With the development of my country's electronics industry, the elimination of waste electronic products and household appliances is increasing. At the same time, a large number of waste circuit boards are produced. At the same time, we can also see that some people specialize in recycling waste circuit boards. So, what is the use of these waste circuit boards? Follow the editor of Zhichuang Circuit Board Factory to find out.
In today's electronic age, smart appliances are completely flooding our lives. Every smart appliance or non-smart appliance is controlled by a circuit board, and each circuit board has its own lifespan, that is, the scrapping period, and some appliances are directly turned into discarded appliances due to external influences, and cannot work . This directly leads to the generation of waste circuit boards.
Circuit Board Hazards:
In the world, billions of circuit boards leave the factory every day in circuit board manufacturers. In daily life, there are probably hundreds of millions of tons of waste circuit boards accumulated. Once the circuit boards pile up, it will cause harm to our ecological environment and human health over time. No matter which circuit board will produce organic pollution to society. In addition, the electronic components on the PCBA board will also cause pollution, the most important pollution is metal pollution; especially heavy metals such as tin, lead and cadmium, which directly endanger human health.
Professionally speaking, waste printed circuit boards are a mixture of glass fiber reinforced resin and various metals. It is a typical electronic waste. If it is not properly handled and disposed of, it will not only cause a large loss of useful resources, but also contain cadmium. A large number of teratogenic, mutagenic and carcinogenic substances such as brominated flame retardants and brominated flame retardants will cause serious harm to the environment and human health.
At present, the recycling and treatment methods of scrap iron generally adopt methods such as direct burial, incineration, water washing and cracking, but all of them release toxic substances, which are likely to cause serious secondary pollution of the air or soil and other environments. The national environmental protection policy does not allow this. Or to limit these processing modes. Internationally, the best way to recycle waste circuit boards is the physical method. The most notable features of this method are the advantages of low environmental pollution, high comprehensive utilization rate, and large added value. It is the development trend of electronic waste treatment in the future; its disadvantages are: It is a recovery treatment mode with a slightly higher treatment cost than incineration or water washing. Due to the high toughness of waste circuit boards and the flat shape, it is difficult to separate metals and non-metals through one-time crushing, and it contains many types of substances; the separation and decomposition process is complicated. These characteristics determine the recycling of waste circuit boards. difficulty.
In electronic waste, although the recycling of circuit boards is difficult; but it has a very high economic value. The metal grade in the circuit board is equivalent to dozens of times to hundreds of times the metal grade in ordinary minerals. The metal content is as high as 40%, the most is copper, and there are also gold, tin, nickel, lead, silicon and other gold, many of which are rare. The metal content of rich ore in nature is usually only 3-5%. In addition, the non-metallic slag of waste circuit boards can be used as building materials. At the same time, solder and plastic on waste circuit boards are also important resources that can be recycled.
Therefore, the establishment of more and more circuit board recycling plants provides a final destination for a large number of waste circuit boards, and can better protect the environment and our own health.
There are various chips, capacitors, pole tubes and other components on the circuit board, which can be recycled. At the same time, there are various metals such as gold plating, tin solder, and copper skeleton on the board. The main process of its recovery is as follows:
1. Process A: Recycling various chips, capacitors, and pole tubes.
The first step: heating: put the circuit board on the coal stove and heat until softened; the second step: extraction: extract various chips, as well as electronic components such as capacitors and pole tubes; the third step: classification: classify various chips and electronic components for classification;
Flow direction and usage: transferred to electrical factories in Shenzhen and Dongguan, and directly used for the production of new products;
2. Process B: extracting solder.
The fourth step of heating: place the circuit board that has removed various chips and electronic components on a stove separated by an iron plate or a pan to continue heating. Solder such as tin on the top melts and drips on a pan or iron plate, and collects and melts it for sale.
3. Process C: Gold extraction: (mainly in the suburbs, this type of production is currently extremely hidden)
The fifth step: acid bath: various things on the circuit board have been removed, if there is a gold-plated part on the circuit board, put it into a strong acid solution;
The sixth step: reduction: the gold in the strong acid is reduced to low-purity gold;
The seventh step: heating and refining: the low-purity gold is further purified to make gold with higher purity;
4, operation D: extract copper.
Step 8: Collect: Collect various copper-containing circuit boards with all appendages removed;
Step 9: Transshipment and smelting: Transshipment to Qingyuan for blast furnace smelting, smelting into low-quality copper alloy;
Flow direction and usage: sold to smelters in Zhuzhou and other places for separation, smelting and purification.
