WO2000061859A1 - Process for the treatment of fly ash, using hydrochloric acid - Google Patents
Process for the treatment of fly ash, using hydrochloric acid Download PDFInfo
- Publication number
- WO2000061859A1 WO2000061859A1 PCT/FI2000/000295 FI0000295W WO0061859A1 WO 2000061859 A1 WO2000061859 A1 WO 2000061859A1 FI 0000295 W FI0000295 W FI 0000295W WO 0061859 A1 WO0061859 A1 WO 0061859A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sulfate
- chloride
- solution
- calcium
- fly ash
- Prior art date
Links
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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/06—Treatment of pulp gases; Recovery of the heat content of the gases; Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds
- D21C11/063—Treatment of gas streams comprising solid matter, e.g. the ashes resulting from the combustion of black liquor
- D21C11/066—Separation of solid compounds from these gases; further treatment of recovered products
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/928—Paper mill waste, e.g. white water, black liquor treated
Definitions
- the present invention relates to a process for the treatment of fly ash accumulated in the flue gas filter of the soda recovery unit used for the recovery of chemicals in the manufacture of sulfate cellulose, so as to separate commercially exploitable chemicals therefrom. According to the invention, a process is provided wherein no waste is formed from the fly ash; all of its components are exploited.
- a soda recovery unit in which the waste liquor of the cellulose mill is burned is used for the recovery of chemicals.
- the flue gas filter of the soda recovery unit there accumulates a very fine-grained fly ash, which is composed of a solid-state salt mixture.
- the composition of the fly ash is typically:
- the fly ash is rather pure, although it does contain a small amount of water-soluble calcium as an impurity. In addition to sulfate, the fly ash contains only carbonate in a significant amount.
- FR patent application 2 761 088 describes a process for the recovery of sodium sulfate from fly ash formed in connection with the manufacture of sulfate cellulose.
- the fly ash is dissolved in water, carbonates are removed from the obtained solution by a sulfuric acid treatment, and the obtained sodium sulfate is separated from the solution by crystallization.
- the remaining solution is in part recycled to the process and in part released into the effluents.
- the sodium carbonate present in the fly ash is converted to sodium sulfate, which can be recovered in an almost pure form.
- potassium sulfate and sodium chloride are still left in the unexploitable solution passing into the effluents.
- hydrochloric acid cannot be used for breaking down the carbonate, since it would only increase the amount of sodium chloride waste.
- the mother liquor from the crystallization can be directed to a subsequent purification step, wherein a portion of the remaining sodium sulfate is separated by precipitation.
- the sulfate is precipitated by adding calcium chloride to the above-mentioned mother liquor, whereupon calcium sulfate (gypsum) which precipitates and can be removed by filtration is obtained as a product.
- US patent 3,833,462 describes a process wherein sodium chloride is separated from fly ash for further exploitation.
- the sodium carbonate is converted to sodium sulfate by means of sulfuric acid, and the solid sodium sulfate obtained in the process is separated from a sodium chloride solution.
- the Na chloride solution contains potassium sulfate as an impurity, and thus it cannot be used directly as a raw material in the chemicals industry.
- the aim is to obtain as high a sodium chloride yield from fly ash as possible.
- the carbonate present in the fly ash is broken down with hydrochloric acid, whereupon a solution which contains in the main Na chloride and sulfate is obtained as the result.
- the Na sulfate need not necessarily be crystallized out from the solution; the entire solution can be fed directly to the precipitation step.
- a chloride for example, calcium chloride or barium chloride, is used for the precipitation of the sulfate.
- the calcium or barium sulfate precipitate obtained by chloride precipitation can be separated by filtration. Thereupon there is left a mother liquor which contains mainly Na chloride.
- Ba sulfate When sulfate is precipitated with barium chloride in accordance with the invention, Ba sulfate is obtained, which is a useful product and can be used, for example, in medicine as a contrast material in radiography and in the paper industry as a pigment and a filler. Barium sulfate is quite poorly soluble, and thus the mother liquor is rather devoid of sulfate and barium. Thus there is left in the solution, dissolved, Na chloride and a small amount of K chloride. This chloride solution is so pure that it can be used as a raw material, for example, in the preparation of chlorine and chlorate.
- the sulfate may first be precipitated with calcium chloride, and the calcium sulfate is separated from the solution.
- the obtained mother liquor still contains as impurities too much calcium and sulfate for the liquor to be used directly as a raw material in the electrolyte industry.
- the mother liquor has to be purified further by the removal, by barium chloride precipitation, of the sulfate left in the solution.
- any excess calcium can be removed from the mother liquor by adding to it a suitable amount of sodium carbonate.
- Example 1 presents a process showing how the degree of purity of the NaCl solution can be raised by the precipitation of the sulfate with barium chloride.
- the calcium concentration in the cell solution may be at maximum 20 ppm, i.e. 0.002%.
- the solution obtained by this process has far too much calcium in proportion to its salt content.
- a salt solution such as this is not suitable for use as an electrolysis raw material without further purification.
- the initial material was a similar salt solution prepared from fly ash as in the reference example, and the carbonate was broken down with sulfuric acid.
- the sulfate was precipitated with a stoichiometric amount of barium chloride, the barium sulfate was separated, and a mother liquor of the following kind was obtained:
- the original fly ash contains as an impurity calcium approximately 10 ppm in a water-soluble form.
- the calcium concentration will be approximately 2 ppm, which is well below the permitted amount.
- the permitted barium concentration is 1 ppm, and thus the solution obtained by this process can be used in an amount of one-third of the salt solution feed of a chlorate factory.
- the K chloride originally present as an impurity in the fly ash is not harmful in the electrolysis.
- the sulfate concentration of the solution was 0.45%, and its amount was 118.1 g.
- 13.5 g of a barium chloride solution was added to this solution.
- the concentration of the solution was 10% BaCl 2 x2H 0, i.e. the sulfate was precipitated with a stoichiometric amount of barium.
- Sulfate precipitate was obtained in an amount of 1.25 g, i.e. the yield was 96.8%.
- the chloride solution obtained after this treatment was sufficiently pure for use as a raw material in the electrolyte industry.
Landscapes
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Processing Of Solid Wastes (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/958,326 US6821384B1 (en) | 1999-04-09 | 2000-04-07 | Process for the treatment of fly ash, using hydrochloric acid |
EP00917110A EP1244844A1 (en) | 1999-04-09 | 2000-04-07 | Process for the treatment of fly ash, using hydrochloric acid |
CA002365967A CA2365967C (en) | 1999-04-09 | 2000-04-07 | Process for the treatment of fly ash, using hydrochloric acid |
AU38229/00A AU3822900A (en) | 1999-04-09 | 2000-04-07 | Process for the treatment of fly ash, using hydrochloric acid |
NO20014777A NO20014777D0 (en) | 1999-04-09 | 2001-10-01 | Process for the treatment of fly ash using hydrochloric acid |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI990781A FI107253B (en) | 1999-04-09 | 1999-04-09 | Method for handling fly ash |
FI990781 | 1999-04-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000061859A1 true WO2000061859A1 (en) | 2000-10-19 |
Family
ID=8554382
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FI2000/000295 WO2000061859A1 (en) | 1999-04-09 | 2000-04-07 | Process for the treatment of fly ash, using hydrochloric acid |
Country Status (8)
Country | Link |
---|---|
US (1) | US6821384B1 (en) |
EP (1) | EP1244844A1 (en) |
AR (1) | AR023433A1 (en) |
AU (1) | AU3822900A (en) |
CA (1) | CA2365967C (en) |
FI (1) | FI107253B (en) |
NO (1) | NO20014777D0 (en) |
WO (1) | WO2000061859A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11725341B2 (en) | 2017-04-28 | 2023-08-15 | Andritz Oy | Method of treating fly ash of a recovery boiler |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070083003A1 (en) * | 2005-10-11 | 2007-04-12 | Gupta Laxmi C | Water curable polyurethane compositions and uses thereof |
JP7344820B2 (en) * | 2020-03-17 | 2023-09-14 | 太平洋セメント株式会社 | Alkali metal removal method and alkali metal removal device |
JP7381378B2 (en) * | 2020-03-19 | 2023-11-15 | 太平洋セメント株式会社 | Alkali metal removal equipment and alkali metal removal method |
CN113955790A (en) * | 2020-07-05 | 2022-01-21 | 四川伟晟环境保护有限公司 | Comprehensive utilization method of fly ash generated by household garbage incineration |
CN113772708A (en) * | 2021-09-23 | 2021-12-10 | 华新绿源环保股份有限公司 | Comprehensive recycling treatment process for complex waste salt system |
CN116282076B (en) * | 2023-04-04 | 2023-10-31 | 广东智环创新环境科技有限公司 | Method for washing fly ash step by step and recovering potassium salt and sodium salt |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0754799A2 (en) * | 1995-07-12 | 1997-01-22 | Eka Chemicals AB | Leaching process |
FR2761088A1 (en) * | 1997-03-20 | 1998-09-25 | Balcke Duerr Swenson Sa | Recovery of sodium sulphate, from solid fly ash obtained by incinerating paper treatment black liquor |
US5919424A (en) * | 1997-06-17 | 1999-07-06 | Thermo Fibergen, Inc. | Method of recovering minerals from papermaking sludge and sludge-derived ash |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3833462A (en) * | 1971-03-15 | 1974-09-03 | Mac Millan Bloedel Ltd | Process of removing sodium chloride from kraft pulping process chemical recovery systems |
US4420369A (en) * | 1982-02-25 | 1983-12-13 | The United States Of America As Represented By The Secretary Of Agriculture | Process for the decolorization of pulp mill bleach plant effluent |
JPH08196332A (en) * | 1995-01-20 | 1996-08-06 | Shiseido Co Ltd | Comb of container with comb |
-
1999
- 1999-04-09 FI FI990781A patent/FI107253B/en not_active IP Right Cessation
-
2000
- 2000-04-07 AU AU38229/00A patent/AU3822900A/en not_active Abandoned
- 2000-04-07 CA CA002365967A patent/CA2365967C/en not_active Expired - Fee Related
- 2000-04-07 US US09/958,326 patent/US6821384B1/en not_active Expired - Fee Related
- 2000-04-07 WO PCT/FI2000/000295 patent/WO2000061859A1/en active Application Filing
- 2000-04-07 EP EP00917110A patent/EP1244844A1/en not_active Withdrawn
- 2000-04-10 AR ARP000101641A patent/AR023433A1/en active IP Right Grant
-
2001
- 2001-10-01 NO NO20014777A patent/NO20014777D0/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0754799A2 (en) * | 1995-07-12 | 1997-01-22 | Eka Chemicals AB | Leaching process |
FR2761088A1 (en) * | 1997-03-20 | 1998-09-25 | Balcke Duerr Swenson Sa | Recovery of sodium sulphate, from solid fly ash obtained by incinerating paper treatment black liquor |
US5919424A (en) * | 1997-06-17 | 1999-07-06 | Thermo Fibergen, Inc. | Method of recovering minerals from papermaking sludge and sludge-derived ash |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11725341B2 (en) | 2017-04-28 | 2023-08-15 | Andritz Oy | Method of treating fly ash of a recovery boiler |
Also Published As
Publication number | Publication date |
---|---|
AR023433A1 (en) | 2002-09-04 |
CA2365967A1 (en) | 2000-10-19 |
AU3822900A (en) | 2000-11-14 |
FI107253B (en) | 2001-06-29 |
FI990781A0 (en) | 1999-04-09 |
US6821384B1 (en) | 2004-11-23 |
CA2365967C (en) | 2009-06-09 |
NO20014777L (en) | 2001-10-01 |
EP1244844A1 (en) | 2002-10-02 |
NO20014777D0 (en) | 2001-10-01 |
FI990781A (en) | 2000-10-10 |
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