CN1239166A - Process for causticizing green solution of alkali recovered from black liquid of paper-making - Google Patents
Process for causticizing green solution of alkali recovered from black liquid of paper-making Download PDFInfo
- Publication number
- CN1239166A CN1239166A CN98109098A CN98109098A CN1239166A CN 1239166 A CN1239166 A CN 1239166A CN 98109098 A CN98109098 A CN 98109098A CN 98109098 A CN98109098 A CN 98109098A CN 1239166 A CN1239166 A CN 1239166A
- Authority
- CN
- China
- Prior art keywords
- liquor
- green liquor
- causticization
- lime
- green
- 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.)
- Granted
Links
Images
Classifications
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/40—Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills
Landscapes
- Paper (AREA)
Abstract
A process for treating black paper-making liquid features that befor causticizing reaction, the black paper-making liquid is pretreated respectively with green liquid and calcium lime to remove impurities and then it goes through causticizing twice, filtering and washing to obtain caustic soda (white liquid) and light calcium carbonate without generation of waste dregs (white mud). Its advantages include no need of step to treat white mud, less investment in apparatus, and low energy consumption.
Description
The invention relates to a process for recovering alkali from papermaking black liquor, in particular to a novel causticizing process for recovering green liquor from the alkali from the papermaking black liquor. It is used for treating the pollution of black liquor in paper making.
At present, the pollution of the papermaking black liquor to the environment is a problem which draws much attention. The basic approach to remediating such pollution is usually to perform caustic recovery. More mature alkali recovery technology is described in detail in the pulping and papermaking process (Jiang Xiongxiang Shu, published by the light industry Press of China in 2 months 1992). The alkali recovery process comprises the following steps: evaporating, burning and dissolving the liquid to be converted into green liquid, clarifying, causticizing the green liquid by using excessive lime, and carrying out causticization reaction:
The present invention aims at providing a new causticizing process for recovering green liquor from alkali in paper-making black liquor, which can avoid the generation of waste residue (white mud) in the process of recovering alkali from paper-making black liquor, and can directly produce another chemical product, namely light calcium carbonate, while producing caustic soda (white liquor). Thus, it not only can eliminate the pollution of black liquor, but also can completely convert the black liquor and lime into two important chemical raw materials necessary for paper-making.
In the process of recovering black liquor alkali in paper making, it is supplied from combustion sectionThe turbid green liquor of (1) contains Na in addition to2CO3In addition to the useful alkali, silt and incompletely burnt carbon particles, also contains metal hydroxides, such as Fe (OH)3、Al(OH)3、Mg(OH)2Sulfides, e.g. Fe2S3And colloidal substances such as FeS and silicon-containing compounds. If the impurities enter the next causticization reaction system, not only the white liquor (caustic soda) is not easy to clarify, and the white mud isnot easy to precipitate, filter and wash, thereby influencing the normal operation of the causticization process, but also the white precipitate (CaCO) generated in the causticization reaction is inevitably mixed3) Once mixed, it is difficult to remove. Therefore, it is necessary to completely remove the green liquor before the green liquor enters the causticization reaction so that the impurities do not enter the causticization reaction system at all.
The solution is as follows:
1. in the process of recovering alkali from black liquor in paper making, before causticization reaction, the turbid green liquor from combustion section is pretreated to remove impurities. The green liquor pretreatment process comprises the following steps: (1) and placing the turbid green liquor in a green liquor preprocessor, heating to 80-100 ℃, adding a small amount of lime milk while stirring, fully stirring, and transferring into a green liquor clarifier for clarification. However, the lime milk and the green liquor should meet the following specified amounts: i.e. every 1m3Na2CO3The green liquor with the content of 100 g/L is added with lime milk with CaO of 1-5 Kg. Thus, before the green liquor is clarified, the green liquor is heated, a small amount of lime milk is added, and under the condition of fully stirring, colloid, carbon particles and other impurities in the green liquor are adsorbed, co-precipitated and broken down through the strong surface adsorption effect, so that the sedimentation speed of the impurities in the clarifier is accelerated. (2) Filtering the clarified green liquor by a fine filter to thoroughly remove solid impurities still existing in the clarified green liquor to obtain clear and transparent refined green liquor, and placing the clear and transparent refined green liquor in a storage tank for causticization.
2. Lime is digested into lime milk in advance before the causticization reaction, coarse lime ash is removed, and then the lime milk is sieved by a sieve with 120-180 meshes to further remove impurities in the lime. Fine lime milk after sieving is prepared for causticization.
3. Two causticizations are carried out successively to produce two products of caustic soda (white liquor) and light calcium carbonate. The process comprises the following steps:
(1) placing the pretreated refined green liquor and excessive fine lime milk into a causticizer according to a specified amount, and carrying out one-time causticization at the temperature of 70-100 ℃, wherein the causticization reaction is as follows:
In the process, the excessive lime milk can make Na in green liquor2CO3Conversion to NaOH to Na as complete as possible2CO3The conversion rate of (2) is high.
(2) And adding excessive refined green liquor into the solid matters filtered out after the primary causticization for secondary causticization until CaO in the solid matters is completely reacted, filtering, returning the filtrate for primary causticization, washing, drying, crushing and sieving the filtered solid matters to obtain the finished product of the light calcium carbonate. However, the above-mentioned excess amount of the essence of green is Na contained in the essence of green2CO3The weight ratio of the excess CaO to the excess CaO which is not reacted in the solid matter filtered out after the first causticization is 2.5-20.
The solids filtered out after the first causticization are removed of CaCO produced by the causticization3In addition, excess CaO is contained without participating in the reaction. When the refined green liquor is added into the system to make secondary causticization, the Na content in the system is2CO3Excess amount of CaO in the solid can completely participate in the reaction and conversion into CaCO3. Filtering, washing to remove NaOH and Na entrained in solid2CO3The soluble substances are mixed to obtain pure water-containing light CaCO3Then drying and the like are carried out to obtain the light CaCO3And (5) finishing. The filtrate after the second causticization contains excessive Na besides NaOH2CO3Therefore, it cannot be sent to the cooking section as white liquor, but should be returned for use in oneAnd (4) performing secondary causticization.
The present invention uses green liquor and quicklime as raw materials in the alkali recovery process of paper-making black liquor, and before causticization reaction, the green liquor and quicklime are respectively pretreated to remove impurities, then the causticization, filtration, washing, drying, pulverizing and sieving are successively carried out twice, so that two products of caustic soda (white liquor) and light calcium carbonate can be directly produced. Compared with the existing alkali recovery process, the process has the advantages of no waste residue (white mud), no secondary pollution, no white mud recovery and treatment process, and no increase in raw material and cost, and can produce another important chemical product, namely light calcium carbonate, besides the same amount of caustic soda as the original process. The invention can effectively reduce the equipment investment and energy consumption of the alkali recovery of the papermaking black liquor, and obviously improve the benefit.
The attached figure is a flow chart of a new causticizing process for recovering green liquor from papermaking black liquor alkali.
The process of the present invention is further illustrated by the following examples.
Example 1:
collecting turbid green liquor from wood pulp and paper mill, collecting Na-containing solution2CO3212 parts (by weight, the same below) of turbid green liquor is placed in a preprocessor, heated to 90 ℃, stirred and added with lime milk containing 5.6 parts of CaO5, fully stirred and transferred into a green liquor clarifier for clarification, and the clarified green liquor is filtered to obtain clear and transparent refined green liquor for causticization. And taking lime containing 112 parts of effective CaO, digesting, removing coarse lime ash, sieving (140 meshes), and preparing fine lime milk after sieving for causticization.
Collecting Na2CO3106 parts of the pretreated refined green liquor are added with fine lime milk containing 67.2 parts of CaO, the mixture is placed into a causticizer for causticization at 90 ℃, and after the reaction is finished, the caustic soda solution (white liquor) separated by filtration is sent to a cooking section. Adding 106 parts of Na into the filtered solid2CO3After pretreatment ofThe refined green liquor is subjected to secondary causticization. Filtering after the reaction of CaO in the special solid matters is completed, sending the filtrate to the next round of causticization, washing, drying, crushing and sieving (120 meshes) the filtered solid matters to obtain the finished product of the light calcium carbonate. Will be describedThe finished light calcium carbonate product is analyzed and measured according to the method specified in GB4794-84, and the results are as follows:
CaCO3(dry basis): 97.82 percent; moisture content: 0.26 percent; screen residue: 125 μm, 0; 45 μm, 0.48%; sedimentation volume: 3.1 ml/g; hydrochloric acid insoluble substance: 0.089%; free base (calculated as CaO): 0.025 percent; iron: 0.051%; manganese: 0.0032%.
It is clear from the results of the analytical measurements that light calcium carbonate (CaCO) is produced by the process3) And meets the standard specified in GB 4794-84.
Example 2:
the turbid green liquor sent from the burning section is collected from a straw pulp paper mill, and the light calcium carbonate finished product obtained in the same way as the example 1 is analyzed and determined to have the following results:
CaCO3(dry basis): 97.15 percent; moisture content: 0.3 percent; screen residue: 125 μm, 0; 45 μm, 0.46%; sedimentation volume: 3.0 ml/g; hydrochloric acid insoluble substance: 0.56 percent; free base (calculated as CaO): 0.058%; iron: 0.066%; manganese: 0.0045 percent.
The analysis and measurement result shows that: light calcium carbonate (CaCO) produced by adopting the process3) Except that the content of hydrochloric acid insoluble substances is slightly higher than the standard, the other substances all meet the standard specified in GB 4794-84. The reason why the hydrochloric acid insoluble substance is slightly higher is because the silicon content in the black liquor of straw pulp papermaking is high, and the quality of the product can completely meet the requirements of industrial use of papermaking, rubber, plastics and the like.
Claims (5)
1. A causticizing process for recovering green liquor from black paper-making liquor alkali includes such steps as evaporating black liquor, burning, dissolving molten substance to obtain green liquor, causticizing the green liquor with lime to obtain white liquor and white mud dregs,
1) and pretreating turbid green liquor from a combustion section to remove impurities in the turbid green liquor before carrying out the causticization reaction. The steps of the pre-treatment process are,
(1) placing the turbid green liquor in a preprocessor, heating to 80-100 ℃, adding a small amount of lime milk while stirring, transferring into a green liquor clarifier for clarification after fully stirring,
(2) filtering the clarified green liquor with fine filter to completely remove solid impurities remained in the clarified green liquor, placing the obtained clear and transparent refined green liquor in a storage tank for causticization,
2) lime is digested into lime milk in advance before the causticization reaction is carried out, coarse lime ash is removed, then the lime milk is sieved, the used sieve is 120-180 meshes to further remove impurities in the lime, the sieved fine lime milk is prepared for causticization,
3) two causticizations are carried out successively to respectively produce two products of caustic soda solution (white liquor) and light calcium carbonate, the process comprises the following steps,
(1) placing the pretreated refined green liquor and excessive fine lime milk into a causticizer according to a specified amount, carrying out causticization at 70-100 ℃, filtering and separating out caustic soda solution (white liquor), sending the caustic soda solution to a cooking section for papermaking for use,
(2) and adding excessive refined green liquor into the solid matters filtered after the primary causticization for secondary causticization until CaO in the solid matters is completely reacted, filtering, returning the filtrate for primary causticization, and washing, drying, crushing and sieving the filtered solid matters to obtain the finished product of the light calcium carbonate.
2. The process for causticizing green liquor from alkali recovery of paper-making black liquor as claimed in claim 1, wherein the amount of turbid green liquor and lime milk used in pretreatment of green liquor is 1m3Na2CO3Lime milk containing CaO 1-5Kg is added into turbid green liquor with the content of about 100 g/L.
3. The novel causticization process of alkali-recovered green liquor of papermaking black liquor as claimed in claim 1, wherein the heating temperature of the green liquor pretreatment is 80-100 ℃.
4. The novel causticizing process for alkali-recovered green liquor of papermaking black liquor as claimed in claim 1, wherein the causticizing reaction temperature is 70-100 ℃.
5. The process of claim 1, wherein the excess refined green liquor is Na contained in refined green liquor2CO3The weight ratio of the excess CaO to the excess CaO which is not reacted in the solid matter filtered out after the first causticization is 2.5-20.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN98109098A CN1084413C (en) | 1998-06-14 | 1998-06-14 | Process for causticizing green solution of alkali recovered from black liquid of paper-making |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN98109098A CN1084413C (en) | 1998-06-14 | 1998-06-14 | Process for causticizing green solution of alkali recovered from black liquid of paper-making |
Publications (2)
Publication Number | Publication Date |
---|---|
CN1239166A true CN1239166A (en) | 1999-12-22 |
CN1084413C CN1084413C (en) | 2002-05-08 |
Family
ID=5219894
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN98109098A Expired - Fee Related CN1084413C (en) | 1998-06-14 | 1998-06-14 | Process for causticizing green solution of alkali recovered from black liquid of paper-making |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN1084413C (en) |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003066961A1 (en) * | 2002-02-09 | 2003-08-14 | Tianzhao Ai | A process of recovering alkali from black liquor of papermaking |
CN1321243C (en) * | 2004-07-20 | 2007-06-13 | 上海东升新材料有限公司 | Method for recovering superfine calcium carbonate by clean causticization of green liquor |
CN101391794B (en) * | 2008-10-24 | 2010-06-09 | 魏湘 | Novel method for preparing light calcium carbonate by recovering solid white slime through alkaline pulping |
CN101020182B (en) * | 2006-02-16 | 2010-09-08 | 王梅林 | Process of comprehensively utilizing caustic sludge from papermaking industry |
CN102561086A (en) * | 2012-02-24 | 2012-07-11 | 天津科技大学 | Method for preparing spindle crystal form alkali recovery white clay |
CN102653411A (en) * | 2012-05-16 | 2012-09-05 | 山东山大华特科技股份有限公司 | Process for preparing light-weight calcium carbonate by recycling white mud by alkali |
WO2013040747A1 (en) * | 2011-09-19 | 2013-03-28 | 北京沃特玛德环境技术股份有限公司 | Method for comprehensively utilizing solid waste during soda recovery in papermaking industry |
CN103303956A (en) * | 2012-09-28 | 2013-09-18 | 湖南文理学院 | Causticizing method and process device for recycling papermaking alkali to prepare precipitated calcium carbonate |
CN104066885A (en) * | 2011-11-04 | 2014-09-24 | 维美德公司 | Method for the causticizing process for producing white liquor |
CN104556183A (en) * | 2013-10-17 | 2015-04-29 | 中国制浆造纸研究院 | Improved technology for preparing lime mud calcium carbonate filler through causticization of straw pulp green liquor |
CN108978310A (en) * | 2018-08-24 | 2018-12-11 | 四川省犍为凤生纸业有限责任公司 | The processing method and application thereof of white clay high-recovery in a kind of paper-making process |
CN111287011A (en) * | 2020-03-26 | 2020-06-16 | 陕西科技大学 | Method for comprehensively recycling pulping waste liquid |
CN112830504A (en) * | 2021-03-16 | 2021-05-25 | 新疆中泰兴苇生物科技有限公司 | Process for recycling papermaking alkali by replacing part of lime with carbide slag |
CN113136736A (en) * | 2021-04-30 | 2021-07-20 | 陕西科技大学 | Energy-saving method for causticization section for alkali recovery of pulping black liquor |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1108328A (en) * | 1994-02-18 | 1995-09-13 | 陈鸣钊 | Causticization at normal temp. for alkali recovered from black liquor of paper-making |
CN1057360C (en) * | 1996-05-27 | 2000-10-11 | 四川省内江市神州机器厂 | Alkali recovery from waste liquid of grass pulp papermaking by multi-point drying and burning |
-
1998
- 1998-06-14 CN CN98109098A patent/CN1084413C/en not_active Expired - Fee Related
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7291245B2 (en) | 2002-02-09 | 2007-11-06 | Tianzhao Ai | Process for causticizing green liquor in chemical recovery from black liquor in alkaline pulping |
WO2003066961A1 (en) * | 2002-02-09 | 2003-08-14 | Tianzhao Ai | A process of recovering alkali from black liquor of papermaking |
CN1321243C (en) * | 2004-07-20 | 2007-06-13 | 上海东升新材料有限公司 | Method for recovering superfine calcium carbonate by clean causticization of green liquor |
CN101020182B (en) * | 2006-02-16 | 2010-09-08 | 王梅林 | Process of comprehensively utilizing caustic sludge from papermaking industry |
CN101391794B (en) * | 2008-10-24 | 2010-06-09 | 魏湘 | Novel method for preparing light calcium carbonate by recovering solid white slime through alkaline pulping |
WO2013040747A1 (en) * | 2011-09-19 | 2013-03-28 | 北京沃特玛德环境技术股份有限公司 | Method for comprehensively utilizing solid waste during soda recovery in papermaking industry |
CN104066885B (en) * | 2011-11-04 | 2015-10-21 | 维美德公司 | Causticization process prepares the method for white liquid |
CN104066885A (en) * | 2011-11-04 | 2014-09-24 | 维美德公司 | Method for the causticizing process for producing white liquor |
CN102561086A (en) * | 2012-02-24 | 2012-07-11 | 天津科技大学 | Method for preparing spindle crystal form alkali recovery white clay |
CN102653411A (en) * | 2012-05-16 | 2012-09-05 | 山东山大华特科技股份有限公司 | Process for preparing light-weight calcium carbonate by recycling white mud by alkali |
CN103303956A (en) * | 2012-09-28 | 2013-09-18 | 湖南文理学院 | Causticizing method and process device for recycling papermaking alkali to prepare precipitated calcium carbonate |
CN103303956B (en) * | 2012-09-28 | 2015-08-26 | 湖南文理学院 | A kind of alkali recovery prepares causticization method and the process unit of precipitated chalk |
CN104556183A (en) * | 2013-10-17 | 2015-04-29 | 中国制浆造纸研究院 | Improved technology for preparing lime mud calcium carbonate filler through causticization of straw pulp green liquor |
CN104556183B (en) * | 2013-10-17 | 2016-08-31 | 中国制浆造纸研究院 | The technique that the straw pulp green liquor causticizing improved prepares white mud calcium carbonate filler |
CN108978310A (en) * | 2018-08-24 | 2018-12-11 | 四川省犍为凤生纸业有限责任公司 | The processing method and application thereof of white clay high-recovery in a kind of paper-making process |
CN111287011A (en) * | 2020-03-26 | 2020-06-16 | 陕西科技大学 | Method for comprehensively recycling pulping waste liquid |
CN112830504A (en) * | 2021-03-16 | 2021-05-25 | 新疆中泰兴苇生物科技有限公司 | Process for recycling papermaking alkali by replacing part of lime with carbide slag |
CN113136736A (en) * | 2021-04-30 | 2021-07-20 | 陕西科技大学 | Energy-saving method for causticization section for alkali recovery of pulping black liquor |
Also Published As
Publication number | Publication date |
---|---|
CN1084413C (en) | 2002-05-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN1084413C (en) | Process for causticizing green solution of alkali recovered from black liquid of paper-making | |
US7291245B2 (en) | Process for causticizing green liquor in chemical recovery from black liquor in alkaline pulping | |
US3639206A (en) | Treatment of waste water from alkaline pulping processes | |
AU603875B2 (en) | Method for green liquor cleaning in sulphate pulp mills | |
WO1998054400A1 (en) | Process for treating spent, waste, alkaline digestion liquor from paper pulping operations and product | |
CN102976387A (en) | Improved preparation technology of white mud calcium carbonate for papermaking filler | |
CN1641100A (en) | Method for recovering superfine calcium carbonate by clean causticization of green liquor | |
EP0672211B1 (en) | A method of producing green liquor in chemical recovery in sulfate and sulfite pulp mills | |
US4481072A (en) | Method for recovery of wastewater residues | |
CN1041450C (en) | Method for treating paper-making black liquor | |
CN1441117A (en) | Technological process of recovering white clay to produce stuffing calcium carbonate | |
DE3043518C2 (en) | Process for the recovery of waste water precipitation or residues | |
CN1054755A (en) | Activation of swelled ground | |
CN1320205C (en) | Technology for mfg, high whiteness paper making filling light calcium carbonate recovered from lime mud | |
CN1110452C (en) | Technique for recovering, treating and closed-loop circulation of papermaking waste water | |
EP0151097A1 (en) | A method for removing resin from a paper pulp process liquor | |
US20220275578A1 (en) | A method and a system for adjusting ph of green liquor dregs | |
CN1755012A (en) | The comprehensive processing method of paper-making sewage black liquor | |
CN114575178A (en) | Method for treating high-concentration wastewater of chemi-mechanical pulp | |
CN1245553C (en) | Water treating method in pulping industry | |
CN113105784A (en) | Method for producing pigment for coating from papermaking white mud | |
JPH07508564A (en) | Product filtration method using caustic treatment |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C06 | Publication | ||
PB01 | Publication | ||
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20020508 Termination date: 20150614 |
|
EXPY | Termination of patent right or utility model |