METHOD FOR PRODUCING RECYCLED PULP FIBERS， AND RECYCLED PULP FIBERS

The purpose of the present invention is to provide a method for producing recycled pulp fibers such that articles using the recycled pulp fibers can easily achieve a uniform whiteness and users are not prone to feel psychological resistance to articles using the recycled pulp fibers. This method is described below. The method is characterized by involving: a step for supplying， from a mixed solution supply port (32) to a treatment tank (31)， a mixed solution (51) which contains superabsorbent polymers and pulp fibers derived from multiple types of used sanitary products; a step for supplying an ozone-containing gas (53) from an ozone-containing gas supply port (43) to a treatment solution (52) inside of the treatment tank (31); a step in which， by raising the ozone-containing gas (53) while lowering the superabsorbent polymers and pulp fibers in the treatment tank (31)， the ozone-containing gas (53) is brought into contact with the superabsorbent polymers and the pulp fibers， and the pulp fibers are bleached to form recycled pulp fibers; and a step for discharging the treatment solution (52) from a treatment solution discharge port (33)， wherein the recycled pulp fibers have a 0-10 ΔYI with respect to a standard white plate. The purpose of the present invention is to provide a method for producing recycled pulp fibers such that articles using the recycled pulp fibers can easily achieve a uniform whiteness and users are not prone to feel psychological resistance to articles using the recycled pulp fibers. This method is described below. The method is characterized by involving: a step for supplying， from a mixed solution supply port (32) to a treatment tank (31)， a mixed solution (51) which contains superabsorbent polymers and pulp fibers derived from multiple types of used sanitary products; a step for supplying an ozone-containing gas (53) from an ozone-containing gas supply port (43) to a treatment solution (52) inside of the treatment tank (31); a step in which， by raising the ozone-containing gas (53) while lowering the superabsorbent polymers and pulp fibers in the treatment tank (31)， the ozone-containing gas (53) is brought into contact with the superabsorbent polymers and the pulp fibers， and the pulp fibers are bleached to form recycled pulp fibers; and a step for discharging the treatment solution (52) from a treatment solution discharge port (33)， wherein the recycled pulp fibers have a 0-10 ΔYI with respect to a standard white plate.