Abstract: A raw paper prepared by a mixed pulp including straw pulp, which can be used to prepare textbooks, writing papers and office paper with good performance, and the producing method of said raw paper are provided. The weight proportion of the straw pulp in the mixed stock is from 10% to 100%, and the straw pulp has a hardness of KMnO4 value 10-17, an average fiber length of 0.1-2.5 mm, a tensile index of 23-57 Nm/g, a tearing index of 3.0-6.0 mN·m2/g, a folding endurance index of 2-6 kPa·m2/g and a whiteness of 28-50%. Either, the L value of the hue of said raw paper is 65-95, a value is 0-5, and b value is 0-40. The KMnO4 value of hardness of the pulp after oxygen delignification is 10-14. The method includes: adding grass-series raw material into a digester, then adding cooking liquor, heating the cooking liquor to 100-200°, pressurizing to 0.3-0.9 MPa, cooking for 150-250 min, extruding the pulp, washing and obtaining the straw pulp.

Abstract: Provided is an unbleached paper product made from grass type pulp, the unbleached paper product has a brightness of 35-60% ISO, the grass type pulp is unbleached. The unbleached paper product includes an unbleached toilet paper, an unbleached hand towel, an unbleached wiping paper, an unbleached duplicating paper, an unbleached meal container, an unbleached food wrapping paper and an unbleached printing paper. The paper products have a high intensity and have no detection of dioxin and absorbable organic halides in the harmful substance detection test.

Abstract: Disclosed is a method for preparing paper pulp from cornstalks comprising the steps of cooking, washing, screening, thickening, bleaching, beating and drying performed under moderate conditions which have little noxious effects on the environment. By using cornstalks as raw materials for paper pulp, it becomes possible to replace import of wood raw materials, to save foreign currency, to increase rural income, and to make high quality paper.

Abstract: A process for peroxide bleaching of mechanical or high yield pulp, the process comprising adding to a pulp slurry at least one stabilizer for stabilizing low valency states of transition metal ions in the slurry; subsequently adding caustic soda to said slurry simultaneously with or subsequent to adding said at least one stabilizer; adding hydrogen peroxide to the slurry at a preselected point; and subjecting the slurry to preselected conditions to complete the bleaching process.

Abstract: The use of low specific gravity wood from thinning operations, for example, will produce a lower brownstock viscosity for a given kappa number target. A differential of 200-cP falling ball pulp viscosity has been detected from Kraft cooks of low and high specific gravity wood. Using low specific gravity wood can reduce the bleach stage temperature and the chemical dose needed in the bleach plant to produce lyocell pulp specifications. Low specific gravity wood also increases the ability to reduce pulp viscosity to very low levels without increasing the copper number of the pulp or the concentration of carbonyl in the pulp above acceptable levels.

Abstract: Provided is a process for making pulp having the steps of:contacting an undigested cellulosic fiber material with a pretreatment liquid formulated from a mixture comprising alkali metal bicarbonate and alkali metal hydrogen sulfide as reaction components which are dissolved or disbursed in an aqueous liquid, under conditions that:(1) the reaction components react to form H.sub.2 S, CO.sup.2 and alkali metal carbonate in situ;(2) HS.sup.- ions are formed by disassociation of H.sub.2 S and/or by disassociation of alkali metal hydrogen sulfide; and(3) at least a portion of the H.sub.2 S and/or HS.sup.- ions is absorbed or diffused into the undigested cellulosicfiber material to enhance the sulfur content of the undigested cellulosic fiber material,to form a sulfur enhanced, undigested cellulosic fiber material, wherein the pretreatment liquid is substantially free of alkali metal hydroxide; anddigesting the sulfur enhanced, undigested cellulosic fiber material in a digester to form a pulp.

Abstract: The present invention relates to a process for producing viscose pulp from lignocelluloses, such as hardwood, softwood or annual plants, in which process the lignocellulose is treated in a digester at first with saturated steam to prehydrolyze hemicelluloses and subsequently, without flashing, with hot black liquor (HSL) of a preceding sulfate pulp digestion as well as, if desired, under addition of fresh white liquor (WL) to neutralize the acidic reaction products formed, neutralization liquor (NL) thus being formed in the digester. Upon addition of the amount of alkali required for delignification in the form of fresh white liquor (WL), if desired, in combination with a displacement of neutralization liquor (NL) and temperature adjustment, digestion then will take place with or without temperature gradient.

Abstract: A process for delignifying raw cellulose which comprises a preliminary treatment for impregnating raw cellulose with a monopersulphuric acid solution, a successive filtration without washing with recycle of the filtered liquid to the first step, and a treatment, at low temperature and in alkaline solution at a pH higher than 9, of the previously impregnated raw cellulose in order to permit the reaction of the monopersulphuric acid with the lignin contained in the raw cellulose.

Abstract: A method for the production of kraft pulps in a digester, by modifying the cooking chemical concentration, and lignin concentration profiles during the cook, has provided extended delignification and improved selectivity in a simpler way than has previously been possible. The cooking is performed at an elevated temperature in two stages. The first stage liquor is a mixture of 1) the spent liquor of the second stage and 2) a portion of the conventional charge of fresh cooking chemicals needed for the complete cook. The second stage liquor is made up by adding an aqueous diluent, for example, fresh water or washing filtrate to the remaining portion of the fresh cooking chemicals.

Abstract: The present invention is directed to a process for pulping of lignocellulosic materials. In the process, the ligoncellulose material is impregnated with an alkaline liquor. The lignocellulose material is maintained in the alkaline liquor for a period of time sufficient to permit infusion of the alkaline liquor and swelling of the lignocellulose material. The alkaline liquor is then drained from the lignocellulose material and the lignocellulose material may be washed with water, although such washing step is not required. The alkaline impregnated lignocellulose material is then immersed in an acidic oxidizing solution comprising peroxymonosulfate anion. The lignocellulose material is maintained in the oxidizing solution for a time sufficient to oxidize at least some of the lignin of the lignocellulose material. Thereafter, a second alkaline liquor is used to solubilize the oxidized lignin.

Abstract: A method of brightening mechanical pulps by chelating and thickening to reduce the manganese content of the pulp to less than 30 parts per million and copper content less than 1 parts per million by adding ions preferably magnesium ions as magnesium sulphate MgSO.sub.4 in the amount of 400 to 3,000 ppm Mg ions retained by the pulp based on the oven dry weight of the pulp and thereafter applying a bleaching liquor composed of peroxide as hydrogen peroxide and an alkali as sodium hydroxide having a ratio of alkali to peroxide of between 1--1 and 2-1 in an amount to apply between 1 to 8 percent peroxide based on the oven dry weight of the pulp and containing no added sodium silicate. Preferably the bleaching liquor will contain magnesium sulphate in the amount of about 0.001 to 0.1% based on the oven dry weight of the pulp.

Abstract: A paper pulp refining and bleaching process wherein the pulp is treated in one or more refiners with a sodium hydrosulfite bleach liquor in the presence of a strong alkali such as NaOH, whereby the bleaching solution has an alkaline pH, preferably 10 to 12, and the pulp is discharged from the refiner at a pH of from about 5 to 6. The bleaching produces a brightness gain of at least 8 to 13 ISO points in the refiners. The process is preferably carried out by passing the pulp successively through a primary refiner at elevated pressure, a secondary refiner at atmospheric pressure and a bleaching tower, an alkaline hydrosulfite solution being fed to each.

Abstract: A method for producing low fines content pulp having successive treatment stages in each of which compressive and shearing forces are applied to the cellulosic fiber while simultaneously one or more chemicals are added. Gradual breakdown of the fibers is achieved with resulting low fines production whereby the pulp may be used for tissue, fluff and towel products.

Abstract: A process for bleaching a lignocellulosic matter in the form of a mechanical, thermomechanical, chemicomechanical or chemicothermomechanical papermaking pulp, or of wood chips while being converted into one of these pulp types by processing in a machine consisting essentially of two interpenetrating spiral surfaces wound around parallel shafts driven in synchronous rotation in the same direction inside a barrel which encloses them, and determining between upstream and downstream in the direction of forward travel of the matter a series of zones for drawing and braking the matter, which comprises combining a bleaching treatment using a reducing agent and a bleaching treatment using an oxidizing agent, characterized in that, after pretreatment using at least one metal-complexing or sequestering agent, the lignocellulosic matter undergoes a washing operation with an efficiency greater than 96% before undergoing in succession a bleaching treatment using a reducing agent at a pH of between about 8 and 12, a washin

Abstract: This invention relates to an improved process for preparing pulp suitable for paper making. Although processes using explosive decompression have been known in the past, it has been believed that these must be conducted at relatively low temperatures. Although such known processes of explosive decompression resulted in a saving of power, the physical strength was low, the color was relatively dark and there was a considerable yield loss. This invention is to provide a process to achieve the saving of power resulting from the use of explosive decompression but in which there is good brightness, high yield and good fiber strength. The process of this invention defines conditions for achieving these objectives. These conditions include impregnation of the chips of other wood fragments under specified conditions and cooking with saturated steam at a high temperature and pressure followed by explosive decompression and refining.

Abstract: Described herein is a process for producing potassium salts from potassium-based liquors for pulping of lignocellulosic material. The process comprises the steps of(a) digesting lignocellulosic material with a potassium-base aqueous cooling liquor to obtain an aqueous slurry of partially delignified pulp of the lignocellulosic material;(b) separating the pulp from the spent potassium-base aqueous cooling liquor;(c) concentrating the spent pulping liquor; and(d) recovering potassium salts including potassium carbonate, potassium sulphate and potassium lignosulphonate from the concentrated spent pulping liquor. The recovered potassium salts find numerous uses, an example being use in fertilizers.

Abstract: Pulps having a tactile sense of softness which are made from hardwoods and processes for making such pulps. The process comprises the steps of: providing hardwood chips having specified sizes; introducing the chips into a digester; removing substantially all the free oxygen from the chips within the digester; providing a cooking liquor comprising from about 0.4% to about 3% ammonia and from about 9% to about 14% sulphur dioxide; completely submerging in cooking liquor all the chips within the digester; sulfonating the lignin within the chips at a temperature of less than about 110.degree. C.; rapidly increasing the temperature to an appropriate hydrolysis temperature; hydrolyzing the lignin sulfonation products at a temperature of from about 140.degree. to about 155.degree. C. at a pH from about 2 to about 3; and rapidly reducing the temperature of the system following the hydrolysis. Pulps made by this process were made into useful tissue paper webs having enhanced softness properties.

Abstract: A modified batch cooking technique for making sulfate pulp with a high degree of delignification or with a normal degree of delignification but with increased pulp viscosity. This is effected by one or several displacements of the liquor in the digester with liquor of the same temperature as the cooking liquor but with a lower lignin content.

Abstract: Pulps having a tactile sense of softness which are made from hardwoods and processes for making such pulps. The process comprises the steps of: providing hardwood chips having specified sizes; introducing the chips into a digester; removing substantially all the free oxygen from the chips within the digester; providing a cooking liquor comprising from about 0.4% to about 3% ammonia and from about 9% to about 14% sulphur dioxide; completely submerging in cooking liquor all the chips within the digester; sulfonating the lignin within the chips at a temperature of less than about 110.degree. C.; rapidly increasing the temperature to an appropriate hydrolysis temperature; hydrolyzing the lignin sulfonation products at a temperature of from about 140.degree. to about 155.degree. C. at a pH from about 2 to about 3; and rapidly reducing the temperature of the system following the hydrolysis. Pulps made by this process were made into useful tissue paper webs having enhanced softness properties.

Abstract: A process is provided for pretreating particulate lignocellulosic material to remove heavy metals and resin without any delignification or defibration, which comprises washing particulate lignocellulosic material; compressing the washed material to a solids content of at least 40% to remove absorbed and excess liquid; impregnating the compressed material with an alkaline aqueous solution comprising alkali and at least one of a heavy metal ion complexing agent and a heavy metal ion reducing agent; heating the impregnated material at a temperature within the range from abut 50.degree. to 100.degree. C. for up to approximately 0.75 hour; compressing the pretreated material to a solids content of at least 40%; and separating undiluted liquor squeezed out during the compression, while maintaining conditions during the pretreating such that the pH of the squeezed-out liquor is within the range from about 4 to about 9.

Abstract: Extraction of chlorine bleached kraft wood pulps with aqueous peracids at pH values of 7 or below, aqueous sulfites at pH values below 10 or with certain non-aqueous solvents provides extracted pulps having lower residual color and permits use of lesser quantities of alkali or chlorine dioxide in subsequent bleach steps to attain brightness and strength levels comparable to those attained with pulps treated by alkaline extraction at pH values of 10 or higher. At a comparable level of alkali and chlorine dioxide or hypochlorite application, extraction of chlorinated pulp with peracids provides bleached pulps with enhanced brightness.

Abstract: In the delignification of chemical wood pulp with oxygen and alkali a larger reduction of the kappa number may be obtained without an increase in the charge of oxygen or alkali, provided the pulp is pretreated with a solution of sulphite or bisulphite in order to introduce hydrophilic groups in the sulphate lignin in the chemical wood pulp.

Abstract: A high yield chemithermomechanical (CTMP) process for obtaining high strength hardwood pulps is disclosed wherein hardwood chips are subjected to a two-stage chemical treatment prior to defibration, the first consisting of chip impregnation and reaction with an alkaline liquor followed by a second stage treatment with sulfite and/or bisulfite; in one embodiment peroxide is added to the alkaline liquor to enhance brightness.

Abstract: A process is provided for the processing of certain organic agricultural foodstuff by-products normally having little commercial value to produce a cellulosic product suitable for human consumption or use in various products. The process of the present invention is characterized by subjecting a variety of certain agricultural by-products having little commercial value, such as, for example, soy bean hulls, to a series of separate steps utilizing certain chemical treating to effect a solubilizing and removal of the non-cellulosic components of the by-product agricultural material to produce residue solids which consist essentially of cellulose. The cellulose residue solids are subjected to specified purification procedures and thereafter dried to produce a short, fine fibered cellulose which may be processed to a fine powdered state suitable for use as a component part in a wide variety of edible or otherwise useable products by humans, an example of such a product being a low calorie bread.

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: A versatile process and apparatus is presented for producing, in high yields, many different grades of pulp from a single wood specie or for pulping any specie or type of woody material, and for storage and recycling of the by-product liquid and gaseous materials. The process of this invention is virtually pollution free, and the reactant chemicals are recoverable from the by-products. In the alternative, the by-products themselves have a commercial value which may forestall recovery of the reactants. The lignin constituent extracted from the pulp is usable as a resin binder, a wood rehardening agent, or a glue.

Abstract: Knots separated from sulphite cellulose produced by a sulphite cellulose cooking process are converted to unbleached sulphite cellulose by first separating and defibrating the sulphite knots and then treating the defibrated sulphite knots with oxygen under pressure in an alkaline milieu at an elevated temperature. The resultant cellulose may be bleached by itself, or mixed with sulphite cellulose produced from knot-free cellulose pulp for bleaching therewith.

Abstract: A dissolving pulp suitable for preparing rayon having a degree of polymerization of greater than about 800 can be produced using bagasse by a sodium hydroxide-sodium sulfite digestion at a ph of about 10.5 to 11.5 and preferably about 10.8 to 11.2 and a caustic-sulfite weight ratio of 1:1 to 1:3 followed by a bleaching sequence of DcEDH or DcEDD. This results in a high purity low silica content fiber which has undergone very little degradation.

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: Sodium polysulphide is formed by reacting sodium sulphide and sodium sulphur-oxygen salts in the presence of carbon and oxygen. The invention is particularly applicable to reacting recovery furnace smelt from a polysulphide pulping process to form a mixture of sodium polysulphide and sodium carbonate which is substantially free from sodium sulphur-oxygen salts, so that dead-load sulphidity is substantially eliminated from the pulping liquor.

Abstract: A process for delignifying lignocellulosic pulps, which comprises the steps of (a) impregnating a lignocellulosic pulp slurry with a water-soluble manganous salt having a manganous ion concentration of from about 1% to about 10%, by weight of oven-dried pulp; (b) mixing the impregnated pulp slurry with an amount of alkali equal to the stoichiometric quantity of alkali required to precipitate the soluble manganous ion as insoluble manganous hydroxide; (c) aerating the pulp slurry with an oxygen-containing gas without further addition of alkali and in the absence of alkali for a period of time sufficient to oxidize substantially all of the manganous hydroxide to manganic hydroxide; (d) treating the pulp slurry with sufficient sulfuric acid to lower the slurry pH to at least about 3, thus releasing soluble manganic ions to oxidize the pulp lignins; (e) separating the effluent containing manganous ions from the pulp slurry with a non-alkaline wash; and then (f) extracting the oxidized lignins from the pulp slurry

Abstract: A process for producing high yield chemimechanical pulps from woody lignocellulosic material, such as wood chips, whereby the material is treated with an aqueous solution of a mixture of sulfite and bisulfite, said solution being of sufficient strength to sulfonate said material to at least about 85% of the maximum level of sulfonation that can be achieved on said material without reducing the pulp yield to below 90% and subjecting the resulting sulfonated material to mechanical defibration.

Abstract: Paper pulp is prepared from dicotyledonous plants by stirring said plants in an alkaline solution in the presence of a surfactant and stain inhibiting agent to obtain a stock containing a woody core fraction and a bark fraction containing bast fibers, separating said fractions and then cooking and bleaching the bark fraction in an alkaline solution containing an oxidizing agent and an alkyl sulfate surfactant.

Abstract: A process is provided for the delignification of lignocellulosic material wherein the lignocellulosic material, prior to the delignification, is treated with water or an aqueous solution to remove compounds which catalyze the degradation of carbohydrates and then the delignification is carried out with oxygen and alkali in the presence of a manganese compound to improve the selectivity of the delignification and increase the rate of delignification.

Abstract: A pulping process which includes the steps of oxidizing vegetable materials with an oxidizing chemical selected from the group comprising Cl.sub.2, Cl.sub.2 O,ClO.sub. 2, Mg(ClO).sub.2, Mg(ClO.sub.2).sub.2 Mg.(ClO.sub. 3).sub.2 and mixtures thereof, extracting the oxidized materials with Mg(OH).sub.2 thereby to delignify and bleach the materials and treating the waste liquor from the oxidation, extraction and washing steps by combustion or thermal decomposition thereby to regenerate the chemicals necessary for the oxidation and extraction steps. The process of the invention produces semi-bleached or completely bleached pulp of high strength with high yield while eliminating the problem relating to environmental pollution.

Abstract: Plant material containing hemicellulose and lignin is prehydrolyzed in the presence of steam and the vapors of a dilute acid solution having a pH of 1.5-3.5 at a temperature of 105.degree. C to 135.degree. C for 7-20 minutes to hydrolyze the hemicellulose into pentoses and hexoses and to leave a fibrous material and a liquid, said liquid containing said pentoses and hexoses. The liquid is separated from the fibrous material, and the pentoses and hexoses are recovered from the liquid. The fibrous material is digested with white liquor at a temperature of 105.degree. C to 135.degree. C.

Abstract: A method is described for increasing the yield of pulp obtained from an alkaline pulping process. A lignocellulosic material, such as wood chips, is first pretreated with an aqueous solution containing from 0.1 to 10% by weight of monoethanolamine, methylamine or dimethylamine and from 0.01 to 1% by weight of copper sulfate or nickel sulfate at elevated temperature and pressure in a closed vessel. This pretreated material is then subjected to conventional alkaline pulping, preferably soda or two-stage soda-oxygen pulping.

Abstract: Delignification of lignocellulosic material, such as wood, straw or bagasse, by treatment with an alkaline pulping liquor containing a diketo hydroanthracene selected from the unsubstituted and lower alkyl substituted Diels Alder adducts of benzoquinone and naphthoquinone.

Abstract: A process for the preparation of cellulose fibers from cellulose containing chips wherein the cellulose containing chips are subjected to a chemical process for the purpose of separating the cellulose from lignin and other extraneous chemicals which prior to digestion of the chips subjecting the chips to a two-step pre-treatment by:1. contacting said chips with an aqueous solution of an alkali metal, alkaline earth metal or ammonium sulfite or bi-sulfite metal; and,2. thereafter radiating the so pre-treated chips by contacting them with charged particles.

Abstract: A chemi-mechanical process for producing unbleached pulp with improved yields at high brightness including impregnating a lignocellulosic material in the form of wood chips with an alkaline solution containing an alkali metal borohydride in an amount over 0.1% by weight at a pH greater than 13, heating the impregnated chips at a temperature less than 150.degree. C to provide semi-cooked chips having a brightness in excess of 60 GE, and then defiberizing the semi-cooked chips to mechanically separate the fibers into an unbleached pulp having said brightness and a yield of at least 85%.

Abstract: A three stage process for pulping lignocellulosic materials, preferably softwood chips comprising: as a first stage treating the lignocellulosic material with a cyanide ion-containing solution at a pH between 7 and 12 to form cyanohydrin groups; in a second stage digesting the thus treated lignocellulosic material with an alkali metal pulping solution containing hydroxyl ions; and as a third stage treating the thus digested lignocellulosic material with 1% to 12% by weight sodium hydroxide, as sodium oxide based on o.d. pulp from the alkaline pulping stage, in the presence of an excess of oxygen.

Abstract: The invention relates to a continuous method of making cellulosic pulp from wood chips within a range of yield from 65 to 90 per cent by digestion with a digestion liquor containing Na.sub.2 S and Na.sub.2 CO.sub.3. The digestion is effected at temperatures between 150.degree. and 190.degree.C and malodorous sulfur compounds are removed from the pulp, the liquor and the vapors prior to their withdrawal from the digesting process. In order to eliminate their capacity of emitting obnoxious odors, the sulfur compounds are oxidized by addition of molecular oxygen to the digester prior to discharge of pulp and spent liquor from the digester after which the spent liquor is removed from the digested pulp, concentrated and burned for renewed use in preparation of fresh digesting liquor.