Abstract: Improved pulp strength and brightness of chemically produced pulp can be obtained by treating the pulp with the addition of 0.05-0.5% based on the weight of the dry fiber of certain amine materials in the hypochlorite bleaching stage.

Abstract: An improved displacement washing process for recovering processing chemicals from a porous medium, particularly wood pulp, is described. The effective mobility of a displacing solution, typically a more dilute solution of the chemical sought to be recovered, is reduced such that it is less than the mobility of the solution to be recovered. In a pulp mill washing system, consumption of wash water may be reduced 0.6 tons of water per ton of pulp produced without reducing chemical recovery. Conversely, chemical effluent from the washer could be reduced by 50% without increasing wash water requirement. Mobility is proportional to the permeability of the porous medium with respect to the solution of interest and inversely proportional to the viscosity of that solution. Mobility of the wash solution relative to the solution to be displaced is preferrably reduced by the addition of a soluble, high molecular weight polymer, greater than 10.sup.

Abstract: Improved pulp strength and brightness of chemically produced pulp can be obtained by treating the pulp with the addition of 0.05-0.5% based on the weight of the dry fiber of certain aromatic materials in the hypochlorite bleaching stage.

Abstract: A process is provided for the manufacture of bleached chemimechanical cellulose pulp in high yield of between 65 and 95% from particulate and preferably washed lignocellulosic material, such as wood chips, featuring the use of spent or waste bleaching liquid, preferably from a lignin-preserving bleaching process, in at least one stage of the process where a cooling and diluting liquid is required, such as during mechanical defibration of the material.

Abstract: The invention relates to a process for bleaching preoxidized paper pulp enabling a pulp having a very high degree of whiteness to be obtained with a limited number of treatment steps and enabling pollution to be reduced without degrading the qualities of the pulp; such a process essentially comprises the combination of the three successive treatment steps, namely:(a) a first step of hot chlorination with gaseous chlorine at a temperature of between about 30.degree. and 80.degree. C., and preferably between 35.degree. and 50.degree. C., in the presence of urea used at a rate of 0.5 to 5% by weight of the chlorine used, and preferably from 1 to 3%, with a concentration of pulp of between 3 and 30%, and a duration of retention of the chlorine of 30 seconds to 45 minutes;(b) a second step of alkaline extraction in the presence of an oxidizing agent of the hypochlorite or peroxide type, at a temperature of between about 30.degree. and 70.degree. C., and at a pH of between about 8 and 12, and preferably between 10.

Abstract: A method is disclosed for inhibiting soft scale precipitation in black liquor systems by adding thereto polyacrylic acid.

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 process of separating fibres from asbestos-bearing material which process comprises the steps by treating said asbestos-bearing material with a chemical agent capable of reacting with, or adsorbing on, asbestos fibres to form a dispersion, and agglomerating said dispersion, and wherein effluents containing said chemical agent are subjected to ultrafiltration prior to re-use in the process. The process given high yields of novel fibres characterized in that the said fibres provide reinforcement in cementitious compositions.

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: 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: Inproved pulp strength and brightness of chemically produced pulp can be obtained by treating the pulp with the addition of 0.05-0.5% based on the weight of the dry fiber of thiourea dioxide in the chlorination or hypochlorite bleaching stages.

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: 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 process for preventing deposition of pitch in papermaking comprising incorporating in a paper pulp slurry a water-soluble linear cationic polymer comprised of units of the formula ##STR1## wherein A is a (C.sub.2 -C.sub.3) alkylene group,R is H or CH.sub.3 ;R.sup.1 is a hydroxyethyl or hydroxypropyl group,R.sup.2 is a (C.sub.1 -C.sub.4) alkyl group,R.sup.3 is a (C.sub.1 -C.sub.4) alkyl group, andX is an anion;said polymer having a viscosity average molecular weight of about 35,000 to 70,000.

Abstract: Pitch formation in paper mill pulp systems may be inhibited by treating such systems, at a point prior to where pitch deposits normally occur, with at least 0.

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 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 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: 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 wood pulp slurry, at a consistency of 0.1% to 10% by weight and having a pH ranging from 1 to 7, is bleached with ozone in the presence of 0.1% to 1.0% by weight of a cationic surfactant.

Abstract: An antifoam/defoam composition used also as a drainage aid in pulp and papermaking process lines which consists of a water-base composition useful in the pH range 7.0-9.0. The milieu in which the composition is utilized such as e.g. black liquor, may be kept at a pH of 4.0-12.0. The composition is as follows:Hydrophobic silicaBisamide of the following formula: ##STR1## where N IS AN INTEGER FROM 1 TO 6; ANDR is a saturated or unsaturated, straight or branched chain hydrocarbyl group having from 5 to 22 carbon atoms.Acid containing crosslinked copolymer of acrylic acidDioctyl sulfosuccinateParaffin oilWaterMore particular formulae are also set out below:______________________________________ (A) Hydrophobic silica 0-30% Ethylene-bis-stearamide .001-50% Acid containing crosslinked acrylic acid polymer .05-10% Dioctyl sulfosuccinate .05-10% Paraffin oil .001-99% H.sub.2 O .001-99% (B) Hydrophobic silica 4-12% Ethylene-bis-stearamide 4-12% Acid containing crosslinked acrylic acid polymer .

Abstract: Efficient lignin removal from cellulosic pulp with decreased cellulose degradation is attained by replacing chlorine with an acidic bromine-chlorine mixture in acidic chlorination of the pulp.

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: 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 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 for the disposal of paper pulp mill sludge by incorporating the sludge in the digestion step of a wood pulping operation without detrimental effects on the quality of the pulp obtained. In one aspect, the sludge is surplus sludge which is obtained from a system which microbiologically purifies spent wood pulping liquor by aeration and sedimentation.

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: When bleaching wood pulp with oxygen the result can be improved if formaldehyde, methanol, ethanol, isopropanol, glycerol, sorbitol, formic acid, or acetone is added to the pulp.

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: The deposition of adhesive pitch particles from aqueous suspension of cellulose fibers is inhibited and, if desired, substantially prevented, from depositing on the surfaces of pulp-making equipment by adding to the suspension an anionic polymer containing at least about 25 mol percent but not more than about 85 mol percent of hydrophobic oleophilic linkages selected from the group comprising styrene, isobutylene, methylstyrene, allyl stearate, octadecyl acrylate, octadecene, dodecene, n-octadecylacrylamide, vinyl stearate and vinyl dodecyl ether and at least about 15 mol percent but not more than about 75 mol percent of hydrophilic acid linkages selected from the group comprising acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylamidoacetic acid, maleamic acid and styrenesulfonic acid, forming a pitch-polymer complex of said particles and said polymer, and removing said complex with the water used to wash said cellulose fiber suspension thereby separating substantially all of the pitch-polymer

Abstract: A process for bleaching wood pulp with sodium hydrosulfite in the presence of at least 2 weight percent of hexamethylenetetramine based upon the weight of sodium hydrosulfite.

Abstract: An aqueous composition for bleaching wood pulp containing sodium hydrosulfite, and at least 2 weight percent hexamethylenetetramine based upon the weight of sodium hydrosulfite, wherein the solution has a pH between about 4 and about 11. The hexamethylenetetramine prevents hydrogen sulfide formation during bleaching of the wood pulp.

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.