Tailings dry discharge device and process for dewatering screen undersize self-closed path

The invention provides a tailings dry discharge process for a dewatering screen undersize self-closed path. The process comprises the following steps: conveying tailings to a first group of hydrocyclones for concentration and classification; conveying an overflow product of the first group of hydrocyclones into an overflow box, and conveying a bottom flow product of the overflow box to a vibrating-dewatering screen for dewatering; outputting an oversize product on the vibrating-dewatering screen, and enabling undersize products to automatically flow into a pump pool; conveying part of the overflow product in the overflow box into the pump pool, controlling the conveying capacity to enable the quantity of a mixture in the pump pool to match with the treatment capacity of a second groups of hydrocyclones; conveying the mixture in the pump pool into the second group of hydrocyclones for concentration and classification; conveying an overflow product of the second group of hydrocyclones into the overflow box, con