A vertical separator for the treatment of slurry comprising a liquid part and solid particles; said vertical separator comprising: - a tubular screen device, with a substantially vertical axis, provided with a perforated filtering wall; - a feeding device (11, 12, 13, 18) to feed the slurry to said tubular screen device; said feeding device (11, 12, 13, 18) comprising pumping means; - a first discharge device (20, 23) to discharge the liquid part after the liquid part has been separated from at least one portion of the solid particles by the perforated filtering wall; and - a second discharge device (21, 22) to discharge said at least one portion of the solid particles; wherein said tubular screen device houses counter-pressing means, which are designed to generate a reaction, which partially counters the pushing action exerted by said pumping means upon the slurry; and wherein said counter-pressing means comprise screw means; wherein the screw means are wound around said vertical axis and are rotated in a direction of rotation so as to generate a head that is opposite to and less than the one generated by said pumping means; said vertical separator being characterized in that: the first discharge device (20, 23) comprises a lower collecting tank to collect the liquid part exiting from said tubular screen device; and the second discharge device (21, 22) comprises an upper chamber to collect the solid material separated from the slurry, and a discharge chute to discharge the solid material from the upper chamber to removing means. said vertical separator comprising: - a tubular screen device, with a substantially vertical axis, provided with a perforated filtering wall; - a feeding device (11, 12, 13, 18) to feed the slurry to said tubular screen device; said feeding device (11, 12, 13, 18) comprising pumping means; - a first discharge device (20, 23) to discharge the liquid part after the liquid part has been separated from at least one portion of the solid particles by the perforated filtering wall; and - a second discharge device (21, 22) to discharge said at least one portion of the solid particles; - a tubular screen device, with a substantially vertical axis, provided with a perforated filtering wall; - a feeding device (11, 12, 13, 18) to feed the slurry to said tubular screen device; said feeding device (11, 12, 13, 18) comprising pumping means; - a first discharge device (20, 23) to discharge the liquid part after the liquid part has been separated from at least one portion of the solid particles by the perforated filtering wall; and - a second discharge device (21, 22) to discharge said at least one portion of the solid particles; wherein said tubular screen device houses counter-pressing means, which are designed to generate a reaction, which partially counters the pushing action exerted by said pumping means upon the slurry; and wherein said counter-pressing means comprise screw means; wherein the screw means are wound around said vertical axis and are rotated in a direction of rotation so as to generate a head that is opposite to and less than the one generated by said pumping means; said vertical separator being characterized in that: the first discharge device (20, 23) comprises a lower collecting tank to collect the liquid part exiting from said tubular screen device; and the second discharge device (21, 22) comprises an upper chamber to collect the solid material separated from the slurry, and a discharge chute to discharge the solid material from the upper chamber to removing means. the first discharge device (20, 23) comprises a lower collecting tank to collect the liquid part exiting from said tubular screen device; and the second discharge device (21, 22) comprises an upper chamber to collect the solid material separated from the slurry, and a discharge chute to discharge the solid material from the upper chamber to removing means.