Plant for recovering and treating residues from crushing scrap, characterized in that it comprises: - a first plant part provided with: a granulator system, that is a first grinding or crushing system, configured to reduce, in dry mode and without pre-screening stages, the residues from crushing into a stream of granular material; separation means (13, 15, 17, 19) located downstream of the granulator system and configured to extract ferrous materials, non-ferrous metals and light or heavy plastic materials (16, 24) from said residues from crushing; - and a second plant part provided with: means (32, 33) to treat and size the plastic materials (16, 24) configured to transform said plastic materials (16, 24) into additive material to be used, in particular, in iron and steel plants such as blast furnaces, electric arc furnaces or suchlike; said means (32, 33) to treat and size the plastic materials (16, 24) comprising a second dry system for cutting and/or grinding the plastic materials (16, 24); said second plant part comprises a thermomechanical transformation system of the plastic materials (16, 24) and said second cutting and/or grinding system is located downstream of said thermomechanical transformation system; the thermomechanical transformation system being able to transform the plastic materials (16, 24) into a series of briquettes or compact cylinders and the second cutting and/or grinding system is able to obtain material in a granular form which is used as additive material, for example to function as fuel or reducing agent, to be fed to in the iron and steel plants. - a first plant part provided with: a granulator system, that is a first grinding or crushing system, configured to reduce, in dry mode and without pre-screening stages, the residues from crushing into a stream of granular material; separation means (13, 15, 17, 19) located downstream of the granulator system and configured to extract ferrous materials, non-ferrous metals and light or heavy plastic materials (16, 24) from said residues from crushing; a granulator system, that is a first grinding or crushing system, configured to reduce, in dry mode and without pre-screening stages, the residues from crushing into a stream of granular material; separation means (13, 15, 17, 19) located downstream of the granulator system and configured to extract ferrous materials, non-ferrous metals and light or heavy plastic materials (16, 24) from said residues from crushing; - and a second plant part provided with: means (32, 33) to treat and size the plastic materials (16, 24) configured to transform said plastic materials (16, 24) into additive material to be used, in particular, in iron and steel plants such as blast furnaces, electric arc furnaces or suchlike; said means (32, 33) to treat and size the plastic materials (16, 24) comprising a second dry system for cutting and/or grinding the plastic materials (16, 24); said second plant part comprises a thermomechanical transformation system of the plastic materials (16, 24) and said second cutting and/or grinding system is located downstream of said thermomechanical transformation system; the thermomechanical transformation system being able to transform the plastic materials (16, 24) into a series of briquettes or compact cylinders and the second cutting and/or grinding system is able to obtain material in a granular form which is used as additive material, for example to function as fuel or reducing agent, to be fed to in the iron and steel plants. means (32, 33) to treat and size the plastic materials (16, 24) configured to transform said plastic materials (16, 24) into additive material to be used, in particular, in iron and steel plants such as blast furnaces, electric arc furnaces or suchlike; said means (32, 33) to treat and size the plastic materials (16, 24) comprising a second dry system for cutting and/or grinding the plastic materials (16, 24); said second plant part comprises a thermomechanical transformation system of the plastic materials (16, 24) and said second cutting and/or grinding system is located downstream of said thermomechanical transformation system; the thermomechanical transformation system being able to transform the plastic materials (16, 24) into a series of briquettes or compact cylinders and the second cutting and/or grinding system is able to obtain material in a granular form which is used as additive material, for example to function as fuel or reducing agent, to be fed to in the iron and steel plants.