How to solve the pollution problem of waste power PCB circuit boards?

  Printed circuit boards are an important part of electronic and electrical products. It has complex components, high hardness, strong toughness, and contains a variety of valuable metals and a variety of harmful substances. Its recycling has always been a difficult problem in the field of electronic waste recycling. In order to solve the problem of secondary pollution in the process of crushing waste printed circuit boards, including waste gas and dust pollution, Shenzhen PCB circuit board manufacturers have invented a wet crushing method that uses water as the crushing medium to achieve the crushing of power supply PCB circuit boards . Cryogenic crushing technology has also begun to be applied to the crushing of waste power supply PCB circuit boards. Eddy current sorting is a method of sorting metal and non-metal parts of waste power supply PCB circuit boards.

　　With economic development and technological progress, the number of discarded electronic products has been on a linear upward trend. On the one hand, a huge number of discarded power supply PCB circuit board electronic products have caused great harm to the environment, and on the other hand, they have wasted precious resources, especially precious metals. This status quo has attracted great attention from governments, environmentalists and business circles around the world. Some countries and regions have taken effective measures and done a lot of work in laws and regulations, recycling systems and recycling technology research and development.

　　From the current research level and depth, Shenzhen PCB circuit board manufacturers use the "mechanical physical separation + hydrometallurgical recycling" process to treat waste printed circuit boards, which has the advantage of realizing industrial production in a short period of time, but the optimization of its overall process flow The prevention and control of environmental pollution in the production process is still the focus of future research

　　The recovery of valuable metals in waste printed circuit boards by hydrometallurgy technology mainly utilizes the characteristics that the valuable metals in circuit boards can dissolve in strong oxidizing media such as nitric acid and aqua regia and enter the liquid phase, so that most precious metals and Other metals enter the liquid phase and separate from other substances, and then various metals are recovered from the liquid phase. When hydrometallurgical technology is used to recover metal from waste printed circuit boards, it needs to be dismantled, selected (large pieces of visible metal, parts that do not contain precious metals), and crushed (usually, the crushed powder is separated from metal and non-metal), etc. process, and then chemical leaching of precious metals or other valuable metals. Therefore, hydrometallurgical technology can be used as a follow-up process for the mechanophysical processing of waste circuit boards.

　　There is also the use of the principle of "cyclone eddy current separation" to independently develop "complete physical recycling equipment for waste power supply PCB circuit boards", which can effectively separate metal and non-metallic materials, and further materialize non-metallic powder. Common power supply PCB The main part of the circuit board is made of thermosetting epoxy resin glass fiber composite material, which not only has the characteristics of insoluble and infusible, but also contains a high concentration of brominated flame retardants, heavy metals and other harmful components. It brings great difficulties to recycling. Currently, most recycling is limited to the metal part, and landfilling and incineration are still the main ways to dispose of waste. Heat treatment methods mainly include incineration, vacuum cracking, direct smelting, etc.

　　The incineration method is to first crush the electronic power supply PCB circuit board waste to a certain particle size, and send it to a primary incinerator for incineration to decompose the organic components, thereby separating the gas from the solid. The residue after incineration is bare metal or its oxide and glass fiber, which can be recovered by physical and chemical methods after crushing. Gases containing organic components enter the secondary incinerator for combustion and discharge.

　　Pyrolysis is also called dry distillation in industry. It is to place the waste of electronic power supply PCB circuit board in a container and heat it under the condition of isolating the air, so that the organic substances in it are decomposed and converted into oil and gas, which can be recovered after condensation and collection, and the components such as metal and glass fiber basically do not change in properties. Left in the reactor as solid residue, it can be separated and recovered by simple physical methods. Different from the incineration of electronic waste, the vacuum pyrolysis process is carried out in the absence of oxygen, so the production of dioxins and furans can be suppressed, and the amount of waste gas is less, which pollutes the environment.