In PCB manufacturing all over the world, there are billions of printed circuit boards out of the factory. And in every day’s life, there are tens of millions of tons of waste PCB scrap accumulation. Once the circuit board is abandoned, it will do great harm to our ecological environment and human health. No matter which circuit board, there will be organic pollution.
From a professional point of view, waste printed circuit board is a mixture of glass fiber reinforced resin and a variety of metals, which is a typical electronic waste. If it is not properly treated and disposed, it will not only cause a large loss of useful resources, but also contain a large number of teratogenic, mutagenic and carcinogenic substances such as cadmium and brominated flame retardant, which will cause serious harm to the environment and human health . At present, the recycling methods of waste printed circuit boards generally adopt the methods of direct burial, incineration, washing and cracking. These methods will release toxic substances and cause serious air or soil pollution, which is not allowed by the national environmental protection policy.
In the world, the best way to recycle waste printed circuit boards is physical recycling. The most significant advantages of this method are low environmental pollution, high comprehensive utilization rate and high added value, which is the inevitable development trend of electronic waste treatment in the future; its disadvantage is that the treatment cost is higher than that of incineration or washing. Due to the toughness of waste printed circuit board, it is difficult to separate metal from nonmetal through one-time crushing, and it contains many kinds of materials, and the separation and decomposition process is complex. These characteristics determine that the recycling of waste printed circuit board is difficult.
In the electronic waste, although it is difficult to recycle PCB, it has high economic value. The grade of metals in circuit boards is equivalent to tens to hundreds of times of that in ordinary minerals. The content of metals is more than 40%. Copper is the most abundant. In addition, there are gold, tin, nickel, lead, silicon and other precious metals, among which there are many rare metals. In general, the content of rich minerals in nature is only 3-5%.
After the metal in PCB has been refined, the remaining non-metallic waste residue powder can also be used as an important filling material in polymer composite materials. In recent years, the resin plastic wood which has become popular in the domestic market is produced by using PCB powder; the resin plastic wood produced with PCB powder can be used in outdoor landscape decoration, such as trestle, outdoor floor, guardrail fence, external wall decoration board, etc Pavilions, flower boxes, leisure chairs and other product forms, for the courtyard, park, square, tourist attractions and other beautiful scenery.