Method and apparatus for breaking into parts of a certain size and screening a bulk material

A method for breaking lumps of a loose bulk material into fractions of a certain size and screening the material, the method comprising feeding the lumps of loose bulk material onto one end of a flat grid, vibrating said flat grid such that at least a vibration movement in the direction perpendicular to the plane of the grid is obtained with an intensity such that large lumps of at least one type of bulk material which do not pass directly through the openings in the grid are, as a result of the said vibration movement, broken on said grid into fragments having a size which allows these fragments to pass through the openings in the grid, removing the lumps of bulk material which have not passed through said grid from a second end thereof as a first fraction, collecting the fragments of bulk material passing through said grid on a screen located below said grid and which vibrates with said grid, some of said fragments of bulk material passing through said screen and some of said fragments remaining on said screen, conveying said fragments of bulk material remaining on said screen through a mechanically driven reduction device at a discharge end of said screen to reduce their sizes, collecting the fragments of bulk material passing through said screen and the fragments of bulk material obtained from said mechanically driven reduction device on a common bottom structure, and discharging said collected fragments through a discharge opening in said bottom structure as a second fraction.