The present invention relates to a device for separating solid materials on the basis of a mutual difference in density, wherein the materials to be separated are brought into contact with a magnetic fluid across which fluid a density gradient is generated by means of a magnetic field such that fractions of solid materials of different densities are obtained, said device being provided with a magnet, an inflow chamber, a separation chamber, and means for discharging fractions of solid materials of different densities in separation, wherein the magnetic fluid flows from the inflow chamber to the separation chamber, wherein the magnet is arranged above the separation chamber, and wherein at least one duct for the supply of the solid materials to be separated is located below the inflow chamber and the separation chamber and encloses an angle with the inflow chamber and the separation chamber.