Abstract: Fibrous organic biomass is converted into pulp in a flow-type process which uses pretreatment of the biomass, specific selection of acid and alkali agents and a low concentration of fiber to liquor.

Abstract: A method for fractionating fibrous biomass comprising cellulose, hemicellulose and lignin components to separate said lignin, cellulose and hemicellulose from one another comprises:

Abstract: A process of treating fibrous ligno-cellulose material to form defibered chemical cellulose pulp suitable, for example, for the manufacture of paper and paperboard and dissolving pulp and to treat defibered ligno-cellulose material to produce basic animal feed or packaging and building boards.The process is based on the nitration and dissolving of the lignin component of the cellulose material either in an alkaline solution or with a two step operation in which the nitration can be in an acid stage comprising the step of submerging the fiberous ligno-cellulosic material in aqueous nitric acid having an HNO.sub.3 concentration in the range of about 0.125 to 9 weight percent, followed by an alkaline stage to dissolve out the nitrated lignin from the fibrous structure. In the production of chemical pulp or animal feed the lignin containing solution (black liquor) is separated from the cellulose material.

Abstract: Fibrous materials are disclosed having incorporated therein upgraded waste sulphite liquor; the liquor is neutralized, e. g., with sodium borate, sodium aluminate, reacidified, if needed, with alum; the modified sulphite waste liquor of hardwoods as well as articles of manufacture of fibrous materials such as corrugated medium made of waste materials are diclosed; further, articles of manufacture thus modified include starch or sizing and are within the scope of the invention.