Abstract: A ceramic sheet comprising 5 to 50 wt. % (absolute dry weight) of a cation-modified pulp having a degree of substitution of cationic group of 0.02 to 0.04 and beaten to freeness of 200 to 100 ml C.S.F. and 50 to 95 wt. % of fine inorganic particles dispersed uniformly in and supported by said cation-modified pulp. This ceramic sheet can be easily prepared from an aqueous suspension of the cation-modified pulp and the fine inorganic particles by using a paper-making treatment.

Abstract: A packaging bag made by the use of a reinforced sheet in which non-woven cross-linked plastic sheets are inserted between cellulosic papers. The non-woven cross-linked sheet consists of split films with narrow width crossing each other laterally and longitudinally with slightly protruded intersections. The reinforced sheet is made by inserting the non-woven cross-linked sheets between cellulosic papers during paper making on a combination paper machine, thereby slightly protruded portions caused by the intersections in the non-woven sheets can be secured on the whole surface of the reinforced sheet. The bag thus manufactured using the reinforced sheet has extremely improved strength and handling properties as well as good air permeability compared with the conventional paper and plastic film bags.

Abstract: A process for producing alkali pulp by using a single, cylindrical pressurized reaction vessel having therein a liquor-inpregnating zone, a cooking zone, a washing zone, and a diluting zone in that order, and having a motor-driven scraping or agitating device and a pulp discharging outlet in the end portion of the diluting zone. Alkaline aqueous medium containing dissolved oxygen therein is introduced into the diluting zone. A part of the introduced alkaline aqueous medium countercurrently contacts cooked cellulosic materials transferred from the washing zone to the diluting zone to proceed with oxygen-alkali delignification, and is finally discharged out of the vessel from the end portion of the cooking zone.

Abstract: A chipper comprised of a disk body, a driving shaft mounted on the disk body for rotating it and at least one spout connected with the casing and a plurality of cutting blades located on the disk body along at least one spiral path extending from the center to the periphery of the disk body, each of the cutting blades having main and auxiliary cutting edges which are positioned and connected angularly to each other, the main cutting edge being inclined to the surface of the disk body with such an angle that one end of the main cutting edge is positioned at a height corresponding to the thickness of chips to be cut with the connecting edge between the main edge and corresponding auxiliary cutting edge positioned two times as high as the one end of the main cutting edge.

Abstract: A chipping device including a disc-like member having a front face and the opposite face connected at its central region to a rotating shaft, said front face being provided with a spiral working surface which consists of main and auxiliary oblique surface portions extending along a spiral path from the central region of said disc-like member to the peripheral edge thereof, and being inclined relative to a plane perpendicular to the rotational axis of the disc-like member with an angle included between said main and auxiliary surface portions, said working surface having a plurality of cutting blades spaced from one another therealong, each of said cutting blades having main and auxiliary cutting edges substantially parallel to said main and auxiliary oblique surface portions, respectively.

Abstract: A process for preparing pulp in a closed system by pre-cooking fibrous raw material in an alkaline aqueous solution of sodium carbonate or a mixture of sodium carbonate and sodium bicarbonate as the only alkaline ingredients at 90.degree.-190.degree. C, defibrating the pre-cooked material, pulping the defibrated material in an alkaline aqueous solution of sodium carbonate or a mixture of sodium carbonate and sodium bicarbonate as the only alkaline ingredients in a pressurized vessel at 90.degree.-170.degree. C in the presence of an oxygen-containing gas, subjecting waste liquor discharged from the pre-cooking and pulping steps to wet combustion to recover an alkaline aqueous substance and recycling the alkaline aqueous substance resulting from combustion to the pre-cooking and/or pulping steps.

Abstract: This invention relates to a new and improved recovery method of chemicals from waste liquor of pulping or bleaching. More particularly, this invention relates to a method for direct recovery of sodium hydroxide from waste liquor of pulping or bleaching which is substantially free from sulfur compounds. Ferric oxide is admixed with concentrated waste liquor and thereafter the admixture is burned to form a smelt. By submerging the smelt in hot water a solution of sodium hydroxide and a ferric oxide precipitate are obtained. The precipitated ferric oxide can be reused in the mixing step.