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How to solve the problem of waste printed circuit board pollution

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  Printed circuit boards are an important part of electronic and electrical products. Its components are disorderly, high hardness, strong toughness, contains a variety of valuable metals and a variety of harmful substances, and its resource has always been a problem in the field of electronic disposal of waste materials. In order to solve the secondary pollution problem that occurs in the process of breaking the printed circuit board, the PCB circuit board manufacturer invented a wet method to destroy the printed circuit board by using water as the destruction medium. Introduction to the ceramic substrate, the low-temperature crushing skills are also beginning to be used to discard the broken printed circuit boards. Eddy current sorting is a method of sorting and discarding metal and non-metal parts of printed wiring boards.

Ceramic substrate

  With the economic development and scientific and technological progress, the number of abandoned electronic products has risen in a straight line. The huge amount of discarded electronic products on printed circuit boards has caused great damage to the environment, and on the other hand, it has ruined valuable resources, especially precious metals. This status has aroused great concern from governments, environmentalists and the business community around the world. Some countries and regions have adopted effective measures and have done a lot of work in laws and regulations, recovery of systems and recovery of skills research and development.

  PCB circuit board manufacturers from the current level of research and depth, the use of "mechanical physics separation + hydrometallurgy recovery" process to abandon printed circuit boards have the advantage of industrial production in a short period of time, but the overall process optimization and Environmental pollution prevention and control in the production process is still the focus of future research

  The hydrometallurgical skills to recover the valuable metals in the discarded printed circuit boards are mainly the use of valuable metals in the circuit board to dissolve in the strong oxidizing medium such as nitric acid, aqua regia and into the liquid phase, so that most of the precious metals and Other metals enter the liquid phase and are separated from others, and then the various metals are withdrawn from the liquid phase. When using hydrometallurgical skills to recover the metal in the waste printed circuit board, the requirements are dismantled, selected (large visible metal, parts without precious metals), damage (generally metal and non-metal separation of the damaged powder), etc. Process, then chemically leaching precious metals or other valuable metals in between. Thus, hydrometallurgical skills can be used as a follow-up process to mechanically dispose of discarded boards.

  In addition, the principle of "whirlwind vortex separation" is used, and the independent research announces that "waste printed circuit board completely physical recovery equipment", effectively complete the separation of metal and non-metal, and further information on non-metallic powder materials. The main part is made of thermosetting epoxy resin glass fiber composite material. This material not only has insoluble and infusible characteristics, but also contains high concentration of brominated flame retardant, heavy metal and other harmful components for regeneration. Use brings great difficulties. At present, most of the recovery is limited to metal parts, and landfill and combustion are still the main ways to dispose of waste. The heat treatment method mainly includes incineration, vacuum cracking, direct smelting and the like.

  The incineration method first breaks the discarded material of the electronic printed circuit board to a certain particle size, and sends it to an incinerator for combustion to differentiate the organic components therebetween, thereby separating the gas from the solid. The residue after combustion is a bare metal or its oxide and glass fiber, which can be recovered by physical and chemical methods after being destroyed. The gas containing organic components is discharged into the secondary incinerator after combustion treatment

  Pyrolysis is also called retorting in industry. The electronic printed circuit board discard is placed in a container and heated under the condition of insulating air, and the organic substance between them is differentiated and converted into oil and gas, and can be recovered after being collected by condensation, and the metal and glass fiber components do not change in nature at all, leaving As a solid phase residue in the reactor, a simple physical method can be used to recover. Different from the combustion treatment of electronic waste, the vacuum pyrolysis process is carried out under anaerobic conditions, so that the occurrence of dioxins and furans can be suppressed, and the amount of exhaust gas is small and environmental pollution is caused.

  The ceramic substrate is described in small series. The fundamental principle of the chemical treatment method is to use the method of recycling the printed circuit board by using the difference in chemical stability of various components in the waste printed circuit board. This method is carried out by refining a metal rich group or a crushed circuit board to gradually reclaim various metals through a multi-stage chemical reaction.
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