Abstract: The subject matter of the invention mainly relates to the technical areas of foundry, manufacture of parts by casting metal in moulds.The process consists in that after moulding the parts and stripping them from the moulds which were broken, during a first cycle the mixture resulting from the knock-out is recovered. This mixture being stored. This mixture is directed from the storage place to an intermediate container; then the mixture from the intermediate container is fed up to a sieve grading separator unit allowing to separate the grains or particles in several different grading batches; each one of these batches is directed to a separating table designed for separating chromite from silica; the chromite on the one hand and the silica on the other hand are recovered in containers.This invention mainly applies to the recovery of components of different densities, especially chromite and silica.