Discarded printed circuit boards have become a hot issue in the current e-waste treatment

As a typical electronic waste, waste printed circuit boards have become a hot issue in current electronic waste disposal. Pyrometallurgy, hydrometallurgy and mechanical/physical methods are currently the main recycling methods. Pyrometallurgy and hydrometallurgy aim to recover metals, and the waste water, waste residue, and toxic fumes generated during the treatment process can easily cause serious secondary pollution. Mechanical/physical methods use physical processes such as crushing, screening, and sorting to enrich and separate metals and non-metals, with low environmental pollution and occupy a dominant position in resource recycling. Existing recycling methods mostly focus on the recycling of metals in circuit boards, and rarely involve the recycling and harmlessness of non-metallic components that account for more than 50% of the total. Except for a small number of non-metallic materials used as fillers, they are mostly used as landfills. Not only are valuable substances such as resin and glass fiber not fully utilized and lost, but also harmful substances such as flame retardants and residual metals are easily passed through. Various ways of polluting the environment. Therefore, reasonable recycling and processing of these materials has become a new issue facing the recycling of waste circuit boards. Pyrolysis is a process in which organic matter is heated to a certain temperature under oxygen-deficient or anaerobic conditions to decompose to produce gas, liquid (oil), and solid (coke) and recover them. In recent years, organic waste pyrolysis technology has been used more and more because of its lower pollution discharge and higher energy recovery rate. The use of pyrolysis technology to treat waste circuit boards can not only recover the metal in the circuit boards, but also realize the resource utilization of non-metallic components such as resin and glass fiber, which has a certain attraction. Therefore, some scholars have successively carried out theoretical research and engineering practice of waste circuit board pyrolysis technology.