Method for manufacturing sodium bicarbonate using sodium sulfate and ph adjuster

Abstract

The present invention relates to a method for manufacturing sodium bicarbonate using sodium sulfate and a pH adjuster and, more specifically, to a method for manufacturing sodium bicarbonate, comprising the steps of: forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH adjuster; and adding carbon dioxide and ammonia into the alkaline sodium sulfate solution to generate sodium bicarbonate (NaHCO3).

Description

Method for producing baking soda using sodium sulfate and pH regulator

[0001] The present invention relates to a method for producing sodium bicarbonate using sodium sulfate and a pH regulator, and more specifically, to a method for increasing the solubility of carbon dioxide, thereby reducing the amount of ammonia used and improving the yield of sodium bicarbonate.

[0002] Baking soda (sodium bicarbonate, NaHCO3) is a compound that can be produced by the reaction of sodium (Na) and carbon dioxide (CO2). It is a white substance at room temperature. In industrial use, it is used as a remover to remove sulfur oxides emitted from exhaust gases, and in medicine, it is widely used as an antacid and a raw material for detergents. Soda ash (sodium carbonate, lime, Na2CO3) is a substance produced by heating baking soda and is used in the glass manufacturing process. It is also used, along with baking soda, as a raw material for making soap or detergent.

[0003] The most widely used method for producing baking soda and soda ash is the Solvay process. The Solvay process involves dissolving salt (sodium chloride, NaCl) in water to create brine, then dissolving ammonia and carbon dioxide to create baking soda, which is then heated to create soda ash. The carbon dioxide used in the Solvay process is generated by decomposing lime (calcium carbonate, CaCO3), and the resulting quicklime (calcium oxide, CaO) is reacted with the remaining waste liquid to create calcium chloride.

[0004] Meanwhile, with the recent increase in interest in the environment and carbon neutrality, the amount of sodium sulfate (Na2SO4) produced is increasing. First, sulfur oxides (SO2SO4) emitted from chimneys x ) can be used to remove sulfur dioxide, and the reaction between sulfur oxides contained in the exhaust gas and the sodium bicarbonate produces sodium sulfate as shown in the equation below.

[0005] 2NaHCO3(s) + SO2(g) + 1 / 2O2(g) → Na2SO4(s) + 2CO2(g) + H2O (g)

[0006] When sulfur oxides are released into the atmosphere, they cause acid rain and act as precursors to ultrafine dust, leading to strengthened regulations. For this reason, the use of sodium bicarbonate is increasing at sulfur oxide-emitting businesses, which in turn is increasing the amount of sodium sulfate produced.

[0007] Meanwhile, the global demand for carbon neutrality is growing to curb climate change. Reducing carbon dioxide emissions from transportation is paramount to achieving carbon neutrality. To meet this goal, the proliferation of electric vehicles is rapidly increasing, and so is the production of secondary batteries used in electric vehicles. The production of secondary batteries requires processes for producing lithium, nickel, and precursors, and recycling waste batteries is also crucial. These processes require the extraction of raw materials such as lithium and nickel from ores or waste batteries. The use of caustic soda and sulfuric acid is essential for this extraction. Processes utilizing caustic soda and sulfuric acid inevitably produce sodium sulfate as a byproduct. Consequently, with the strengthening of environmental regulations worldwide and the expansion of the secondary battery industry, the amount of sodium sulfate generated is also increasing significantly, raising concerns about the management of the large quantities of sodium sulfate generated.

[0008] Since sodium sulfate contains sodium, if a technology for producing baking soda and soda ash using sodium sulfate is developed, it could be a good alternative for dealing with the large amount of sodium hydroxide generated due to strengthened environmental regulations and the production of secondary battery materials. However, sodium sulfate solution has different chemical properties from existing salt solutions. The most notable difference is the type of anion dissolved in the solution. While salt forms chloride ions, sodium sulfate contains sulfate ions. Furthermore, the sodium sulfate generated after sulfur oxide removal and the sodium sulfate generated in the secondary battery material production process have different characteristics in terms of impurity content and impurity amounts from the brine solution used in the existing Solvay process. Therefore, there is an urgent need for technology to improve the baking soda and soda ash processes using sodium sulfate solutions with these characteristics.

[0009] One aspect of the present invention is to provide a method for producing sodium bicarbonate, which can increase the amount of dissolved CO2 while reducing the amount of ammonia added to the carbonation reaction, thereby improving the yield of sodium bicarbonate.

[0010] According to one aspect of the present invention, a method for producing sodium bicarbonate is provided, comprising: forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH adjuster; and adding carbon dioxide and ammonia to the alkaline sodium sulfate solution to produce sodium bicarbonate (NaHCO3).

[0011] The method for producing sodium bicarbonate using a sodium sulfate solution according to the present invention forms a basic sodium sulfate solution by mixing a pH adjuster into a sodium sulfate-containing solution, thereby increasing the dissolution of carbon dioxide introduced for a carbonation reaction, thereby reducing the amount of ammonia used in the sodium bicarbonate production process and increasing the yield of sodium bicarbonate. Therefore, the effect of increasing the efficiency of the sodium bicarbonate production process using sodium sulfate can be expected.

[0012] Figure 1 schematically illustrates an exemplary process flow diagram of the present invention.

[0013] Figure 2(a) is a graph showing the change in the yield of sodium bicarbonate according to the amount of Na2CO3 and Figure 2(b) is a graph showing the change in the yield of sodium bicarbonate according to the amount of NaOH added.

[0014] Figure 3 is a graph showing the change in sodium bicarbonate yield according to the Na2CO3 content and ammonia input amount.

[0015] Figure 4 schematically illustrates the flow of an exemplary device that can be used in the method for producing sodium bicarbonate using sodium sulfate and a pH regulator of the present invention.

[0016] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. However, the embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0017] The method for producing sodium bicarbonate of the present invention uses sodium sulfate (Na2SO4) and further forms an alkaline sodium sulfate solution including a pH adjuster, thereby increasing the dissolution of carbon dioxide and further reducing the amount of ammonia used, as well as increasing the yield of sodium bicarbonate.

[0018] More specifically, the method for producing sodium bicarbonate of the present invention comprises the steps of forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH adjuster; and the step of adding carbon dioxide and ammonia to the alkaline sodium sulfate solution to produce sodium bicarbonate (NaHCO3).

[0019] Figure 1 schematically illustrates an exemplary process flow diagram of the present invention, which includes a step (100) of forming an alkaline sodium sulfate solution by mixing sodium sulfate (Na2SO4) (101) and a pH adjuster (102) by stirring or the like, and a carbonation (200) step, wherein sodium bicarbonate (201) is produced in the carbonation step. Subsequently, an ammonia recovery process (300) may be performed, and the ammonia (301) recovered in the ammonia recovery process may be input into the carbonation step, and the remaining waste liquid may be subjected to wastewater treatment (302).

[0020] Meanwhile, the sodium sulfate solution may be obtained by dissolving a sodium sulfate-containing material, for example, a sodium sulfate-containing material such as a desulfurization by-product, in a dissolving agent, and may be obtained using a material having a sodium sulfate content of 50 wt% or more. For example, the sodium sulfate-containing waste may be generated by desulfurizing flue gas containing sulfur oxide (SOx) components with sodium bicarbonate, or may be waste generated as a by-product in a lithium production plant. For example, it may be generated by desulfurizing flue gas generated by combustion in thermal power plants, factories, incinerators, etc., or flue gas generated from an electrostatic precipitation treatment in a steel mill sintering plant using sodium bicarbonate. The sodium sulfate-containing waste may contain dissolved heavy metal components such as lead (Pb) and zinc (Zn), and has a high content of alkali components such as sodium (Na), potassium (K), and calcium (Ca), and also has a high content of chlorine (Cl). Most of the sodium bicarbonate used as a desulfurization agent reacts with SOx to convert into sodium sulfate, and some insoluble gangue components contained in the flue gas are also included. Specifically, the main crystal phases constituting the desulfurization waste are sodium sulfate, sodium chloride, potassium chloride, sodium carbonate, calcium sulfate, and calcium carbonate, and include iron oxide. Among the main crystal phases of the desulfurization dust aqueous solution, sodium sulfate, sodium chloride, and potassium chloride are highly soluble components in water, and thus can be dissolved in water to produce an alkaline desulfurization dust aqueous solution. As such, the sodium sulfate-containing material of the present invention may be a desulfurization byproduct.

[0021] The above eluting agent is not particularly limited as long as it is a substance that can elute sodium ions when combined with a sodium sulfate-containing substance, but may be, for example, one or more selected from water and ammonia, and may be, for example, water.

[0022] More specifically, in such a case, in order to recover sodium sulfate in the form of a sodium sulfate solution containing sodium ions from the sodium sulfate-containing waste, the ratio of the sodium sulfate-containing waste to the eluent is important. If the ratio of the eluent is too low, the sodium sulfate waste will not be completely dissolved, resulting in a large amount of residue, which will reduce the sodium recovery rate. The ratio of the eluent that prevents sodium sulfate from being lost as a residue is at least 1.2 parts by weight of the eluent per 1 part by weight of the sodium sulfate waste. Preferably, 1.4 to 3 parts by weight, for example, 2 to 3 parts by weight, of the eluent is mixed per 1 part by weight of the sodium sulfate waste. If the eluent is included in an excessive amount exceeding this range, even if carbon dioxide is subsequently dissolved in the sodium-containing solution, it will not be precipitated as sodium bicarbonate, and therefore, the content of sodium bicarbonate that flows out in a dissolved state in the solution will increase, which will lower the sodium bicarbonate recovery rate.

[0023] In relation to the step of forming an alkaline sodium sulfate solution containing the above sodium sulfate (Na2SO4) and a pH adjuster, sodium (Na + ) when carbon dioxide is dissolved in a raw material containing sodium bicarbonate, sodium bicarbonate with the lowest solubility is preferentially precipitated. Carbon dioxide is an acidic gas, so in order to dissolve in a solution, the solution must be basic. However, when sodium sulfate is dissolved in water, the pH is neutral (~7), so carbon dioxide does not dissolve well. Therefore, in the present invention, an efficient reaction can be obtained by forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH adjuster.

[0024] For this purpose, any substance with high basicity can serve as a pH regulator in the sodium bicarbonate production process, but considering the purity and yield of the sodium bicarbonate, the pH regulator of the present invention is Na. + A pH regulator of the series, i.e., a sodium salt having a pH of 9 to 12. More specifically, the pH regulator of the present invention may be Na +The basic substance of the series may be at least one selected from the group consisting of caustic soda (NaOH, pH=13), sodium carbonate (Na2CO3, pH=11.7), and baking soda re-added. In particular, since the sodium carbonate is produced by heating baking soda (sodium bicarbonate, NaHCO3), it has the advantage of being able to be supplied through internal circulation.

[0025] Meanwhile, the carbon dioxide may be added to a mixture formed by adding an aqueous ammonia solution to an aqueous alkaline sodium sulfate solution.

[0026] In the method for manufacturing the sodium bicarbonate of the present invention, the contents of sodium sulfate (Na2SO4), pH regulator, ammonia, and water at each step may be input so as to include 10 to 30 wt% of sodium sulfate (Na2SO4), 1 to 20 wt% of pH regulator, 3 to 15 wt% of ammonia, and the remainder water, based on the weight of the mixed solution. For example, the contents may be input so as to include 17 to 26 wt% of sodium sulfate (Na2SO4), 1 to 17 wt% of pH regulator, 3.5 to 10 wt% of ammonia, and the remainder water.

[0027] The above pH regulator not only regulates pH but also acts as a bicarbonate derivative for making baking soda. When the pH regulator is caustic soda, ammonia may be included in an amount of 2 to 10 wt% based on the weight of the mixture of sodium sulfate (Na2SO4), the pH regulator, ammonia, and water. When the pH regulator is sodium carbonate (Na2CO3), ammonia may be included in an amount of 5 to 10 wt% based on the weight of the mixture of sodium sulfate (Na2SO4), the pH regulator, ammonia, and water. When the pH regulator is outside the scope of the present invention, the purity and yield of baking soda may be reduced.

[0028] The alkaline sodium sulfate solution thus obtained may have a pH of greater than 7 to pH 14, for example, a pH of 8 to 13.

[0029] The method for producing sodium bicarbonate of the present invention further includes a step of producing sodium bicarbonate (NaHCO3) by adding carbon dioxide and an aqueous ammonia solution to the alkaline sodium sulfate solution.

[0030] When the step of generating the above sodium bicarbonate (NaHCO3) is performed as in the present invention separately from the step of forming the above-described alkaline sodium sulfate solution, the generation of impurities can be reduced, thereby producing sodium bicarbonate with high purity and yield.

[0031] Carbon dioxide is an acidic gas, so it dissolves well in sodium sulfate solutions. However, if sodium bicarbonate is produced using only carbon dioxide and sodium sulfate solutions, the pH will continuously decrease, resulting in a decrease in the yield of sodium bicarbonate production. In the present invention, the yield of sodium bicarbonate can be improved by mixing ammonia, which can act as a pH buffer, with sodium sulfate. Therefore, for example, an ammonia aqueous solution is mixed with a sodium sulfate solution.

[0032] In general, to dissolve ammonia in a solution such as water, ammonia in a gaseous state is aerated in the aqueous solution. However, when ammonia is aerated in an aqueous solution, the pH increases further, and in a basic aqueous solution, ammonia becomes NH4. + Because it exists in the NH3 state rather than the ammonia state, it has the characteristic of easily dissociating out of the water. Therefore, aeration alone has the disadvantage of not being able to sufficiently dissolve ammonia. Therefore, in general, to produce high-concentration ammonia water, the device that dissolves the ammonia gas must be operated at high pressure.

[0033] Therefore, for example, in order to sufficiently dissolve ammonia in a sodium leaching solution using sodium sulfate-containing waste, ammonia may be mixed in the form of ammonia water rather than injected in the form of gas, but the form of ammonia is not particularly limited.

[0034] The above ammonia aqueous solution may be included in an amount of 15 to 35 wt% based on the total weight of the sodium sulfate solution and the ammonia aqueous solution, and may be included in an amount of, for example, 32 to 33 wt%. If the pH adjusting agent is outside the range of the present invention, the purity and yield of the sodium bicarbonate may be reduced.

[0035] Meanwhile, the sodium sulfate solution and ammonia may be mixed so that the molar ratio of ammonia (NH3) / sodium (Na+) is 0.9 to 1.8, and may be included so that it is, for example, 1.2 to 1.6. If the molar ratio of ammonia (NH3) / sodium (Na+) is outside the range of the present invention, the purity and yield of the sodium bicarbonate may decrease. At this time, if an excessive amount of ammonia is added to dissolve carbon dioxide, the ammonia and carbon dioxide may react to produce a solid such as ammonium carbonate ((NH4)2CO3), which may decrease the purity of the sodium bicarbonate.

[0036] When using an ammonia aqueous solution, the ammonia aqueous solution may be a 25-30 wt% ammonia aqueous solution, and may contain sodium sulfate (Na2SO4), a pH adjuster, and an ammonia aqueous solution in an amount of 32 to 35 wt% based on the total weight of the solution.

[0037] The above sodium sulfate solution can react with carbon dioxide and ammonia to produce solid sodium bicarbonate through a carbonation reaction of the following formula 1.

[0038] Na2SO4+ 2CO2+2NH3+ 2H2O → NaHCO3+ (NH4)2SO4(1)

[0039] As shown in Equation 1 above, the Gibbs free energy of the reaction that produces sodium bicarbonate is -851.0 kJ / mol, which is a negative number, so the reaction that produces sodium bicarbonate can occur spontaneously. In addition, since this reaction is an exothermic reaction, it has the advantage of not consuming much additional energy during the sodium bicarbonate production process.

[0040] The reaction pressure of the carbonation reactor in which the above carbonation reaction occurs may be 1 to 10 atm, and the reaction temperature may be 80°C or lower. If the pressure of the carbonation reactor exceeds 10 atm, a sufficient amount of carbon dioxide can be dissolved, but the energy required for the carbonation reactor is high, which reduces the economic feasibility of the final products, sodium bicarbonate and gypsum.

[0041] Meanwhile, the carbonation reaction time varies depending on the method of carbon dioxide injection. The carbon dioxide of the present invention may be injected in gaseous form. When injected in gaseous form, aeration can be performed, allowing for a reaction time of up to 4 hours. However, the optimized pressure and reaction time may vary depending on the size, space, and conditions of the reactor.

[0042] The above step may be performed at a temperature of 25°C or higher and less than 100°C, and if the temperature is outside this range, the solubility of sodium sulfate tends to decrease, which may lower the yield.

[0043] The carbon dioxide of the present invention may be at least one selected from the group consisting of pure carbon dioxide, FINEX off gas (FOG), FINEX tail gas (FTG), blast furnace gas (BFG), converter gas, coal-fired power plant exhaust gas, gas-fired power plant exhaust gas, incinerator exhaust gas, glass melting exhaust gas, thermal equipment exhaust gas, petrochemical process exhaust gas, petrochemical process gas, pre-combustion exhaust gas, and gasifier exhaust gas. In addition, the carbon dioxide may be concentrated by at least one method selected from the group consisting of a wet amine process, a PSA process, and a membrane process.

[0044] The sodium sulfate (Na2SO4) solution that can be used in the present invention can be, for example, in the form of a 30 to 35 wt% sodium sulfate aqueous solution, the sodium carbonate (Na2CO3) can be, for example, in the form of a 30 to 35 wt% sodium sulfate aqueous solution, and the NaOH can be, for example, in the form of a 50 to 60 wt% aqueous solution, but is not limited thereto.

[0045] Furthermore, a sodium bicarbonate washing step for washing the sodium bicarbonate may be additionally included, and as the amount of washing increases, the purity of the produced sodium bicarbonate may be improved. The washing solution used for the washing may be, for example, one or more selected from water, an aqueous sodium solution, and an aqueous ammonia solution, and furthermore, the solution used for the washing may be recycled as a dissolving agent.

[0046] In addition, the washed sodium bicarbonate may further include a step of drying and crushing the sodium bicarbonate. At this time, the drying temperature is preferably 50°C or lower, for example, 20 to 50°C, preferably 40 to 50°C. If the drying temperature exceeds 50°C, the problem of the sodium bicarbonate being decomposed into sodium carbonate again occurs, and therefore, it is preferable to perform the drying at a temperature exceeding the freezing point of the washing solution. Meanwhile, the crushing may be performed by a ball mill or a cutter mill, but is not limited thereto.

[0047] Meanwhile, the method for producing the sodium bicarbonate of the present invention may additionally include a step of recovering the sodium bicarbonate and adding a calcium-containing material to the remaining residue to produce gypsum. That is, the residue obtained after the carbonation reaction contains sulfate ions (SO4 2- ) is contained in large quantities, a calcium-containing material can be added to manufacture the sulfate ions contained in the filtrate into gypsum. At this time, the molar ratio of calcium ions and sulfate ions (Ca 2+ : SO4 2- ) is preferably 1:1.0 to 1.3, and if the ratio of sulfate ions exceeds 1.3, the purity of gypsum decreases, and if the ratio of sulfate ions is less than 1.0, the pH of the filtrate is too low, which causes a problem in that ammonia cannot be sufficiently recovered in the ammonia stripping step.

[0048] The above calcium-containing material may be at least one selected from the group consisting of waste cement, waste concrete, coal ash, fly ash, iron ore slag, quicklime (CaO), calcium chloride (CaCl2), wollastonite, limestone, olivine, serpentine, asbestos, and deinking ash.

[0049] Furthermore, the method for manufacturing the sodium bicarbonate of the present invention may additionally include an ammonia recovery step of recovering the gypsum and heating the remaining residue to recover ammonia.

[0050] It is preferable that the pH of the ammonia recovery step be maintained at 8.0 or higher. If the pH of the ammonia recovery step is lower than 8.0, there is a problem that the ammonia recovery rate is low. In addition, the ammonia recovery step heats the remaining filtrate, and it is preferable that the heated filtrate is at least 50°C. If the temperature of the filtrate is lower than 50°C, there is a problem that the ammonia recovery rate is low.

[0051] The recovered ammonia can be reused in the form of gas or remanufactured into ammonia water and reused.

[0052] The above-described FIG. 4 of the present invention illustrates an exemplary device that can be used in the method for producing sodium bicarbonate using sodium sulfate and a pH regulator of the present invention, and as shown in FIG. 4, the device can be configured to include a stirring device (S1), a carbonation device (S2), and an ammonia recovery device (S3). In the stirring device (S1), a step of forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH regulator can be performed, and in the carbonation device (S2), a step of generating sodium bicarbonate (NaHCO3) by adding carbon dioxide and ammonia to the alkaline sodium sulfate solution can be performed, and then, in the ammonia recovery device (S3), a step of recovering the sodium bicarbonate and adding a calcium-containing material to the remaining filtrate to generate gypsum can be performed, followed by an ammonia recovery step of recovering the gypsum and heating the remaining filtrate to recover ammonia.

[0053] Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely illustrative examples to aid understanding of the present invention and are not intended to limit the scope of the present invention.

[0054] Example

[0055] 1. Manufacturing of baking soda and gypsum using sodium sulfate and pH adjuster

[0056] Manufacturing Example 1

[0057] 200 g of water was added to 100 g of sodium sulfate (Na2SO4) and stirred at 40°C for 1 hour to prepare a sodium sulfate solution with a concentration of 33 wt%.

[0058] 200 g of water was added to 100 g of sodium carbonate (Na2CO3) in the same ratio and stirred at 40°C for 1 hour to prepare a 33 wt% sodium carbonate solution.

[0059] 100 g of water was added to 100 g of solid NaOH and stirred for 1 hour to prepare a 50 wt% NaOH solution.

[0060] To 80 g of the sodium sulfate solution prepared above, 33 wt% sodium carbonate and 50 wt% NaOH were added, as shown in Table 1 below, and placed in a reactor, followed by adding 25 wt% ammonia water. Additionally, carbon dioxide was bubblingly injected into the reactor at 7 bar, and the reaction was performed at 40°C for 8 hours. After the reaction was completed, the resulting sodium bicarbonate slurry was subjected to solid-liquid separation. The sodium bicarbonate thus obtained was dried in an oven at 50°C for more than 12 hours, and its mass was measured to confirm the yield.

[0061] The yield of sodium bicarbonate is determined by the amount of sodium sulfate and sodium carbonate added and the amount of sodium bicarbonate produced. + Calculated on a mol basis. The purity of the sodium bicarbonate was measured using XRD (X-ray Diffraction) and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) methods. The yield and purity results of the sodium bicarbonate are shown in Table 1 and Figure 2 below.

[0062] As can be seen in Table 1 below, even when the same amount of ammonia water is added, the yield of sodium bicarbonate improves as Na2CO3 and NaOH are added. On the other hand, it can be confirmed that the yield of sodium bicarbonate is higher when NaOH with a higher pH is used.

[0063] [Table 1] Purity and yield of sodium bicarbonate according to the amount of sodium carbonate and NaOH added

[0064]

[0065] However, as can be confirmed in Table 1 above, it was confirmed that although the sodium bicarbonate yield improved as the amount of sodium carbonate or NaOH added increased, it did not increase by more than 80%.

[0066] Experimental Example 1

[0067] A 33 wt% sodium hydroxide, sodium carbonate, and NaOH solution was prepared using the same process as in Manufacturing Example 1. The prepared solution was added to a reactor along with 25 wt% ammonia water as shown in Table 2 below. The reaction, drying, purity, and yield measurement conditions were all the same as in Manufacturing Example 1. The yield and purity results of the sodium bicarbonate are shown in Table 2.

[0068] As a result, as can be seen in Table 2 and Figure 3, when a certain amount of sodium carbonate is added and ammonia is additionally added, the yield of sodium bicarbonate, which had not increased further by the addition of sodium carbonate and / or NaOH, is further increased, and the purity of sodium bicarbonate is also maintained at a certain value.

[0069] Meanwhile, since more than 90% of the ammonia used can be recovered in the actual process, the purity and yield of the sodium bicarbonate can be efficiently increased by adding a certain amount of soda ash and increasing the amount of ammonia water added.

[0070] [Table 2] Purity and yield of sodium bicarbonate according to the amount of sodium carbonate and ammonia added

[0071]

[0072] Meanwhile, in the actual process, more than 90% of ammonia can be recovered and reused through a stripper, and experimental results have confirmed that the yield can be increased by more than 70% by adding a small amount of NaOH and Na2CO3 even when using the same amount of ammonia.

[0073] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible within a scope that does not depart from the technical spirit of the present invention described in the claims.

[0074] [Explanation of symbols]

[0075] 100: Form a sodium sulfate solution through stirring, etc.

[0076] 101: Mangcho 102: pH adjuster

[0077] 200: Carbonation reactor

[0078] 201: Medium

[0079] 300: Ammonia recovery

[0080] 301: Ammonia

[0081] 302: Wastewater

Claims

1. A step of forming an alkaline sodium sulfate solution containing sodium sulfate (Na2SO4) and a pH regulator; and A step of generating sodium bicarbonate (NaHCO3) by adding carbon dioxide and ammonia to the above alkaline sodium sulfate solution; A method for manufacturing a sodium bicarbonate, comprising:

2. A method for producing sodium bicarbonate in the first paragraph, wherein the pH adjusting agent is at least one sodium salt having a pH of 9 to 12 selected from the group consisting of sodium carbonate (Na2CO3), caustic soda, and sodium bicarbonate.

3. A method for producing sodium bicarbonate in the first paragraph, wherein the carbon dioxide is added to a mixed solution formed by adding an ammonia aqueous solution to an alkaline sodium sulfate aqueous solution.

4. A method for producing sodium bicarbonate in the third paragraph, wherein the contents of sodium sulfate (Na2SO4), a pH regulator, ammonia, and water are added so as to include 10 to 30 wt% of sodium sulfate (Na2SO4), 1 to 20 wt% of a pH regulator, 3 to 15 wt% of ammonia, and the remainder of water, based on the weight of the mixed solution.

5. A method for producing sodium bicarbonate, wherein in the third paragraph, when the pH regulator is caustic soda, ammonia is included in an amount of 1 to 10 wt% based on the weight of a mixture of sodium sulfate (Na2SO4), a pH regulator, ammonia, and water.

6. A method for producing sodium bicarbonate, wherein in the third paragraph, when the pH regulator is sodium carbonate (Na2CO3), ammonia is included in an amount of 5 to 10 wt% based on the weight of a mixture of sodium sulfate (Na2SO4), a pH regulator, ammonia, and water.

7. A method for producing sodium bicarbonate, further comprising the step of recovering the sodium bicarbonate and adding a calcium-containing material to the remaining solution to produce gypsum.

8. A method for producing sodium bicarbonate, further comprising an ammonia recovery step of recovering the gypsum and heating the remaining residue to recover ammonia in the 7th paragraph.

9. A method for producing sodium bicarbonate, wherein in paragraph 1, the sodium sulfate solution and the ammonia aqueous solution are mixed so that the ratio of ammonia (NH3) / sodium (Na+) is 0.9 to 1.

8.

10. A method for producing sodium bicarbonate in the first paragraph, wherein the carbon dioxide is injected in gaseous form.

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