Abstract: Lignocellulosic materials such as wood, bagasse, straw, reeds, and other plants and crops can be delignified effectively by a soda-type pulping with an alkaline liquor containing small quantities of both ethylenediamine or like amino compound, and a cyclic keto compound, such as anthraquinone. Pulping rates comparable to kraft are achieved and the pulps thereby obtained have excellent physical properties, especially tear strength.

Abstract: Disclosed is a process for producing stone groundwood pump from wood chips, by compressing a wood chip mass into an apparent volume corresponding to 70% or less, preferably, from 40 to 60%, of the original apparent volume of the wood chip mass and by grinding the compressed wood chip mass, under pressure, with a stone grinder. The wood chips may be treated, before the grinding step, with both or either one of steam and a treating agent, such as sodium monosulfite, sodium disulfite and sodium bicarbonate.

Abstract: A process is provided for the chemical refining of cellulose pulp which comprises, in sequence, the steps of:(1) impregnating the cellulose pulp with refining chemicals in an amount selected to effect chemical modification of the pulp;(2) adjusting the pulp consistency to within the range from about 30 to about 70%; and(3) passing the pulp in turbulent flow through an elongated reaction zone from one end to another end thereof in a gaseous atmosphere consisting essentially of steam and preferably containing less than 1% by volume of oxygen at a superatmospheric pressure within the range from about 5 to about 400 kPa and a temperature within the range from about 100 to about 150.degree. C. at which the chemical modification proceeds without a mechanical working sufficient to change the degree of beating of the pulp by more than about 2.degree.

Abstract: A new industrial product, namely 1,2,3,4,4a,9a-hexahydro-9,10-anthracene-dione, is disclosed together with a process for its preparation and its use in conventional alkali metal hydroxide cook or Kraft cook processes for the delignification of lignocellulose materials.

Abstract: High-yield pulp suitable for the production of corrugating medium is produced by cooking hardwood chips at a temperature 180.degree.-192.degree. with sodium carbonate solutions of a concentration 65 to 120 g/l as Na.sub.2 O, at a liquor to wood ratio of 1.2-2.5, and mechanically refining the cooked chips in a primary refining stage to a C. S. Freeness less than 480, and then refining the pulp in a secondary refining stage.

Abstract: A process for the delignification of lignocellulosic material is described wherein the lignocellulosic material is cooked with an alkaline or neutral sulphite pulping liquor, and there is added to the pulping liquor at least 0.001% by weight of an additive compound or mixture of additive compounds selected from quinones and hydroquinones.

Abstract: A process for the preparation of viscose by adding to cellulose pulp, manufactured by alkali cooking without prehydrolysis or by acid cooking without alkali extraction, steeping lye and an organic compound, steeping the pulp to form alkali cellulose, aging the alkali cellulose, xanthating the aged alkali cellulose with carbon disulfide to obtain cellulose xanthate and dissolving the cellulose xanthate to obtain viscose.

Abstract: A Kraft pulp bleaching process comprising from one to about three treatments with ozone and a final treatment with an alkaline peroxide solution, the treatments being separated by an alkaline extraction, wherein effluent from the bleach treatments is utilized in subsequent bleaching operations or in the chemical recovery system of a Kraft pulping process.

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: An improvement in the delignification (pulping) of raw cellulose by treatment with oxygen and an alkaline buffer solution at elevated temperature and pressure, which comprises carrying out the process in an unflooded condition, that is, where contact between the raw cellulose and buffer solution is intermittent, both gaseous and liquid phases being present at all times. Optionally, cupric ion may be present as a catalyst.

Abstract: An improved process for the production of pulp from lignocellulosic material characterized by the employment of a cooking aid is disclosed. The cooking of the lignocellulosic material is carried out in the presence of a small amount of a compound selected from the group consisting of hydroxyanthracenes and derivatives thereof.

Abstract: A delignification process using amine cooking liquors which also contain a quinoid or hydroquinoid compound. The process also encompasses a pretreatment step using the quinoid or hydroquinoid compounds.

Abstract: A one-stage oxygen delignification system in which wood chips are first pressurized with oxygen and the oxygen allowed to reach equilibrium within the chips before the addition of cooking liquor. Cooking liquor is added to the chips while they are maintained under the pressurized oxygen. After the addition of cooking liquor under pressure, the oxygen pressure may be further raised. The cooking liquor may be at cooking temperature when added, or the slurry may be raised to cooking temperature after the liquor is added or after the additional pressure has been applied. The pressure may be pulsed by lowering and raising it during cooking.

Abstract: The process for producing pulp according to the present invention consists in the subsequent steps of an aqueous treatment of a vegetable stock at a temperature within the range of from 110.degree. to 170.degree. C. under a pressure of from 2 to 7 atm.g. for a period of from 0.3 to 4 hours at a weight ratio of the vegetable stock to water of 1:2-4 respectively; a simultaneous impregnation and cooking of said vegetable stock in a solution of nitric acid at a temperature of from 70.degree. to 90.degree. C. for 0.5-3 hours; cooking at a temperature of from 100.degree. to 130.degree. C. under a pressure of from 1 to 4 atm.g. for 0.3-0.5 hour; an alkali extraction of the vegetable stock; decontamination of the gaseous cooking products by mixing thereof with the air in a volumetric ratio of 1:0.5-1 respectively, and treatment with the spent liquor resulting from the stage of alkali extraction.

Abstract: A novel process for producing pulp is disclosed, by which cooking of lignocellulosic materials can be carried out advantageously in the presence of a novel cooking aid added to the cooking liquor. Representative examples of such cooking aids include maleic acid, sodium maleate, potassium maleate, maleic anhydride, fumaric acid, sodium fumarate, potassium fumarate, mesaconic acid and sodium mesaconate. Both cooking yield and quality of pulp are substantially improved. The cooking aids can be used in combination with dihydroxydihydroanthracene.

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 the delignification of a lignocellulosic material, which comprises the steps of: (a) digesting the lignocellulosic material with an aqueous, alkaline pulping liquor containing from about 0.1% to about 10% based on the weight of oven-dried lignocellulosic material, of a cyclic amino compound selected from the group consisting of phenazine, dihydrophenazine, quinoxaline, and their alkyl, alkoxy, hydroxy, carboxy and amino derivatives at a temperature of from about 150.degree. C. to about 200.degree. C. for a period of from about 5 to about 480 minutes; and then (b) removing the aqueous pulping liquor from the lignocellulosic material with water or an aqueous wash liquor inert to the lignocellulosic material to obtain a delignified cellulosic material.

Abstract: Cellulose pulp is mixed with a base consisting of magnesium oxide, magnesium hydroxide or magnesium peroxide, and treated with oxygen gas at an elevated pressure, at a temperature in the range of 90.degree.-160.degree. C, preferably 120.degree.-140.degree. C for 0.5-6 hours in the absence of alkali metal hydroxide.

Abstract: By pretreating lignocellulose with an alkaline pretreatment liquor containing anthraquinone or a related compound, prior to alkaline digestion, a higher yield of pulp having a lower lignin content can be produced using less alkali. The pretreatment step is carried out under conditions that ensure survival of at least 50% of the anthraquinone or related compound in the pretreatment liquor, which is separated from the pretreated lignocellulose and reused to pretreat other lignocellulose.

Abstract: A process for pulping hardwood to produce cellulose pulp in good yield and of high quality, with a low requirement for causticized pulping liquor, which comprises in a first pulping stage pulping the hardwood in an alkaline pulping liquor containing sodium sulfide at a pH of about 10.5 to about 13 and at a temperature within the range from about 110.degree. to about 170.degree. C while generating hydrogen sulfide in situ by reaction of sodium sulfide with organic acids liberated in the pulping; and then in a second pulping stage, following directly after the first pulping stage, continuing the pulping at a pH higher than said first stage pH, within the range of about 12.5 to about 14 and at a temperature higher than said first stage temperature within the range from about 145.degree. to about 190.degree. C, in the presence of added alkaline pulping liquor comprising sodium hydroxide and sodium sulfide until cellulose pulp is produced.

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 lignocellulosic material, such as wood chips, is pretreated with an aqueous solution containing from 0.1 to 10% by weight of a water soluble lower aliphatic amine selected from monoethanolamine, methylamine and dimethylamine, at elevated temperature and pressure in a closed vessel. This pretreated material is then subjected to conventional soda or two-stage soda-oxygen pulping.

Abstract: Cellulosic material is delignified with oxygen previously dissolved into a fresh alkaline aqueous medium, all of the oxygen contacting said cellulosic material being introduced into said cellulosic material by said alkaline aqueous medium containing oxygen dissolved therein and the cellulosic material consistency during delignification being such as to form an agglomeration of said cellulosic material and alkaline aqueous medium in the form of a layer without any gaseous space therein.

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: The colored body content of the effluent from the alkali of a multi-stage cellulosic pulp bleach process is greatly reduced by extracting bleached cellulosic pulp with hypochlorite at a pH from about 6 to less than 9.

Abstract: The pulping of lignocellulosic material in the presence of oxygen gas and an alkaline liquid is improved by carrying out the process in two stages. In the first stage, the alkaline liquid is trickled over the material as the oxygen is passed up through the material. In the second stage, the material is submerged in oxygenated alkaline liquid which flows through the material.

Abstract: Particulate lignocellulosic material, having a moisture content of about 10-80 weight percent, is treated at temperatures below about 50.degree. C. with 2 to 8 weight percent nitric oxide based on the weight of dry lignocellulosic material. Thereafter, said nitric oxide treated material is reacted with molecular oxygen to form nitric acid in situ. This reaction is followed by washing of said material with alkali and extraction of said material with alkali at a temperature above about 140.degree. C. to delignify the lignocellulose and form pulp.

Abstract: 70 To 85% yield semichemical wood pulping may be prepared for mechanical defibration by cooking comminuted hardwood in a continuous digestion vessel with an alkaline cooking solution wherein 50 to 100% as sodium oxide thereof is sodium carbonate. The solution may be formulated from unmodified kraft recovery process green liquor or, if a sulfur free cooking process is desired, the solution may be formulated from soda ash.

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: 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: 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 nitrate or nickel nitrate 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, with a soda pulping liquor containing a diketo hydroanthracene selected from the unsubstituted and lower alkyl-substituted Diels Alder adducts of naphthoquinone and benzoquinone and a nitro aromatic compound selected from mono and di-nitrobenzenes and the amino, carboxy, hydroxy and methyl derivatives of said nitrobenzenes.

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 is provided for delignifying and bleaching cellulose pulp, which comprises carrying out the delignification and bleaching with oxygen and alkali in the presence of sodium bicarbonate, while removing carbon dioxide from the gas phase as required to maintain a carbon dioxide partial pressure within the range from about 0.001 to about 3 bars, thereby improving the selectivity of the delignification and bleaching.

Abstract: Delignification of lignocellulosic material by treatment with an alkaline liquor in the presence of a cyclic keto compound such as anthraquinone.

Abstract: The delignification and bleaching of lignocellulosic products is effected by mixing an aqueous suspension of the lignocellulosic product with a chlorine-containing substance and an oxygen-containing substance, simultaneously or sequentially, and they, by reaction in situ, give rise to gases in the nascent state. The chlorine and/or oxygen are in the so-called "singlet" state, or in a state of higher energy. The treatment occurs at a temperature below 100.degree. C and for a time less than 60 minutes.

Abstract: An process for increasing the yields of wood pulp and improving the viscosity of the pulp during oxygen-alkali delignification is provided whereby, in a wood pulp at a consistency of about 1-10%, there are present, in the pulp to be delignified, small amounts of ammonia or a compound which releases ammonia under the alkaline conditions of the process.

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.

Abstract: A cooking liquor for the pulping of hardwoods which completely eliminates the use of all sulfur containing compounds is disclosed. The cooking liquor contains 15 to 50% of the total chemical as sodium hydroxide and 50 to 85% of the total chemical as sodium carbonate, the preferred liquor contains about 20% by weight of sodium hydroxide and 80% by weight of sodium carbonate. No adverse effect on the properties of the corrugating medium produced from such a liquor is observed when compared with the medium produced by the conventional neutral sulfite semichemical process.

Abstract: A method of employing the combination of ammonia and ketones as the cooking chemicals in a digester of a pulping process. This method results in a pulp which has a higher yield than the kraft process yet is characterized by kraft's high strength and fair bleachability. The spent liquor extracts are primarily lignin and contain little cellulose and hemi-cellulose.

Abstract: Wood pulp is delignified and bleached with oxygen in the presence of a mixture of an alkali, a magnesium compound and TEA.

Abstract: A process is provided for producing cellulose pulp of high brightness, which comprises pulping lignocellulosic material such as wood with oxygen under superatmospheric pressure in two stages, in the first at a pH within the range from about 6 to about 9, and in the second at a more alkaline pH of at least about 10.

Abstract: Prior to cooking, fragments of raw ligno-cellulosic material are impregnated with a solution of a lignin-solubilizing reactant in an organic solvent which has a boiling point higher than the cooking temperature in order for the material to absorb an amount of solution containing at least the amount of reactant required for solubilizing the lignin, then the impregnated material is immersed in a liquid which is substantially non-miscible with the solvent of said solution, said liquid having a boiling point higher than the cooking temperature, and said liquid is maintained at the cooking temperature until the lignin has been substantially converted to a derivative which is soluble in water or a water-miscible organic solvent.