A system for separating components of a residual concrete mixture comprising a frame with a rail, a lifting device suspending vibrating sieves of different mesh sizes configured to move horizontally and vertically and to change and angle of inclination, a process tank with a water under the vibrating sieves with water level control means, a pump in a bottom the process tank configured to move a water-cement mixture previously passed through the vibrating sieves, comprising a movable control nipple configured to determine a cement concentration and directing subsequently the water-cement mixture in a first tank if its density is higher to a predetermined value, or in the second tank, if the density of the mixture is below the predetermined value, through a sand filter, also serving as a sand hopper of sand sifted on a lower sieve; and a control unit configured to control the system.