In the prior art this recuperation is done by first mincing the articles constituted by different materials with the aim of obtaining a granulate having a mean dimension of in the order of 0.5 to 25 mm.
The granulate comprises a mass made up of granules of different materials which in order to be re-used must be separated such as to obtain homogeneous masses comprising granules of the same material.
Separation methods are known which are based on the application of the tribo-electric effect, which do not always produce satisfactory results and involve the use of sophisticated plants which are expensive and difficult to run.
The prior art comprises plants equipped with a sedimentation tank in which the separation of plastic products is done by simple gravitational effect: the materials having a lower density with respect to the density of the liquid remain floating, while the materials having a heavier density that that of the liquid precipitate to the bottom of the tank.