Metal and non-metal pyrogenation separation method on waste printed plate board

Abstract

The invention discloses a pyrolysis and separation method of metals and non-metals in waste printed circuit boards. The method comprises the following steps: waste printed circuit boards are placed into a furnace cavity of a pyrolysis device, after the furnace door is tightly closed, nitrogen gas is introduced; the material in the furnace cavity is heated at the heating rate of 15-20 DEG C per minute, the temperature thereof is raised to 600-700 DEG C and kept for 20-30min, then the furnace is shut down, micro-positive pressure is kept in the furnace cavity in the process of heating the material, and the material are stirred irregularly; (3) the pyrolysis product is discharged from the pyrolysis device, and a liquid product and a gaseous product are separated after the pyrolysis product exchanges heat with a cooling medium. The method can realize effective separation of the metals and non-metals in the waste PCB, and realize harmless thermal separation of solid wastes; and the method avoids environmental pollution caused by waste water, waste gas, waste liquid, and the like, produced in the treatment process of the prior art; and the recovery purity of the metals is higher.

Description

technical field [0001] The invention relates to resource recovery and recycling of waste printed circuit boards, in particular to a pyrolytic separation method for metal and nonmetal in waste printed circuit boards. Background technique [0002] With the popularization and elimination of home appliances, the number of discarded printed circuit boards (PCBs) is increasing dramatically. Due to the characteristics of high hazard, high value, and refractory disposal of waste PCBs, more and more attention has been paid to the harmless and resourceful treatment of waste PCBs. [0003] At present, the processing methods for waste printed circuit boards at home and abroad mainly include pyrometallurgy, chemical hydrometallurgy, mechanical physical method and incineration method. The main goal of pyrometallurgy and chemical hydrometallurgy is to recover precious metals such as platinum, palladium, gold, silver, lead, and copper. However, both of these two treatment processes have r...

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Problems solved by technology

However, both of these two treatment processes have relatively serious environmental pollution problems. Among them, chemical hydrometallurgy also introduces pollutants such as toxic and harmful chemical solutions, and other usable materials cannot be effectively recovered, so it can no longer meet the needs of resource recovery. and environmental protection requirements; the mechanical physical treatment method is to sort the various components according to their different physical properties, but a large amount of dust containing glass fibers and resins will be produced during the mechanical crushing process, and the flame retardant contains Bromine, etc. will also emit toxic gas due to heat during the continuous crushing process, which seriously damages the environment; the process of incineration treatment is to first mechanically crush the discarded PCB to a size of 1 to 2 inches, and then send it to an incinerator incineration to separate the organic gas from the solid matter, and the residue is bare metal and glass fiber

However, this treatment method will oxidize the surface of the metal at high temperature, reducing the recovery rate and purity of the metal. At the same time, the flame retardant in the PCB contains a large amount of bromine or chlorine, and it is easy to generate toxic and harmful gases after burning, which will pollute the air.

[0004] It can be seen that the above processing methods all have different deficiencies and shortcomings, and it is urgent to find a more environmentally friendly and efficient recycling method.

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