Abstract: Paper pulp is produced by a process in which raw sugar mill bagasse is moist depithed, wet bulk stored in the presence of an inorganic and organic preservative, wet depithed by hydraulic shearing in the presence of an inorganic color remover, pulped, washed, cleaned and dewatered.

Abstract: The invention relates to a method in or relating to grinding of vegetable material in a grinding apparatus equipped with discs mounted rotatably relatively one another in a casing, within which a superatmospheric pressure is maintained by steam. This steam is introduced into the casing together with the vegetable material to be ground through a central inlet into an interspace defined by the discs. The material and the steam pass radially outward through said interspace. Immediately on departure from the interspace the ground pulp is received by an atmosphere of a non-condensable gas, the action of which gives the final product desired properties.

Abstract: Method and apparatus for producing pulp from moisture-containing lignocellulosic material, such as wood chips, which is ground in a grinding space defined between a pair of grinding discs which rotate relative to one another in an environment of pressurized steam generated during the grinding process, in a closed housing. The ground fiber or pulp discharged from the grinding housing is propelled by the accompanying steam into a cyclone, where the ground pulp is separated from the steam for further treatment, while the steam is recycled for further use in the pulping process. The pressure in the cyclone is so controlled that a pressure is maintained therein which is substantially equal to a pressure drop which is sufficient merely to maintain the propellant force of the steam to convey the ground pulp from the grinding housing to the cyclone while discharging the separated steam and recycling it for further use in the pulping process.

Abstract: Properties of mechanical paper pulp which is produced by grinding or otherwise frictionally acting on natural fibrous raw material containing plasticizable constituents which become heated to a temperature sufficiently high to soften the plasticizable constituents thereof are improved by the addition of paper filler material which is chemically inert to the pulp at a time which results in the filler being in contact therewith while the plasticizable constituents are plasticized and thus softened and sticky. This causes the filler, without chemical reaction, to adhere to the plasticized constituents and thus to the fibers of the pulp to result in improved properties of a totally mechanical pulp. The properties which are improved include the optical and printing properties of the paper made from the pulp.

Abstract: Method and apparatus for refining fiberous material in a disc refiner for withdrawing steam developed during refining of such fiberous material. The disc refinger comprises a pair of refining discs each of which includes a inner refining surface. The refining discs are mounted for rotation relative to one another in a housing with the refining surfaces opposing one another during the relative rotation and defining a refining space therebetween. Each of the refining surfaces of the refining discs is provided with a passageway for withdrawing steam developed in the refining space. The passageways extend from the respective refining surfaces in a direction away from the refining space and radially inward relative to the direction that the fiberous material moves through the refining space.

Abstract: A method of making fiberboard using a substantially closed white water system. One or more layers of separately prepared surface pulp is applied to a layer of base pulp at the wet sheet forming stage. Lignocellulose chips in a pressure-sealed defibrating zone under generation of steam. The steam is separated at the discharge end of the defibrating zone under atmospheric pressure. The atmospheric steam is utilized to presteam the raw chips. The presteamed chips are thereafter dewatered to a moisture content coordinated to the energy demand of the defibrating treatment and the desired generation of steam prior to entering the defibrating zone. The water removed at the dewatering stage is collected for use in preparing the surface layer pulp suspension. A small portion of the base pulp to be used for the surface layer pulp is diverted to a refiner and diluted with water.

Abstract: A process is provided for preparing groundwood pulp from debarked pulpwood logs, which comprises grinding the logs under a superatmospheric pressure of a gas selected from the group consisting of steam, air, and steam and air, while continuously supplying thereto water comprising spent bleaching liquor at a temperature of at least 70.degree. C. and forming a pulp suspension in the resulting aqueous liquor; centrifugally separating steam from the pulp suspension and using the separated hot steam to heat spent bleaching liquor supplied for the grinding; thickening the pulp suspension to a concentration within the range from about 5 to about 40% and supplying water separated therefrom to the grinding; diluting the pulp suspension to a concentration within the range from about 0.5 to about 4.

Abstract: A process is provided for preparing groundwood pulp from debarked pulpwood logs which comprises grinding the logs under a superatmospheric pressure of a gas selected from the group consisting of steam, air and steam and air, while continuously supplying thereto process white water and water separated in thickening groundwood pulp suspension at a temperature within the range from about 75.degree. to about 100.degree. C.

Abstract: Method of producing mechanical pulp of improved brightness and light-scattering properties in a defibration apparatus in which wood chips are ground between a pair of discs which rotate relative to one another in a pressurized grinding zone. Prior to the defibrating process, the chips are impregnated with a solution of alkali, selected from the group consisting of sodium hydroxide, alkali silicate, alkali carbonate and alkali bicarbonate, and peroxide, surplus impregnating solution is removed from the chips by compression of the chips, the chips are introduced into a pressure vessel which is in communication with the grinding zone and compressed air is introduced into the pressure vessel in an amount sufficient to maintain the chips in the pressure vessel at a temperature below 90.degree. C. and to maintain superatmospheric pressure within the defibrating zone.

Abstract: A high-strength, high-yield sulfite-modified thermomechanical pulp is formed by subjecting lignocellulose to multistage mechanical attrition, the first stage being conducted at elevated temperature and pressure and the second stage being run under atmospheric conditions. A sulfite chemical is added to the lignocellulose prior to the second stage, the lignocellulose being sulfonated so that a percent bound sulfur level of at least about 0.15% is provided. A novel linerboard composition is unexpectedly produced employing replacement quantities of the above described pulp.

Abstract: In the continuous production of paper pulp from ligno-cellulose raw material, the raw material is subjected to grinding and/or delignification by passing it in the form of small pieces between interpenetrating helicoidal surfaces driven synchronously in rotation inside a casing. The pitch of the helicoidal surfaces is arranged to provide at least one supply zone in which the material is driven downstream by rotation of the surfaces and at least one braking zone in which the material is braked.

Abstract: Cellulosic pulp is made in 85% yield by mechanically defiberizing lignocellulose in a steam atmosphere, mixing the resulting aqueous fibrous pulp with a lignocellulose-pulping quantity of finely divided lime, and digesting the pulp in the presence of the lime to a predetermined degree of pulp digestion. The resulting digested fiber can then be mechanically beated in aqueous medium until it is substantially converted to a hydrated cellulosic gel product.

Abstract: Raw fibrous material is preheated in a preheater in the presence of steam under a pressure greater than atmospheric pressure and then continuously introduced into a disc refiner, without prior defibration, whereby steam is generated in said disc refiner. The generated steam is continuously conducted away from said disc refiner as subsequent fibrous material is continuously being introduced into the disc refiner in order to obtain a pressure in the disc refiner which is greater than atmospheric pressure but less than the pressure in said preheater.

Abstract: A stream of disintegrated fibrous cellulosic pulp material and steam under pressure is subjected to an instantaneous pressure reduction as said stream and steam pass through a throttling nozzle, in a throttling zone, wherein a liquid solution of a bleaching agent is admixed with said stream and which stream, admixed with bleaching agent, is then passed into an expansion zone ahead of the throttling nozzle resulting in a uniform dispersion of the bleaching agent into the fibers in the stream of fibrous cellulosic pulp material.

Abstract: Lignocellulose fiber containing chips, preheated with steam liberated from a previous chip defibration, are dewatered and then defibrated in an atmosphere of saturated steam and in the presence of backwater and suspended in backwater to form a pulp suspension whereafter wet sheets are formed from the pulp suspension, water is mechanically removed from the wet sheets and recycled as backwater to be supplied simultaneously, with dewatered chips, to the defibration step and to form a new pulp suspension and said wet sheets are dried.