CN110589857A - Method for preparing alkali by using waste salt in combination manner - Google Patents
Method for preparing alkali by using waste salt in combination manner Download PDFInfo
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- CN110589857A CN110589857A CN201911034391.8A CN201911034391A CN110589857A CN 110589857 A CN110589857 A CN 110589857A CN 201911034391 A CN201911034391 A CN 201911034391A CN 110589857 A CN110589857 A CN 110589857A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/16—Halides of ammonium
- C01C1/164—Ammonium chloride
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D7/00—Carbonates of sodium, potassium or alkali metals in general
- C01D7/02—Preparation by double decomposition
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D7/00—Carbonates of sodium, potassium or alkali metals in general
- C01D7/12—Preparation of carbonates from bicarbonates or bicarbonate-containing product
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
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- Water Treatment By Sorption (AREA)
Abstract
The invention discloses a method for preparing alkali by utilizing waste salt in a combined manner, belonging to the technical field of waste salt recovery treatment in industrial production. At normal temperature, the waste salt collected in a centralized way is dissolved in an ammonium bicarbonate solution after being pretreated to prepare a saturated salt water solution with a certain concentration, the saturated salt water solution is moved to a high-pressure reaction kettle to absorb ammonia, then the temperature is reduced after the ammonia absorption is finished, and CO is continuously introduced into the high-pressure reaction kettle under the condition of water bath temperature preservation2Carbonating, when the temperature in the kettle begins to decrease, heating in a water bath and preserving heat, cooling and discharging after the reaction is finished, filtering and washing the sodium bicarbonate filter cake for multiple times to reduce the NaCl content, drying and weighing, and measuring the purity; heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4Cl crystal, drying, weighing, measuring purity, treating mother liquor with adsorbent, and recycling. The invention can realize the purpose of obtaining higher purity soda ash and NH by exploring different reaction conditions4And (4) Cl products.
Description
Technical Field
The invention relates to a process method for preparing alkali by utilizing waste salt in a combined way, which relates to the technical field of waste salt recovery treatment in industrial production, realizes the purpose of recycling by using a combined alkali preparation method and reusing mother liquor repeatedly and belongs to the technical field of waste salt recovery treatment in industrial production.
Background
The industrial utilization of waste salt for preparing alkali mainly comprises an ammonia alkali method and a combined alkali preparation method. The ammonia-soda process is to calcine limestone to produce lime and carbon dioxide, slake lime to obtain lime milk, and carbonating with ammoniated ammonia salt water to produce heavy soda. CO from limestone calcination and heavy alkali calcination2Compressing, cooling and sending to a carbonization tower. Filtering and washing heavy alkali, and distilling and recovering ammonia in mother liquor. The combined soda production method is characterized in that salt, ammonia and carbon dioxide which is a byproduct in the synthetic ammonia industry are used as raw materials, and soda ash and ammonium chloride are produced simultaneously, namely the combined method for producing soda ash and ammonium chloride is called as the combined method and is called as the combined soda production method for short.
The former part of the combined alkali method is the same as the ammonia-alkali method, and finally, ammonium chloride crystals are separated out to be used as a nitrogen fertilizer product, and the rest salt is returned to be used for preparing sodium bicarbonate. Compared with the ammonia-soda process, the combined soda process has the following advantages: the utilization rate of raw materials is high; limestone and coke are not needed, so that the cost is reduced; the soda part does not need heavy equipment such as an ammonia still, a lime pit, an ash melting machine and the like, the flow is shortened, and the cost of building long investment is reduced; no large amount of waste liquid and waste residue are discharged, and the factory can be built in the country.
Disclosure of Invention
Aiming at the method, the invention recycles the recovered waste salt, improves the effective utilization rate of the reaction materials through process optimization, and further improves the existing industrialized production method.
In order to achieve the purpose, the technical scheme adopted by the invention is a method for preparing alkali by using waste salt in a combined manner, and the method is carried out according to the following steps:
(1) at normal temperature, the waste salt collected in a centralized way is dissolved in an ammonium bicarbonate solution after being pretreated to prepare a saturated salt water solution with a certain concentration, the saturated salt water solution is moved to a high-pressure reaction kettle to absorb ammonia, then the temperature is reduced after the ammonia absorption is finished, and CO is continuously introduced into the high-pressure reaction kettle under the condition of water bath temperature preservation2Carbonating, when the temperature in the kettle begins to decrease, heating in a water bath and preserving heat, cooling and discharging after the reaction is finished, filtering and washing the sodium bicarbonate filter cake for multiple times to reduce the NaCl content, drying and weighing, and measuring the purity;
(2) heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4And drying and weighing Cl crystals, measuring the purity, treating the mother liquor by using an adsorbent, and recycling and reusing the mother liquor.
The waste salt in the step (1) is subjected to calcination pretreatment in advance, the content of organic matters in the waste salt is reduced, the mass concentration of NaCl is ensured to be 60-85%, the molar ratio of ammonia to NaCl in the waste salt is (1.0-2.0) to 1, the mass concentration of a saline solution is 30-50%, the feeding amount of ammonium bicarbonate is 10-18% (wt.) of the mass of the waste salt, the water bath heating temperature is 50-80 ℃, and the pressure in the carbonation process is always kept at 1-5 MPa.
Wherein the adsorbent in the step (2) is one of activated carbon, macroporous sulfonic acid resin, acrylate-dimethacrylate copolymer and porphyrin cross-linked chitosan, and the dosage of the adsorbent is 5-30% (wt.) of the waste salt.
Compared with the prior art, the invention has the following advantages:
1. the invention can realize the purpose of obtaining higher purity soda ash and NH by exploring different reaction conditions4And (4) Cl products.
2. The method has the advantages of simple reaction equipment, strong operability, no great potential safety hazard and improvement on the safety of the reaction process.
3. The method is simple and convenient to operate and wide in application range, and can provide an effective method for recycling the waste salt.
Drawings
FIG. 1 is a process flow diagram of the method for producing alkali by using waste salt in combination.
Detailed Description
The present invention is described in detail with reference to the following examples, which are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept within the technical scope of the present invention.
Example 1
(1) Preparing treated waste salt (NaCl content 60%) and ammonium hydrogen carbonate whose waste salt content is 10% (wt.) into brine, transferring it into high-pressure reactor to absorb ammonia, making the mole ratio of ammonia gas and NaCl in waste salt be 1.1: 1, cooling after ammonia absorption is completed, continuously introducing CO at 30 deg.C in water bath2Carbonating, keeping the pressure at 1MPa, heating in water bath to 50 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain yield of 80.5% and purity of 90.5%.
(1) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4Drying Cl crystal, weighing, measuring the purity of 94.3%, treating the mother liquor with active carbon, and recycling.
Example 2
(1) Preparing treated waste salt (NaCl content 65%) and 12% (wt.) ammonium bicarbonate of waste salt dosage into brine, transferring into high-pressure autoclave to absorb ammonia, wherein the molar ratio of ammonia gas to NaCl in waste salt is 1.2: 1, cooling after ammonia absorption, keeping temperature in water bath at 30 deg.C, and continuously introducing CO2Carbonating, keeping the pressure at 2MPa, heating in water bath to 60 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain yield of 82.6% and purity of 91.5%.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while it is hot, cooling the filtrate to obtain a filtrateNH is crystallized out4Drying Cl crystal, weighing, measuring the purity of 92.7%, treating the mother liquor with macroporous sulfonic acid resin adsorbent, and recycling.
Example 3
(1) Preparing treated waste salt (NaCl content 65%) and 13% (wt.) ammonium bicarbonate of waste salt dosage into brine, transferring into high-pressure autoclave to absorb ammonia, the mol ratio of ammonia gas and NaCl in waste salt is 1.3: 1, cooling after ammonia absorption, keeping temperature in water bath at 30 deg.C, continuously introducing CO2Carbonating, keeping the pressure at 2MPa, heating in water bath to 60 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain yield 83.2% and purity 90.2%.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4And drying Cl crystals, weighing, measuring the purity of 92.8%, treating the mother liquor by using a chitosan adsorbent, and recycling and reusing.
Example 4
(1) Preparing treated waste salt (NaCl content 70%) and 14% (wt.) ammonium bicarbonate of waste salt dosage into brine, transferring into high-pressure autoclave to absorb ammonia, wherein the molar ratio of ammonia gas to NaCl in waste salt is 1.3: 1, cooling after ammonia absorption, keeping temperature in water bath at 30 deg.C, and continuously introducing CO2Carbonating, keeping the pressure at 4MPa, heating in water bath to 60 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain 81.8% yield and 93.5% purity.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4Drying Cl crystal, weighing, measuring the purity of 96.5%, treating the mother liquor with acrylate-dimethacrylate copolymer adsorbent, and recycling.
Example 5
(1) Preparing treated waste salt (NaCl content 75%) and 15% (wt.) ammonium hydrogen carbonate of waste salt dosageForming brine, transferring into a high-pressure kettle, absorbing ammonia with the mol ratio of ammonia to NaCl in waste salt being 1.1: 1, cooling after ammonia absorption, keeping the temperature in water bath at 30 deg.C, and continuously introducing CO2Carbonating, keeping the pressure at 4MPa, heating in water bath to 70 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain yield 83.2% and purity 94.5%.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4And drying Cl crystals, weighing, measuring the purity of the Cl crystals to be 93.6%, treating the mother liquor by using an activated carbon adsorbent, and recycling and reusing the mother liquor.
Example 6
(1) Preparing treated waste salt (NaCl content is 80%) and 15% (wt.) ammonium bicarbonate of waste salt dosage into brine, transferring into high-pressure autoclave to absorb ammonia, the mole ratio of ammonia gas and NaCl in waste salt is 1.1: 1, cooling after ammonia absorption, continuously introducing CO at 30 deg.C in water bath2Carbonating, keeping the pressure at 3MPa, heating in water bath to 50 deg.C when the temperature begins to decrease, cooling after the reaction is finished, discharging, filtering, washing sodium bicarbonate filter cake for several times, and reducing NaCl content. Oven drying and weighing to obtain yield 83.6% and purity 94.7%.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate, crystallizing and separating NH out4And drying Cl crystals, weighing, measuring the purity of 95.3%, and treating the macroporous sulfonic acid resin adsorbent for recycling.
Example 7
(1) Preparing treated waste salt (NaCl content 85%) and 18% (wt.) ammonium bicarbonate of waste salt dosage into brine, transferring into high-pressure autoclave to absorb ammonia, the mol ratio of ammonia gas and NaCl in waste salt is 1.3: 1, cooling after ammonia absorption, keeping temperature in water bath at 30 deg.C, continuously introducing CO2Carbonating under 4MPa, heating in water bath to 70 deg.C when the temperature begins to decrease, cooling, discharging, filtering, washing sodium bicarbonate filter cake for several times to reduce NaCl contentAmount of the compound (A). Oven drying and weighing to obtain yield of 84.1% and purity of 93.7%.
(2) Heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4Drying Cl crystal, weighing, measuring the purity to be 94.6%, treating with porphyrin cross-linked chitosan adsorbent, and recycling for use.
Claims (3)
1. The method for preparing alkali by using waste salt in a combined manner is characterized by comprising the following steps of:
(1) at normal temperature, the waste salt collected in a centralized way is dissolved in an ammonium bicarbonate solution after being pretreated to prepare a saturated salt water solution with a certain concentration, the saturated salt water solution is moved to a high-pressure reaction kettle to absorb ammonia, then the temperature is reduced after the ammonia absorption is finished, and CO is continuously introduced into the high-pressure reaction kettle under the condition of water bath temperature preservation2Carbonating, when the temperature in the kettle begins to decrease, heating in a water bath and preserving heat, cooling and discharging after the reaction is finished, filtering and washing the sodium bicarbonate filter cake for multiple times to reduce the NaCl content, drying and weighing, and measuring the purity;
(2) heating the filtrate to evaporate ammonia and carbon dioxide, adding waste salt until the filtrate is saturated, heating the filtrate, filtering while the filtrate is hot, cooling the filtrate to crystallize and separate out NH4And drying and weighing Cl crystals, measuring the purity, treating the mother liquor by using an adsorbent, and recycling and reusing the mother liquor.
2. The method for preparing alkali by using waste salt in combination as claimed in claim 1, wherein the waste salt in step (1) is subjected to calcination pretreatment in advance to reduce the organic content therein, so as to ensure that the mass concentration of NaCl is 60-85%, the molar ratio of ammonia gas to NaCl in the waste salt is (1.0-2.0): 1, the mass concentration of the brine solution is 30-50%, the dosage of ammonium bicarbonate is 10-18% (wt.) of the mass of the waste salt, the water bath heating temperature is 50-80 ℃, and the pressure in the carbonation process is always kept at 1-5 MPa.
3. The method for preparing alkali by using waste salt in combination as claimed in claim 1, wherein the adsorbent in step (2) is one of activated carbon, macroporous sulfonic acid resin, acrylate-dimethacrylate copolymer and porphyrin cross-linked chitosan, and the amount of the adsorbent is 5-30% (wt.) of the mass of the waste salt.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911034391.8A CN110589857A (en) | 2019-10-29 | 2019-10-29 | Method for preparing alkali by using waste salt in combination manner |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113135582A (en) * | 2021-04-01 | 2021-07-20 | 常州大学 | Production method for jointly preparing sodium carbonate and ammonium chloride by using sodium chloride |
| CN113636576A (en) * | 2021-10-15 | 2021-11-12 | 国能龙源环保有限公司 | System and method for disposing and recycling miscellaneous salt in coal chemical industry |
| CN114162837A (en) * | 2021-11-29 | 2022-03-11 | 浙江工商大学 | Waste salt recycling treatment system and treatment method thereof |
| CN114715919A (en) * | 2022-06-07 | 2022-07-08 | 中国科学院过程工程研究所 | Method for preparing sodium bicarbonate and co-producing ammonium chloride by using sodium chloride waste salt |
| CN115634900A (en) * | 2022-11-29 | 2023-01-24 | 国能龙源环保有限公司 | Method and system for recycling solid waste miscellaneous salt resources |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113135582A (en) * | 2021-04-01 | 2021-07-20 | 常州大学 | Production method for jointly preparing sodium carbonate and ammonium chloride by using sodium chloride |
| CN113636576A (en) * | 2021-10-15 | 2021-11-12 | 国能龙源环保有限公司 | System and method for disposing and recycling miscellaneous salt in coal chemical industry |
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| CN114715919B (en) * | 2022-06-07 | 2022-09-06 | 中国科学院过程工程研究所 | Method for preparing sodium bicarbonate and co-producing ammonium chloride by using sodium chloride waste salt |
| CN115634900A (en) * | 2022-11-29 | 2023-01-24 | 国能龙源环保有限公司 | Method and system for recycling solid waste miscellaneous salt resources |
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