| 摘要 |
A method for reducing colored foreign substances in a water absorbent resin by a convenient and simple technique in the production of a water absorbent resin, without requiring any modification of raw materials or high capital investment, is provided. The method for producing a particulate water absorbent resin includes a step of polymerizing an aqueous solution of an unsaturated monomer; and a step of drying a particulate water-containing gel-like cross-linked polymer having a solids concentration of 30% by weight or greater that is obtainable in a gel grain refining step during polymerization or after polymerization, with one or more apparatuses for aerating a water absorbent resin with a high temperature gas stream being installed in the drying step and/or in at least one of the subsequent steps, while in the aerating apparatus, the high temperature gas stream is passed through a filter and then is reused in the same step as the step where the aerating apparatus is installed, or in a different step.
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