CA1136808A - Dispersion for use in pulp production - Google Patents
Dispersion for use in pulp productionInfo
- Publication number
- CA1136808A CA1136808A CA000325807A CA325807A CA1136808A CA 1136808 A CA1136808 A CA 1136808A CA 000325807 A CA000325807 A CA 000325807A CA 325807 A CA325807 A CA 325807A CA 1136808 A CA1136808 A CA 1136808A
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- CA
- Canada
- Prior art keywords
- dispersion
- dispersion according
- sodium
- solution
- organic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/22—Other features of pulping processes
- D21C3/222—Use of compounds accelerating the pulping processes
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- Paper (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
Abstract of the Disclosure The invention provides dispersions for use in pulp production which dispersion contains organic, cyclic compounds containing keto groups and/or hydroxyl groups, and a liquid dispersing agent having a specific density which is the same as or similar to that of said organic, cyclic compounds containing keto groups and/or hydroxyl groups. Also included in the invention are pro-cesses for pulp production using the dispersions of the invention.
Description
l~ki~
It is described (see, for example, B.Bach and G.Fiehn, Zellstoff und Papier 21, 3 (1972); H.H. Holton, Pulp and Paper Canada 78, 19 (1977); u.s. Patent Specifica-tion 4, 012,280; U.S. Patent Specification 4, 036, 680; U.S.
Patent Specification 4,036,681, Canadian Patent Specifica-tion 986,662, Japanese Laid-Open Specification 112,903/75, Japanese Laid-Open Specification 43,403/?6, Japanese Laid-Open Specification 109,303/76 and German Democratic Republic Patent Specification 98,549) tha~ anthraquinone, certain anthraquinone derivatives and certain diketohydroanthracenes exert a favourable effect in certain processes for the production and bleaching of pulp from lignocellulose materials, such as wood, straw and bagasse, when from 0.001 to lQ% by weight of them, relative to the lignocellulose material, is employed. In addition to anthraquinone, anthrahydroquinone and Diels-Alder adducts of butadiene and its derivatives with p-benzoquinone or 1,4-naphthoquinone, the mono- and poly-alkyl, -alkoxy, -amino, -hydroxyl and/or -sulpho derivatives of these compounds are recommended for this. In the following text, these substances are collectively designated additives.
In general, the additives are accessible in the form of powders. However, the incorporation of pulverulent additives of this type into processes for the production of pulps from lignocellulose materials and for the bleaching thereof presents problems. If the pulverulent additives are added to the lignocellulose material to be employed, it must be expecteds in this case, that the finer constituents of the additives pass into the environment in the form of a dust and are thus partly withdrawn from the intended use, are troublesome to people working near the place of addition and can give rise to the danger of dust explosions. In addition, uniform distribution is difficult with the rela-tively small amount of additives required. However, uniform distribution of the additives is desirable in order to achieve uniform quality of the pulp.
Uniform distribution of the additives is also made difficult by the fact that the additives are generally only Le A 18 801 ' ~
113~
very slightly soluble in water and in the aqueous elec-trolyte solutions used in pulp production Ifor example, only 6.10 4 g of 9,10-anthraquinone dissolves in 1 litre of water at 50C).
Furthermore, the additives are so poorly wetted by water and aqueous electrolyte solutions, such as are used in pulp production, that the finer constituents of the pulverulent additives cannot be stirred in, or can only be stirred in to a poor extent, but float non-wetted on the surface, air sometimes being included. Moreover, the additives have a relatively high specific density (for example anthraquinone has a specific density of 1.438 g/cm at 20C), so that the coarser constituents of the pulverulent additives, which can be stirred into water or an electrolyte solution, rapidly settle again and, after standing for a short time, form on the floor of the vessel a compact layer which can be stirred up again only with difficulty. The addition of the additives directly to the cooking liquor, to the mixture of lignocellulose material and cooking liquor or in the form of a slurry in water or dilute electrolyte solutions is thus also no way of achieving with certainty a uniform distribution of the additives.
A dispersion has now been found for use in pulp pro-duction, which is characterised in that it contains an art recog-nized pulp additive selected from organic, cyclic compounds con-taining keto and/or hydroxyl groups, and a liquid dispersing agent having a specific density which is the same as or similar to said organic, cyclic compound.
1~3~
Elere and in the fol]owing text, the expression pulp production is understood as all processes and process staqes in which the lignin in lignin-containing and cellulose-containing materials is acted upon in a chemical manner. Examples of these processes are alkaline, neutral and acid pulping processes with lignocellulose materials, such as wood, straw, bagasse and grasses, and bleaching processes with partially or sub-stantially pulped - 3a -i li~nocellulose materials.
Examples of possible organic, cyclic compounds con~
taining keto groups and/or hydroxyl groups are preferably carbocyclic aromatic compounds which are monocyclic, dicyclic and/or polycyclic, in particular monocyclic, di-cyclic and/or tricyclic, and particularly preferably tri-cyclic, especially condensed ring tricyclic compounds which contain two keto groups and/or two hydroxyl groups and are preferably hydrocarbons except for the keto or hydroxy groups but can be further substituted. Compounds which can be used here are, preferably, ?-benzoquinone, l,4-naphthoquinone, 9,lO-anthraquinone and/or Diels-Alder adducts of l,3-dienes, for example of unsubstituted or substituted butadiene, with p-benzoquinone and/or l,4-naphthoquinone, and/cr mono- and poly-alkyl, -hydrcxyl, -amino, -alkoxy, -alkylamino and/or sulpho derivatives thereof. The alkyl, alkoxy and alkylamino moieties can each contain, for example~1 to 12 carbon atoms, preferably l to 4 carbon atoms. For example, the dispersions according to the invention can contain 9,lO-anthraquinone, 2-methyl-anthraquinone, 2-ethylanthraquinone, 2,3-dimethyl-9,lO-anthraquinone, 2,6-dimethylanthraquinone, 2,7-dimethylanthraquinone, 2-aminoanthraquinone, l-methoxy-anthraquinone, l,4 9 4a,9a-tetrahydro-9,lO-diketoanthracene,
It is described (see, for example, B.Bach and G.Fiehn, Zellstoff und Papier 21, 3 (1972); H.H. Holton, Pulp and Paper Canada 78, 19 (1977); u.s. Patent Specifica-tion 4, 012,280; U.S. Patent Specification 4, 036, 680; U.S.
Patent Specification 4,036,681, Canadian Patent Specifica-tion 986,662, Japanese Laid-Open Specification 112,903/75, Japanese Laid-Open Specification 43,403/?6, Japanese Laid-Open Specification 109,303/76 and German Democratic Republic Patent Specification 98,549) tha~ anthraquinone, certain anthraquinone derivatives and certain diketohydroanthracenes exert a favourable effect in certain processes for the production and bleaching of pulp from lignocellulose materials, such as wood, straw and bagasse, when from 0.001 to lQ% by weight of them, relative to the lignocellulose material, is employed. In addition to anthraquinone, anthrahydroquinone and Diels-Alder adducts of butadiene and its derivatives with p-benzoquinone or 1,4-naphthoquinone, the mono- and poly-alkyl, -alkoxy, -amino, -hydroxyl and/or -sulpho derivatives of these compounds are recommended for this. In the following text, these substances are collectively designated additives.
In general, the additives are accessible in the form of powders. However, the incorporation of pulverulent additives of this type into processes for the production of pulps from lignocellulose materials and for the bleaching thereof presents problems. If the pulverulent additives are added to the lignocellulose material to be employed, it must be expecteds in this case, that the finer constituents of the additives pass into the environment in the form of a dust and are thus partly withdrawn from the intended use, are troublesome to people working near the place of addition and can give rise to the danger of dust explosions. In addition, uniform distribution is difficult with the rela-tively small amount of additives required. However, uniform distribution of the additives is desirable in order to achieve uniform quality of the pulp.
Uniform distribution of the additives is also made difficult by the fact that the additives are generally only Le A 18 801 ' ~
113~
very slightly soluble in water and in the aqueous elec-trolyte solutions used in pulp production Ifor example, only 6.10 4 g of 9,10-anthraquinone dissolves in 1 litre of water at 50C).
Furthermore, the additives are so poorly wetted by water and aqueous electrolyte solutions, such as are used in pulp production, that the finer constituents of the pulverulent additives cannot be stirred in, or can only be stirred in to a poor extent, but float non-wetted on the surface, air sometimes being included. Moreover, the additives have a relatively high specific density (for example anthraquinone has a specific density of 1.438 g/cm at 20C), so that the coarser constituents of the pulverulent additives, which can be stirred into water or an electrolyte solution, rapidly settle again and, after standing for a short time, form on the floor of the vessel a compact layer which can be stirred up again only with difficulty. The addition of the additives directly to the cooking liquor, to the mixture of lignocellulose material and cooking liquor or in the form of a slurry in water or dilute electrolyte solutions is thus also no way of achieving with certainty a uniform distribution of the additives.
A dispersion has now been found for use in pulp pro-duction, which is characterised in that it contains an art recog-nized pulp additive selected from organic, cyclic compounds con-taining keto and/or hydroxyl groups, and a liquid dispersing agent having a specific density which is the same as or similar to said organic, cyclic compound.
1~3~
Elere and in the fol]owing text, the expression pulp production is understood as all processes and process staqes in which the lignin in lignin-containing and cellulose-containing materials is acted upon in a chemical manner. Examples of these processes are alkaline, neutral and acid pulping processes with lignocellulose materials, such as wood, straw, bagasse and grasses, and bleaching processes with partially or sub-stantially pulped - 3a -i li~nocellulose materials.
Examples of possible organic, cyclic compounds con~
taining keto groups and/or hydroxyl groups are preferably carbocyclic aromatic compounds which are monocyclic, dicyclic and/or polycyclic, in particular monocyclic, di-cyclic and/or tricyclic, and particularly preferably tri-cyclic, especially condensed ring tricyclic compounds which contain two keto groups and/or two hydroxyl groups and are preferably hydrocarbons except for the keto or hydroxy groups but can be further substituted. Compounds which can be used here are, preferably, ?-benzoquinone, l,4-naphthoquinone, 9,lO-anthraquinone and/or Diels-Alder adducts of l,3-dienes, for example of unsubstituted or substituted butadiene, with p-benzoquinone and/or l,4-naphthoquinone, and/cr mono- and poly-alkyl, -hydrcxyl, -amino, -alkoxy, -alkylamino and/or sulpho derivatives thereof. The alkyl, alkoxy and alkylamino moieties can each contain, for example~1 to 12 carbon atoms, preferably l to 4 carbon atoms. For example, the dispersions according to the invention can contain 9,lO-anthraquinone, 2-methyl-anthraquinone, 2-ethylanthraquinone, 2,3-dimethyl-9,lO-anthraquinone, 2,6-dimethylanthraquinone, 2,7-dimethylanthraquinone, 2-aminoanthraquinone, l-methoxy-anthraquinone, l,4 9 4a,9a-tetrahydro-9,lO-diketoanthracene,
2-ethyl-1,4,4a~9a-Tetrahydro-9,lO-diketoanthracene, 2,3-dimethyl-l,4,4a,9a-tetrahydro-9,lO-diketoanthracene, l,4,4a,5,8,8a,9a 9 lOa-octahydro-9,lO-diketoanthracene, l,3-dimethyl-l,4,4a,9a-tetrahydro-9,lO-diketoanthracene and 2,3,6,7-tetramethyl-1,4,4a,5,8,8a,9a,10a-octahydro-9,lO-di-ketoanthracene. Specifically included as compounds which can be used are the above named compounds in reduced form containing hydroxy instead of keto groups. Such as for example hy~roquinone and anthrahydroquinone. The dispersions according to the inven-tion can contain two or more of these substances, in par-ticular two or more of these substances which have specific densities which are close to one another. It is also possible to employ compounds which carry two or more of the substituents ~entioned, for example hydroxyl groups and amino groups. However, the dispersion accord-Le A 18 801 ~ ~ 3 ing to the invention preferably contains only one of thesesubstances~ very particularly preferably 9,10-anthraquin-one. In the following text, the organic, cyclic com-pounds containing keto groups and/or hydroxyl groups are designated as "dispersed substances".
The dispersed substances, in particular 9,10-anthraquinone, can be present in the most diverse particle sizes. For example, the dispersed substances, in particular monocyclic, dicyclic and/or polycyclic com-pounds containlng keto groups and/or Hydroxyl groups,especially 9,lO~anthraquinone, can consist to the extent o~
at least 80% by weight of particles with particle sizes in the range from 1 ~m to 5 mm. The dispersed substances, in particular anthraquinone, can also have particle sizes in the range from about 50 to 500 ~m, with the highest fre quency of particles in the range from about 200 to 300 ~m.
The particle size distribution has no particular influence.
me particle size distribution can lie relatively closely around a mean value, but it can also extend over the entire aboYementioned ranges and beyond. With regard to the use of 9,10-anthraquinone, this has the advantage that anthraquinone can be introduced into the dispersion accord-ing to the invention in the form in which it is generally obtained in the industrial preparation.
Liquids which have a specific density which is the same as or similar to the dispersed substance or the dis-persed substances are suitable dispersing agents for the dispersion according to the invention. Liquids are understood here as pure liquid substances, solutions and dispersions. m e dispersing agent can be, for example, an aqueous solution of electrolytes which has a specific density in the range from 1.2 to 1.6 g/cm3. In the case where 9,10-anthraquinone is the dispersed substance, the specific density of the dispersing agent is preferably 1.35 to 1.5 g/cm3, particularly preferably 1.4 to 1.45 g/cm~.
Le A 18 8cl 113~i~0 The aqueous solution of electrolytes can be, for example, a solution of oxides, hydroxides and/or salts of the metals of the first and/or second main group of the periodic system, andlor a solution of nitrogen bases and/or of salts of nitrogen bases or a solution of acids. The first and second main groups of the periodic table are those given as group Ia and group IIa in, for example, the end sheets of Cotton & Wil~inson "Advanced Inorganic Chemistry", second edition. Which of these electrolytes dissolve in water in amounts such that solutions of the desired specific density are formed can be easily determined by simple preliminary e.Yperiments or by reference to corres-ponding tables.
m e aqueous solution is preferably a solution of oxides, hydroxides, sulphides, sulphites, bisulphites, sulphates, thiosulphates and/or carbonates of sodium, potassium, calcium and/or magnesium. Examples of nitrogen bases are alkylamines, hydroxy-alkylamines or alkylene dia-mines having preferably up to 12 carbon atoms such as ethylene diamine 9 propylamine and/or ethanolamine, examples of salts of nitrogen bases are ammonium salts such as acid-addition salts or quaternary salts and examples for acids are sulfuric acid, phosphoric acid and nitric acid. The aqueous solution is particularly preferably a solution of sodium hydroxide, sodi~ sulphide, sodium sulphite, sodium bisul-phite, sodium sulphate, sodium thiosulphate~ sodium car-bonate, potassium sulphide9 magnesium bisulphite, calcium bisulphite and/or ammonium sulphite or sulphonic acid~ A
solution of sodium hydroxide, sodium bisulphite and/or sodium thiosulphate is especially preferred as the aqueous solution.
It is not necessary to restrict the electrolyte to a single one of the electrolytes indicated. Rather, solutions or suspensions o~ mixtures of the electrolytes listed can also be used. It is advantageous to use those aqueous solu-tions of electrolytes such as can be removed at variouspoints in the installations for pulp production. Elec-r ~--Le A 18 801 . .
trolyte solutions which are removed from various points inthe installation for pulp production can appropriately be used as dispersing agents, after concentration, for example by evaporating off water, or after adding further amounts of electrolytes. For example, the so-Galled white liquors, cooking liquors, black liquors, thick liquors and/or green liquors can be used as dispersing agents, if appropriate after accordingly adjusting the den-sity by evaporating off water or adding further amounts of electrolyte.
Here and in the following text, by these terms there are understood the following solutions:
"Cooking liquor"is defined as solutions which are combined with the lignocellulose material before the pulp-ing. meir composition, with respect to the natureand concentration of the constituents, can vary within wide limits, depending on the nature of the lignocellulose material to be pulped and on the pulping process applied.
For example, the cooking liquor can contain 8 to 20~ by weight of alkali metal base, expressed as per cent of effective alkali, relative to the weight of the lignoc~llu-lose material, and in addition can usually also contain alkali metal carbonate. However, cooking liquor can also contain, for example, 8 to 15% by weight of alkali metal base, expressed as per cent of effective alkali (TAPPI T-120 S 61) and 5 to 40% by weight of alkali metal sulphide, expressed as per cent sulphidity (TAPPI T-1203 OS-61), relative to lignocellulose material. mis cook-ing liquor usually also containsalkali metal sulphate and alkali metal carbonate, and optionally also sulphur in an amount of l to 5% by weight.
"Black liquors" are defined as the spent cooking liquors separated off from the pulp after the pulping of the lignocellulose material has been carried out. m ese contain, as organic constituents, the concomitant substances of cellulose, which have been rendered soluble, for example Le A 18 ~01 __ lignin-sulphonates and/or alkali-lignins, and appropriately also hemicelluloses and low-molecular conversion products of the constituents of the lignocellulose material, and as inorganic constituents, for example, mainly alkali metal sulphate and alkali metal carbonate, as well as alkali metal base bonded to acid organic constituents, and in addition usually also free alkali metal base, alkali metal sulphide, alkali metal sulphite and alkali metal thiosulphate.
m e specific densities of the black liquors can be, for example, 1.05 to 1.40 g/cm3, depending on the concentration of the dissolved substances. The solids content can vary, for example, within the limits of lO to 70% by weight.
"Thick liquor" is defined as those black liquors which, because of a high solids content of, for example, more than 50% by weight. are highly viscous at room tem-perature. Depending on the pulping process, thick liquors can be obtained immediately by separating off from pulps, or by evaporating black liquors with a low solids content.
"Green liquors" are defined as solutions which con-tain, for example, 5 to 20% by weight of alkali metal car-bonate and, for example, l to 5% by weight of alkali metal sulphide and which are prepared from water and that salt melt which is obtained during combustion of the organic constituents of the thick liquors. Green liquors usually also contain sodium sulphate, sodium sulphite, sodium thiosulphate and sulphur. Green liquor has a specific density, for example, in the range from l.l to l.30 g/cm3.
"White liquors"are defined as the liquors obtained from green liquors by treatment with quicklime. White liquors contain, for example9 80 to 200 g of alkali metal base, lO to 80 g of ~lkali metal sulphide and 20 to 50 g of alkali metal carbonate per litre of solution. They Le A 18 801 ~3~0~
g ~
usually al50 contain alkali metal sulphite, alkali metal sulphate and alkali metal thiosulphate, and optionally also sulphur. Their solids content is, for example, about 10 to 35% by weight. The specific density of the white liquors is, for example, between l.l and l.3 g/cm3.
The concentration of dispersed substances in the dispersion according to the invention can be adjusted as desired within wide limits. Practical limits are given by the need to be able to pump the material in the case of a high content of dispersed substances, and, in the case of a low content of dispersed substances, by the high amount of electrolyte employed in relation to the dispersed sub-stance. me dispersion according to the invention can have, for example, a content of dispersed substances of 5 to 70% by weight, preferably of 30 to 60% by weight.
A particular embodiment of the dispersion according to the invention is characterised in that it additionally contains wetting agents. Possible wetting agents are cationic, anionic or non-ionic wetting agents, preferably those which are obtained as by-products in the processes for pulp production. Examples of these are black liquor, thick liquor and/or the lignin-sulphonates or alkali-lignins obtainable therefrom. Wetting agents can be added in amounts of, for example, O.Ol to 20 per cent, preferably of 0.05 to lO per cent, relative to the weight of the dispersion. m e addition of wetting agents can be ef~ected, for example, by adding the pulverulent wetting agent to the pulve~ulent substance to be dispersed, before the preparation of the dispersion. The wetting agent can also be added in the liquid or solid form to the liquid dispersing agent.
A further particular embodiment of the dispersions according to the invention is characterised in that theyaddi-tionally contain substances which increase the viscosity.
Examples of possible substances which increase the viscosity Le A 18 801
The dispersed substances, in particular 9,10-anthraquinone, can be present in the most diverse particle sizes. For example, the dispersed substances, in particular monocyclic, dicyclic and/or polycyclic com-pounds containlng keto groups and/or Hydroxyl groups,especially 9,lO~anthraquinone, can consist to the extent o~
at least 80% by weight of particles with particle sizes in the range from 1 ~m to 5 mm. The dispersed substances, in particular anthraquinone, can also have particle sizes in the range from about 50 to 500 ~m, with the highest fre quency of particles in the range from about 200 to 300 ~m.
The particle size distribution has no particular influence.
me particle size distribution can lie relatively closely around a mean value, but it can also extend over the entire aboYementioned ranges and beyond. With regard to the use of 9,10-anthraquinone, this has the advantage that anthraquinone can be introduced into the dispersion accord-ing to the invention in the form in which it is generally obtained in the industrial preparation.
Liquids which have a specific density which is the same as or similar to the dispersed substance or the dis-persed substances are suitable dispersing agents for the dispersion according to the invention. Liquids are understood here as pure liquid substances, solutions and dispersions. m e dispersing agent can be, for example, an aqueous solution of electrolytes which has a specific density in the range from 1.2 to 1.6 g/cm3. In the case where 9,10-anthraquinone is the dispersed substance, the specific density of the dispersing agent is preferably 1.35 to 1.5 g/cm3, particularly preferably 1.4 to 1.45 g/cm~.
Le A 18 8cl 113~i~0 The aqueous solution of electrolytes can be, for example, a solution of oxides, hydroxides and/or salts of the metals of the first and/or second main group of the periodic system, andlor a solution of nitrogen bases and/or of salts of nitrogen bases or a solution of acids. The first and second main groups of the periodic table are those given as group Ia and group IIa in, for example, the end sheets of Cotton & Wil~inson "Advanced Inorganic Chemistry", second edition. Which of these electrolytes dissolve in water in amounts such that solutions of the desired specific density are formed can be easily determined by simple preliminary e.Yperiments or by reference to corres-ponding tables.
m e aqueous solution is preferably a solution of oxides, hydroxides, sulphides, sulphites, bisulphites, sulphates, thiosulphates and/or carbonates of sodium, potassium, calcium and/or magnesium. Examples of nitrogen bases are alkylamines, hydroxy-alkylamines or alkylene dia-mines having preferably up to 12 carbon atoms such as ethylene diamine 9 propylamine and/or ethanolamine, examples of salts of nitrogen bases are ammonium salts such as acid-addition salts or quaternary salts and examples for acids are sulfuric acid, phosphoric acid and nitric acid. The aqueous solution is particularly preferably a solution of sodium hydroxide, sodi~ sulphide, sodium sulphite, sodium bisul-phite, sodium sulphate, sodium thiosulphate~ sodium car-bonate, potassium sulphide9 magnesium bisulphite, calcium bisulphite and/or ammonium sulphite or sulphonic acid~ A
solution of sodium hydroxide, sodium bisulphite and/or sodium thiosulphate is especially preferred as the aqueous solution.
It is not necessary to restrict the electrolyte to a single one of the electrolytes indicated. Rather, solutions or suspensions o~ mixtures of the electrolytes listed can also be used. It is advantageous to use those aqueous solu-tions of electrolytes such as can be removed at variouspoints in the installations for pulp production. Elec-r ~--Le A 18 801 . .
trolyte solutions which are removed from various points inthe installation for pulp production can appropriately be used as dispersing agents, after concentration, for example by evaporating off water, or after adding further amounts of electrolytes. For example, the so-Galled white liquors, cooking liquors, black liquors, thick liquors and/or green liquors can be used as dispersing agents, if appropriate after accordingly adjusting the den-sity by evaporating off water or adding further amounts of electrolyte.
Here and in the following text, by these terms there are understood the following solutions:
"Cooking liquor"is defined as solutions which are combined with the lignocellulose material before the pulp-ing. meir composition, with respect to the natureand concentration of the constituents, can vary within wide limits, depending on the nature of the lignocellulose material to be pulped and on the pulping process applied.
For example, the cooking liquor can contain 8 to 20~ by weight of alkali metal base, expressed as per cent of effective alkali, relative to the weight of the lignoc~llu-lose material, and in addition can usually also contain alkali metal carbonate. However, cooking liquor can also contain, for example, 8 to 15% by weight of alkali metal base, expressed as per cent of effective alkali (TAPPI T-120 S 61) and 5 to 40% by weight of alkali metal sulphide, expressed as per cent sulphidity (TAPPI T-1203 OS-61), relative to lignocellulose material. mis cook-ing liquor usually also containsalkali metal sulphate and alkali metal carbonate, and optionally also sulphur in an amount of l to 5% by weight.
"Black liquors" are defined as the spent cooking liquors separated off from the pulp after the pulping of the lignocellulose material has been carried out. m ese contain, as organic constituents, the concomitant substances of cellulose, which have been rendered soluble, for example Le A 18 ~01 __ lignin-sulphonates and/or alkali-lignins, and appropriately also hemicelluloses and low-molecular conversion products of the constituents of the lignocellulose material, and as inorganic constituents, for example, mainly alkali metal sulphate and alkali metal carbonate, as well as alkali metal base bonded to acid organic constituents, and in addition usually also free alkali metal base, alkali metal sulphide, alkali metal sulphite and alkali metal thiosulphate.
m e specific densities of the black liquors can be, for example, 1.05 to 1.40 g/cm3, depending on the concentration of the dissolved substances. The solids content can vary, for example, within the limits of lO to 70% by weight.
"Thick liquor" is defined as those black liquors which, because of a high solids content of, for example, more than 50% by weight. are highly viscous at room tem-perature. Depending on the pulping process, thick liquors can be obtained immediately by separating off from pulps, or by evaporating black liquors with a low solids content.
"Green liquors" are defined as solutions which con-tain, for example, 5 to 20% by weight of alkali metal car-bonate and, for example, l to 5% by weight of alkali metal sulphide and which are prepared from water and that salt melt which is obtained during combustion of the organic constituents of the thick liquors. Green liquors usually also contain sodium sulphate, sodium sulphite, sodium thiosulphate and sulphur. Green liquor has a specific density, for example, in the range from l.l to l.30 g/cm3.
"White liquors"are defined as the liquors obtained from green liquors by treatment with quicklime. White liquors contain, for example9 80 to 200 g of alkali metal base, lO to 80 g of ~lkali metal sulphide and 20 to 50 g of alkali metal carbonate per litre of solution. They Le A 18 801 ~3~0~
g ~
usually al50 contain alkali metal sulphite, alkali metal sulphate and alkali metal thiosulphate, and optionally also sulphur. Their solids content is, for example, about 10 to 35% by weight. The specific density of the white liquors is, for example, between l.l and l.3 g/cm3.
The concentration of dispersed substances in the dispersion according to the invention can be adjusted as desired within wide limits. Practical limits are given by the need to be able to pump the material in the case of a high content of dispersed substances, and, in the case of a low content of dispersed substances, by the high amount of electrolyte employed in relation to the dispersed sub-stance. me dispersion according to the invention can have, for example, a content of dispersed substances of 5 to 70% by weight, preferably of 30 to 60% by weight.
A particular embodiment of the dispersion according to the invention is characterised in that it additionally contains wetting agents. Possible wetting agents are cationic, anionic or non-ionic wetting agents, preferably those which are obtained as by-products in the processes for pulp production. Examples of these are black liquor, thick liquor and/or the lignin-sulphonates or alkali-lignins obtainable therefrom. Wetting agents can be added in amounts of, for example, O.Ol to 20 per cent, preferably of 0.05 to lO per cent, relative to the weight of the dispersion. m e addition of wetting agents can be ef~ected, for example, by adding the pulverulent wetting agent to the pulve~ulent substance to be dispersed, before the preparation of the dispersion. The wetting agent can also be added in the liquid or solid form to the liquid dispersing agent.
A further particular embodiment of the dispersions according to the invention is characterised in that theyaddi-tionally contain substances which increase the viscosity.
Examples of possible substances which increase the viscosity Le A 18 801
3~
are water-soluble polymeric compounds, such as polyvinyl alcohol and/or methylcellulose. Thick liquor can also be used, that is to say black liquor concentrated, for example, to a solids content of 50 to 70%. Pure thick liquor, for example with a solids content of 64%, which is a highly vis-cous mass at 20C, forms, for example at 80C, a stable dis-persion with anthraquinone, in spite of a specific density of only 1.25 g/cm3. The favourable viscosity-increasing ef~ect of the thick liquor is also exerted in the case of mixtures of 60 parts of thick liquor and 40 parts of water or in the case of mixtures of 50 parts of thick liquor and 50 parts of white liquor. Inorganic substances, such as polysilicates, for example pyrogenically obtained silicic acid with a specific surface area of about 380 m2/g, can also be employed as substances which increase the viscosity.
It is usually not particularly advantageous to use inorganic substances which increase the viscosity, since these are not removed by combustion and can become enriched in the pro-cess for pulp production. Polyvinyl alcohol and methyl-cellulose are therefore particularly preferably used assubstances which increase the viscosity. The use of thick liquor or mixtures containing thick liquor with water or electrolyte solutions is also favourable. The dis-persing agent can contain polyvinyl alcohol and/or methyl-cellulose, for example, in amounts of 5 to 20% by weight,and thick liquor in amounts of, for example, 50 to 100% by weight.
The dispersion according to the invention which contains substances which increase the viscosity has the advantage that this dispersion is also stable if the speci-fic density of the dispersing agent deviates markedly from - the specific density of the dispersed substance. An electrolyte solution with a relatively low concentration can therefore be used as the dispersing agent if substances which increase the viscosity are present. For example, dispersions containing 9,10-anthraquinone (specific density Le A 18 801 0~
of anthraquinone at 20C: 1.438 g/cm3) are obtained, in the presence of substances which increase the viscosity, if the dispersing agent has a specific density of about 1.25 g/cm3. Some of the electrolytes for the prepara-tion of the dispersing agent can therefore be saved.
A similar effect to the addition of substances which increase the viscosity is obtained in the dispersions according to the invention if a carrier dispersion is used as the dispersing agent. By the term carrier dispersion there is understood here, and in the follo~ing text, a dis-persing agent which is already present as a dispersion before the addition of the organicy cyclic compounds con-taining keto groups and/or hydro~yl groups. Carrier dis-persions of this type can be obtained, for example, by bringing together thick liquor or black liquor and concen-trated aqueous electrolyte solutions of the type described above or solid electrolytes of the type described above, in particular sodium hydroxide solution or sodium hydroxide.
The use of carrier dispersions has the particular advantage that using waste substances of the process itself and a reduced amount of electrolytes, a dispersion is obtained which can be handled at room temperature without problems.
m e temperature is not a decisive parameter in the preparation, storage and application of the dispersion according to the invention and can be chosen as desired within wide limits. me ambient temperature is to be regarded as a practical lower value and the temperature at which substantial amounts of water evaporate offunder normal pressure, the specific density of the dispersing agent being shifted, is to be regarded as a practical upper value.
If thick liquor is employed as a wetting agent, as a viscosity-increasing substance and/or as a com-ponent for the formation of a carrier dispersion, a working temperature in the ra~ge from 50 to 90C is advisable, since thick liquor solidifies on contact with cold water or cold electrolyte solution and is only gradually dissolved or dis-persed.
- Le A 18 801 ___ ~3~Q~
The dispersion according to the invention can be prepared in various manners. For example, the substance to be dispersed can be stirred into -the prepared dispersing agent. If the dispersing agent is composed of two or more constituents, the sequence of the addition can be chosen freely. me substance to be dispersed can be stirred into the previously prepared dispersing agent, which optionally contains a wetting agent and/or a substance which lncreases the viscosity and/or a carrier suspension.
The substance to be dispersed can also be stirred into the aqueous electrolyte solution, having the same density or a similar density, and a wetting agent and/or a viscosity-increasing substance can be subsequently added. It is also possible to follow a procedure in which the substance to be dispersed is first mixed with a wetting agent in the solid or liquid form, and this mixture is then introduced into an electrolyte solution. Furthermore, the substance to be dispersed can be mixed with the solid electrolyte, for example with solid sodium hydroxide, optionally together with a wetting agent, and water can be added to this mixture, or this mixture can be added to water.
m e substance to be dispersed can also be dispersed in thick liquor and an electrolyte solution canthenbe added, acarrier dispersion being formed.
~ particularly preferred dispersion within the scope of the dispersions according to the invention is charac-terised in that it contains 30 to 60% by weight of 9,lO-anthraquinone, which has, to the extent of at least 80%, a particle size in the range from 50 to 500 ~m, and contains 40 to 70% by weight of an aqueous solution, which contains sodium hydroxide, sodium sulphide, sodium sulphite, sodium thiosulphateS sodium carbonate, magnesium bisulphite, calsium bi-sulphite and/or ammonium ~ulphite or sulfuric acid and has a den-sity in the range from 1.35 to 1.5 g/cm3, and contains 0.05 to ~13g-~0&~
- 13 _ 10% by weight of a wetting agent, and the aqueous solution in the dispersion is optionally replaced, to the extent of 50 to 100% by weight? by thick liquor or by a carrier dis-persion. A very particularly preferred dispersion within the scope of the dispersion according to the invention has the above characteristics, the aqueous solution containing sodium hydroxide, sodium bisulphite and/or sodium thio-sulphate.
m e dispersion according to the invention, in par-ticular the dispersion containing anthraquinone, is used inprocesses for pulp production. In pulp production, the dispersion according to the invention can be fed in before the cooking, but advantageously already before the impreg-nation, in which the lignocellulose material is impregnated withanaqueous solution ofthepulpingchemicals at a tempera-ture of80to100C. m e aqueous solution of the pulping chemicals also serves as a conveying medium for charging the impregnator and/or cooker with lignscellulose material.
me dispersion according to the invention, in particular a dispersion containing anthraquinone, can be metered, by pumping, into the refluxing solution or into the solution charged with chips, or optionally also directly into the impregnator or cooker. The anthraquinone generally thereby dissolves and can thus penetrate in molecular form into the chips during the impregnating process. This has the result that pulps of uniform quality are obtained.
The amount and composition of the dispersion accord-ing to the invention used in pulp production can be chosen so that, for example, 0.01 to 1.0% by weight of the amount of chemicals required for the pulping is added, in the form of the dispersion according to the invention, to the pulping solution. In a process for pulp production with, for example, 99% recycling of the pulping chemicals, this corresponds to 0.01 to 1.0 times the amount of pulping chemicals which must be freshly added to compensate losses.
me dispersion according to the invention, in par-ticular a dispersion containing anthraquinone~ has a number of advantages. Thus, the preparation of these disper-Le A 18 801 3~
sions is simple and can be carried out without special equipment. me dispersion according to the invention can be pumped, that is to say it can be metered, and conveyed through pipelines, with the aid of a pump suitable for pump-ing dispersions, for example a peristaltic pump, an eccen-tric screw pump or a piston pump~ The dispersion accord-ing to the invention is stable for a relatively long time.
It can be stored for at least several days, in general for one or more weeks, during which the dispersed substances do not settle or float to the surface, or settle or float to the surface only to such a slight extent that they can be brought into the dispersed state again by a simple means, for example a slow-speed stirrer. This has the advantage that a relatively large amount of the dispersion can be pre-pared all at once, the metering ofwhichcanthenbeeffected,for example, by a simple measurement of volume or amount.
The preparation of the dispersion according to the invention can be carried out at a different place to the pulp production, for example at the anthraquinone ~anu-facturer's premises. In this case, the finished disper-sion can be made available to the pulp producer. However, the preparation of the dispersion according to theinvention canalso takeplace atthepulpproducer's premisessince, for example, with the exception of the substance to be dispersed, it is possible to use only those substances which can any-way be used in pulp production and/or are obtained thereby.
In this case, only the pure active compound, for example anthraquinone, needs to be transported.
The metering of the dispersion according to the invention is particularly simple. At a given feed capacity of a metering pump, the metering of the dispersed substance into the installation for pulp production can be changed by establishing higher contents of dispersed sub-stance by adding pulverulent substance to be dispersed and establishing lower contents of dispersed substance by adding dispersing agent. Thus, the dispersion according to the invention can be adapted to the operating conditions for pulp production and can be changed, without altering - Le A 18 801 1~L3t~;~0E~
the capacity of the metering pump.
By employing the dispersion according to the inven-tion in processes for pulp production, including the bleaching of pulp, the favourable effects of the presence of organic, cyclic substances containing keto groups and/or hydroxyl groups can be utilised in an optimum manner, with-out disadvantages thereby arising. The organic constitu-ents of the dispersion according to the invention are also burned during the combustion of the effluents from the pro-cess. The inorganic constituents of the dispersionaccording to the invention, in particular the aqueous electrolyte solutions, can be chosen so that no substances which are foreign to the process enter into the particular process for pulp production. Furthermore, the inorganic constituents can be adapted to the various processes for pulp production. No concentration of substances which are foreign to the process can then occur, which is par-ticularly important in the case of modern processes for pulp production, in which the pulping chemicals are re-cycled.
It is to be described as distinctly surprising thatthe dispersion according to the invention completely fulfils the requirements for use in pulp production, including the bleaching of pulp. Stable dispersions are, in fact, usually only obtained if the dispersed particles have a particle size in the order of magnitude of colloid par-ticles. In coarser dispersions, the dispersed particles usually settle sooner or later (see R8mpp, Chemielexikon (R8mpp's Chemical Dictionary), 6th edition, page 6,286 (1966)). Colloid particles can only be obtained in expensive grinding processes. Such grinding processes are not required for the preparation of the dispersion according to the invention.
Furthermore, it was surprising that the dispersion according to the invention can be prepared with dispersing agents which enable the dispersion to be adapted to the particular process for pulp production, since the dispersing agents can be chosen from a wide range. A dispersion Le A 18 801 1~3~ 0 according to the invention can thus be made available for virtually any customary process for pulp production in which no substances which are foreign to the process may be introduced.
Moreover, a process has been found for pulp produc-tion from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, which is characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of one of the dispersions described above. With the exception of the use of the dispersion according to the invention, this process can be carried out in a manner which is in itself known. For example, this process can be carried out by digesting ligno-cellulose materials in a sulphite solution, which can beacid, neutral or alkaline, and adding the dispersion according to the invention to the digestion solution9 before or after adding the lignocellulose material It is also possible to employ the dispersion according to the inven-tion in the known processes for pulp production, which arecalled the Kraft process, soda process and polysulphide pro-cess. Furthermore, the dispersion according to the invention can be employed in the known oxygen/alkali pro-cess for pulp production and/or in the bleaching processes known for pulp production.
The dispersion according to the invention can be employed in the process according to the invention for pulp production and the bleaching of pulp in an amountl for example, such that 0.01 to 1.0~ by weight of the amount of chemicals required in the particular process are added in the form of a dispersion according to the invention.
Preferably, 9,10-anthraquinone is employed in the process according to the invention in the form of one of the dispersions according to the invention. In this case~ it is particularly preferable to use the dispersion designated as particularly preferred within the scope o~ the dis-persions according to the invention.
- The process according to the invention has a number Le A 18 801 1~3~0 of advantages. Thus, for example, it is possible to meter and uni~ormly distribute the organic, cyclic com-pounds containing keto groups and/or hydroxyl groups without difficulties, and as a result thereof, pulps of uniform quality are obtained. Furthermore, it is possible to realise the advantageous effects, determined on a laboratory scale under ideal conditions, of the addition of organic, cyclic compounds, containing keto groups and/or hydroxyl groups, in industrial installations for pulp production.
In the laboratory experiments, for exampl~, the lignocellulose material was agitated in the pulping liquid or bleaching liquid, which facilitated distribution of the additives. In industrial installations for pulp produc-tion, this is the case only to a minor extent, and the dis-tribution of the additives is thus made moredifficultifthey are not employed in the form of the dispersion according to the invention.
Examples Unless otherwise indicated, an anthraquinone such as is obtained in an industrial manufacturing process was e~ployed in the Examples. 80% by weight of this anthra-quinone has a particle size in the range from 100 to 500 ~m.
Example 1 50 g of 9,lO~anthraquinone are introduced into 50 g of a 41% strength aqueous sodium hydroxide solution (specific den-sity 1.44 g/cm3), whilst stirring. The anthraquinone is wetted well, ancl a thickish, pumpable dispersion is obtained, the solids constituent of which floats to the sur-face in the course of a few days as the result of included air bubbles. Homogeneous distribution is achieved by slowly stirring the dispersion.
Example 2 20 g of 9,10-anthraquinone are introduced, whilst stirring, into a mixture of 75 g of 41% strength aqueous sodium hydroxide solution and 5 g of black liquor with a specific density of 1.1 g/cm~ and a solids content of 16.4% by weight. A uniform mobile dispersion results. If, after the dispersion has stood without being agitated for Le A 18 801 0~
-about 24 hours, included air is allowed to escape by careful stirring, the dispersion is stable over a period of weeks.
E~ample ~
5,500 g of 9,10-anthraquinone are stirred into a mixture of 4,000 g of 41% strength aqueous sodium hydroxide solution and 500 g of black liquor corresponding to the black liquor used in Example 2.
The thick, smooth, slightly thixotropic dispersion can be pumped excellent]y and, even over a period of weeks, shows no tendency towards separation.
Example 4 5 g of 9,10-anthraquinone are gradually stirred with a mixture of 90 g of 41% strength aqueous sodium hydroxide solution and 5 g of black liquor corresponding to the black liquor used in Example 2. The solids constituent of the very mobile dispersion obtained neither floats to the surface nor settles.
Example 5 (Comparison Example) 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of water and 5 g of black liquor correspondingto the black liquor used in Example 2. m e anthraquinone is completely wetted and forms a relatively mobile disper-sion, which, however, already begins to separate after a short time. After a few days, the solid has consolidated to form a hard sediment) which can virtually no longer be stirred up.
Example 6 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of 37% strength aqueous sodium hydroxide solution (specific density 1.40 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. The anthraquinone can be readily wetted to give a viscous dis-persion w~ich can be easily metered by means of pumps.
After some days, the anthraquinone has settled loosely on the floor of the vesselO
Example 7 The dispersion prepared from 40 g of 9,10-anthra-quinone, 55 g of 50% strength aqueous odium hydroxide solution Le A 18 801 l~3~.~as - ~9 -~
(specific density 1.53 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2 allows the solid to float to the surface. After 24 hours, the dispersion can still be re-prepared in a simple manner.
After 14 days, however, the solids layer has consolidated to form a thick viscous skin, so that re-preparation of the dispersion is made more difficult. The separation can already be avoided by stirring slowly.
Example 8 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of 41% strength aquesus sodium hydroxide solution and 2 g of thick liquor with a specific density of 1.30 g/cm3 and a solids content of 64% by weight, which was diluted with 3 g of water before combining with the sodium hydroxide solution. m e dispersion, which is stable over a period of several weeks, exhibits no difference to a dispersion of the same concentration, in the preparation of which, how-ever, 5 g of black liquor corresponding to the black ]iquor used in Example 2 were employed as the wetting agent.
a~ 2 100 parts of 9,10-anthraquinone are mixed in a mill, with grinding, with 1 part of isolated dry lignin-sulphonate.
The particle size of the anthraquinone was about 40 to 100 ~m. 50.5 g of this mixture are stirred into 49.5 g of 41% strength aqueous sodium hydroxide solution. A thick dis-persion is obtained which is stable over a period of weeks and can be easily conveyed and metered by means of pumps.
Example 10 18.5 g of sodium hydroxide are added to 50 g of 9,10-anthraquinone and the components are mixed, with grind-ing. Thereafter, the particle size of the anthraquinone was about 40 to 100 ~m. After adding 5 g of black liquor corresponding to the black liquor used in Example 2, and 26.5 g of water, a uniform dispersion, the stability of whiGh is unchanged over a period of weeks, results.
Example 11 20.3 g of sodium hydroxide are added to 50.5 g of the mixture, described in Example 9, of 9,10-anthraquinone Le A 18 801 : ;
~l~3~
and lignin-sulphonate in the ratio 100:1, and the components are mixed, with grinding. The dry powder (anthraquinone content: 70.6%) is stirred with 29.2 g of water to give a 50% strength anthraquinone dispersion. The dispersion is stable over a period of at least 4 weeks.
ExamPle 12 30 g of 9,10-anthraquinone are dispersed in a mixture of 65 g of a 47.5% strength aqueous sodium thiosulphate solu-tion (specific density at 50C: 1044 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. The mobile dispersion shows no tendency at all towards separation of the solid phase from the liquid phase.
Example 13 300 g f Na2S203 . 5 H20 are dissolved in 100 ml of water at 50C to give a 47.5% strength aqueous sodium thiosulphate solution, which has the same density at 50C as 9,10-anthraquinone. 5 g of black liquor corresponding to the black liquor used in Example 2, and then 50 g of 9,10-anthraquinone are added to 45 g of this solution. The dispersion, which is thickish and pumpable at room tempera-ture, is mobile at 80C and remains stable as a dispersion over a period of at least 3 weeks.
Example lL~
120 g of 9,10-anthraquinone are dispersed in a mix-ture of 100.7 g of white liquor, 54.3 g of sodium hydroxide and 15 g of black liquor. The white liquor contained 92.8 g of NaOH, 34.3 g of Na2S and 23.3 g of Na2C03 per litre. This corresponds to an effective alkalinity of 113 g/l and a sulphidity of 27.5%. The white liquor had a specific density of 1.14 g/cm3 at 20C. The black liquor corresponded to the black liquor used in Example 2.
The specific density of the mixture of white liquor and sodium hydroxide is 1.44 g/cm3 at 20C. Relatively little sodium hydroxide is required for the stable mobile dispersion, which becomes reddish-coloured in the course of some hours. (25% more sodium hydroxide is required for the dispersion described in Example 8).
Le A 18 801 1~3~
It is advisable to first add the black liquor and only then the sodium hydroxide to the white liquor, since white liquor and sodium hydroxide otherwise form, in the ratio indicated, a coarsely crystalline precipitate.
Example 15 (Comparison Example) 40 g of 9,10-anthraquinone introduced into 48 g of white liquor corresponding to the white liquor used in Example 14, with the addition of 12 g of black liquor corresponding to the black liquor used in Example 2, form a dispersion in which the anthraquinone rapidly sinks to the ground and forms a compact layer which can only be stirred up with difficulty.
Example 16 40 g of 9,10-anthra~uinone form an almost black dispersion in 54 g of thick liquor~ corresponding to the thick liquor used in Example 8, which has been diluted with 6 g of water. This dispersion is very viscous at room temperature, but can be pumped at 80C.
ExamPle 17 50 g of 9,10-anthraquinone are mixed with 50 g of thick liquor, warmed to 80C, corresponding to the thick liquor used in F~ample 8~ 5 g of water are added to this mixture in order to improve the ease of pumping of the mix-ture. At 80C, the dispersion is stable and can be metered. It is highly viscous at room temperature.
Exam~le 18 40 g of 9,10-anthraquinone are mixed, at 80C, with 48 g of thick liquor with a specific density of 1.25 g/cm3 at 80C and a solids content o~ 64% by weight, and 12 g of saturated sodium carbonate solution. m e specific den-sity of the dispersing agent is 1.34 g/cm3 at 20C.
At 80C the dispersion has a slight tendency to settle. This can be avoided by stirring the dispersion slowly.
~3~oe~
40 g of 9,10-anthraquinone are stirred into a mix-ture of 48 g of thick liquor corresponding to the thick liquor used in Example 8 and 12 g of white liquor corres-Le A 18 801 . ~
~31 3~
ponding to the white liquor used in Example 14. At 80C, the stable dispersion, which can be poorly stirred at room temperature, tends to form a sediment in the course of two weeks, which can be stirred up again. The settling can be avoided by stirring slowly.
Example 20 A stable dispersion which can be easily handled is obtained from 40 g of 9,10-anthraquinone and 60 g of a carrier dispersion prepared from 12 g of black liquor corresponding to the black liquor used in Example 2 and 48 g of a 50% strength aqueous sodium hydroxide solution.
Example 21 50 g of 9,lO~anthraquinone are added to a carrier dispersion which has been prepared from 32.5 g of black liquor corresponding to the black liquor used in Example 2 and 17.5 g of the sodium hydroxide. The disper,sion has a specific density of 1.39 g/cm3 at 20C. The resulting dispersion can be pumped and does not settle.
ExamPle 22 40 g of 9,10-anthraqu~none are stirred into a mixture of 55 g of 56 96 strength aqueous sulfuric acid (specific density 1.46 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. A~ter two months, from the remarcably mobile dispersion the anthraquinone has settled loosely on the ground of the ves~el.
Example 23 The mobile dispersion prepared from 40 g of 9,10-anthraquinone and 60 g of 60 % strength aqueous phosphoric acid (specific density 1.43 g/cm3) remains stable as a dispersion over a period of at least two weeks.
Le A 18 801 .
Le A 18 801
are water-soluble polymeric compounds, such as polyvinyl alcohol and/or methylcellulose. Thick liquor can also be used, that is to say black liquor concentrated, for example, to a solids content of 50 to 70%. Pure thick liquor, for example with a solids content of 64%, which is a highly vis-cous mass at 20C, forms, for example at 80C, a stable dis-persion with anthraquinone, in spite of a specific density of only 1.25 g/cm3. The favourable viscosity-increasing ef~ect of the thick liquor is also exerted in the case of mixtures of 60 parts of thick liquor and 40 parts of water or in the case of mixtures of 50 parts of thick liquor and 50 parts of white liquor. Inorganic substances, such as polysilicates, for example pyrogenically obtained silicic acid with a specific surface area of about 380 m2/g, can also be employed as substances which increase the viscosity.
It is usually not particularly advantageous to use inorganic substances which increase the viscosity, since these are not removed by combustion and can become enriched in the pro-cess for pulp production. Polyvinyl alcohol and methyl-cellulose are therefore particularly preferably used assubstances which increase the viscosity. The use of thick liquor or mixtures containing thick liquor with water or electrolyte solutions is also favourable. The dis-persing agent can contain polyvinyl alcohol and/or methyl-cellulose, for example, in amounts of 5 to 20% by weight,and thick liquor in amounts of, for example, 50 to 100% by weight.
The dispersion according to the invention which contains substances which increase the viscosity has the advantage that this dispersion is also stable if the speci-fic density of the dispersing agent deviates markedly from - the specific density of the dispersed substance. An electrolyte solution with a relatively low concentration can therefore be used as the dispersing agent if substances which increase the viscosity are present. For example, dispersions containing 9,10-anthraquinone (specific density Le A 18 801 0~
of anthraquinone at 20C: 1.438 g/cm3) are obtained, in the presence of substances which increase the viscosity, if the dispersing agent has a specific density of about 1.25 g/cm3. Some of the electrolytes for the prepara-tion of the dispersing agent can therefore be saved.
A similar effect to the addition of substances which increase the viscosity is obtained in the dispersions according to the invention if a carrier dispersion is used as the dispersing agent. By the term carrier dispersion there is understood here, and in the follo~ing text, a dis-persing agent which is already present as a dispersion before the addition of the organicy cyclic compounds con-taining keto groups and/or hydro~yl groups. Carrier dis-persions of this type can be obtained, for example, by bringing together thick liquor or black liquor and concen-trated aqueous electrolyte solutions of the type described above or solid electrolytes of the type described above, in particular sodium hydroxide solution or sodium hydroxide.
The use of carrier dispersions has the particular advantage that using waste substances of the process itself and a reduced amount of electrolytes, a dispersion is obtained which can be handled at room temperature without problems.
m e temperature is not a decisive parameter in the preparation, storage and application of the dispersion according to the invention and can be chosen as desired within wide limits. me ambient temperature is to be regarded as a practical lower value and the temperature at which substantial amounts of water evaporate offunder normal pressure, the specific density of the dispersing agent being shifted, is to be regarded as a practical upper value.
If thick liquor is employed as a wetting agent, as a viscosity-increasing substance and/or as a com-ponent for the formation of a carrier dispersion, a working temperature in the ra~ge from 50 to 90C is advisable, since thick liquor solidifies on contact with cold water or cold electrolyte solution and is only gradually dissolved or dis-persed.
- Le A 18 801 ___ ~3~Q~
The dispersion according to the invention can be prepared in various manners. For example, the substance to be dispersed can be stirred into -the prepared dispersing agent. If the dispersing agent is composed of two or more constituents, the sequence of the addition can be chosen freely. me substance to be dispersed can be stirred into the previously prepared dispersing agent, which optionally contains a wetting agent and/or a substance which lncreases the viscosity and/or a carrier suspension.
The substance to be dispersed can also be stirred into the aqueous electrolyte solution, having the same density or a similar density, and a wetting agent and/or a viscosity-increasing substance can be subsequently added. It is also possible to follow a procedure in which the substance to be dispersed is first mixed with a wetting agent in the solid or liquid form, and this mixture is then introduced into an electrolyte solution. Furthermore, the substance to be dispersed can be mixed with the solid electrolyte, for example with solid sodium hydroxide, optionally together with a wetting agent, and water can be added to this mixture, or this mixture can be added to water.
m e substance to be dispersed can also be dispersed in thick liquor and an electrolyte solution canthenbe added, acarrier dispersion being formed.
~ particularly preferred dispersion within the scope of the dispersions according to the invention is charac-terised in that it contains 30 to 60% by weight of 9,lO-anthraquinone, which has, to the extent of at least 80%, a particle size in the range from 50 to 500 ~m, and contains 40 to 70% by weight of an aqueous solution, which contains sodium hydroxide, sodium sulphide, sodium sulphite, sodium thiosulphateS sodium carbonate, magnesium bisulphite, calsium bi-sulphite and/or ammonium ~ulphite or sulfuric acid and has a den-sity in the range from 1.35 to 1.5 g/cm3, and contains 0.05 to ~13g-~0&~
- 13 _ 10% by weight of a wetting agent, and the aqueous solution in the dispersion is optionally replaced, to the extent of 50 to 100% by weight? by thick liquor or by a carrier dis-persion. A very particularly preferred dispersion within the scope of the dispersion according to the invention has the above characteristics, the aqueous solution containing sodium hydroxide, sodium bisulphite and/or sodium thio-sulphate.
m e dispersion according to the invention, in par-ticular the dispersion containing anthraquinone, is used inprocesses for pulp production. In pulp production, the dispersion according to the invention can be fed in before the cooking, but advantageously already before the impreg-nation, in which the lignocellulose material is impregnated withanaqueous solution ofthepulpingchemicals at a tempera-ture of80to100C. m e aqueous solution of the pulping chemicals also serves as a conveying medium for charging the impregnator and/or cooker with lignscellulose material.
me dispersion according to the invention, in particular a dispersion containing anthraquinone, can be metered, by pumping, into the refluxing solution or into the solution charged with chips, or optionally also directly into the impregnator or cooker. The anthraquinone generally thereby dissolves and can thus penetrate in molecular form into the chips during the impregnating process. This has the result that pulps of uniform quality are obtained.
The amount and composition of the dispersion accord-ing to the invention used in pulp production can be chosen so that, for example, 0.01 to 1.0% by weight of the amount of chemicals required for the pulping is added, in the form of the dispersion according to the invention, to the pulping solution. In a process for pulp production with, for example, 99% recycling of the pulping chemicals, this corresponds to 0.01 to 1.0 times the amount of pulping chemicals which must be freshly added to compensate losses.
me dispersion according to the invention, in par-ticular a dispersion containing anthraquinone~ has a number of advantages. Thus, the preparation of these disper-Le A 18 801 3~
sions is simple and can be carried out without special equipment. me dispersion according to the invention can be pumped, that is to say it can be metered, and conveyed through pipelines, with the aid of a pump suitable for pump-ing dispersions, for example a peristaltic pump, an eccen-tric screw pump or a piston pump~ The dispersion accord-ing to the invention is stable for a relatively long time.
It can be stored for at least several days, in general for one or more weeks, during which the dispersed substances do not settle or float to the surface, or settle or float to the surface only to such a slight extent that they can be brought into the dispersed state again by a simple means, for example a slow-speed stirrer. This has the advantage that a relatively large amount of the dispersion can be pre-pared all at once, the metering ofwhichcanthenbeeffected,for example, by a simple measurement of volume or amount.
The preparation of the dispersion according to the invention can be carried out at a different place to the pulp production, for example at the anthraquinone ~anu-facturer's premises. In this case, the finished disper-sion can be made available to the pulp producer. However, the preparation of the dispersion according to theinvention canalso takeplace atthepulpproducer's premisessince, for example, with the exception of the substance to be dispersed, it is possible to use only those substances which can any-way be used in pulp production and/or are obtained thereby.
In this case, only the pure active compound, for example anthraquinone, needs to be transported.
The metering of the dispersion according to the invention is particularly simple. At a given feed capacity of a metering pump, the metering of the dispersed substance into the installation for pulp production can be changed by establishing higher contents of dispersed sub-stance by adding pulverulent substance to be dispersed and establishing lower contents of dispersed substance by adding dispersing agent. Thus, the dispersion according to the invention can be adapted to the operating conditions for pulp production and can be changed, without altering - Le A 18 801 1~L3t~;~0E~
the capacity of the metering pump.
By employing the dispersion according to the inven-tion in processes for pulp production, including the bleaching of pulp, the favourable effects of the presence of organic, cyclic substances containing keto groups and/or hydroxyl groups can be utilised in an optimum manner, with-out disadvantages thereby arising. The organic constitu-ents of the dispersion according to the invention are also burned during the combustion of the effluents from the pro-cess. The inorganic constituents of the dispersionaccording to the invention, in particular the aqueous electrolyte solutions, can be chosen so that no substances which are foreign to the process enter into the particular process for pulp production. Furthermore, the inorganic constituents can be adapted to the various processes for pulp production. No concentration of substances which are foreign to the process can then occur, which is par-ticularly important in the case of modern processes for pulp production, in which the pulping chemicals are re-cycled.
It is to be described as distinctly surprising thatthe dispersion according to the invention completely fulfils the requirements for use in pulp production, including the bleaching of pulp. Stable dispersions are, in fact, usually only obtained if the dispersed particles have a particle size in the order of magnitude of colloid par-ticles. In coarser dispersions, the dispersed particles usually settle sooner or later (see R8mpp, Chemielexikon (R8mpp's Chemical Dictionary), 6th edition, page 6,286 (1966)). Colloid particles can only be obtained in expensive grinding processes. Such grinding processes are not required for the preparation of the dispersion according to the invention.
Furthermore, it was surprising that the dispersion according to the invention can be prepared with dispersing agents which enable the dispersion to be adapted to the particular process for pulp production, since the dispersing agents can be chosen from a wide range. A dispersion Le A 18 801 1~3~ 0 according to the invention can thus be made available for virtually any customary process for pulp production in which no substances which are foreign to the process may be introduced.
Moreover, a process has been found for pulp produc-tion from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, which is characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of one of the dispersions described above. With the exception of the use of the dispersion according to the invention, this process can be carried out in a manner which is in itself known. For example, this process can be carried out by digesting ligno-cellulose materials in a sulphite solution, which can beacid, neutral or alkaline, and adding the dispersion according to the invention to the digestion solution9 before or after adding the lignocellulose material It is also possible to employ the dispersion according to the inven-tion in the known processes for pulp production, which arecalled the Kraft process, soda process and polysulphide pro-cess. Furthermore, the dispersion according to the invention can be employed in the known oxygen/alkali pro-cess for pulp production and/or in the bleaching processes known for pulp production.
The dispersion according to the invention can be employed in the process according to the invention for pulp production and the bleaching of pulp in an amountl for example, such that 0.01 to 1.0~ by weight of the amount of chemicals required in the particular process are added in the form of a dispersion according to the invention.
Preferably, 9,10-anthraquinone is employed in the process according to the invention in the form of one of the dispersions according to the invention. In this case~ it is particularly preferable to use the dispersion designated as particularly preferred within the scope o~ the dis-persions according to the invention.
- The process according to the invention has a number Le A 18 801 1~3~0 of advantages. Thus, for example, it is possible to meter and uni~ormly distribute the organic, cyclic com-pounds containing keto groups and/or hydroxyl groups without difficulties, and as a result thereof, pulps of uniform quality are obtained. Furthermore, it is possible to realise the advantageous effects, determined on a laboratory scale under ideal conditions, of the addition of organic, cyclic compounds, containing keto groups and/or hydroxyl groups, in industrial installations for pulp production.
In the laboratory experiments, for exampl~, the lignocellulose material was agitated in the pulping liquid or bleaching liquid, which facilitated distribution of the additives. In industrial installations for pulp produc-tion, this is the case only to a minor extent, and the dis-tribution of the additives is thus made moredifficultifthey are not employed in the form of the dispersion according to the invention.
Examples Unless otherwise indicated, an anthraquinone such as is obtained in an industrial manufacturing process was e~ployed in the Examples. 80% by weight of this anthra-quinone has a particle size in the range from 100 to 500 ~m.
Example 1 50 g of 9,lO~anthraquinone are introduced into 50 g of a 41% strength aqueous sodium hydroxide solution (specific den-sity 1.44 g/cm3), whilst stirring. The anthraquinone is wetted well, ancl a thickish, pumpable dispersion is obtained, the solids constituent of which floats to the sur-face in the course of a few days as the result of included air bubbles. Homogeneous distribution is achieved by slowly stirring the dispersion.
Example 2 20 g of 9,10-anthraquinone are introduced, whilst stirring, into a mixture of 75 g of 41% strength aqueous sodium hydroxide solution and 5 g of black liquor with a specific density of 1.1 g/cm~ and a solids content of 16.4% by weight. A uniform mobile dispersion results. If, after the dispersion has stood without being agitated for Le A 18 801 0~
-about 24 hours, included air is allowed to escape by careful stirring, the dispersion is stable over a period of weeks.
E~ample ~
5,500 g of 9,10-anthraquinone are stirred into a mixture of 4,000 g of 41% strength aqueous sodium hydroxide solution and 500 g of black liquor corresponding to the black liquor used in Example 2.
The thick, smooth, slightly thixotropic dispersion can be pumped excellent]y and, even over a period of weeks, shows no tendency towards separation.
Example 4 5 g of 9,10-anthraquinone are gradually stirred with a mixture of 90 g of 41% strength aqueous sodium hydroxide solution and 5 g of black liquor corresponding to the black liquor used in Example 2. The solids constituent of the very mobile dispersion obtained neither floats to the surface nor settles.
Example 5 (Comparison Example) 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of water and 5 g of black liquor correspondingto the black liquor used in Example 2. m e anthraquinone is completely wetted and forms a relatively mobile disper-sion, which, however, already begins to separate after a short time. After a few days, the solid has consolidated to form a hard sediment) which can virtually no longer be stirred up.
Example 6 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of 37% strength aqueous sodium hydroxide solution (specific density 1.40 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. The anthraquinone can be readily wetted to give a viscous dis-persion w~ich can be easily metered by means of pumps.
After some days, the anthraquinone has settled loosely on the floor of the vesselO
Example 7 The dispersion prepared from 40 g of 9,10-anthra-quinone, 55 g of 50% strength aqueous odium hydroxide solution Le A 18 801 l~3~.~as - ~9 -~
(specific density 1.53 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2 allows the solid to float to the surface. After 24 hours, the dispersion can still be re-prepared in a simple manner.
After 14 days, however, the solids layer has consolidated to form a thick viscous skin, so that re-preparation of the dispersion is made more difficult. The separation can already be avoided by stirring slowly.
Example 8 40 g of 9,10-anthraquinone are stirred into a mix-ture of 55 g of 41% strength aquesus sodium hydroxide solution and 2 g of thick liquor with a specific density of 1.30 g/cm3 and a solids content of 64% by weight, which was diluted with 3 g of water before combining with the sodium hydroxide solution. m e dispersion, which is stable over a period of several weeks, exhibits no difference to a dispersion of the same concentration, in the preparation of which, how-ever, 5 g of black liquor corresponding to the black ]iquor used in Example 2 were employed as the wetting agent.
a~ 2 100 parts of 9,10-anthraquinone are mixed in a mill, with grinding, with 1 part of isolated dry lignin-sulphonate.
The particle size of the anthraquinone was about 40 to 100 ~m. 50.5 g of this mixture are stirred into 49.5 g of 41% strength aqueous sodium hydroxide solution. A thick dis-persion is obtained which is stable over a period of weeks and can be easily conveyed and metered by means of pumps.
Example 10 18.5 g of sodium hydroxide are added to 50 g of 9,10-anthraquinone and the components are mixed, with grind-ing. Thereafter, the particle size of the anthraquinone was about 40 to 100 ~m. After adding 5 g of black liquor corresponding to the black liquor used in Example 2, and 26.5 g of water, a uniform dispersion, the stability of whiGh is unchanged over a period of weeks, results.
Example 11 20.3 g of sodium hydroxide are added to 50.5 g of the mixture, described in Example 9, of 9,10-anthraquinone Le A 18 801 : ;
~l~3~
and lignin-sulphonate in the ratio 100:1, and the components are mixed, with grinding. The dry powder (anthraquinone content: 70.6%) is stirred with 29.2 g of water to give a 50% strength anthraquinone dispersion. The dispersion is stable over a period of at least 4 weeks.
ExamPle 12 30 g of 9,10-anthraquinone are dispersed in a mixture of 65 g of a 47.5% strength aqueous sodium thiosulphate solu-tion (specific density at 50C: 1044 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. The mobile dispersion shows no tendency at all towards separation of the solid phase from the liquid phase.
Example 13 300 g f Na2S203 . 5 H20 are dissolved in 100 ml of water at 50C to give a 47.5% strength aqueous sodium thiosulphate solution, which has the same density at 50C as 9,10-anthraquinone. 5 g of black liquor corresponding to the black liquor used in Example 2, and then 50 g of 9,10-anthraquinone are added to 45 g of this solution. The dispersion, which is thickish and pumpable at room tempera-ture, is mobile at 80C and remains stable as a dispersion over a period of at least 3 weeks.
Example lL~
120 g of 9,10-anthraquinone are dispersed in a mix-ture of 100.7 g of white liquor, 54.3 g of sodium hydroxide and 15 g of black liquor. The white liquor contained 92.8 g of NaOH, 34.3 g of Na2S and 23.3 g of Na2C03 per litre. This corresponds to an effective alkalinity of 113 g/l and a sulphidity of 27.5%. The white liquor had a specific density of 1.14 g/cm3 at 20C. The black liquor corresponded to the black liquor used in Example 2.
The specific density of the mixture of white liquor and sodium hydroxide is 1.44 g/cm3 at 20C. Relatively little sodium hydroxide is required for the stable mobile dispersion, which becomes reddish-coloured in the course of some hours. (25% more sodium hydroxide is required for the dispersion described in Example 8).
Le A 18 801 1~3~
It is advisable to first add the black liquor and only then the sodium hydroxide to the white liquor, since white liquor and sodium hydroxide otherwise form, in the ratio indicated, a coarsely crystalline precipitate.
Example 15 (Comparison Example) 40 g of 9,10-anthraquinone introduced into 48 g of white liquor corresponding to the white liquor used in Example 14, with the addition of 12 g of black liquor corresponding to the black liquor used in Example 2, form a dispersion in which the anthraquinone rapidly sinks to the ground and forms a compact layer which can only be stirred up with difficulty.
Example 16 40 g of 9,10-anthra~uinone form an almost black dispersion in 54 g of thick liquor~ corresponding to the thick liquor used in Example 8, which has been diluted with 6 g of water. This dispersion is very viscous at room temperature, but can be pumped at 80C.
ExamPle 17 50 g of 9,10-anthraquinone are mixed with 50 g of thick liquor, warmed to 80C, corresponding to the thick liquor used in F~ample 8~ 5 g of water are added to this mixture in order to improve the ease of pumping of the mix-ture. At 80C, the dispersion is stable and can be metered. It is highly viscous at room temperature.
Exam~le 18 40 g of 9,10-anthraquinone are mixed, at 80C, with 48 g of thick liquor with a specific density of 1.25 g/cm3 at 80C and a solids content o~ 64% by weight, and 12 g of saturated sodium carbonate solution. m e specific den-sity of the dispersing agent is 1.34 g/cm3 at 20C.
At 80C the dispersion has a slight tendency to settle. This can be avoided by stirring the dispersion slowly.
~3~oe~
40 g of 9,10-anthraquinone are stirred into a mix-ture of 48 g of thick liquor corresponding to the thick liquor used in Example 8 and 12 g of white liquor corres-Le A 18 801 . ~
~31 3~
ponding to the white liquor used in Example 14. At 80C, the stable dispersion, which can be poorly stirred at room temperature, tends to form a sediment in the course of two weeks, which can be stirred up again. The settling can be avoided by stirring slowly.
Example 20 A stable dispersion which can be easily handled is obtained from 40 g of 9,10-anthraquinone and 60 g of a carrier dispersion prepared from 12 g of black liquor corresponding to the black liquor used in Example 2 and 48 g of a 50% strength aqueous sodium hydroxide solution.
Example 21 50 g of 9,lO~anthraquinone are added to a carrier dispersion which has been prepared from 32.5 g of black liquor corresponding to the black liquor used in Example 2 and 17.5 g of the sodium hydroxide. The disper,sion has a specific density of 1.39 g/cm3 at 20C. The resulting dispersion can be pumped and does not settle.
ExamPle 22 40 g of 9,10-anthraqu~none are stirred into a mixture of 55 g of 56 96 strength aqueous sulfuric acid (specific density 1.46 g/cm3) and 5 g of black liquor corresponding to the black liquor used in Example 2. A~ter two months, from the remarcably mobile dispersion the anthraquinone has settled loosely on the ground of the ves~el.
Example 23 The mobile dispersion prepared from 40 g of 9,10-anthraquinone and 60 g of 60 % strength aqueous phosphoric acid (specific density 1.43 g/cm3) remains stable as a dispersion over a period of at least two weeks.
Le A 18 801 .
Le A 18 801
Claims (24)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An aqueous dispersion comprising an art reeognized pulp additive selected from organic, cyclic compounds containing keto and/or hydroxyl groups, and a liquid dispersing agent having a specific density which is the same as or similar to that of said organic, cyclic compound.
2. Dispersion according to claim 1, charaeterized in that the pulp additive is at least one compound seleeted from (a) p-benzoquinone, (b) 1,4-naphthoquinone, (c) 9,10-anthraquinone, (d) Diels-Alder adduets of 1,3-dienes with p-benzoquinone and/or 1,4-naphthoquinone, (e) mono- and poly-alkyl, -hydroxyl, -amino, -alkoxy, -alkylamino, and/or sulpho derivatives thereof, and (f) the reduced forms of (a) to (e).
3. Dispersion according to claim l, characterised in that the pulp additive is 9,10-anthraquinone.
4. Dispersion aecording to elaim l, charaeterised in that it eontains an aqueous solution of electrolytes as the liquid dispersing agent, this aqueous electrolyte solution having a density in the range from 1.2 to 1.6 g/em3.
5. Dispersion according to claim 1, 2 or 3, characterised in that at least 80 % by weight of the pulp additive has a particle size in the range from 1 µm to 5 mm.
6. Dispersion according to claim 1, eharaeterised in that the pulp additive is an organie tricyclic compound which contains two keto groups and/or two hydroxyl groups.
7. Dispersion according to claim 1, 2 or 3, characterised in that it contains 5 to 70% by weight of said pulp additive.
8. Dispersion according to claim 4, characterised in that the aqueous solution is a solution of an oxide, hydroxide and/or salt of a metal of the first and/or second main group of the periodic system, and/or a solution of a nitrogen base and/or of a salt of a nitrogen base, or a solution of acids.
9. Dispersion according to claim 4 or 8, characterised in that the aqueous solution is a solution of an oxide, hydroxide, sulphide, sulphite, bisulphite, sulphate, thiosulphate and/or carbonate of sodium, potassium, calcium and/or magnesium.
10. Dispersion according to claim 4 or 8, characterised in that the aqueous solution is a solution of sodium hydroxide, sodium sulphide, sodium sulphite, sodium bisulphite, sodium sulphate, sodium thiosulphate, sodium carbonate, potassium sulphide, magnesium bisulphite, calcium bisulphite and/or ammonium sulphite.
11. Dispersion according to claim 4 or 8, characterised in that the aqueous solution is a solution of sodium hydroxide, sodium bisulphite and/or sodium thiosulphate.
12. Dispersion according to claim 4 or 8, characterised in that the aqueous solution is a solution of sulfuric, phosphoric and/or nitric acid.
13. Dispersion according to claim l, 2 or 3, characterised in that it additionally contains wetting agents.
14. Dispersion according to claim 1, 2 or 3, characterised in that it additionally contains, as a wetting agent, a by-product obtained in pulp production.
15. Dispersion according to claim 1, 2 or 3, characterised in that it additionally contains, as a wetting agent, black liquor, thick liquor and/or the lignin-sulphonates and/or alkali-lignins obtainable therefrom, in amounts of 0.01 to 20%, relative to the weight of the dispersion.
16. Dispersion according to claim 1, 2 or 3, characterised in that it additionally contains a substance which increases the viscosity.
17. Dispersion according to claim 16, characterised in that it additionally contains polyvinyl alcohol, methylcellulose and/or thick liquor as a substance which increase the viscosity.
18. Dispersion according to claim 1, 2 or 3, characterised in that the dispersing agent is already a dispersion.
19. Dispersion according to claim l, 2 or 3, characterised in that the dispersing agent is a dispersion which has been obtained from thick liquor or black liquor, by adding concentrated aqueous electrolyte solutions or by adding solid electrolytes.
20. Dispersion according to claim 1, characterised in that it contains 30 to 60% by weight of 9,10-anthraquinone, which has, to the extent of at least 80%, a particle size in the range from 50 to 500 µm, and contains 40 to 70% by weight of an aqueous solution, which contains sodium hydroxide, sodium sulphide, sodium sulphite, sodium thiosulphate, sodium carbonate, magnesium bisulphite, calcium bisulphite and/or, ammonium sulphite or sulfuric acid and has a density in the range from 1.35 to 1.5 g/cm3, and contains 0.05 to 10% by weight of a wetting agent, and the aqueous solution in the dispersion is optionally replaced, to the extent of 50 to 100% by weight, by thick liquor or by a carrier dispersion.
21. Process for pulp production from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of a dispersion according to claim 1, 2 or 3.
22. Process for pulp production from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of a dispersion according to claim 1, 2 or 3, and further characterised in that 0.01 to 1.0% by weight of the chemicals required for pulp production are employed in the form of a said dispersion.
23. Process for pulp production from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of a dispersion according to claim 20.
24. Process for pulp production from lignocellulose materials in the presence of organic, cyclic compounds containing keto groups and/or hydroxyl groups, characterised in that the organic, cyclic compounds containing keto groups and/or hydroxyl groups are employed in the form of a dispersion according to claim 20, and further characterised in that 0.01 to 1.0% by weight of the chemicals required for pulp production are employed in the form of a said dispersion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2816473.0 | 1978-04-15 | ||
| DE19782816473 DE2816473A1 (en) | 1978-04-15 | 1978-04-15 | DISPERSION FOR USE IN CELL PROCESSING |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136808A true CA1136808A (en) | 1982-12-07 |
Family
ID=6037102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000325807A Expired CA1136808A (en) | 1978-04-15 | 1979-04-12 | Dispersion for use in pulp production |
Country Status (17)
| Country | Link |
|---|---|
| EP (1) | EP0004928B1 (en) |
| JP (1) | JPS54138603A (en) |
| AR (1) | AR220189A1 (en) |
| AT (1) | AT372716B (en) |
| AU (1) | AU4607679A (en) |
| BR (1) | BR7902259A (en) |
| CA (1) | CA1136808A (en) |
| DE (2) | DE2816473A1 (en) |
| ES (1) | ES479476A1 (en) |
| FI (1) | FI64668C (en) |
| IN (1) | IN150690B (en) |
| NO (1) | NO791151L (en) |
| NZ (1) | NZ190182A (en) |
| PH (1) | PH14724A (en) |
| PT (1) | PT69477A (en) |
| TR (1) | TR20509A (en) |
| ZA (1) | ZA791770B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2827111A1 (en) * | 1978-06-21 | 1980-01-10 | Bayer Ag | AGENTS FOR USE IN CELL PROCESSING |
| NZ204262A (en) * | 1982-06-02 | 1986-10-08 | Champion Int Corp | Kraft and alkaline pulping processes using synergistic composition to enhance pulp yield |
| JPS6197492A (en) * | 1984-10-18 | 1986-05-15 | 川崎化成工業株式会社 | High concentrated pulp digestion aid aqueous solution |
| WO1995029288A1 (en) * | 1994-04-26 | 1995-11-02 | Harima Chemicals, Inc. | Pulp digestion aid |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2049567A (en) * | 1934-06-05 | 1936-08-04 | Du Pont | Manufacture of paper pulp |
| US3147179A (en) * | 1959-06-26 | 1964-09-01 | St Joe Paper Company | Pulping processes |
| US3446700A (en) * | 1966-03-07 | 1969-05-27 | Diamond Shamrock Corp | Process for cooking woodchips with a liquor containing condensation product of vicinal epoxide and phenol |
| DE2407620C3 (en) * | 1974-02-16 | 1979-05-03 | Chemische Werke Huels Ag, 4370 Marl | Process for the preparation of stable aqueous dispersions |
| SE384883B (en) * | 1974-09-06 | 1976-05-24 | Kopparfors Ab | WAY TO INCREASE THE CELLULOSE YIELD WHEN SULPHITE BOILING OF WOOD |
-
1978
- 1978-04-15 DE DE19782816473 patent/DE2816473A1/en not_active Withdrawn
-
1979
- 1979-03-16 IN IN177/DEL/79A patent/IN150690B/en unknown
- 1979-04-05 PH PH22355A patent/PH14724A/en unknown
- 1979-04-05 NO NO791151A patent/NO791151L/en unknown
- 1979-04-09 DE DE7979101084T patent/DE2960241D1/en not_active Expired
- 1979-04-09 EP EP79101084A patent/EP0004928B1/en not_active Expired
- 1979-04-10 ES ES479476A patent/ES479476A1/en not_active Expired
- 1979-04-11 PT PT69477A patent/PT69477A/en unknown
- 1979-04-11 BR BR7902259A patent/BR7902259A/en unknown
- 1979-04-11 AR AR276157A patent/AR220189A1/en active
- 1979-04-12 ZA ZA791770A patent/ZA791770B/en unknown
- 1979-04-12 FI FI791211A patent/FI64668C/en not_active IP Right Cessation
- 1979-04-12 NZ NZ190182A patent/NZ190182A/en unknown
- 1979-04-12 CA CA000325807A patent/CA1136808A/en not_active Expired
- 1979-04-13 AT AT0280179A patent/AT372716B/en not_active IP Right Cessation
- 1979-04-13 TR TR20509A patent/TR20509A/en unknown
- 1979-04-13 JP JP4446379A patent/JPS54138603A/en active Pending
- 1979-04-17 AU AU46076/79A patent/AU4607679A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0004928B1 (en) | 1981-04-08 |
| AR220189A1 (en) | 1980-10-15 |
| ZA791770B (en) | 1980-05-28 |
| PH14724A (en) | 1981-11-13 |
| NZ190182A (en) | 1981-07-13 |
| FI64668B (en) | 1983-08-31 |
| DE2816473A1 (en) | 1979-10-25 |
| PT69477A (en) | 1979-05-01 |
| BR7902259A (en) | 1979-12-11 |
| ATA280179A (en) | 1983-03-15 |
| FI64668C (en) | 1983-12-12 |
| AU4607679A (en) | 1979-10-25 |
| FI791211A (en) | 1979-10-16 |
| EP0004928A1 (en) | 1979-10-31 |
| ES479476A1 (en) | 1979-07-16 |
| AT372716B (en) | 1983-11-10 |
| DE2960241D1 (en) | 1981-04-30 |
| NO791151L (en) | 1979-10-16 |
| IN150690B (en) | 1982-11-20 |
| TR20509A (en) | 1981-09-03 |
| JPS54138603A (en) | 1979-10-27 |
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