PCB board recycling method

    The main methods of recycling PCB boards include physical methods, chemical methods and biotechnology. ‌

    Physical methods

    The physical method is to achieve recycling through mechanical means and differences in physical properties. The specific steps include:

‌    1. Crushing: Crushing the PCB board into small particles to dissociate the metal and organic matter in it. Usually, when the particle size reaches 0.6 mm, the metal can be 

basically dissociated. ‌

    2. Sorting: According to the physical properties of the material such as density, particle size, conductivity, etc., wind shaking table technology, flotation separation 

technology, cyclone separation technology and other methods are used for separation.

Chemical methods

    The chemical method uses the different chemical stability of various components in PCB for extraction. The main methods include:

    1. Heat treatment method: Separate organic matter and metal by high-temperature incineration or cracking. After the incineration method incinerates the electronic waste, 

the residue is mainly metal and glass fiber; the cracking method is carried out under anaerobic conditions to reduce the emission of harmful gases.

‌    2. Hydrometallurgy: Use the solubility of metals in acid to extract metals from electronic waste. This method has low waste gas emissions, and the residue after extraction is 

easy to handle, with significant economic benefits. ‌

    Biotechnology

    Biotechnology uses the adsorption and oxidation of microorganisms to recover metals. Specific methods include:

‌    1. Microbial adsorption: Use hydrogen sulfide produced by bacteria to fix metal ions, or use the oxidizing property of trivalent iron ions to expose precious metals for easy 

recovery.

‌    2. Bioleaching: Through microbial activity, other metals in precious metal alloys are oxidized into soluble substances and enter the solution, exposing precious metals for 

recovery. ‌

    Comprehensive utilization of resources

    PCB boards contain metal resources such as copper, aluminum, gold, and silver. Recycling these metals can not only reduce the exploitation of natural resources, but also 

effectively reduce the pollution of waste to the environment. With the development of science and technology, new recycling technologies such as supercritical fluid 

processing and microwave processing technologies are also emerging, providing new ideas and ways for the recycling of PCB boards. ‌