Method for recycling waste from printed circuit board assemblies from electrical and electronic devices

A method for recycling printed circuit boards from electric or electronic devices comprising the steps of:

• a) removing, separating and disposing of components containing contaminants from the printed circuit boards,
• b) mechanically precomminuting the printed circuit boards to obtain precomminuted particles of a size of not more than 30 mm,
• c) cryogenically embrittling the precomminuted particles by cooling with a liquefied gas to obtain cryogenically embrittled particles,
• d) comminuting the cryogenically embrittled particles in a hammermill to obtain fragments,
• e) separating the fragments into ferrous metals, nonferrous metals and residues,
• wherein
• the cryogenically embrittled particles are selectively comminuted batchwise in a grinding chamber of the hammermill into a fine fragment fraction emerging from the grinding chamber through a sieve at the bottom of the grinding chamber and a coarser fragment fraction of metallic material particles which remain ductile in a cryogenic state and remain in the grinding chamber to be separately discharged batchwise,
• the fine fraction is sorted into several, narrow-band size classes with a particle-size band width of about 1:1.16 per size class,
• each individual size class of particles, except for a dust fraction with a particle size of less than 0.1 mm, is separately divided by electrostatic precipitators into metallic material particles and residue material particles, and
• the metallic material particles from the selective comminution step and those from the electrostatic separation step are divided into different metal classes.