Abstract: A process is provided for delignifying bleaching lignin-containing cellulose pulp which comprises:(1) activating cellulose pulp by reacting the pulp at a pulp consistency within the range from about 20% to about 60% and at a temperature within the range from about 20.degree. to about 130.degree. C. with a gas comprising NO.sub.2 and oxygen in the presence of water, sodium nitrate in an amount of at least 0.15 g mole per kg of water, and optionally nitric acid;(2) washing the activated pulp with water or an aqueous solution; and(3) treating the activated washed pulp with an aqueous alkaline solution at a temperature within the range from about 70.degree. to about 170.degree. C., optionally in the presence of oxygen gas until the lignin content of the pulp is so reduced that the Kappa number of the pulp is within the range from about 10 to about 60% of the Kappa number of the pulp entering the activating stage (1).

Abstract: A process is provided for manufacturing groundwood pulp of uniform quality by maintaining a high and uniform moisture content in the wood in the grinding zone which comprises grinding debarked wood logs or wood chips in a closed pocket grinder under atmospheric or superatmospheric pressure while applying shower water both to the free surfaces of the grindstone and to the grinding zone where the logs or chips are in contact with the grindstone, such as by spraying the water at the end portions of the logs or chip mass, optionally together with applying shower water via the ram plates and a water trap arranged around the lower part of the log pockets, and preferably retaining shower water within the grinding zone by filling with shower water the hollows between the logs or chips located nearest the surface of the grindstone.

Abstract: A process for manufacturing bleached groundwood pulp of improved and uniform quality, in which debarked wood logs or wood chips are ground in a closed pocket grinder at atmospheric or super-atmospheric pressure, while applying shower water to the free surfaces of the grindstone, and shower water containing bleaching chemicals to the grinding zone where the wood is in contact with the grindstone, i.e.

Abstract: A two-stage process is provided for the conversion of lignocellulosic material, for instance, wood, to cellulose pulp, first oxidizing the lignocellulosic material to form aldonic acid end groups, preferably bound with 1,4-glycosidic bonds, in the polysaccharides, in an alkaline medium in the presence of the oxidized form of a redox additive which is converted into a reduced form in reaction with the wood and/or products formed from the wood, withdrawing the alkaline medium and then reoxidizing the reduced form of the redox additive in the absence of the lignocellulosic material at a rate to maintain the oxidized form of the redox additive in a major proportion in the alkaline medium during oxidation of the lignocellulosic material by contacting the withdrawn alkaline medium with oxygen-containing gas, and then continuing the digestion in an alkaline medium at a temperature within the range from about 160.degree. to about 200.degree. C.

Abstract: A method for delignifying and/or bleaching cellulose pulp adds to the cellulose pulp a liquid which contains chlorine dioxide, causes the pulp to react with the chlorine dioxide over a selected period of time, and then reduces the amount of available active chlorine, optionally to a negligible amount, either by reducing the amount of liquid accompanying the cellulose pulp and/or by displacing such liquid with a newly supplied liquid containing no active chlorine or at most only a small amount of active chlorine; the displaced liquor can be replenished with chlorine and optionally with chlorine dioxide, and then added mainly to fresh cellulose pulp in the same bleaching stage, and/or to cellulose pulp in another bleaching stage.

Abstract: A process is provided for the recovery of sulfur dioxide liberated in the chemical pulping of lignocellulosic material, which comprises(1) collecting sulfur dioxide-containing gas emitted during the pulping and separating it into at least two portions;(2) contacting at least one portion with chlorine gas, thereby forming a gaseous mixture comprising sulfur dioxide and chlorine;(3) effecting reaction of sulfur dioxide, chlorine and water to form hydrochloric acid and sulfuric acid while forming an intimate dispersion in said gaseous mixture of an aqueous solution of hydrochloric acid and sulfuric acid;(4) dissolving said hydrochloric acid and sulfuric acid in said solution;(5) recovering said solution and separating it from substantially sulfur dioxide-free residual gas.

Abstract: A process is provided for inhibiting the formation of deposits in the course of pulping lignocellulosic material and in the treating of cellulose pulp, by addition to the cellulose pulping or treating process of compounds of polyvalent metals other than aluminum and manganese capable of complexing deposit-forming anions, thereby maintaining the deposit-forming anions in solution in the form of a liquor-soluble complex.

Abstract: A process for delignifying bleaching cellulose pulp in three stages, an activating stage, and first and second alkaline stages, NO and/or NO.sub.2 and O.sub.2, and optionally HNO.sub.3, being supplied to the water-containing pulp in the activating stage; in the first alkaline stage, alkali being supplied as carbonate, primarily HCO.sub.3.sup.-, with oxygen gas having a partial pressure, on average, of from 0 to 0.2 MPa, the lignin content of the pulp being lowered in this stage so that the Kappa number of the pulp after the stage is from 10 to 60% of the Kappa number of the pulp entering the activating stage; in the second alkaline stage, alkali being supplied as carbonate, primarily CO.sub.3.sup.=, with oxygen gas at a partial pressure, on average, of from 0.1 to 3 MPa.

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 two-stage oxygen bleaching of chemical cellulose pulp is provided, in which an alkaline oxygen bleaching stage is preceded by a nitrogen dioxide activating stage in which oxygen is added to the activating stage in an amount such that nitrogen monoxide formed as an intermediate during the activation process is consumed, so regulating the amount of oxygen added that when the activation reaction is practically complete, substantially all of the nitrogen dioxide and nitrogen monoxide has been consumed.

Abstract: A ground-clearing and mound-building device is provided that can be towed along the ground to move material on the surface to one side, expose the surface of the ground, and build mounds on the cleared ground for planting and forest regeneration, having a scarifier means mounted for rotation about its central axis, circular in cross-section, and having a peripheral surface that digs into the ground during rotation thereof when in contact with the ground under pressure, arranged to be brought into contact with the ground at any selected contact pressure; with control of at least one of the selected contact pressure and the selected rotation rate to dig, loosen, and displace a surface layer of the ground and push such loosened ground into mounds.

Abstract: A process is provided for the bleaching delignification of cellulose pulp with oxygen gas in the presence of alkali, wherein the pulp is first activated with nitrogen dioxide and then washed, preferably with water. The invention is characterized in that the acid solution obtained is used to pretreat the digested pulp subsequent to washing the pulp with waste liquor obtained from the oxygen gas bleaching delignification stage.

Abstract: Apparatus is provided for debarking logs and cut timber, comprising a debarking drum rotatable in either direction and having an inlet at one end and a plurality of lifter means shaped and disposed on an interior wall of the drum in a manner to engage and lift logs and cut timber with rotational movement of the drum in either direction; and a conveyor feeding logs and cut timber into the interior of the debarking drum; the conveyor being movable between a first position and a second position with respect to the inlet and the center axis of the debarking drum; and means for driving the drum in one direction when the conveyor occupies the first position, and in the opposite direction when the conveyor occupies the second position, so as to wear the lifter means more evenly.

Abstract: A process is provided for the alkaline oxygen delignification and bleaching of chemical cellulose pulp while inhibiting degradation of carbohydrates in the pulp, due to the presence of one or more aromatic diamines, preferably having the diamine groups directly linked to an aromatic ring.

Abstract: A method is provided for controlling the supply of delignifying and/or bleaching chemicals in the continuous delignification and/or bleaching of lignocellulosic material such as wood and pulp in a through flow delignification and/or bleaching stage which commprises admixing the lignocellulosic material with delignifying and/or bleaching chemicals and flowing the lignocellulosic material under delignifying and/or bleaching conditions through the stage while controlling the addition of the delignifying and/or bleaching chemicals according to the ratio of the quantity of delignifying and/or bleaching chemicals consumed to the quantity of delignifying and/or bleaching chemicals originally charged, referred to hereinafter as relative consumption, the time and the temperature in a manner to maintain substantially constant the relative consumption of delignifying and/or bleaching chemicals at a predetermined time by the lignocellulosic material during flow through the stage.

Abstract: A digging and planting machine is provided having a tubular digging and planting tool mounted on a vehicle travelling along the ground surface, and at least one sensing and signalling means for sensing the resistance of the ground to penetration by the digging tip of the tool, thus gauging the condition of the ground, and detecting obstacles to such penetration, so as to ensure that the digging tip provides and a plant is fed to a planting hole of the desired depth, when ground condition is suitable, and, when ground condition is not suitable, that new digging attempts continue to be made at closely-spaced intervals as the vehicle travels over the ground until a planting hole of the desired depth is dug, so as to plant as many plants as close together as desired per unit area.

Abstract: Apparatus is provided for removing particulate material not normally larger than about 0.5 dm.sup.3 in volume such as wood chips, bark, coal, ore, slag, municipal waste or industrial waste, from a pile whose sides are at an angle of at least 40.degree. to the horizontal. The apparatus includes an elongated scraper means arranged for oscillating movement along its longitudinal axis in contact with the sides of the pile from the bottom to the top of the pile for scraping material down from the pile towards approximately ground level where the material is carried by conveying means away from the pile site. The scraper means is carried on a frame arranged for movement along the base of the pile of material and at right angles thereto to selected parts of said pile for scraping material from the pile.

Abstract: A process is provided for preparing groundwood pulp from debarked pulpwood logs, which comprises grinding the logs in the presence of water under a superatmospheric pressure of a gas selected from the group consisting of steam, air, and steam and air, and forming and discharging a pulp suspension in the resulting aqueous liquor, while continuously supplying water during the grinding in a volume of less than 35 parts per part of bone dry pulp at a rate of addition such that the temperature of the discharged pulp suspension is below 200.degree. C. and preferably below 180.degree. C. and within the range from about 1.5 to about 50, preferably from 2 to 8, times the temperature in .degree.C. of the added water at a pressure within the range from about 8 to about 40 kiloponds/cm.sup.2, preferably from 10 to 30 kiloponds/cm.sup.2, higher than the superatmospheric pressure and at a temperature within the range from about 2 to about 63.degree. C.

Abstract: Apparatus is provided for removing particulate material, such as wood chips, bark, municipal waste or industrial waste, from a pile thereof, comprising a support extending along the base of the pile and a carriage movable on the support along its longitudinal axis. Mounted on the carriage are an elongated scraper for scraping material from the pile, and a conveyor for collecting and carrying away particulate material scraped down from the pile.

Abstract: Apparatus is provided for controlling the degree of causticization of white liquor in its preparation from green liquor by the addition of calcium oxide, which comprises determining the sodium carbonate concentration of green liquor fed to the causticization; determining the sodium carbonate concentration of white liquor resulting from the causticization; and controlling the degree of causticization within a predetermined range while taking both sodium carbonate concentrations into account, so as to maintain the degree of causticization of the white liquor within the range despite variations in sodium carbonate concentration of the green liquor and variations in calcium oxide content of the calcium oxide added for causticization.