Abstract: The present invention relates to a process for separating waste material such as domestic refuse that has already been pretreated in order to eliminate the larger part of the paper, plastic film, food remnants and ferromagnetic materials and the particle size of which has been reduced to less than 70 mm through grinding. The waste material contains both glass and aluminium, in addition to other components. The ground waste material is separated by specific gravity in three hydrocyclones or hydrocyclone-batteries connected in series. In the first hydrocyclone, in which water is used as the separating medium, the lightest materials are separated. In the second hydrocyclone, a final heavy fraction is separated. In the third hydrocyclone, the intermediate fraction obtained in the second hydrocyclone is separated into a final fraction containing practically all the glass and a final fraction containing practically all the aluminium.

Abstract: The present invention relates to a process for separating scrap essentially consisting of non-ferromagnetic metals into several fractions by specific gravity in which only one heavy separating medium is required. The scrap has been recovered from waste products composed of metals and non-metals by reducing the particle size of the waste through grinding to a size less than 50 mm including particles as small as 0.5 mm. Thereafter, the ferromagnetic components are magnetically separated from the ground waste and the ground waste is fed to a primary specific-gravity separator where non-metallic components are separated from the non-ferromagnetic portion of the ground waste. Thereafter, further separation of the non-ferromagnetic portion in a secondary and, in some cases, tertiary separators is accomplished.