Method and device for recycling substrates by thermally cracking wasted printed circuit boards

Abstract

The invention discloses a method and a device for recycling substrates by thermally cracking wasted printed circuit boards. Through the method and the device, combustion is avoided in a thermal cracking process and treatment safety is enhanced mainly by adding the introduction of water (vapor) in a reaction process and creating a completely-sealed low-pressure treatment environment; and by condensing and purifying organic gases to form reusable fuels or industrial chemicals, the treatment cost is reduced, recycling values are increased and a plurality of benefits, such as safe treatment devices and the like, can be created; therefore, the method and the device are of great industrial utilization value.

Description

technical field [0001] The invention relates to a method and a device for recovering substrates of waste printed circuit boards by pyrolysis. Background technique [0002] The inventor of this case filed the invention patent No. 095102342 "Method of Recycling Waste Printed Circuit Boards" in Taiwan on January 20, 2006, and was approved and announced on December 11, 2006 to obtain the patent certificate of invention patent No. I268184. This invention patent has been implemented by the inventor and has achieved good results. Using molten nitrate to pyrolyze the epoxy resin in the circuit board to separate metal and carbonized glass fibers has obvious effects. It is mainly to put waste printed circuit boards into molten nitrate, which can pyrolyze the brominated epoxy resin in the circuit board, and chemically react with it to form a large amount of organic gases and nitrogen oxides, such as figure 1 shown. However, if the concentration of organic gas is high, if there is oxy...

AI Technical Summary

Problems solved by technology

[0003] (1) The amount of gas produced by the pyrolysis reaction increases with the rise of the temperature. The higher the temperature, the more intense the reaction, and it is difficult to grasp the curve change of the gas. It is impossible to use the estimation to know the instantaneous amount, and there is a risk to the safety of the operators.

[0004] (2) The circuit board will float during pyrolysis, and when the circuit board is placed horizontally in the reaction furnace for processing, the glass fiber and copper foil on the circuit board will hinder the discharge of gas, and there will be a large amount of exhaust gas under the circuit board and The circuit board is not easy to react; and there is a lot of exhaust gas when taking out the reactant, which affects the operator and has operational risks

[0005] (3) During the pyrolysis reaction process, air intrusion at high temperature may easily cause combustion, fire and gas explosion. The higher the temperature, the more obvious it will be, which will easily cause operational danger.

[0006] (4) Carbon slag gathers on the surface of molten nitrate during a large amount of operation, and the carbon slag is inversely proportional to the gas production, especially when the operation is below 370°C, because carbon needs a very high temperature to decompose and destroy, and there is still some gas under the carbon slag Remains, and there is also gas coming out when it is removed, which will affect the safety of operators

[0007] (5) When thermal cracking waste gas treatment directly uses oxygen-increased combustion, due to the variable gas production, additional fuel treatment is required, which increases operating costs

[0008] (6) Using oxygen-increased combustion to induce the windmill to extract the front-end exhaust gas, the exhaust effect is not good and the reaction furnace forms a negative pressure during the extraction process, which makes it easier for air to be introduced into the reaction furnace, increasing operational risks (easy to cause gas explosion and combustion), Make the system more unstable and the exhaust gas concentration will be reduced and the utilization efficiency will be reduced

[0009] (7) The thermal cracking reaction of waste printed circuit boards needs to be moved into and out of the reaction furnace, and it is also easy to cause air intrusion during the switching process of the reaction furnace. Erosion and destruction

[0012] It can be seen that the above-mentioned existing methods still have many deficiencies, are not really good designers, and need to be improved urgently.

Images