Abstract: A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising

Abstract: A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising contacting said substantially lignin-free pulp or paper with an aqueous reductive bleaching solution comprising hydroxymethane sulfinic acid during a reductive bleaching stage for sufficient amount of time to at least partially bleach said substantially lignin-free pulp or paper.

Abstract: A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising

Abstract: A method for white liquor oxidation in a kraft mill utilizes a two-stage selective oxidation system in which the first stage is operated to remove sulfide while the second stage is operated to oxidize a significant fraction of the remaining oxidizable sulfur compounds to sulfate. The resulting selectively oxidized white liquor products are used as alkali sources for various process steps in the mill. Optionally, white liquor can be oxidized in a single stage to convert a significant fraction of the oxidizable sulfur compounds to sulfate. Methods for controlling the selective oxidation process are disclosed.

Abstract: A method is disclosed for the detackification of stickies in the production of recycled paper products containing secondary fibers. Oxygen is used to reduce the tackiness of stickies in secondary pulps, and optionally is used with alkali and/or detackification agents for optimum stickies control.

Abstract: Color is removed from secondary pulps with non-chlorine based bleaching agents in treating sequences using oxygen with combinations of peroxide, ozone, and/or hydrosulfite at/controlled pH conditions. Acid treatment prior to bleaching steps improves color removal and protects fibers from damage at more severe bleaching conditions.

Abstract: Color is removed from secondary pulps with non-chlorine based bleaching agents in treating sequences using oxygen with combinations of peroxide, ozone, and/or hydrosulfite at/controlled pH conditions. Acid treatment prior to bleaching steps improves color removal and protects fibers from damage at more severe bleaching conditions.

Abstract: Secondary pulp is deinked and bleached by contacting the pulp simultaneously with oxygen, alkali, and a surfactant in a reaction zone followed by washing to recover a secondary fiber product. Simultaneous contacting with oxygen and surfactant yields higher pulp brightness than sequential contacting in oxygen bleaching and washing stages, and enhances bleachability in further bleaching stages.

Abstract: A method is disclosed for the detackification of stickies in the production of recycled paper products containing secondary fibers. Oxygen is used to reduce the tackiness of stickies in secondary pulps, and optionally is used with alkali and/or detackification agents for optimum stickies control. The preferred alkali source is fully oxidized white liquor.

Abstract: Color from dyes is removed from secondary pulps with non-chlorine based bleaching agents in treating sequences using oxygen with combinations of peroxide, ozone, and/or hydrosulfite at controlled pH conditions (less than 8 or greater than 10). Acid treatment prior to bleaching steps improves color removal and protects fibers from damage at more severe bleaching conditions.