US3883391A - Treatment of lignocellulosic material with an aqueous containing cyanide ions and an alkaline earth metal salt - Google Patents
Treatment of lignocellulosic material with an aqueous containing cyanide ions and an alkaline earth metal salt Download PDFInfo
- Publication number
- US3883391A US3883391A US433868A US43386874A US3883391A US 3883391 A US3883391 A US 3883391A US 433868 A US433868 A US 433868A US 43386874 A US43386874 A US 43386874A US 3883391 A US3883391 A US 3883391A
- Authority
- US
- United States
- Prior art keywords
- alkaline
- accordance
- cyanide
- earth metal
- metal salt
- 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 - Lifetime
Links
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 title claims abstract description 36
- -1 alkaline earth metal salt Chemical class 0.000 title claims abstract description 33
- 229910052784 alkaline earth metal Inorganic materials 0.000 title claims abstract description 29
- 239000012978 lignocellulosic material Substances 0.000 title claims abstract description 27
- 238000011282 treatment Methods 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 claims abstract description 48
- 238000004537 pulping Methods 0.000 claims abstract description 19
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 6
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 5
- 239000000243 solution Substances 0.000 claims description 16
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical group [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 14
- 239000001110 calcium chloride Substances 0.000 claims description 14
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 14
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 claims description 11
- 239000002023 wood Substances 0.000 claims description 11
- 239000007864 aqueous solution Substances 0.000 claims description 10
- 239000011575 calcium Substances 0.000 claims description 5
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 4
- 229910052791 calcium Inorganic materials 0.000 claims description 4
- 150000003839 salts Chemical group 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 7
- 239000002655 kraft paper Substances 0.000 abstract description 4
- 238000006243 chemical reaction Methods 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 150000004676 glycans Chemical class 0.000 description 7
- 229920001282 polysaccharide Polymers 0.000 description 7
- 239000005017 polysaccharide Substances 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000000123 paper Substances 0.000 description 5
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 4
- 239000008103 glucose Substances 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 235000005018 Pinus echinata Nutrition 0.000 description 2
- 241001236219 Pinus echinata Species 0.000 description 2
- 235000017339 Pinus palustris Nutrition 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 125000003172 aldehyde group Chemical group 0.000 description 2
- 150000001299 aldehydes Chemical group 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 125000002843 carboxylic acid group Chemical group 0.000 description 2
- 238000010411 cooking Methods 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000011221 initial treatment Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- MNWBNISUBARLIT-UHFFFAOYSA-N sodium cyanide Chemical compound [Na+].N#[C-] MNWBNISUBARLIT-UHFFFAOYSA-N 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- XJFPIMNKQGXREL-UHFFFAOYSA-L 13812-88-9 Chemical compound [Ca+2].[O-]S(=O)(=O)S([O-])(=O)=O XJFPIMNKQGXREL-UHFFFAOYSA-L 0.000 description 1
- KQMCGGGTJKNIMC-UHFFFAOYSA-N 2-hydroxy-3-propyl-2h-furan-5-one Chemical compound CCCC1=CC(=O)OC1O KQMCGGGTJKNIMC-UHFFFAOYSA-N 0.000 description 1
- ZKQDCIXGCQPQNV-UHFFFAOYSA-N Calcium hypochlorite Chemical compound [Ca+2].Cl[O-].Cl[O-] ZKQDCIXGCQPQNV-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- CWVZGJORVTZXFW-UHFFFAOYSA-N [benzyl(dimethyl)silyl]methyl carbamate Chemical compound NC(=O)OC[Si](C)(C)CC1=CC=CC=C1 CWVZGJORVTZXFW-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- NKQIMNKPSDEDMO-UHFFFAOYSA-L barium bromide Chemical compound [Br-].[Br-].[Ba+2] NKQIMNKPSDEDMO-UHFFFAOYSA-L 0.000 description 1
- 229910001620 barium bromide Inorganic materials 0.000 description 1
- ISFLYIRWQDJPDR-UHFFFAOYSA-L barium chlorate Chemical compound [Ba+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O ISFLYIRWQDJPDR-UHFFFAOYSA-L 0.000 description 1
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 1
- 229910001626 barium chloride Inorganic materials 0.000 description 1
- UNLSXXHOHZUADN-UHFFFAOYSA-N barium cyanide Chemical compound [Ba+2].N#[C-].N#[C-] UNLSXXHOHZUADN-UHFFFAOYSA-N 0.000 description 1
- 229910052916 barium silicate Inorganic materials 0.000 description 1
- VEASZGAADGZARC-UHFFFAOYSA-L barium(2+);dibromate Chemical compound [Ba+2].[O-]Br(=O)=O.[O-]Br(=O)=O VEASZGAADGZARC-UHFFFAOYSA-L 0.000 description 1
- HMOQPOVBDRFNIU-UHFFFAOYSA-N barium(2+);dioxido(oxo)silane Chemical compound [Ba+2].[O-][Si]([O-])=O HMOQPOVBDRFNIU-UHFFFAOYSA-N 0.000 description 1
- NUZIUQUIUFXLAH-UHFFFAOYSA-N barium(2+);iron(2+);hexacyanide Chemical compound [Fe+2].[Ba+2].[Ba+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] NUZIUQUIUFXLAH-UHFFFAOYSA-N 0.000 description 1
- IELPSGPHQCRVQW-UHFFFAOYSA-L barium(2+);sulfanide Chemical compound [SH-].[SH-].[Ba+2] IELPSGPHQCRVQW-UHFFFAOYSA-L 0.000 description 1
- VSGNNIFQASZAOI-UHFFFAOYSA-L calcium acetate Chemical compound [Ca+2].CC([O-])=O.CC([O-])=O VSGNNIFQASZAOI-UHFFFAOYSA-L 0.000 description 1
- 239000001639 calcium acetate Substances 0.000 description 1
- 235000011092 calcium acetate Nutrition 0.000 description 1
- 229960005147 calcium acetate Drugs 0.000 description 1
- LVGQIQHJMRUCRM-UHFFFAOYSA-L calcium bisulfite Chemical compound [Ca+2].OS([O-])=O.OS([O-])=O LVGQIQHJMRUCRM-UHFFFAOYSA-L 0.000 description 1
- 229910001622 calcium bromide Inorganic materials 0.000 description 1
- WGEFECGEFUFIQW-UHFFFAOYSA-L calcium dibromide Chemical compound [Ca+2].[Br-].[Br-] WGEFECGEFUFIQW-UHFFFAOYSA-L 0.000 description 1
- 239000000279 calcium ferrocyanide Substances 0.000 description 1
- 235000012251 calcium ferrocyanide Nutrition 0.000 description 1
- 235000010260 calcium hydrogen sulphite Nutrition 0.000 description 1
- FAYYUXPSKDFLEC-UHFFFAOYSA-L calcium;dioxido-oxo-sulfanylidene-$l^{6}-sulfane Chemical compound [Ca+2].[O-]S([O-])(=O)=S FAYYUXPSKDFLEC-UHFFFAOYSA-L 0.000 description 1
- YAECNLICDQSIKA-UHFFFAOYSA-L calcium;sulfanide Chemical compound [SH-].[SH-].[Ca+2] YAECNLICDQSIKA-UHFFFAOYSA-L 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 235000014633 carbohydrates Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000010025 steaming Methods 0.000 description 1
- FRTABACCYANHFP-UHFFFAOYSA-L strontium chlorate Chemical compound [Sr+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O FRTABACCYANHFP-UHFFFAOYSA-L 0.000 description 1
- 229910001631 strontium chloride Inorganic materials 0.000 description 1
- AHBGXTDRMVNFER-UHFFFAOYSA-L strontium dichloride Chemical compound [Cl-].[Cl-].[Sr+2] AHBGXTDRMVNFER-UHFFFAOYSA-L 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 235000000346 sugar Nutrition 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
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
Definitions
- ABSTRACT A process for increasing the yields in alkaline pulping of lignocellulosic materials, such as by the Kraft process, comprising treatment of the cellulosic materials with cyanide and a water'soluble, alkaline-earth metal salt. The lignocellulosic material is then filtered, washed and digested with an alkali-metal pulping solution having a pH of at least about 7.
- the process of the invention comprises an initial treatment of lignocellulosic materials at a pH of at least about 7.0, up to about 12.0, preferably 8.5 to 10.5, in an aqueous solution containing cyanide ions, hydroxyl ions, along with a watensoluble, alkaline-earth metal salt.
- the cellulosic material is removed from the aque ous initial treatment solution and digested in an alkalimetal pulping solution having a pH of at least about 7, preferably not higher than 12.0.
- the alkaline earth metal salt employed is desirably soluble in water at 25C. to the extent of at least about 50 grams per liter.
- the water-soluble, alkaline-earth metal salt is desirably employed in an amount of at least about 0.1 percent, preferably at least about 1.0 percent, by weight of the treatment solution.
- a treatment solution of at least about 0.25 molar with respect to calcium chloride has been shown to provide excellent increase in pulping yields.
- the amount of alkaline-earth metal salt addition should take into account the realization that metal ion residing in the chips following pretreatment by the cyanide solution will consume active alkali in the subsequent kraft cook by the reaction:
- cyanide preferably introduced as alkali-metal cyanide, such as sodium cyanide, may vary widely, but amounts of between 0.25 and 2.0 percent by weight of treatment solution are preferred, with the optimum between about 1 and 1.5 percent.
- the pretreatment with the cyanide and watersoluble, alkaline-earth metal salt over a broad range of temperatures, such as from ambient temperature to about 130C. is satisfactory. Temperatures in excess of 130C., while providing improvement, are less desirable than temperatures below 130C.
- the preferred temperatures are between about C. and C.
- alkaline earth salts which may be employed are calcium chloride, which is preferred, calcium acetate, calcium bromide, calcium hypochlorite, calcium cyanide, calcium ferrocyanide, calcium hydrosulfide, calcium bisulfite, calcium dithionate, calcium thiosulfate, barium bromate, barium bromide, barium chlorate, barium chloride, barium cyanide, barium ferrocyanide, barium hydrosulfide, barium silicate, strontium chloride, strontium chlorate, etc.
- calcium chloride which is preferred, calcium acetate, calcium bromide, calcium hypochlorite, calcium cyanide, calcium ferrocyanide, calcium hydrosulfide, calcium bisulfite, calcium dithionate, calcium thiosulfate, barium bromate, barium bromide, barium chlorate, barium chloride, barium cyanide, barium ferrocyanide, barium hydrosulfide, barium silicate, strontium chloride,
- hydrocellulose in the amount of 1.0 grams, was used as a model of the cellulosic substrate to ascertain the improvement in yields under varying conditions and amounts of sodium cyanide and calcium chloride.
- an aqueous suspension of the hydrocellulose powder was first treated at 75C. for 2 hours in 150 ml. of aqueous solution containing the additives set forth in Table 1 below. The treatment was continued for 2.0 hours. The hydrocel-' lulose was then filtered, washed with water, then acetic acid, followed by water. The washed powder was transferred to a flask containing 150 ml. of one normal sodium hydroxide.
- Examples IV and V indicate that pretreatment with sodium cyanide alone (0.25 molar) increased the stability of the hydrocellulose so that after treatment in boiling one normal sodium hydroxide for two hours, the yield obtained was in the order of 65 percent.
- Example VIII shows that the increase in yield in Examples VI and VII was due to the combined presence of cyanide and calcium chloride, and not one of these reagents alone.
- Example IX shows that yields can be increased to the order of about percent by increasing the amount of calcium chloride to about 2.5 molar in combination with the 0.25 molar concentration of cyanide in the pretreatment.
- Examples X-XX a series of pulping experiments was conducted using southern pine chips. In these experiments, a one cubic foot digester was used in some cases, while in others a four liter digester was used. The results were found to be unaffected by the size of the digester.
- the calcium chloride employed may be replaced by equivalent amounts of other watersoluble, alkaline-earth metal salts such as, calcium acetate, calcium bromide, calcium hypochlorite, calcium cyanide, calcium ferrocyanide, calcium hydrosulfide, calcium bisulfite, calcium dithionate, calcium thiosulfate, barium bromate, barium bromide, barium chlorate, barium chloride, barium cyanide, barium ferrocyanide, barium hydrosulfide, barium silicate, strontium chloride, strontium chlorate, etc.
- other watersoluble, alkaline-earth metal salts such as, calcium acetate, calcium bromide, calcium hypochlorite, calcium cyanide, calcium ferrocyanide, calcium hydrosulfide, calcium bisulfite, calcium dithionate, calcium thiosulfate, barium bromate, barium bromide, barium chlorate, barium chloride, barium cyanide, barium ferrocyanide, bar
- a process for increasing the yields of alkaline pulp ing of lignocellulosic material comprising treatment of the lignocellulosic material with an aqueous solution containing cyanide ions and a water-soluble, alkalineearth metal salt.
- cyanide ion containing solution shall contain at least about 0.25 percent by weight of cyanide and up to about 2 percent.
- a process for increasing the yields of alkaline pulping of lignocellulosic material comprising treatment of said lignocellulosic material with an aqueous solution containing cyanide ions and a water-soluble, alkalineearth metal salt, removing the lignocellulosic material from said aqueous solution, and digesting the thus treated lignocellulosic material with an alkali-metal pulping solution having a pH above about 7 and up to about 12.
- lignocellulosic material is in the form of wood chips.
- a process in accordance with claim 9 wherein the cyanide ion containing solution shall contain at least about 0.25 percent by weight of cyanide and up to about 2 percent.
- water-soluble alkaline-earth metal salt is a salt of calcium.
Landscapes
- Paper (AREA)
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US433868A US3883391A (en) | 1974-01-16 | 1974-01-16 | Treatment of lignocellulosic material with an aqueous containing cyanide ions and an alkaline earth metal salt |
| CA198,000A CA1012708A (en) | 1974-01-16 | 1974-04-23 | Nitrile pulping in the presence of calcium chloride |
| SE7405422A SE391205B (sv) | 1974-01-16 | 1974-04-23 | Sett att oka massautbytet vid alkalisk kokning av lignocellulosahaltigt material |
| FR7416912A FR2257733A1 (enExample) | 1974-01-16 | 1974-05-15 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US433868A US3883391A (en) | 1974-01-16 | 1974-01-16 | Treatment of lignocellulosic material with an aqueous containing cyanide ions and an alkaline earth metal salt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3883391A true US3883391A (en) | 1975-05-13 |
Family
ID=23721851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US433868A Expired - Lifetime US3883391A (en) | 1974-01-16 | 1974-01-16 | Treatment of lignocellulosic material with an aqueous containing cyanide ions and an alkaline earth metal salt |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US3883391A (enExample) |
| CA (1) | CA1012708A (enExample) |
| FR (1) | FR2257733A1 (enExample) |
| SE (1) | SE391205B (enExample) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3929559A (en) * | 1974-12-16 | 1975-12-30 | Mac Millan Bloedel Ltd | Stabilization of cellulosic material by treatment with ferricyanide ion |
| US5728265A (en) * | 1995-06-12 | 1998-03-17 | Henkel Corporation | Process for enhancing white liquor penetration into wood chips by contacting the chips with a mixture of the white liquor and a polymethylalkyl siloxane |
| WO2010066026A1 (en) * | 2008-12-08 | 2010-06-17 | Fpinnovations | Increasing alkaline pulping yield for softwood with metal ions |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3532596A (en) * | 1967-09-22 | 1970-10-06 | Westvaco Corp | Method for stabilizing polysaccharides against alkaline attack |
| US3663358A (en) * | 1970-04-29 | 1972-05-16 | Westvaco Corp | A METHOD FOR INCREASING BISULFITE PULP YIELD COMPRISING TREATING LIGNOCELLULOSIC MATERIAL WITH CYANIDE IONS AT A pH OF 7{14 12 PRIOR TO DIGESTION |
| US3695994A (en) * | 1970-04-03 | 1972-10-03 | Mac Millan Bloedel Ltd | Impregnation of wood chips with a cellulose protector followed by a soda-oxygen pulping stage |
-
1974
- 1974-01-16 US US433868A patent/US3883391A/en not_active Expired - Lifetime
- 1974-04-23 CA CA198,000A patent/CA1012708A/en not_active Expired
- 1974-04-23 SE SE7405422A patent/SE391205B/xx unknown
- 1974-05-15 FR FR7416912A patent/FR2257733A1/fr not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3532596A (en) * | 1967-09-22 | 1970-10-06 | Westvaco Corp | Method for stabilizing polysaccharides against alkaline attack |
| US3695994A (en) * | 1970-04-03 | 1972-10-03 | Mac Millan Bloedel Ltd | Impregnation of wood chips with a cellulose protector followed by a soda-oxygen pulping stage |
| US3663358A (en) * | 1970-04-29 | 1972-05-16 | Westvaco Corp | A METHOD FOR INCREASING BISULFITE PULP YIELD COMPRISING TREATING LIGNOCELLULOSIC MATERIAL WITH CYANIDE IONS AT A pH OF 7{14 12 PRIOR TO DIGESTION |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3929559A (en) * | 1974-12-16 | 1975-12-30 | Mac Millan Bloedel Ltd | Stabilization of cellulosic material by treatment with ferricyanide ion |
| US5728265A (en) * | 1995-06-12 | 1998-03-17 | Henkel Corporation | Process for enhancing white liquor penetration into wood chips by contacting the chips with a mixture of the white liquor and a polymethylalkyl siloxane |
| WO2010066026A1 (en) * | 2008-12-08 | 2010-06-17 | Fpinnovations | Increasing alkaline pulping yield for softwood with metal ions |
| US8591702B2 (en) | 2008-12-08 | 2013-11-26 | Fpinnovations | Increasing alkaline pulping yield for softwood with metal ions |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2257733A1 (enExample) | 1975-08-08 |
| SE391205B (sv) | 1977-02-07 |
| CA1012708A (en) | 1977-06-28 |
| SE7405422L (enExample) | 1975-07-17 |
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