Abstract: The present invention provides: a process for treating a particulate water-absorbent resin, which enables to carry out pulverization stably in a process for producing a particulate water-absorbent resin, and transportation or storage of the particulate water-absorbent resin stably during or after producing the particulate water-absorbent resin, and to prevent contamination of cohered matters of the particulate water-absorbent resin; and involves no or little deterioration of properties. The process for treating a particulate water-absorbent resin is characterized by carrying out at least one selected from the group consisting of: (1) heating at least one portion of a surface getting contact with the particulate water-absorbent resin from the outside, (2) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin at 30 to 150° C.

Abstract: The present invention provides: a process for treating a particulate water-absorbent resin, which enables to carry out pulverization stably in a process for producing a particulate water-absorbent resin, and transportation or storage of the particulate water-absorbent resin stably during or after producing the particulate water-absorbent resin, and to prevent contamination of cohered matters of the particulate water-absorbent resin; and involves no or little deterioration of properties. The process for treating a particulate water-absorbent resin is characterized by carrying out at least one selected from the group consisting of: (1) heating at least one portion of a surface getting contact with the particulate water-absorbent resin from the outside, (2) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin at 30 to 150° C.

Abstract: The present invention provides a process for classifying a particulate hydrophilic polymer and a sieving device, which can carry out a classification in a small separation particle diameter with high efficiency and exhibit classification ability inherent in the sieving device. The process comprises the step of classifying a particulate hydrophilic polymer in dry particle size with a sieving device, wherein the sieving device is used in a heated and/or thermally insulated state. The sieving device comprises a thermally insulating means.

Abstract: Continuous agglomeration of an absorbent resin powder is accomplished by a method which comprises introducing the absorbent resin powder into a cylindrical member having an open lower end by means of a current of air through a dispersing member disposed in the upper part of the cylindrical member and, at the same time, spraying minute droplets of an aqueous liquid downwardly through a nozzle disposed inside the dispersing member thereby establishing mutual parallel flow contact between the absorbent resin powder descending toward the lower part of the cylindrical member as dispersed with the current of air and the liquid droplets descending toward the lower part of the cylindrical member as diffused in the radial direction, and removing the produced agglomerate having a plurality of particles of the absorbent resin powder cohesively united through the medium of the liquid droplets via the lower part of the cylindrical member. An apparatus for working the method is also disclosed.