The present invention is directed to a method for scouring and increasing the brightness of non-wood fibers. The method comprises forming a mixture of non-wood fibers, exposing the mixture to a scouring liquor and a scouring agent comprising oxygen gas to form a scouring mixture, and scouring the scouring mixture by radially circulating the scouring liquor throughout the scouring mixture to provide scoured fibers.

The present invention is directed to a method of increasing the brightness of non-wood fibers. The method comprises forming a mixture of non-wood fibers and exposing the mixture to a brightening agent, the brightening agent being a permanganate compound, an acid, or a combination of the permanganate compound and the acid. The resulting brightened fibers have a brightness greater than the fibers of the mixture before exposure as measured by MacBeth UV-C standard.

This disclosure relates to methods of making novel dissolving wood pulps by processes comprising acid prehydrolysis, pulping, and a multi-stage bleaching process comprising oxidation with a catalyst and peroxide under acidic conditions, as well as to products made therefrom having a combination of medium-purity, low viscosity, and improved reactivity, filterability, and/or clogging that can be used as a substitute for traditional high-purity dissolving pulps in a wide variety of applications.

Compositions and methods that preserve and enhance the brightness of pulp, and also improve the color of pulp or paper, when applied during different stages of a papermaking process, are disclosed. The compositions and methods maintain or enhance brightness, prevent yellowing, and enhance the performance of paper products. The compositions can include a mixture of reducing agents and can also include optical brighteners, chelants, polycarboxylates, or other additives. The mixture of reducing agents can include a borohydride, such as sodium borohydride, and any other reducing agent, such as a sulfite or bisulfite.

The present disclosure provides methods and compositions for improving the oxygen delignification process. The methods may include adding low doses of a borohydride stabilized in an alkaline solution to brownstock pulp. The methods may result in significant chemical savings, increased pulp brightness, increased pulp yield, and reduced kappa number.