Abstract: The invention relates to a method and an equipment for preparing NaCMC, in which (a) cellulose is slushed in the reaction medium until a consistency of c. 5-15%, preferably 5-10%, (b) the fibre suspension obtained in step (a) is thickened to a consistency of c. 20-35% and (c) the pulp containing reaction medium obtained in the second step is homogenized by means of a screw conveyor having a screw pitch which decreases from an inlet opening thereof towards an outlet opening thereof, in order to increase the reactivity, whereby a mercerization activating the cellulose is carried out after step (b) and/or (c), and the cellulose thus pretreated is etherified in a manner known per se.

Abstract: A process is provided for the bleaching of wood pulp with hydrogen or sodium peroxide. The process includes the steps of adding to a wood pulp a bleach liquor having an effective amount of hydrogen or sodium peroxide bleaching agent and, by weight of the diluted wood pulp, 0.5 to 6% sodium hydroxide, 0 to 5% sodium silicate, 0 to 1%, preferably 0.02 to 0.05%, magnesium sulphate, and a chelating agent in an amount sufficient to sequester heavy metal ions in the pulp, to produce a pulp consistency of 1 to 16% at a temperature in the range of the bleach liquor freezing point to 25.degree. C., uniformly mixing the bleach liquor with the wood pulp, and immediately thickening the diluted wood pulp to a consistency in the range of 20 to 70% for bleaching of the thickened wood pulp.

Abstract: Resin is removed from mechanical pulps, such as TMP, CTMP, and the like, in a quick and simple manner. Mechanical pulp at a consistency of about 7-20 percent (preferably 8-15 percent) is subjected to high turbulence. The high turbulence may be effected by fluidizing the pulp, as in a centrifugal fluidizing pump, or otherwise by subjecting it to high turbulence as in a mixer, screen, or disc mill refiner. By subjecting the pulp to high turbulence treatment for a time period of about 0.2-10 seconds, resin removal is greatly enhanced, and in subsequent dewatering of the pulp a pressate is formed which has a higher concentration of resin in the pressate than in pressates produced by conventional processes. After dewatering the pulp is preferably diluted (again to about 7-20 percent consistency), and the turbulence and dewatering steps are repeated. Chemicals to improve deresination can be added to the pulp while it is subjected to high turbulence.

Abstract: The bleaching chemicals are added to the pulp immediately after heating of the raw pulp thickened to more than 20% by weight and immediately prior to a dispersing process. This is carried out in a high-speed, high-efficiency disperser, where the heated, thickened pulp is forced through a plurality of narrow slits in a disperser lining and is exposed to strong shearing, impact and kneading stresses. In this way, the dispersing process is reduced to a time period less than 3 seconds, preferably about 1 second or less. As a result, the total time required for reductive bleaching is reduced to less than 15 seconds and no further measures are required for displacing and excluding air from the system. The method can also be advantageously used with oxidative bleaching at reduced reaction time requirements. A high dispersing temperature in the region of 40.degree. C. to 110.degree. C., preferably about 95.degree. C.

Abstract: A chemical pulping process is disclosed wherein wood chips are partially defiberized such that the fibers in the chips are substantially separated from one another but sufficient interfiber bonding is maintained to preserve chip integrity and thereby provide chips having an open porous fibrous network; and the chips are subjected to chemical pulping at an elevated temperature to remove a majority of the lignin in the chips.

Abstract: For bleaching cellulose pulp or a fraction thereof, e.g. reject pulp, the cellulose pulp or fraction, having a concentration of 0.5-10%, preferably 3-6%, is introduced into a screw press comprising at least a first (47) and a second (48) dewatering zone, is dewatered in the first zone to a concentration of 20-40%, whereupon a liquor of bleach chemicals is introduced centrally into the pulp which, during continued treatment, is dewatered in the second zone to a discharge pulp concentration of 15-50, preferably 15-30%, the liquid pressed out of the second zone, together with fresh bleach chemicals, being returned to the pulp in the screw press as liquor of bleach chemicals.

Abstract: Method and apparatus for delignifying chemical pulp by means of oxygen, in which an aqueous slurry of chemical pulp is formed, then mixed with a caustic agent, followed by contact with a delignifying fluid. Water is drained off the slurry without reduction of pressure and while maintaining temperature following which the resulting slurry is maintained under these temperature and pressure conditions for a discrete period of time. The thus-obtained treated slurry is then washed.

Abstract: A process for preparing a cellulose paste by treatment of lignocellulose materials which comprises impregnating wood or vegetable shavings in divided form with an aqueous solution containing 2 to 20% by weight of alkaline metal hydroxides, alkali metal salts, or alkaline earth metal hydroxides, adjusting the weight of the solution retained by impregnation to a value representing 1 to 3 times the weight of treated material, the ratio of the weight of the impregnated mass to the dry weight of the lignocellulosic material being preferably not more than about 2.6:1, subjecting the impregnated masses to cooking treatment by exclusively indirect heating at a temperature varying from 150.degree. to 200.degree. C. without exerting any mechanical disintegrating action for a period varying from 15 to 60 minutes, and pressing the cooked product so as to extract therefrom the solubilized lignin in the form of a black liquor containing about 50% of dry material.

Abstract: Sulfite pulp having increased tear, Scott bond, and stretch properties and above about 90% dirt reduction without bleaching. Methods for making such sulfite pulp by increasing the consistency of conventional sulfite pulp to above about 12 percent, shearing the increased consistency pulp under compressive forces to improve the tear and stretch properties of the pulp, refining the sheared pulp at pressures above atmospheric to remove dirt particles and achieve a desired freeness level, and removing fiber knots from the refined pulp.

Abstract: A recovery method for settled black liquor in ponds and lagoons is disclosed so that ponds and lagoons which can no longer be pumped to recovery evaporators and furnaces are reconstituted by augering the settled black liquor and passing the augered material through filters, partical micronization chambers and static mixers.

Abstract: Air is removed from wood chips, and they are impregnated by treatment liquid, in a process that is an alternative to presteaming and is particularly applicable to environments where presteaming is undesirable, such as in the sulphite treatment of chips during the production of mechanical pulp. The chips are passed in a continuous manner in a generally serpentine, vertically oriented path so that the chips are subjected to a pressure build-up pulsation as they move downwardly, and a pressure release pulsation as they move upwardly. The diameters or cross-sectional areas of the conduit portions defining the upward and downward portions of the path are controlled so that there is about twice the residence time during pressure build-up than there is during pressure release. A high pressure feeder and pump with a fly wheel are operatively connected to one end of the serpentine path, while an in-line drainer and other apparatus are connected to the other end.

Abstract: A method of, and washing machine or washer for, washing stock suspensions, wherein a rotatable cylinder having a solid smooth surface is encircled along a portion of its circumference by a movable endless wire or filter band. The stock suspension to be dewatered and washed is infed by a flat jet nozzle between the rotatable solid cylinder and the movable endless wire. The fiber web formed between the rotatable solid cylinder and the movable endless wire has a weight of less than 100 grams per square meter, preferably 30 to 70 grams per square meter. The wire speed and the circumferential speed of the rotatable solid cylinder is in the order of about 400 to 1,200 meters per minute. After through-flow of the stock suspension between the rotatable solid cylinder and the movable endless wire, the dewatered and washed fiber material is removed from the movable endless wire and the rotatable solid cylinder, respectively, collected in a collecting container and delivered for further processing.

Abstract: Apparatus and process for compressing moisture containing material including a pair of opposed rolls for receiving and advancing the material therebetween to apply rolling load thereto to compress the material and remove at least a portion of said moisture therefrom, and differential means for causing one of said rolls to rotate at a lower speed than the rolling speed of the other of the rolls, the differential rolling speeds developing friction between the rolls causing the rolls to be heated and apply heat to said material to further remove moisture therefrom, to cause the compressed material to adhere to the one roll and to cause the removed moisture to adhere to the other roll, also alone and in combination, apparatus and process of decomposing organic material such as an animal biomass by the action of aerobic microorganisms in the presence of oxygen, including introducing the organic material into a container having an end adapted to receive the organic material and an output end adapted to discharge th

Abstract: Method for the washing of chemical pulp (1) by means of a fourdrinier wire machine in two or more stages (6,10; 6',10'; 6", 10"; 6'", 10'") while the pulp web runs on the wire (3). The liquid contained in the pulp web is displaced by a washing liquid. The pulp web and the wire (3) run, during the washing, as submerged in the washing liquid while the washing liquid flows through the pulp web and the wire. One embodiment comprises passing the washing liquid upwardly through the pulp and then downwardly through the pulp.

Abstract: A method and apparatus are provided for effecting presteaming and deaeration of wood chips, or like comminuted cellulosic fibrous material. Presteaming takes place in a vertical presteaming vessel, utilizing a plurality of uniformly radially spaced nozzles adjacent the bottom of the vessel, a plurality of generally uniformly radially spaced steam introduction pipes in a central portion of the vessel, and a pair of synchronized rotating valves for feeding steam to the introduction nozzles and pipes in a coordinated manner. After presteaming, the chips pass through a chips meter to a vertical chute in which they are entrained in liquid, and then pass to a horizontal deaerating vessel. In the deaerating vessel, deaerated liquid is passed in a path generally perpendicular to the path of the material flowing through the deaeration vessel.

Abstract: The present invention seeks to provide a method for treating the cellulose obtained from the cellulose cooking process for paper-making purposes. According to this method, the cellulose is separated from black liquor or other similar waste slurry produced in the cooking process by means of compression and washed, bleached and dried, and an essential feature of the present invention is that all the phases of treatment are carried out in a pressure filter (4). The treatment is performed so that black liquor or similar waste slurry is first compressed from the cellulose pulp slurry, whereafter the resulting cellulose cake is washed by conducting washing liquid into the filter, after which the cellulose is bleached by treating the cake with one or several bleaching chemicals led into the filter and by re-washing, if necessary, the cake between the various bleaching phases, and finally, the cellulose cake is dried and removed from the filter.

Abstract: A wire machine, especially for washing stock suspensions, contains one or a number of dewatering cylinders about which there is trained an endless wire or filter band. There is provided at least one stock infeed device which infeeds a substantially flat jet of the suspension which is to be dewatered into a substantially wedge-shaped space or throat located between the wire band and the dewatering cylinder. The dewatering cylinder has a longitudinal axis which is essentially vertically arranged. There are possible different arrangements of the dewatering cylinder or cylinders, the stock infeed devices and material removal devices for removing from the rotatable dewatering cylinder solid constituents or the like contained in the stock suspension. Also there are possible different arrangements and uses of guide rolls for guiding the wire or wire band.

Abstract: A method of, and wire machine for, washing stock suspensions is disclosed wherein a cylinder having a solid smooth surface is encircled along a portion of its circumference by an endless wire or filter band. The stock suspension which is to be dewatered is infed between the solid cylinder and the wire by means of a flat jet nozzle. After throughflow of the stock suspension between the cylinder and the wire the dewatered fiber material is removed from the wire and the cylinder, respectively, collected in a collecting container and delivered for further processing.

Abstract: The invention relates to a process for the delignification of unbleached chemical pulp, comprising the following stages:(a) oxidation of the unbleached pulp with a peroxide, in an alkaline medium with a % ratio of peroxide/pulp with respect to the Kappa index of said pulp which may vary between 0.01 and 0.1 and a pH kept at between 9 and 12, the said oxidation stage being followed by(b) mechanical pressing of the oxidized pulp, with recycling of the extraction effluents from the pressing stage,partly above the oxidation stage,partly below the oxidation stage, with a view to ensure the prior dilution of the pulp oxidized before the pressing,and if necessary partly towards the wash of the unbleached pulp.Advantages: A reduction in the quantities of reagents to be used, a saving of heat energy and a reduction of the pollution.

Abstract: A process and apparatus for producing pulp from impregnated cellulose-containing starting materials such as wood, straw, grass, waste materials etc. in a compacting apparatus comprising a shell (1) and two mutually opposite pistons (4, 4') contained in the shell. The material to be compacted is disposed between the pistons and constitutes a resistive electrical load. The pistons are movable relative to each other and the shell is movable relative to the pistons. The impregnated starting materials are digested at a relatively low hydromodulus of 0.5 to 2 with a direct action of heat on the impregnated starting materials in the compacting apparatus at a digesting temperature of 160.degree. to 300.degree. C. The digesting times are short and depend on the digesting temperature.

Abstract: A process and apparatus are provided for the deresination and brightness improvement of cellulose pulp, by adjusting the pulp concentration to within the range from about 15 to about 35%; adding sufficient alkali to the pulp to bring the amount of alkali, calculated as NaOH, within the range from about 0.5 to about 17 g/kg of water accompanying the pulp; adding sufficient oxidizing bleaching agent to the pulp to bring the amount of oxidizing bleaching agent to within the range from about 0.2 to about 22 g/kg of water; subjecting the pulp to a mild, mechanical working in the bite of twin interdigitated rotating screws at an energy input of from 8 to 100 kWh per ton of pulp; removing and reacting the pulp with the added alkali and bleaching agent for from about 0.1 to about 5 hours; and then washing out dissolved resin from the pulp.

Abstract: A method is provided for treating pulp fibres, that have already been curled which method comprises: subjecting the pulp to a heat treatment while the pulp is at a high consistency, thereby to render the curl permanent to subsequent mechanical action. This permanent curl has advantages for papermachine runnability and for increasing the toughness of the finished product.

Abstract: Bleached wood pulp is treated with a sulphite after bleaching and before or during flash drying to reduce the formation of nodules of agglomerated wood pulp fibres in the dried pulp, particularly in short fibre pulp from hard woods such as birch and eucalyptus. The sulphite is preferably added to the bleached pulp in the form of an aqueous solution of an alkali metal sulphite for example a 0.4 to 5 percent by weight solution of sodium sulphite. The process of the invention is particularly suitable for drying pulp which is at an acid pH due to residual acids remaining on the pulp from the bleaching process, for example pulp bleached by treatment with chlorine dioxide.

Abstract: A method and a device for the manufacture of mechanical pulp from lignocellulosic material by forcing the said material into contact with a grindstone (1) which revolves about an axle (2). The material is supplied in bulk, particulate form, preferably as wood chips, a large number of particles simultaneously being retained, compressed and, in the presence of water, forced into contact with one or more grinding areas on the circumferential surface of the grindstone (1). The grindstone (1) is enclosed in a sealed, pressurized housing (5).

Abstract: Sorbed sodium ions in the wood pulp are recovered in the washing operation following cooking with the minimum use of pH control acid, thereby reducing cost and any possible undesirable side effects. A washing press is used in the pulp process. Means are provided for adding an acidifying chemical to the washing press for controlling pH of the pulp suspension. The filtrate from the washing press is divided, with the larger portion of the filtrate being fed to the pulp suspension line to the washing press for pulp suspension pH control. A smaller portion of the filtrate is fed countercurrently through the brown stock washing system. The chemicals are then recovered from the brown stock washing system filtrate.

Abstract: A method and apparatus for the treatment of fiber material by oxygen bleaching. Digested cellulosic fiber material is treated with oxygen to reduce the Kappa number thereof further to about 15 or below. The reaction products are removed immediately after formation, and during the oxygen bleaching process. The fiber material is at a first consistency of about 8 to 15% consistency, and treatment with oxygen is accomplished by mixing the pulp with O.sub.2, NaOH solution, and water to thereby form an integral mixture of pulp with oxygen at a second consistency, thickening the integral mixture to return it to generally its first consistency, and repeating the mixing and thickening until pulp of a desired Kappa number (15 or below) is reached. The pulp is then washed and may be subsequently treated to reduce the Kappa number thereof to any desired value. A thickener is used which can thicken pulp at superatomspheric pressures and at a temperature greater than 100.degree. C.

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: The continuous treatment of a cellulosic material in the form of chips to produce at least partial delignification of the material without true mechanical grinding is effected in apparatus comprising two parallel meshing screws which are rotated in the same direction in a sheath and have identical threads providing a plurality of zones of different pitch. The material is passed in succession through a first zone for feeding the material downstream, a first braking zone for causing a first compression of the material, a second zone for feeding the material downstream and in which the material is brought into contact with a reagent, e.g. steam or a chemical reagent, and a second braking zone for causing a second compression of the material.

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 method of removing liquid from a slurry of solid material in liquid in which the liquid is squeezed from the slurry by passing the slurry through a roll nip and, simultaneously with the squeezing and passing, the liquid squeezed from the slurry is blocked from flowing through the roll nip.Apparatus for removing liquid from a slurry of solid material in a liquid includes a plurality of liquid guides, disposed in a spaced-apart parallel relationship, being inclined away from and opening adjacent the roll nip.

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: Cellulose fibers are treated by providing the fibers in a 10-90% concentration in liquid, and applying elastic pressure shocks to the fibers for a duration not exceeding one second and of a magnitude causing the pressure in the interior of the fibers to exceed 0.2 atmospheres excess pressure. Thereafter the fibers are permitted to expand. The pressure shocks cause liquid to be expelled from the fibers without permanent deformation of the fibers occurring. When the fibers expand, liquid is adsorbed. These steps are repeated until the fibers are completely impregnated with liquid. This prevents the formation of fiber knots when the fibers are substantially dried before being formed into paper. The elastic pressure shocks can be applied by a rotating paddle wheel which intermittently elastically compresses the fibers against an elastic surface of a container.

Abstract: A wood chip stream capable of being selectively delaminated is produced by separating a mill-wood chip stream into respective first and second fractions on the basis of wood chip thickness. The first fraction consisting of wood chips having a predetermined thickness, is then pulped by conventional techniques. The wood chips in the second fraction are reduced to said predetermined thickness and are then selectively delaminated by compression means. After being subjected to selective delamination, the delaminated chips are pulped by conventional techniques. Accordingly, a high yield, uniform wood pulp having reduced pulp screen rejects is produced.

Abstract: A process for the manufacture of paper pulp from waste paper in which the waste paper is comminuted in water in a pulper, pre-cleaned for removal of coarse foreign contaminants, dewatered, kneaded at high concentration, diluted, after-cleaned for removal of finer or coherent soft foreign contaminants and adjusted to a concentration suitable for paper-making, the water respectively used for dilution and obtained during dewatering being circulated in two separate circuits upstream and downstream respectively of the kneading apparatus.