The task of processing electronic scrap is today especially urgent, since a twofold increase in the volume of these wastes occurs every 5 years. Electronic scrap is an especially valuable material containing almost all metals, including precious ones. It is ten times cheaper to extract these metals from electronic scrap than from ore. Many plastics are now acquiring the value of metals, and electronic scrap contains at least 70% of plastics.

 However, the known technologies do not allow plastics to be removed during the processing of electronic scrap, so they are sent to dumps.

 The known method of pyrometallurgical processing of scrap is aimed at burning plastics, however, it is not possible to catch all the secreted diaxin, therefore, companies using this method are switching to other technologies.

 Processing electronics in heavy suspensions is also harmful to the environment.

 The most rational and environmentally friendly methods are electromechanical technologies, which make it possible to obtain a polymetallic concentrate without the use of liquids, free it from non-metals, and then direct this concentrate to pyrohydrometallurgical processes to produce individual metals.

 A known method of processing polymetallic waste (Japan, application N 58-6537, B 03 B 04.02.83,), including crushing, grinding, classification by size and separation. The disadvantage of this method is the need to use water for most of the processing processes, as well as the use of hydroseparation processes that do not provide high-quality separation of metals from non-metals.

 Known adopted for the prototype method according to the patent of Germany N 3313872, B 03 C 07/26/84, including crushing, grinding, classification by size and separation of polymetallic scrap. The basis of the method is the electromagnetic effect on the transported shredded scrap. Due to this effect, the scrap is divided into two streams: metallic and non-metallic. The process is carried out without the use of water, however, its significant drawback is coarse separation with incomplete extraction of metals and the inability to separate particles smaller than 8 mm.

 The present invention is the provision of almost complete extraction of metals up to 98%. Another objective of the proposed method is the elimination of harmful or non-recyclable waste. The third objective of the invention is the simplification of technology while reducing capital and operating costs.

 The tasks are solved by the proposed method for processing electronic and cable scrap, including its crushing, grinding, size classification and separation, in which, in accordance with the present invention, the grinding process is carried out selectively in hammer crushers, performing impact and intralayer grinding in a closed cycle, with air and sieve classification, while the particles of the material are brought to a particle size smaller than 5 mm and are directed as a monolayer on a conveyor with a metal belt, to which high volt corona electric discharge, simultaneously doizmelchaya particles and particle charging electrostatic charge and dividing it at the outlet from the conveyor to a conductive metal, and a dielectric intermediate fraction which is recycled to the metal strip for re-separation.

 The drawing shows a process diagram of the implementation of the method.

 In accordance with the invention, the source material in the form of a cable, gaming machines, computers or other products is loaded into a knife crusher 1, from which it enters a high-speed hammer mill 2 of stage I. The product of the mill 2 is sent for classification to the drum screen 4, from which particles larger than 5 mm enter the hammer mill 3 of the II stage. The product of the mill 3 is also sent to a screen 4, from which particles of material smaller than 5 mm are fed to an electropulse belt or drum separator 5. The monolayer material flow on this separator is subjected to high-voltage short-circuit discharge from high-voltage electrode 7, which is supplied with power from high-voltage generator 6.

 Corona discharges pass mainly along the contact surface of a metal and a dielectric in intergrowths of particles and destroy them along these surfaces, providing good separation selectivity. At the same time, the particles receive an electrostatic charge, but the metal immediately gives it to the tape as a low-voltage electrode and falls from the tape like a neutral bulk material. The dielectric adheres to the tape and comes off already under it, forming its own flow. The intermediate product, which is not yet disclosed intergrowths, falls into its container between the first and second flows and is sent again to the separator belt for additional processing.

 The primary selective opening is provided in special high-speed hammer mills, in which each rotor carries over two hundred flat percussion elements that strike their ends with pieces of scrap and destroy it through weak bonds due to different inertia of the dielectric and metal. The remaining intergrowths are selectively crushed in a layer against each other and beat according to the principle of tumbling. Reaching the size of the holes in the grill of the mill, they enter the next unit. In the process of grinding in mills create a vacuum that ensures the removal of light particles of the dielectric into the suction system. If it is necessary to separate the dielectric into separate grades of plastics, additional electropulse separators are used with special settings for a specific grade of plastics.

 Due to the selectivity of the disclosure, that is, the thorough separation of the metal from non-metal during scrap processing, efficient separation and a high percentage of metal from the feedstock up to 98% are ensured. Such minimal losses cannot be achieved in any of the known methods.

Claims (1)

 A method of processing electronic and cable scrap, including its crushing, grinding, size classification and separation, characterized in that the grinding process is carried out selectively in hammer crushers, performing impact and intralayer grinding in a closed cycle with air and sieve classification, while the particles of the material are adjusted to a particle size smaller than 5 mm and direct it in a monolayer onto a conveyor with a metal belt, to which high-voltage corona electrodischarges are fed, at the same time refining and charging an hour Itza electrostatic charge and dividing it at the outlet from the conveyor to a conductive metal, and a dielectric intermediate fraction which is recycled to the metal strip for re-separation.