The application relates to a method for preparing dissolving pulp by totally chlorine-free bleaching of poplar kraft pulp, including: preparing poplar kraft pulp by pre-hydrolysis kraft process with poplar as raw material; ZOQP bleaching of poplar kraft pulp to obtain dissolving pulp, wherein Z denotes ozone bleaching, O denotes oxy delignification, Q denotes chelation treatment, and P denotes hydrogen peroxide bleaching. In this way, washing and bleaching wastewater can be recycled in entire preparation process described above, achieving zero discharge. The dissolving pulp prepared by the method has no residual toxic substances, and exhibits that all indexes exceed the requirements of qualified products in dissolving pulp industry standard (QB/T 4898-2015), and most of indexes meet those of excellent products; thus, it can replace imported dissolving pulp. The use of the method significantly solved the problems of large pollution in the production and shortage of raw materials for viscose fibers.

The present application relates to a method for preparing dissolving pulp by TCF bleaching of poplar KP, including: preparing poplar KP by pre-hydrolysis kraft process with poplar as a raw material, and OZQP bleaching of the poplar KP to obtain dissolving pulp, wherein O denotes oxygen delignification, Z denotes ozone bleaching, Q denotes chelating treatment, and P denotes hydrogen peroxide bleaching. The dissolving pulp prepared by the same exhibits that all indexes can meet the requirements of excellent products in dissolving pulp industry standard (QB/T4898-2015), and most of the indexes are far superior to those of excellent products, and thus it can completely replace imported dissolving pulp.

The present application relates to a method for preparing dissolving pulp by TCF bleaching of poplar KP, including: preparing poplar KP by pre-hydrolysis kraft process with poplar as a raw material, and OZQP bleaching of the poplar KP to obtain dissolving pulp, wherein O denotes oxygen delignification, Z denotes ozone bleaching, Q denotes chelating treatment, and P denotes hydrogen peroxide bleaching. The dissolving pulp prepared by the same exhibits that all indexes can meet the requirements of excellent products in dissolving pulp industry standard (QB/T4898-2015), and most of the indexes are far superior to those of excellent products, and thus it can completely replace imported dissolving pulp.

An ozone generator includes a high-voltage electrode and at least one counter electrode, which define an interstice in which at least one dielectric is arranged and through which a gas flows in the flow direction. The high-voltage electrode and the at least one counter electrode are provided with a connection for an electrical voltage supply to generate silent discharges which are discharged from surface discharge locations. The mean sparking distance and the mean spacing between the high-voltage electrode and the at least one counter-electrode are constant. The number of surface discharge locations decreases in the flow direction.

An ozone generator includes a high-voltage electrode and at least one counter electrode, which define an interstice in which at least one dielectric is arranged and through which a gas flows in the flow direction. The high-voltage electrode and the at least one counter electrode are provided with a connection for an electrical voltage supply to generate silent discharges which are discharged from surface discharge locations. The mean sparking distance and the mean spacing between the high-voltage electrode and the at least one counter-electrode are constant. The number of surface discharge locations decreases in the flow direction.

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. The method includes: a solid-liquid separation step (S18) of crushing up a highly water-absorbable polymer while separating an inactivated aqueous solution containing pulp fibers and the highly water-absorbable polymer both separated from a dirty absorbent article into a solid material (98) containing the pulp fibers and the highly water-absorbable polymer and a liquid material (E) containing the highly water-absorbable polymer and the inactivated aqueous solution; and a removal step (S21) of washing away the remaining highly water-absorbable polymer by washing the separated solid pulp fibers in a solution or another means to produce pulp fibers to be saccharified.

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. This method comprises: a supply step (S19-2a) for supplying an aqueous solution containing a mixture (98) to a driving fluid supply port (DI) of an ejector (107) and simultaneously supplying, to a suction fluid supply port (AI) of the ejector, a gaseous substance (Z2) which is capable of degrading a high water-absorption polymer so as to make the degraded polymer dissolvable; and a treatment step (S19-2b) for discharging, from a mixed fluid discharge port (CO) of the ejector that is connected to a lower part of a treatment tank (105), a mixed liquid, which is formed when the aqueous solution and the gaseous substance are mixed within the ejector, into a treatment liquid (P2) within the treatment tank, so as to lessen the high water-absorption polymer in the mixture.

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.

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.

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.