Method and apparatus for printed circuit board different material layer separation in supercritical liquid

Abstract

The present invention refers to method and device for separating different material layer of printed-circuit board in supercutical fluid. It features setting printed-circuit board in supercritical fluid environment of reactor until printed-circuit board bonding layer lost cohesive action, intensifying substrate and conducting layer separation, respectively collecting separated substrate, conducting layer, and bonding layer material. Said invention has high recovery, small energy consumption, and simple structure.

Description

Technical field: [0001] The invention relates to a layered recycling method and device for printed circuit boards. Background technique: [0002] With the rapid development of the information industry, the production of circuit boards is increasing rapidly. The average annual growth rate of the world circuit board industry is 8.7%. As of 2003, my country has become the second largest producer of printed circuit boards in the world, with an annual output of 60.74 million square meters and an output value of 5.488 billion US dollars, with an average annual growth rate of more than 20%. According to the survey data of the National Bureau of Statistics in 2003, my country will eliminate about 15 million waste household appliances every year. As of 2004, about 5 million computers and tens of millions of mobile phones have entered the phase-out period in my country every year. All these waste electrical and electronic products contain a considerable amount of printed circuit bo...

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Problems solved by technology

At the same time, because the base material contains brominated flame retardants, conventional burning or incineration will produce carcinogenic, teratogenic and mutagenic substances diphenyldioxin and diphenylfuran, which are harmful to human health

[0004] At present, the recycling and treatment methods of printed circuit boards mainly include mechanical physical method, chemical treatment method, incineration or pyrolysis method. Among them, the mechanical physical method is pretreatment, crushing and sorting, and finally obtains powdery material enrichment, and then carries out subsequent Treatment. The key to efficient recycling of mechanical and physical methods is to ensure that the monomers of circuit board materials are fully dissociated. Due to the complex composition of waste printed circuit boards, a large amount of dust containing glass fibers and resins will be generated during the crushing process, and toxic gases will be emitted. It will cause heat generation and cause problems for the dissociation of monomers. For this reason, Germany has begun to adopt low-temperature freezing and crushing technology. There are also water flow cooling and dust removal during the crushing process, but it causes waste and pollution of water resources. Chemical treatment methods also It is called wet method, which is treated by pickling or corrosion method, and the metal elements are extracted through the chemical reaction between the metal layer and the added chemical solvent. The chemical method is expensive to recover, and if it is not handled properly, it will cause serious pollution to water resources. Therefore, industrial applications are limited to a certain extent. Incineration or pyrolysis is to heat circuit boards in an oxygen-free or oxygen-free environment to produce products with certain reuse value. It has a certain effect, but the combustion will lead to the waste of some valuable and volatile components, and will also cause the emission of toxic and harmful substances such as diphenyl dioxin and diphenyl furan. Among the above three methods, the chemical method is simple in process, but economical The incineration method has a low resource recovery rate; the pyrolysis method has poor environmental performance and cannot be widely applied. The mechanical physical method is better than the previous two methods in terms of economy, environment and recovery efficiency. At present, many countries have carried out research on this technology and carried out industrial application. However, due to the fact that the mechanical physics method is derived from mining metallurgy technology, with the continuous use of high-tech and new materials in circuit board manufacturing, the technical development of the mechanical physics method is relatively backward. It is difficult to be suitable for processing new printed circuit boards. It is mainly reflected in: low recycling efficiency, only 75% of metal materials can be recycled, and other reinforced filling materials cannot be recycled; economic benefits are poor, due to the low purity of recycled metals, high follow-up processing costs, Therefore, the overall economic benefit is low; the environmental pollution is serious, and the energy consumption in the recycling process is huge.

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