Abstract: Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

Abstract: Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

Abstract: A method is provided for recovering pulp fibers having little damage from a used absorbent article that contains pulp fibers and a superabsorbent polymer. The used absorbent article is treated at a temperature of greater than or equal to 80° C. with an organic acid aqueous solution having a pH no greater than 2.5, and the superabsorbent polymer is deactivated. Preferably, the pulp fibers and the deactivated superabsorbent polymer are separated from the used absorbent article after treatment with the organic acid aqueous solution, and further, a mixture including the separated pulp fibers and deactivated superabsorbent polymer is treated with an oxidizing agent, the deactivated superabsorbent polymer is decomposed, reduced in molecular weight and solubilized.

Abstract: The purpose of the present disclosure is to provide a method for regenerating a highly water-absorbing polymer that has been deactivated by an acid, the method enabling formation of a highly water-absorbing recycled polymer having predetermined water absorption properties. The regeneration method according to the present disclosure is configured as follows. This method regenerates a highly water-absorbing polymer that has been deactivated by an acid into a highly water-absorbing recycled polymer having predetermined water absorption properties.

Abstract: Provided is a process for recovering pulp fiber from used sanitary goods which contain both pulp fiber and a superabsorbent polymer and producing a recycled pulp which contains little ash and which is reusable for sanitary goods. This process comprises: a calcium treatment step for treating used sanitary goods with a water-soluble calcium compound and thereby conducting the dehydration of a superabsorbent polymer contained in the used sanitary goods; a disintegration step for applying a physical force to the used sanitary goods to disintegrate the used sanitary goods into pulp fiber and other materials; a separation step for separating the pulp fiber from a pulp fiber/other materials mixture which has been formed in the disintegration step; a disinfecting step using a disinfectant; and a citric acid treatment step for subjecting the separated pulp fiber to treatment with an aqueous citric acid solution at an acidic pH.

Abstract: Provided is a method for producing pulp fibers to be saccharified, whereby it becomes possible to reduce the amount of a highly water-absorbable polymer and therefore increase the collection efficiency in the production of a saccharified solution when pulp fibers for a saccharified liquid is produced from a dirty absorbent article. The method is a method for producing pulp fibers to be saccharified, from pulp fibers in a dirty absorbent article.

Abstract: The present invention provides a method which, in the process of manufacturing recycled pulp fibers from a mixture of pulp fibers and a high water-absorption polymer, enables efficient manufacturing of the recycled pulp fibers while properly removing the high water-absorption polymer from the pulp fibers.

Abstract: Recycled pulp that derives from a used sanitary article includes an antibacterial activity value of 2.0 or more and an acid. Recycled pulp that derives from a used sanitary article includes an antibacterial activity value of 2.0 or more and an ash content of 0.65% by weight or less, and further includes an acid. The acid is a citric acid. The recycled pulp further includes a cationic antibacterial agent. The cationic antibacterial agent is a quaternary ammonium salt. The cationic antibacterial agent is a benzalkonium chloride or a cetylpyridinium chloride. At least a portion of the cationic antibacterial agent is adsorbed on the recycled pulp.

Abstract: Provided is a method that, when pulp fibers are recovered from used absorbent articles that have been put into collection bags, makes it possible to safely and sanitarily crush the used absorbent articles while suppressing costs. A method for recovering pulp fibers from used absorbent articles, the method comprising: a crushing step (S12) in which collection bags (A) in which used absorbent articles have been sealed are put into a container (65), the collection bags in the container are transferred to a crushing device (12) that communicates with the container, and, bag by bag, the crushing device crushes the used absorbent articles in the collections bags in a deactivating aqueous solution; and a separation step (S13) in which the pulp fibers, a highly water-absorbent polymer, and the deactivating aqueous solution are separated from the crushed product and deactivating aqueous solution obtained in the crushing step.

Abstract: The purpose of the present disclosure is to provide a recovery method for an organic acid. The recovery method makes it possible to efficiently recover an organic acid that is included in a deactivating aqueous solution that includes excrement. This recovery method has the following features.

Abstract: The purpose of the present invention is to provide a recycled pulp fiber manufacturing method with which it is possible to easily obtain recycled pulp fibers containing less of a high water-absorption polymer without requiring any mechanical equipment such as an ozone generation apparatus.

Abstract: The present invention addresses the problem of efficiently manufacturing a recycled pulp from a used sanitary article, said recycled pulp being reusable for sanitary articles and having an ash content and antibacterial properties both meeting the standards for sanitary articles. A method for manufacturing a recycled pulp reusable for sanitary articles by recovering a pulp fiber from a used sanitary article that contains the pulp fiber and a high water-absorbing polymer, said method comprising an ozone treatment step for immersing the used sanitary article or pulp fiber in an ozone-containing aqueous solution and thus disintegrating the high water-absorbing polymer contained in the used sanitary article or sticking to the pulp fiber, characterized in that the used sanitary article or pulp fiber is treated with a cationic antibacterial agent before, after or together with the ozone treatment step.

Abstract: Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: 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.

Abstract: In this method of producing recycled fibers by removing superabsorbent polymers from fibers containing superabsorbent polymers, recycled fibers are efficiently produced while the superabsorbent polymers are suitably removed from the fibers. This method produces recycled fibers from a mixture of fibers and superabsorbent polymers. This method involves a continuous treatment step (S36) in which, in a treatment tank (31) having a treatment solution that can dissolve superabsorbent polymers, superabsorbent polymers are dissolved while a mixed solution (51) that contains water and fibers containing superabsorbent polymers is continuously supplied at a first flow rate, and the treatment solution (52) containing the removed fibers is continuously discharged to outside of the treatment tank at a second flow rate.

Abstract: Provided is a method for efficiently recovering pulp fiber from used hygiene products that include pulp fiber and a polymer absorbent. This method is characterized by including a step for introducing the used hygiene product into a treatment tank in which an aqueous solution with ozone dissolved therein has been introduced, and a step for treating the used hygiene product while infusing water into the treatment tank at a first flow rate, extracting the aqueous solution from the treatment tank at a second flow rate and introducing a gas containing ozone into the aqueous solution in the treatment tank, thereby decomposing the polymer absorbent, lowering the molecular weight thereof, and making the same dissolvable.

Abstract: The purpose of the present disclosure is to provide a method for producing pulp fibres for saccharification from the pulp fibres of used sanitary items, said pulp fibres for saccharification having low lignin contents distributed within a narrow range, and enabling the production of pulp fibres for saccharification having superior saccharification properties.

Abstract: The purpose of the present invention is to provide a method which is for producing pulp fibers for cellulose nanofiberization from pulp fibers of used sanitary products, and which can produce pulp fibers for cellulose nanofiberization that have low lignin content and a low distribution thereof and that have excellent cellulose nanofiberization properties. This method is described below.