Plant for the recovery of plastic materials of post-consumption products, such as demolished vehicle bumpers and tanks, comprising: - a volumetric reduction grinder for the production of a coarse grain-size of the material of, for example, 50-80 cm, with associated iron removal stage, - a windmill/granulator for the reduction of the grain-size to a small size of, for example, 5-30 mm, - a vat for washing the material, - a centrifuge, - downstream of the volumetric reduction grinder, there is provided an intermediate grinder for an intermediate reduction of the grain-size from about 50-80 cm to an intermediate grain-size of, for example, about 30-100 mm, wherein said volumetric reduction grinder and intermediate grinder are connected by a means or belt for conveying the material, - the washing vat and the centrifuge are arranged upstream of the windmill/granulator and they are fluidically associated with a purification plant for the purification of the treatment water, characterised in that: - the intermediate grinder has a configuration analogous to that of the volumetric reduction grinder, it has an associated iron removal stage, and it is connected, through a conveyor means or belt, with the inlet of the washing vat which is carried out for the simultaneous elimination of the various components, such as ferrous and non-ferrous metal, rubber, nylon, ABS, glass, sand parts due to the different specific weight, wherein said washing and separation vat has - at the lower part - a pipe with an auger for the discharge of the separated foreign components, and wherein said centrifuge is a centrifuge of mixed type, i.e. with preliminary washing in a lower water chamber and subsequent drying in an upper air chamber, - the centrifuge is adapted to receive material with an intermediate grain-size between about 20 mm and about 250 mm, wherein the outlet of the centrifuge is connected through a connection means or screw feeder, with the inlet of the windmill/granulator provided for the grinding/granulation of the washed and dried material and substantially without abrasive metal and adherent sand parts, of intermediate grain-size of about 30-100 mm, to the desired small grain-size of about 5-30 mm. - a volumetric reduction grinder for the production of a coarse grain-size of the material of, for example, 50-80 cm, with associated iron removal stage, - a windmill/granulator for the reduction of the grain-size to a small size of, for example, 5-30 mm, - a vat for washing the material, - a centrifuge, - downstream of the volumetric reduction grinder, there is provided an intermediate grinder for an intermediate reduction of the grain-size from about 50-80 cm to an intermediate grain-size of, for example, about 30-100 mm, wherein said volumetric reduction grinder and intermediate grinder are connected by a means or belt for conveying the material, - the washing vat and the centrifuge are arranged upstream of the windmill/granulator and they are fluidically associated with a purification plant for the purification of the treatment water, - the intermediate grinder has a configuration analogous to that of the volumetric reduction grinder, it has an associated iron removal stage, and it is connected, through a conveyor means or belt, with the inlet of the washing vat which is carried out for the simultaneous elimination of the various components, such as ferrous and non-ferrous metal, rubber, nylon, ABS, glass, sand parts due to the different specific weight, wherein said washing and separation vat has - at the lower part - a pipe with an auger for the discharge of the separated foreign components, and wherein said centrifuge is a centrifuge of mixed type, i.e. with preliminary washing in a lower water chamber and subsequent drying in an upper air chamber, - the centrifuge is adapted to receive material with an intermediate grain-size between about 20 mm and about 250 mm, wherein the outlet of the centrifuge is connected through a connection means or screw feeder, with the inlet of the windmill/granulator provided for the grinding/granulation of the washed and dried material and substantially without abrasive metal and adherent sand parts, of intermediate grain-size of about 30-100 mm, to the desired small grain-size of about 5-30 mm.