Method for preparing sodium carbonate from industrial waste salt and rotary disc for preparing sodium carbonate

Abstract

In the process of preparing sodium carbonate from industrial waste salt, sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine are blended into a reaction solution, carbon dioxide gas is introduced for alkali preparation reaction, and sodium bicarbonate solid and alkali preparation mother liquor are obtained; separating the sodium bicarbonate solid from the reaction system, washing with cold water to respectively obtain the sodium bicarbonate solid and an alkali-making mother solution, drying the obtained sodium bicarbonate solid, calcining the dried sodium bicarbonate solid to obtain a sodium carbonate solid, adding calcium hydroxide into the alkali-making mother solution, and stirring to obtain the sodium carbonate. According to the present invention, the organic amine can provide stable amine and high carbon dioxide absorption rate during the alkali production process, such that the entrainment of part of ammonium bicarbonate in the sodium bicarbonate product is avoided so as to improve the alkali production efficiency; the purity of a sodium carbonate product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of waste salt resource utilization, in particular to a method for preparing soda ash from industrial waste salt and a soda ash preparation rotating disk. Background Art

[0002] With the rapid development of my country's petrochemical, pesticide, pharmaceutical and fine chemical industries, a large amount of waste salt has been generated. The National List of Hazardous Wastes, which came into effect on January 1, 2021, clearly defines industrial waste salt and its waste liquid and residue as hazardous waste. Turning these waste salts into treasures not only conforms to the concept of sustainable development, but also brings certain benefits to enterprises.

[0003] Sodium chloride waste salt is mainly composed of sodium salt, calcium salt and a small amount of organic impurities. After detoxification, purification and refinement, the sodium chloride waste salt can be used in the process of producing soda ash.

[0004] The main alkali production methods include the Leblanc process, the Solvay process, and the combined alkali production method. The combined alkali production method has been widely used in recent years. At present, some units and universities have begun to use miscellaneous salts for resource-based alkali production. For example, patent CN115490384A discloses a method for combined alkali production by comprehensive utilization of gas field water and its waste salt. The invention is divided into two process routes, including evaporation and crystallization of NaCl and combined alkali production using NH3·H2O. Although the invention can make comprehensive use of gas field water and its waste salt that are difficult to be treated green by the prior art, its process is complex, energy consumption is high, and the composition of gas field water is complex, which is easy to affect the alkali production results; patent CN110589857A discloses a method for combined alkali production using waste salt, which uses saturated brine and ammonium bicarbonate to produce sodium carbonate solid and ammonium chloride as by-products. The presence of sodium sulfate in this process will affect the product and increase the processing cost.

[0005] In the above disclosed alkali preparation method, the traditional method or the method of absorbing carbon dioxide with ammonia water is used to prepare alkali, which has the disadvantages of high reaction temperature, interference from sodium sulfate / sodium bicarbonate co-crystallization, and easy volatilization of ammonia in water, which affects the reaction yield and product purity. Therefore, an improved technology is urgently needed to solve this problem existing in the prior art. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing soda ash from industrial waste salt and a rotating disk for preparing soda ash based on a method for preparing soda ash by double decomposition reaction, according to which organic amine can provide stable amine and high carbon dioxide absorption rate in the process of preparing soda ash, and organic amine is used to replace ammonium bicarbonate or ammonia water in double decomposition reaction alkali preparation. In a saturated sodium chloride solution, the organic amine and carbon dioxide can be combined at a lower temperature, which is conducive to the formation of carbonate ions. The organic amine is a non-free amine, which avoids entrainment of part of ammonium bicarbonate in the sodium bicarbonate product and improves the purity of the sodium carbonate product, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing soda ash from industrial waste salt, the method for preparing soda ash from industrial waste salt comprising:

[0008] Preparation: preparing sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine for preparing soda ash;

[0009] Alkali production reaction: sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine are prepared into a reaction solution, and carbon dioxide gas is introduced to carry out an alkali production reaction to obtain sodium bicarbonate solid and alkali production mother liquor;

[0010] Separation and washing: separating the sodium bicarbonate solid from the reaction system and washing with cold water to obtain the sodium bicarbonate solid and the alkali mother liquor respectively;

[0011] Drying: drying the obtained sodium bicarbonate solid, and then calcining the dried sodium bicarbonate solid to obtain sodium carbonate solid;

[0012] Recycling of alkali-making mother liquor: Calcium hydroxide is added to the alkali-making mother liquor, and after the reaction, it is cooled to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor, the solid is separated, and the amine-containing mother liquor is recycled to prepare the reaction liquid for alkali production.

[0013] Preferably, the ratio of sodium sulfate in the sodium chloride / sodium sulfate saturated solution prepared in the alkali production reaction is 0.1-9%.

[0014] Preferably, in the alkali production reaction, the molar ratio of the organic amine solution to sodium chloride is 1-1.1, the reaction temperature is 10-25° C., the reaction time is 1.5-2.5 h, and the carbon dioxide gas flow rate is 80-120 ml / min.

[0015] Preferably, the amount of cold water used for washing during the separation and washing process is 5 ml, and the number of washing times is 2 times.

[0016] Preferably, the drying temperature in the drying process is 105°C and the drying time is 2h. The solid obtained after drying is Na2CO3·H2O. The calcination temperature is 300°C, the heating rate is 5° / min, and the time is 2h.

[0017] Preferably, the sodium carbonate content ratio measured during the drying process is in the range of 92.23%-98.51%.

[0018] Preferably, the cooling temperature during the recycling of the alkali-making mother liquor is 5-10°C.

[0019] Preferably, during the alkali production reaction, sodium chloride or a sodium chloride / sodium sulfate mixed salt and an organic amine are modulated into a reaction solution and placed in the central tube of a rotating disk. A maze channel is provided outside the central tube, and the maze channel is connected to the central tube. Carbon dioxide is pressed into the rotating disk from the edge of the rotating disk and discharged from the central tube. During the alkali production reaction, the rotating disk rotates rapidly, the width of the maze channel inside the rotating disk is 0.5 mm-1.2 mm, and the rotating disk rotates at a speed of 400 rpm to 2100 rpm.

[0020] Preferably, the system used in the alkali production reaction process includes a CO2 gas cylinder, a gas pressure reducing valve A, a gas pressure reducing valve B, a gas flow meter, a chromatography column, and a carbon dioxide gas absorption bottle. The gas pressure reducing valve A, the gas pressure reducing valve B, the gas flow meter, and the chromatography column are connected by pipes, one end of the gas flow meter is connected to the bottom of the chromatography column, and the top of the chromatography column is connected to the top center of the carbon dioxide gas absorption bottle by a pipe.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) In the alkali production reaction, the molar ratio of the organic amine solution to sodium chloride is 1-1.1. The organic amine is a non-free amine, which can avoid entrainment of part of ammonium bicarbonate in the sodium bicarbonate product, thereby improving the purity of the sodium carbonate product;

[0023] (2) Carbon dioxide is pressed into the rotating disk from the edge and discharged from the central tube. During the alkali production reaction, the rotating disk rotates rapidly, and the mother liquor with sodium bicarbonate solid after the reaction is discharged from the maze outlet at the edge of the rotating disk. After further solid-liquid separation, sodium bicarbonate solid crystals are obtained;

[0024] (3) The present invention is based on the method of making alkali by double decomposition reaction. According to the fact that organic amines can provide stable amines and high carbon dioxide absorption rate in the process of making alkali, organic amines are used to replace ammonium bicarbonate or ammonia water in the double decomposition reaction alkali making process. In a saturated sodium chloride solution, the organic amines and carbon dioxide can be combined at a lower temperature, which is conducive to the formation of carbonate ions. The organic amines are non-free amines, which avoids the entrainment of part of ammonium bicarbonate in the sodium bicarbonate product, thereby improving the purity of the sodium carbonate product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a laboratory organic amine solution absorbing carbon dioxide to produce alkali according to the present invention;

[0026] Figure 2 Industrial waste salt AC is a comparison of the results of alkali production by traditional process and alkali production by organic amine in Example 2, Example 3 and Example 6, I is the conversion rate of Na by organic amine alkali production, and II is a schematic diagram of the conversion rate of Na by traditional process;

[0027] Figure 3 AC are XRD patterns of products of Example 2, Example 3 and Example 6 of the present invention, respectively;

[0028] Figure 4 It is a schematic diagram of the method for preparing alkali of the present invention;

[0029] Figure 5 It is a cross-sectional view of the rotating disk used for alkali production reaction of the present invention.

[0030] In the figure: 1. CO2 gas cylinder; 2. Gas pressure reducing valve A; 3. Gas pressure reducing valve B; 4. Gas flow meter; 5. Chromatographic column; 6. Carbon dioxide gas absorption bottle. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1-Figure 5 The present invention provides a technical solution: a method for preparing soda ash from industrial waste salt, the method for preparing soda ash from industrial waste salt comprising:

[0033] Preparation: Prepare sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine for preparing soda ash;

[0034] Alkali production reaction: sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine are prepared into a reaction solution, and carbon dioxide gas is introduced to carry out an alkali production reaction to obtain sodium bicarbonate solid and alkali production mother liquor;

[0035] Separation and washing: separating the sodium bicarbonate solid from the reaction system and washing with cold water to obtain the sodium bicarbonate solid and the alkali mother liquor respectively;

[0036] Drying: drying the obtained sodium bicarbonate solid, and then calcining the dried sodium bicarbonate solid to obtain sodium carbonate solid;

[0037] Recycling of alkali-making mother liquor: Calcium hydroxide is added to the alkali-making mother liquor, and after the reaction, it is cooled to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor, the solid is separated, and the amine-containing mother liquor is recycled to prepare the reaction liquid for alkali production.

[0038] The waste salt in the method for preparing soda ash from industrial waste salt includes sodium chloride type waste salt and sodium chloride and sodium sulfate mixed type waste salt. The ratio of sodium sulfate in the prepared sodium chloride / sodium sulfate saturated solution is 0.1-9%, the molar ratio of the added organic amine solution to the sodium chloride is 1-1.1, the reaction temperature is 6-25°C, the carbon dioxide introduction flow rate is 80-120ml / min, the reaction time is 1.5-2.5h, the cooling temperature of the alkali mother liquor is 5-10°C, and the Na conversion rate is the ratio of the Na content in the sodium carbonate in the product to the added Na.

[0039] The ratio of sodium sulfate in the sodium chloride / sodium sulfate saturated solution prepared in the alkali production reaction is 0.1-9%, the molar ratio of the organic amine solution to sodium chloride in the alkali production reaction is 1-1.1, the reaction temperature is 10-25° C., the reaction time is 1.5-2.5 hours, and the carbon dioxide gas flow rate is 80-120 ml / min. The organic amine is a non-free amine, which can avoid entrainment of part of ammonium bicarbonate in the sodium bicarbonate product, thereby improving the purity of the sodium carbonate product.

[0040] The sodium bicarbonate solid is separated from the reaction system, and washed with cold water to obtain the sodium bicarbonate solid and the alkali production mother liquor, respectively. In the process of separating and washing the sodium bicarbonate solid, the amount of cold water used for washing is 5 ml, and the number of washing times is 2 times.

[0041] The drying temperature during the drying process is 105°C and the drying time is 2h. The solid obtained after drying is Na2CO3·H2O. The calcination temperature is 300°C, the heating rate is 5° / min, and the time is 2h. The sodium carbonate content ratio measured during the drying process ranges from 92.23% to 98.51%.

[0042] Calcium hydroxide is added to the alkali production mother liquor, and after the reaction, it is cooled to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. The solid is separated, and the amine-containing mother liquor is recycled to prepare the reaction liquid for alkali production. The cooling temperature during the recycling of the alkali production mother liquor is 5-10°C.

[0043] The system used in the alkali production reaction process includes a CO2 gas cylinder 1, a gas pressure reducing valve A2, a gas pressure reducing valve B3, a gas flow meter 4, a chromatography column 5, and a carbon dioxide gas absorption bottle 6. The gas pressure reducing valve A2, the gas pressure reducing valve B3, the gas flow meter 4, and the chromatography column 5 are connected by pipes. One end of the gas flow meter 4 is connected to the bottom of the chromatography column 5, and the top of the chromatography column 5 is connected to the top center of the carbon dioxide gas absorption bottle 6 by a pipe.

[0044] In the alkali production reaction process, sodium chloride or a sodium chloride / sodium sulfate mixed salt and an organic amine are prepared into a reaction solution and placed in the central tube of a rotating disk. A labyrinth passage is arranged outside the central tube, and the labyrinth passage is connected to the central tube. Carbon dioxide is pressed into the rotating disk from the edge of the rotating disk and discharged from the central tube. In the alkali production reaction process, the rotating disk rotates rapidly, and the mother liquor with sodium bicarbonate solid after the reaction is discharged from the labyrinth outlet at the edge of the rotating disk. After further solid-liquid separation, sodium bicarbonate solid crystals are obtained. The width of the labyrinth passage inside the rotating disk is 0.5 mm-1.2 mm, and the rotating speed of the rotating disk is 400 rpm to 2100 rpm.

[0045] Example 1

[0046] This embodiment provides a method for preparing soda ash from industrial waste salt, wherein the added sodium chloride content is 100%. The organic amine solution and sodium chloride are fully reacted at a molar ratio of 1, the temperature is room temperature, high-purity carbon dioxide is introduced, the carbon dioxide gas flow rate is 80 ml / min, the reaction time is 1.5 hours, the reaction is stopped, and the pH value of the solution is measured to be 8.2. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in an oven at 105°C for drying for 2 hours, at this time, Na2CO3·H2O is obtained, and the dried sample is calcined at 300°C for 2 hours. After calcium hydroxide is added to the alkali mother liquor for reaction, the mother liquor is separated and filtered again, and cooled at 5°C to obtain a calcium chloride / calcium sulfate solid and an amine-containing mother liquor mixture. After calcination, the purity of sodium carbonate is measured to be 95.12%, and the conversion rate of Na is 75.33%.

[0047] Example 2

[0048] The present embodiment provides a method for preparing soda ash from industrial waste salt. The raw waste salt is taken from a landfill, and the sodium chloride content is 99.90%, and the sodium sulfate content is 0.1%. The organic amine solution and sodium chloride are fully reacted at a molar ratio of 1.05, the temperature is room temperature, and high-purity carbon dioxide is introduced. When the carbon dioxide gas flow rate is 100ml / min, the reaction time is 2h, the reaction is stopped, and the pH value of the solution is measured to be 8.01. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in an oven at 105°C for drying for 2h, and Na2CO3·H2O is obtained at this time. The dried sample is then calcined at 300°C for 2h, and the alkali mother liquor is added with calcium hydroxide for reaction, and the mother liquor is separated and filtered again, and cooled at 5°C to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. After calcination, the purity of sodium carbonate is measured to be 91.48%, and the conversion rate of Na is 77.38%.

[0049] Example 3

[0050] The present embodiment provides a method for preparing soda ash from industrial waste salt. The raw waste salt is taken from a landfill, and the sodium chloride content is 96.42%, and the sodium sulfate content is 0.27%. An organic amine solution and sodium chloride are fully reacted at a molar ratio of 1.1. The temperature is room temperature, and high-purity carbon dioxide is introduced. When the carbon dioxide gas flow rate is 100 ml / min and the reaction time is 2.5 hours, the reaction is stopped, and the pH value of the solution is measured to be 7.49. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in an oven at 105° C. and dried for 2 hours to obtain Na2CO3·H2O. The dried sample is then calcined at 300° C. for 2 hours. After calcium hydroxide is added to the alkali mother liquor for reaction, the filtered mother liquor is separated and filtered again, and the mother liquor is cooled at 7° C. to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. After calcination, the purity of sodium carbonate is measured to be 90.28%, and the conversion rate of Na is 71.21%.

[0051] Example 4

[0052] The present embodiment provides a method for preparing soda ash from industrial waste salt. The raw waste salt is taken from a landfill, and the sodium chloride content is 97.38%, and the sodium sulfate content is 0.56%. The organic amine solution and the sodium chloride molar ratio of 1.05 are fully reacted, the temperature is room temperature, and high-purity carbon dioxide is introduced. When the carbon dioxide gas flow rate is 120ml / min, the reaction time is 2.5h, the reaction is stopped, and the pH value of the solution is measured to be 7.60. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in a 105°C oven for drying for 2h, and Na2CO3·H2O is obtained at this time. The dried sample is then calcined at 300°C for 2h, and the alkali mother liquor is added with calcium hydroxide to react, and the mother liquor is separated and filtered again. The mother liquor is cooled at 8°C to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. After calcination, the purity of sodium carbonate is measured to be 95.29%, and the conversion rate of Na is 77.18%.

[0053] Example 5

[0054] The present embodiment provides a method for preparing soda ash from industrial waste salt. The raw waste salt is taken from a landfill, and the sodium chloride content is 95.00%, and the sodium sulfate content is 5.00%. An organic amine solution and sodium chloride are fully reacted at a molar ratio of 1.05. The temperature is room temperature, and high-purity carbon dioxide is introduced. When the carbon dioxide gas flow rate is 100 ml / min and the reaction time is 2 hours, the reaction is stopped, and the pH value of the solution is measured to be 7.62. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in an oven at 105° C. and dried for 2 hours to obtain Na2CO3·H2O. The dried sample is then calcined at 300° C. for 2 hours. After calcium hydroxide is added to the alkali mother liquor for reaction, the filtered mother liquor is separated and filtered again, and the mother liquor is cooled at 8° C. to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. After calcination, the purity of sodium carbonate is measured to be 98.51%, and the conversion rate of Na is 70.27%.

[0055] Example 6

[0056] The present embodiment provides a method for preparing soda ash from industrial waste salt, wherein the raw waste salt is taken from a landfill, and the sodium chloride content is 80.91%, and the sodium sulfate content is 8.22%. Sodium chloride and organic amine are fully reacted at a molar ratio of 1.05, the temperature is room temperature, high-purity carbon dioxide is introduced, and the reaction is stopped at a carbon dioxide gas flow rate of 100 ml / min, and the reaction time is 2 hours. The pH value of the solution is measured to be 7.56, at which time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in an oven at 105° C. and dried for 2 hours, and Na2CO3·H2O is obtained at this time. The dried sample is then calcined at 300° C. for 2 hours, and the alkali mother liquor is added with calcium hydroxide to react, and the mother liquor is separated and filtered again, and the mother liquor is cooled at 9° C. to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor. After calcination, the purity of sodium carbonate is measured to be 92.83%, and the conversion rate of Na is 72.37%.

[0057] Example 7

[0058] The present embodiment provides a method for preparing soda ash from industrial waste salt, wherein the raw waste salt is taken from a landfill, and the sodium chloride content is 90.90%, and the sodium sulfate content is 9.0%. The organic amine solution and sodium chloride are fully reacted at a molar ratio of 1.05, the temperature is room temperature, and high-purity carbon dioxide is introduced. When the carbon dioxide gas flow rate is 80 ml / min and the reaction time is 2.5 hours, the reaction is stopped, and the pH value of the solution is measured to be 7.54. At this time, the obtained sodium bicarbonate precipitate is filtered, and the filtered solid is placed in a 105° C. oven and dried for 2 hours, and Na2CO3·H2O is obtained at this time. The dried sample is then calcined at 300° C. for 2 hours, and the alkali mother liquor is added with calcium hydroxide to react, and the mother liquor is separated and filtered again, and cooled at 10° C. to obtain a calcium chloride / calcium sulfate solid and an amine-containing mother liquor mixture. After calcination, the purity of sodium carbonate is measured to be 96.88%, and the conversion rate of Na is 70.57%.

[0059] The invention is based on the method of making alkali by double decomposition reaction, and according to the fact that the organic amine can provide stable amine and high carbon dioxide absorption rate in the process of making alkali, the organic amine is used to replace the ammonium bicarbonate or ammonia water in the double decomposition reaction alkali making. In the saturated sodium chloride solution, the organic amine and the carbon dioxide can be combined at a lower temperature, which is conducive to the formation of carbonate radicals. The organic amine is a non-free amine, so that part of the ammonium bicarbonate is avoided to be entrained in the sodium bicarbonate product, and the purity of the sodium carbonate product is improved.

[0060] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing soda ash from industrial waste salt, characterized in that: The method for preparing soda ash from industrial waste salt comprises: Preparation: preparing sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine for preparing soda ash; Alkali production reaction: sodium chloride or sodium chloride / sodium sulfate mixed salt and organic amine are prepared into a reaction solution, and carbon dioxide gas is introduced to carry out an alkali production reaction to obtain sodium bicarbonate solid and alkali production mother liquor; Separation and washing: separating the sodium bicarbonate solid from the reaction system and washing with cold water to obtain the sodium bicarbonate solid and the alkali mother liquor respectively; Drying: drying the obtained sodium bicarbonate solid, and then calcining the dried sodium bicarbonate solid to obtain sodium carbonate solid; Recycling of alkali-making mother liquor: Calcium hydroxide is added to the alkali-making mother liquor, and after the reaction, it is cooled to obtain a mixture of calcium chloride / calcium sulfate solid and amine-containing mother liquor, the solid is separated, and the amine-containing mother liquor is recycled to prepare the reaction liquid for alkali production.

2. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The proportion of sodium sulfate in the sodium chloride / sodium sulfate saturated solution prepared in the alkali production reaction is 0.1-9%.

3. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: In the alkali production reaction, the molar ratio of the organic amine solution to sodium chloride is 1-1.1, the reaction temperature is 10-25° C., the reaction time is 1.5-2.5 h, and the carbon dioxide gas flow rate is 80-120 ml / min.

4. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The amount of cold water used for washing during the separation and washing process is 5 ml, and the number of washing times is 2 times.

5. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The drying temperature in the drying process is 105° C. and the drying time is 2 h. The solid obtained after drying is Na 2 CO 3 · H 2 O. The calcination temperature is 300° C., the heating rate is 5° / min, and the time is 2 h.

6. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The sodium carbonate content ratio measured during the drying process ranges from 92.23% to 98.51%.

7. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The cooling temperature during the recycling of the alkali-making mother liquor is 5-10°C.

8. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: In the alkali production reaction process, sodium chloride or a sodium chloride / sodium sulfate mixed salt and an organic amine are prepared into a reaction solution and placed in the central tube of a rotating disk. A labyrinth channel is arranged outside the central tube, and the labyrinth channel is connected to the central tube. Carbon dioxide is pressed into the rotating disk from the edge of the rotating disk and discharged from the central tube. In the alkali production reaction process, the rotating disk rotates rapidly, the width of the labyrinth channel inside the rotating disk is 0.5 mm-1.2 mm, and the rotating disk rotates at a speed of 400 rpm to 2100 rpm.

9. The method for preparing soda ash from industrial waste salt according to claim 1, characterized in that: The system used in the alkali production reaction process includes a CO2 gas cylinder (1), a gas pressure reducing valve A (2), a gas pressure reducing valve B (3), a gas flow meter (4), a chromatography column (5), and a carbon dioxide gas absorption bottle (6). The gas pressure reducing valve A (2), the gas pressure reducing valve B (3), the gas flow meter (4), and the chromatography column (5) are connected by pipes. One end of the gas flow meter (4) is connected to the bottom of the chromatography column (5), and the top of the chromatography column (5) is connected to the top center of the carbon dioxide gas absorption bottle (6) by a pipe.

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