A method for treating waste printed circuit board includes carbonizing waste printed circuit board together with a calcium compound at 400 C. to 600 C. in a non-oxidizing atmosphere to fix a halogen contained in the board as calcium halide and to melt a solder of the board to allow mounted parts to be easily separated from the board, performing crushing after the carbonizing, and sieving crushed materials into fine particles of less than 0.5 mm containing the calcium compounds, medium particles containing the mounted parts, and coarse particles containing board pieces such that the crushed materials are sorted into the calcium compounds, the mounted parts, and the board pieces.

A system for processing compounds having constituent materials of different mechanical characteristics to extract their constituent materials. The system includes (a) a grinder configured to grind a bulk compound material into an initial mixture of tiny particles; (b) a preimpact separator configured to separate the particles into two groups based on their respective mechanical properties, one group being a preimpact mixture comprising the compound particles; (c) a kinetic impactor configured to impact, via an acoustic shockwave, the compound particles of the preimpact mixture, thereby creating a postimpact mixture comprising (i) subparticles of 1.sup.st-constituent-material and (ii) reduced-compound particles comprising a 2nd constituent material; and (d) a postimpact separator configured to separate the reduced compound particles from the postimpact mixture based on a mechanical property.

A stirring and separating device for high-value components of a waste PCB and a control method thereof are disclosed. The stirring and separating device comprises an insulated outer tank for accommodating a desoldering flux. The insulated outer tank is provided with a stirring mechanism. The stirring mechanism includes a main rotation shaft. A plurality of spaced cross beams are mounted at a bottom of the main rotation shaft. Each of the cross beams is provided with a secondary rotation shaft. A bottom of each of the secondary rotation shafts is rotationally connected with a stirring wheel through at least two connecting rods. At least two connection points are formed between each of the at least two connecting rods and the stirring wheel. When any one or more of the at least two connection points are disconnected, the stirring wheel rotates to a different angle.