Abstract: Oxidized weak black liquor or effluents from alkaline bleaching stages, particularly oxygen delignification and/or ozone and/or hydrogen peroxide bleaching effluents are treated in process stages which include an electrolytic cell to recover NaOH, lignin, O.sub.2, H.sub.2 and to achieve other important benefits, the most important of these are (i) to unload the evaporator-recovery furnace and lime-kiln causticizing plant, and (ii) to enable a mill to implement low- or no-chlorine bleaching techniques without overloading their recovery furnace and/or lime kiln or requiring a new, larger recovery system, the electrolytic treatment can be carried out with one or a combination of the above types of effluents; it is also possible to increase the conductivity if required and thus the efficiency of the electrolytic cells and the yield/production of NaOH by the introduction of Na.sub.2 SO.sub.

Abstract: A method for the preparation of a mixture of fused ring quinone type compounds from lignin and lignin-derived substances. The mixture of fused ring quinone compounds has been found useful in the wood pulping process as an accelerator in the degradation and separation of wood lignin from the other principal wood constituents, cellulose and hemicellulose.

Abstract: A process for increasing the pulp producing capacity of a kraft mill including the steps of removing at least a portion of the lignin from kraft black liquor and separating the lignin from the aqueous phase. The next step is treating the aqueous phase to separate the inorganics and organics with the organics preferably being recycled to the process loop to be burned in the recovery furnace. The inorganics are converted into pulping chemicals which bypass the recovery furnace and are transported to white liquor preparation.

Abstract: A lignosulfonate useful pharmacologically as an anti-thrombotic that inhibits deep venous thrombophlebitis without effecting blood coagulation, and which causes no apparent increased bleeding or side effects. The lignosulfonate is isolated from softwood spent sulfite liquor, and is administered in low dosages of from about 0.05 to about 1.0 mg/milliter of blood. A method of making and administering the lignosulfonate is also disclosed.

Abstract: A process for the thermal and chemical treatment of lignocellulose-containing biomass and for the production of furfural and cellulose-containing fiber masses. In order to ensure a high yield of furfural:lignocellulose-containing biomass is continuously fed into a cooker containing a cooking liquor and, upon heating of the biomass in a heating zone and guidance of the heated biomass through a consecutive retention zone, cellulose or pretreated biomass is continuously withdrawn from the cooker,cooking liquor is continuously withdrawn from the cooker,the cooking liquor withdrawn is continuously fed to a furfural production plant, andthe cooking liquor at least largely freed from pentoses and furfural is continuously returned to the cooker, wherein heating may be effected by direct steam or via the cooking liquor.

Abstract: The chemical components of lignocellulosic material which have been dissociated by a steam explosion process can be extracted from the mixture of components using a solvent extraction process. The solvents are water, alcohol and a mild caustic in that order, or the alcohol step can be by-passed and only water and caustic are used. The caustic is a stronger solvent and it will extract the alcohol solubles along with the caustic only solubles. The eluant from the these extractions contains a range of lignin derived substances, which have different applications, such as thermoplastic and thermosetting characteristics. This invention describes a method for partitioning these lignin components into reproducible fractions having definable characteristics for particular applications. For instance, many copolymer applications require a thermosetting only fraction of the lignin. Other applications require a thermoplastic only lignin.

Abstract: A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

Abstract: The present invention solves the problem of managing resin-containing waste liquors within the cellulose pulp industry. The invention relates to a method for purifying resin-containing waste liquor in the manufacture of cellulose pulp, in which method a pH-adjusting chemical is, when necessary, added to resin-containing waste liquor removed from the cellulose pulps, so that the pH of the waste liquor will lie within the pH range 1-7, and in which a water-soluble organic polymer is added to the waste liquor in the form of a forwardly moving liquid stream. The method is characterized by dividing up the requisite amount of polymer into part quantities which are introduced into the liquid stream on at least two occasions, by subjecting the liquid stream to a pronounced shearing and/or turbulent treatment process, and by subsequently separating agglomerated resin from the waste liquor.

Abstract: In a combined process for the thermal and chemical treatment of lignocellulose-containing biomass and for the production of furfural, biomass is supplied to a cooker in batches, is heated in the cooker under the addition of cooking liquor, and cellulose or pre-treated biomass is withdrawn from the cooker in batches. In order to guarantee a high yield of furfural, cooking liquor is withdrawn from the cooker during the heating phase and is fed to a furfural production plant, and the cooking liquor at least largely freed from pentoses and furfural is returned to the cooker.

Abstract: The chemical components of lignocellulosic material that have been dissociated by a stream explosion process can be extracted from the mixture of components using a solvent extraction process. The dissociated lignocellulosic material is put in a column and the substances which are soluble in water, alcohol and caustic are leached out of the mixture by solvent extraction with relatively small volumes of those solvents. No agitation is used. Substantially pure cellulose remains in the column and it can be bleached before removal from the column.

Abstract: A method for the manufacture of products containing compressed and adhesive-bonded wood chippings, preferably of different sizes. Before the chippings are combined together by glueing to form a product of high dimensional stability, they are impregnated with lignin in conjunction with water and at a pH which essentially does not exceed 12.5. Once the lignin has been absorbed by the wood chippings it is fixed against leaching by the water by the modification of same into an essentially water-insoluble form by impregnating the chips with a weakly acid aqueous solution of a metal salt.

Abstract: Lignin is removed from a crude tall oil in the production of tall oil fractions suitable for use as chemical ingredients and additives in other products by sparging the crude tall oil at a temperature of between about 350.degree. F. to 400.degree. F. with a carrier gas to depolymerize and remove from the tall oil lower molecular weight lignin materials.

Abstract: A method of rapidly and efficiently treating ligno-cellulosic material for removal of lignin and other non-carbohydrates as well as non-cellulosic carbohydrates from cellulosic matter. Such material is first impregnated with a liquor which is a reaction product obtained by mixing triethyleneglycol with an arylsulfonic or other organic acid. The impregnated material is then rapidly heated by microwaving or application of rf energy to a temperature between about 119 degrees Centigrade to 130 degrees Centigrade and maintained at that temperature for only two to five minutes to reduce the effects of hydrolysis. Thereafter, conventional filtration and washing techniques are applied to achieve a residue material suitable for further use as a wood pulp or for further hydrolysis for the production of organic chemicals.

Abstract: Lignin is precipitated in high yields and at high rates from a black liquor produced by pulping wood at high temperatures and pressures with an aqueous lower aliphatic alcohol solvent. The lignin is precipitated by diluting the black liquor with water and an acid to form a solution with a pH of less than about 3, an alcohol content of less than about 30% by volume and a temperature of less than about 75.degree. C. The precipitated lignin, when subsequently dried, is in the form of a powder which requires little or no crushing to convert it into a fine uniform size suitable for use without further significant processing.

Abstract: A wet, pressure, partial oxidation process to favor the partial oxidation of black liquor obtained from soda pulping. This is obtained by adjusting the equivalent of sodium ion content of a soda pulping black liquor within the range of about 21 to 26 weight % based on the total weight of the dissolved black liquor solids. This adjustment favorably reduces lignin fragments into short chain organic acids and thereby increases their production. In the case of potassium, the adjustment of the sodium content is carried out using an equivalent amount of a molar basis of potassium ion. A product wherein the amount of short chain organic acid salts is between 70 and 90%, the amount of aromatic lignin fragments and aromatic products thereof is between 0 and 10% and sodium carbon/bicarbonate mixture constitutes not more than 20% on the dry solids basis is also disclosed.

Abstract: A deicing product comprising a mixture having, based upon the total weight of solid in said deicing product between 12% and 75% acetate salts, trace amounts and 36% carbonate salts, 1 and 24% formate salts, 1 and 32% pseudolactate salts. The cations of said salts are selected from the class consisting of sodium, magnesium, calcium, potassium. Lignin fractions and low molecular weight sugars may also be present, as well as other chemicals derived from the method of making black liquor and this new product. A method of making same is disclosed. It comprises using a black liquor obtained from a pulp mill operation, fractionating said black liquor into a low molecular weight fraction, concentrating said collected low molecular weight fraction to produce a concentrated deicing product.

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: A deicing product comprising a mixture having, based upon the total weight of solid in said deicing product between 12% and 75% acetate salts, trace amounts and 36% carbonate salts, 1 and 24% formate salts, 1 and 32% pseudolactate salts. The cations of said salts are selected from the class consisting of sodium, magnesium, calcium, potassium. Lignin fractions and low molecular weight sugars may also be present, as well as other chemicals derived from the method of making black liquor and this new product. A method of making same is disclosed. It comprises using a black liquor obtained from a pulp mill operation, fractionating said black liquor into a low molecular weight fraction, concentrating said collected low molecular weight fraction to produce a concentrated deicing product.

Abstract: An autoclave extraction apparatus where a supercritical fluid is used for supercritical fluid extraction of one or several compounds. The supercritical fluid containing the compoound(s) may then be processed in a pressurized, fluidized, bed reactor under supercritical conditions. The fluidized bed reactor is used to carry out a catalytic reaction of the compound(s). The method is particularly applicable to recover valuable lignin and other extractable components from kraft black liquor.

Abstract: A method and apparatus are provided for the treatment of comminuted cellulosic fibrous material to effect prehydrolysis, and then subsequently kraft digestion, thereof, to produce paper pulp. The material is steamed, entrained in liquid to form a suspension, and transferred by a high pressure feeder in a first circulation loop to the top of a first vertical vessel. At the top of the vessel, a liquid/solids separator is provided, and the liquid withdrawn from the top of the first vessel into the return conduit of the first circulation loop includes recoverable hydrolysate (which contains hemicellulose, sugars, and the like). In the first vessel, countercurrent acid hydrolysis takes place in the top of the vessel, and a countercurrent wash is effected in the bottom of the vessel. A part of the liquid in the return conduit of the first circulatory loop is diverted to one or more flash tanks, to produce steam and a liquid with a high concentration of hydrolysate.

Abstract: The present invention provides a method for the recovery of a wood preservative chemical from aqueous waste sludges containing said wood preservative chemical in both its liquid and solid phases. The method comprises treating said aqueous waste sludges to effect an initial separation and recovery of the liquid and solid phases, individually. The recovered liquid phase comprises the first liquid phase product stream. The recovered solid phase then is subjected to elevated temperatures sufficient to liquefy the solid phase, said liquefied solid phase comprising the second liquid phase product stream. During the liquefaction of the recovered solid phase, it may be contacted with a quantity of a fresh wood preservative chemical, a portion of a dehydrated first liquid phase product stream or a portion of a dehydrated second liquid phase product stream to prevent the precipitation of any normally solid constituents therein and to enhance the liquefaction of said recovered solid phase.

Abstract: Deicing chemicals intended primarily for decing pavement such as roads, bridges, and runways are prepared from polysaccharide sources (e.g., waste products such as sawdust) by reaction at a pressure of less than 600 psi and a temperature less than 200.degree. C. with a treating agent comprising alkali metal carbonates or bicarbonates or a mixture thereof and excess oxygen in the presence of water followed by the removal of oxalate and the treating agent. The reaction produces a liquid or a liquid/solid reaction product wherein the liquid contains the deicing chemical and the solid comprises a valuable pulp by-product. Calcium oxide or calcium hydroxide may be added to reduce the pressure resulting from the formation of large amounts of carbon dioxide during the reaction process and to aid in the removal of any oxalic acid formed during the reaction process.

Abstract: Microcrystalline cellulose has many applications in the pharmaceutical, food, paper and structural composite industries. Level off DP (Degree of Polymerization) microcrystalline cellulose is made up of a chain of about 250 glucose molecules in the form of microcrystal. In nature, several microcrystals are hinged together and surrounded by amorphous cellulose to form a cellulose microfibril. If the amorphous cellulose is removed, the resultant product is called level off DP (Degree of Polymerization) microcrystalline cellulose. When lignocellulosic material is processed according to applicant's earlier processes (Canadian Pat. Nos. 1,096,374 and 1,141,376), the dissociated material is partitioned by removing the lignin and the xylan leaving a low DP (320) cellulose fraction.

Abstract: Sulfite spent liquor is subjected to a two-step chromatographic separation to form substantially purified fractions of sugars and lignosulfonates. The process for the separation of sugars and lignosulfonates comprises the steps of(a) introducing sulfite spent liquor with a pH of 2.5 to 3.5 onto a chromatographic column containing a resin in metal salt form;(b) eluting the sulfite spent liquor from the column with water to recover a substantially sugar-free lignosulfonate-rich fraction and a sugar-rich fraction;(c) collecting the sugar-rich fraction for further purification;(d) adjusting the pH of the collected sugar-rich material to between 5.5 and 6.5 and introducing the material onto a second chromatographic column containing a resin in monovalent salt form; and(e) eluting the sugar-rich material from the second column with water, whereby a second sugar-rich fraction and a second lignosulfonate-rich fraction are formed.

Abstract: A process for producing peracids from lactic acid-containing solutions derived from biomass processing systems comprising: adjusting the pH of the solution to about 8-9 and removing alkaline residue fractions therefrom to form a solution comprised substantially of lower aliphatic hydroxy acids; oxidizing the solution to produce volatile lower aliphatic aldehydes; removing said aldehydes as they are generated; and converting said aldehydes to peracids.

Abstract: A method of treating biomass having fermentable material is provided utilizing acid hydrolysis in a countercurrent diffusion treatment structure. By practicing the invention acid usage is minimized, pentose concentration in the hydrolysate solution is maximized, and ethanol, butanol, butanediol, and the alcohols can be produced without the input of any external energy whatsoever into the production method. Biomass is particlized and slurried, and then is continuously subjected to acid hydrolysis at temperature, acid concentration, and residence time conditions sufficient to effect hydrolysis of the hemicellulose in the biomass to effect separation of pentose and hexose sugars into a hydrolysate having insufficient furfural to substantially inhibit fermentation microorganism growth, while not substantially hydrolyzing the cellulose in the biomass.

Abstract: High yield pulping is achieved by cooking a lignocellulosic material in a confined chamber in the absence of added oxygen at elevated temperatures up to 240.degree. C. with an initially neutral or acidic mixture of alcohol and water in volume ratio between 50:50 and virtually anhydrous alcohol cooking liquor, using a lower aliphatic alcohol namely methanol, ethanol or n-propanol, carrying in solution at least about 0.002 moles per liter of a magnesium, calcium or barium salt as a primary catalyst soluble in at least catalytic amounts in the mixture to form barium, calcium and magnesium ions. The cooking time may range from at least two (2) minutes to under three (3) hours. The process yields bright, free-fiber pulp even at residual lignin of 80 Kappa number as high as 80% of softwood and up to 75% of hardwood weight, of viscosity (TAPPI 0.5% Cu En) above 18 up to 60 centipoise. Addition of trace amounts of an acidic compound as a secondary catalyst increases the rate of delignification.

Abstract: An aliphatic organic acid fraction is separated from the kraft black liquor by subjecting the liquor to ultrafiltration, treating the resulting permeate by electrodialysis, acidifying the resultant deionate to about pH 4-5, separating the lignin solids which precipitate following this acidification, raising the pH of the separated solution to about 7-8 and finally subjecting the neutralized solution to electrodialytic water-splitting.

Abstract: A formulation for the reduction of amine and ammonia odors of organic waste material comprising spent sulfite liquor containing substantially undegraded lignosulfonates and sugars, to which is added from 1 to 15%, by weight of the total solids content, of acetic acid and from 0.5 to 10 grams, per liter of formulation, of phenolic carbonyl compounds, the formulation having a pH of from 6.5 to 8.0 and preferably having being stripped of dissolved SO.sub.2.

Abstract: A method and apparatus for continuously producing pulp from previously unusable agricultural fibers, such as plantain. The pulp is used in papermaking. The pulp effluent is recycled and concentrated during the process, thereby enabling economical recovery of chemical by-products for use as fertilizer or animal feed material.

Abstract: A portion of the spent cooking liquor from a pulping process is diverted from the washing step directly to the machine chest of a paper machine for pre-sizing the paper made on the paper machine. The preferred pulping process is an unbleached kraft or sulfate process and the preferred raw material for the pulping process is pine or softwood chips. Moreover, the preferred point in the washing step for diverting the black liquor is near or at the final washing stage.

Abstract: A method for cultivating, under alkaline conditions, microorganisms in a culture medium containing, as a carbon source, the extracted liquor or spent liquor derived from alkaline pulping is presented. In this cultivation, organic acids contained in the extracted liquor or spent liquor can be effectively utilized. Typical microorganisms cultured are bacteria belonging to the genera Bacillus, Arthrobacter, Corynebacterium and Brevibacterium.

Abstract: A method for delignifying ligno-cellulosic materials and efficiently separate from each other the constituents thereof. Said materials are heated in an aqueous acid medium in the presence of phenol compounds. Then the reaction medium is drained and washed for isolating the purified solid cellulose pulp, the liquid phase separating into two layers: an aqueous layer rich with pentoses and an organic layer rich with phenols and lignin, the latter providing, by distillation and pyrolysis of the residue, a quantity of phenols at least equal to that of the phenols used in the delignification stage.

Abstract: A method for recovery of wastewater residues containing the activated sludge biomass, fibre and bark comprising the steps of treating these with alkali solution having a concentration of 5-80 g/l on the Na.sub.2 O basis at a temperature of 20.degree.-70.degree. C. and dewatering the reaction mixture obtained, the alkali filtrate decanted containing the activated sludge alkali hydrolysis products being used to dissolve the melt in the course of preparing the alkali pulping liquor, and the dewatered alkali mass being added, in an amount of up to 40 percent by mass, to the fibred mass composition for the manufacture of cardboard and wood-fibre board.

Abstract: The present invention relates to a kraft overload recovery process for the treatment of kraft black liquor (b.l.) which comprises acidifying the b.l. with an acid comprising sulfuric acid, separating the lignin therefrom, and further treating the residual b.l. for recovery of inorganics contained therein for use as a source of cooking chemical in kraft cooks.

Abstract: Comminuted cellulosic materials which may or may not contain lignin are partially or totally hydrolyzed or saccharified by an improved organosolv process using an aqueous acetone solvent mixture containing a small amount of an acidic compound and containing at least about 70 percent by volume of acetone and up to virtually anhydrous acetone. The process is performed at elevated reaction temperatures, preferably at 145.degree. C. to 230.degree. C., for a limited period of time and then with cooling such that the resultant dissolved sugars from the hydrolysis are not degraded into non-sugars. In particular the reaction is conducted such that the cellulosic material is dissolved and such that at least ninety percent or more of available sugars in the cellulosic material are recovered. Unexpectedly it has been found that acetone at high concentration forms stable complexes with the sugars which prevents their degradation and also facilitates separation of the sugars.

Abstract: A method of recovering or extracting chemicals, such as furfural, formic acid, acetic acid and other organic compounds from acidic hydrolysates of plants or vegetable matter, especially spent sulfite liquors after conversion of the pentosans into pentoses and then into furfural by heating the hydrolysate in an acidic environment. The conversion of the pentosans pentoses into furfural, preferably with acidulation, is accomplished in a counterflow or countercurrent flow heat exchanger and a reactor, preferably a tubular reactor. The hydrolysate which has additionally been heated and converted in the reactor is used as a heating medium or heat carrier for heating up the hydrolysate which is converted in the counterflow heat exchanger, whereupon there is recovered as the distillate furfural in conjunction with the formic acid, acetic acid and the like.

Abstract: A method of cooking cellulose material and effectively preserving the heat and terpentine content of the cooking liquor is disclosed. The cooking liquor is allowed to expand and the expansion steam (blow steam) is conveyed into a bed of cellulose material in a storage container (3', 3) to heat and impregnate the cellulose material before cooking. A heated zone is maintained in the bed of material below the surface of the bed by regulating the flow of expansion steam into the container. Uncondensed, evil-smelling and poisonous gases are at the same time prevented from flowing out into the atmosphere. These gases are drawn off from the storage container for destruction.

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: A method for washing of crude tall oil soap obtained from the sulfate pulping process using alkalized spent acid from tall oil acidulation as washing liquid by mixing the crude soap and the washing liquid coming from the process and by cooling the mixture in a separation tank by either stirring with a slowly moving agitator or by circulating the soap or soap mixture through a pump and a cooler.

Abstract: Tall oil containing anthraquinone is fractionally distilled for producing the tall oil heads cut enriched in said anthraquinone.

Abstract: A pulp mill bleach plant operation having a low effluent volume, a low consumption of water, energy and chemicals, and yet provides efficient bleaching, caustic extraction and washing is described. Water conservation is practised by controlling the use of wash water in the bleach plant, controlling the design and operation of washers, deckers and other mechanical devices used in the bleach plant and controlling the inflow of water with chemicals. An aqueous polluting effluent-free pulp mill water utilization system is also described.

Abstract: Chemicals produced during pulping operations are recovered and separated by passing chemical-containing liquors from said operations through one or more units containing activated carbon. The chemicals are recovered from said units by introducing a solvent into said unit and separating the materials removed therefrom in a fractionating column.

Abstract: Volatile organic components are removed from the effluent liquor of an acid sulfite digestion process by concentrating the effluent liquor in multiple stages to form an organic-rich aqueous fraction, an organic-lean aqueous fraction and a high solids content fraction, continuously withdrawing the organic-lean and high solids content fraction from the recovery process, continuously recycling the organic-rich fraction to the digestion step to form a closed loop which acts to build up the concentration of volatile organic components, and continuously separating and withdrawing from the closed loop the bulk of the volatile organic components in a stream more concentrated than that of the closed loop.

Abstract: A free-radical prepolymer, disclosed in U.S. Pat. No. 3,873,417 as being a dispersant, when added at 10 to 500 parts per million to a reaction mixture in which raw tall oil soap is acidulated to obtain tall oil, is found to act as a separating agent and increase the quantity of tall oil recovered.

Abstract: A method for the recovery of sulphur compounds, volatile alcohols such as methanol, as well as by-products such as turpentine and the like, which are formed in connection with pulping, from the blow-expansion condensates from the evaporating series of a digestery, from turpentine mother liquors, or from other liquids in a separate treatment unit. The liquids are treated in a vacuum stripping unit by means of a proportion of secondary steam which is obtained from the last step of a multi-stage evaporating plant. The excess of secondary steam is condensed by means of indirect condensation in a first surface condenser, whose exhaust vapors, together with the vapors leaving the stripping unit and with gases that are to be removed from the evaporating steps, are condensed by means of indirect condensation in a second surface condenser.

Abstract: A method of recovering heat as well as fractions containing volatile alcohols and sulphur compounds from black liquor obtained from pulping. In a vapor generator, water is, by means of vapor, liberated at a high temperature and under a high pressure from the expansion of black liquor removed from a digester, indirectly vaporized into low-pressure vapor, which is used for vapor treatment of chips before their introduction into the digester. The condensate produced in the vapor generator is, under pressure control, passed into a condenser device, which is operated at a pressure that is lower than the pressure in the black liquor escaping from the digester, preferably at the atmospheric pressure. The condensate fraction formed in the condenser device as well as the uncondensed gas fraction are cooled by means of indirect cooling and the volatile alcohols and sulphur compounds are recovered from these fractions.

Abstract: Solvent pulping of wood chips or other fibrous plant material is effected using an aqueous solution of a lower aliphatic alcohol in a plurality of batch extraction vessels. The charge in each vessel is heated rapidly to pulping temperature by recirculation of a primary extraction liquor having a relatively high dissolved solids content, and thereafter the charge is subjected to a series of once-through extractions or washes with successively cleaner liquors, including a final extraction or wash with fresh liquor. The extraction liquor from one extraction stage in one vessel is used in another extraction stage in another vessel. Upon completion of the extraction, the liquor is drained from the vessel, the vessel is depressurized to a solvent condenser, and the remaining solvent is steam stripped from the charge and recovered. The used extraction liquor is treated in an alcohol recovery system by flash vaporization, condensation of the solvent vapors, and vacuum stripping of the residual liquor with steam.

Abstract: Color is removed from paper mill waste waters by treatment with a cationic water soluble polyamine having an average molecular weight of at least 300 at a pH of 2 to 5, preferably 2.5 to 3.5, followed by precipitation with a water soluble anionic or non-ionic organic polymer having an average molecular weight of at least 10,000.

Abstract: As a tall-oil-soap skimming aid, there is added to black liquor resulting from the pulping of coniferous trees a terpolymer of (a) an alpha-beta-unsaturated acid, (2) an alkylate of an alpha-beta-unsaturated acid, and (3) allyl alcohol. The acid contains 3 to 4 carbon atoms and comprises about 60 to about 88 percent by weight of the terpolymer. The alkylate comprises about 6 to 28 parts by weight of the terpolymer, being an ester of the abovementioned acids, the ester having an alkyl portion containing 1 to 18 carbon atoms. Allyl-alcohol units are present in the terpolymer to an extent of 4.5 to 20 weight percent. The terpolymer can be produced by free-radical polymerization in accordance with the customary procedures. With the use of such a copolymer, the proportion of tall oil recovered from black liquor is very substantially increased.