Preparation method of large-particle sodium bicarbonate

Abstract

The invention discloses a large-particle sodium bicarbonate crystal and a preparation method thereof, sodium chloride and ammonium bicarbonate are used as raw materials, sodium bicarbonate is generated through a double decomposition reaction in an aqueous solution, ammonium bicarbonate is added in batches for reaction crystallization, and the large-particle sodium bicarbonate crystal product is obtained through the steps of cooling, filtering and drying. The large-particle sodium bicarbonate crystal is simple in preparation process, stable in process, low in energy consumption, high in economical efficiency, high in reproducibility and free of complex equipment and additional additives. The primary yield of the product reaches 60% or above, the circulating yield reaches 98% or above, the purity of the product reaches 99.5% or above, and the obtained large-particle sodium bicarbonate is spherical and has large particle size (D50gt; 200 [mu] m), the particle size distribution is uniform (C.V.lt; 30), the bulk density is high, the fluidity is good, filtering and drying are easy, the production cost can be effectively reduced in actual industrial production, and the market competitiveness of the product is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry and relates to a method for preparing large-particle sodium bicarbonate, in particular to a method for preparing large-particle sodium bicarbonate by double decomposition. Background Art

[0002] Sodium bicarbonate (NaHCO3) is an important inorganic chemical raw material, widely used in food, medicine, chemical industry and other fields, with good market prospects and economic value. In recent years, with the acceleration of industrialization and the improvement of environmental protection requirements, the traditional production method of sodium bicarbonate faces problems such as resource waste and environmental pollution. At the same time, my country's coal chemical, pharmaceutical, fine chemical and other industries produce a large amount of high-salt wastewater every year, and its corresponding treatment and resource utilization have gradually received attention. The use of high-salt wastewater to prepare large-particle sodium bicarbonate can not only effectively reduce wastewater discharge and reduce environmental burden, but also meet the market's growing demand for sodium bicarbonate products and promote resource recycling and sustainable development. Therefore, it is of great theoretical significance and practical application value to develop an efficient and economical process route to realize the resource utilization of high-salt wastewater.

[0003] At present, the methods for preparing sodium bicarbonate in industry mainly include soda ash carbonization method, waste alkali liquor recovery method, natural alkali method and double decomposition method. Soda ash carbonization method is to react sodium carbonate and carbon dioxide to prepare sodium bicarbonate. The sodium bicarbonate product prepared by soda ash carbonization method has high purity and is suitable for use in fields such as food and medicine that have high requirements for product quality. However, this method has the disadvantages of high cost, high energy consumption and high requirements for equipment. Waste alkali liquor recovery method is a process for preparing sodium bicarbonate using industrial waste (such as waste alkali liquor). This method can not only effectively treat waste, but also realize the recycling of resources. However, this method requires pretreatment of impurities in waste alkali liquor, and the composition and concentration of waste alkali liquor may fluctuate, affecting the stability of the reaction and the quality of the product, and the technical maturity of this method in industrial application may be low, requiring further research and development. Natural alkali method is a process for preparing sodium bicarbonate using natural ore (such as natural alkali ore), but natural alkali ore resources are relatively limited, and the mining cost is high, so the application of natural alkali method in industry is subject to certain restrictions. Double decomposition is a process that generates new compounds by chemically reacting two or more compounds. It is often used to prepare sodium bicarbonate. Since sodium bicarbonate has a low solubility, it is directly precipitated from the solution to generate the target product, sodium bicarbonate. This production process does not generate three wastes and does not pollute the environment. It is one of the effective ways to use abundant pure natural raw salt resources. However, the existing double decomposition production methods generally have disadvantages such as unstable quality, uneven particles, and easy nucleation.

[0004] Chinese patent CN115650259A discloses a method for preparing large-particle sodium bicarbonate by carbonization of soda ash. The prepared large-particle sodium bicarbonate product is spindle-shaped, approximately spherical, has good fluidity, and the particles in the particle size range of 180-425μm account for more than 80%. The product quality meets the standards of the "Chinese Pharmacopoeia" and can meet the requirements of large-particle sodium bicarbonate for hemodialysis. However, the required equipment includes multiple special devices (such as carbonization reactors, crystallizers, centrifuges, etc.), and the multi-step reaction process and precise control of temperature and pressure increase the complexity of the operation.

[0005] Chinese patent CN104136372B discloses a method of using a soda carbonization method with a polycarboxylic acid and / or its salt additive to improve the sodium bicarbonate crystallization process. The equipment is complex, the operation is relatively cumbersome, and the particle size of the final product is also small.

[0006] Chinese patent CN112919502A discloses a method for preparing food-grade sodium bicarbonate by double decomposition, but the obtained sodium bicarbonate product has a small particle size and uneven distribution.

[0007] Chinese patent CN118026219A discloses a crystallization method for preparing spherical large-particle sodium bicarbonate by adding one of sodium polyacrylate, polyacrylamide, hydroxymethyl cellulose, sodium tartrate or a mixture of the above additives. However, additives such as sodium polyacrylate, polyacrylamide, hydroxymethyl cellulose and sodium tartrate may increase production costs and may introduce new impurities into the product.

[0008] Therefore, it is very necessary to provide an efficient and low-cost method for preparing large-particle sodium bicarbonate. Summary of the invention

[0009] The object of the present invention is to provide a method for preparing large-particle sodium bicarbonate crystals, which is a method for preparing large-particle sodium bicarbonate crystals by adding ammonium bicarbonate in batches to a sodium chloride solution. The obtained large-particle sodium bicarbonate has a large particle size (D 50 >200μm), uniform particle size distribution (CV<30), easy to filter and dry, good fluidity, convenient storage and transportation. In actual industrial production, it can effectively reduce production costs and greatly improve the market competitiveness of products.

[0010] In order to achieve the above object, the present invention provides a large-particle sodium bicarbonate crystal, wherein the X-ray powder diffraction pattern of the large-particle sodium bicarbonate crystal is at a diffraction angle of 2θ=15.0±0.2, 18.3±0.2, 21.9±0.2, 23.8±0.2, 25.6±0.2, 27.2±0.2, 27.6±0.2, 28.9±0.2, 29.2±0.2, 30.2±0.2, 31.7±0.2, 33.4±0.2, 34.5±0.2, 35.5±0.2 , there are characteristic peaks at 36.8±0.2, 37.3±0.2, 38.0±0.2, 39.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3, and 54.3±0.2 degrees.

[0011] The X-ray powder diffraction pattern of the large-particle sodium bicarbonate crystals is shown in the attached Figure 2 shown.

[0012] The polarized light microscope image of the large-grained sodium bicarbonate crystals is shown in the attached Figure 4 shown.

[0013] Preferably, the molecular formula of the large-particle sodium bicarbonate crystals is NaHCO3.

[0014] Any of the above is preferably that the particle size D of the large-particle sodium bicarbonate crystals is 50 >200μm.

[0015] The present invention also provides a method for preparing the large-particle sodium bicarbonate crystals described in any one of the above, comprising the following steps:

[0016] Step 1: Dissolve sodium chloride fully in deionized water;

[0017] Step 2: Add ammonium bicarbonate and allow to react until it no longer dissolves;

[0018] Step 3: Add sodium bicarbonate seed crystals and continue stirring for 15 to 30 minutes;

[0019] Step 4: Add ammonium bicarbonate in batches to fully react;

[0020] Step 5: Cool the solution to 0-10°C;

[0021] Step 6: Filter and wash the product obtained in step 5;

[0022] Step 7: Dry the product obtained in step 6; after drying, a large-particle sodium bicarbonate product is obtained, namely the large-particle sodium bicarbonate crystals.

[0023] Preferably, in any of the above items, in step 1, the dissolution temperature is 10 to 50° C. Further, the dissolution temperature is preferably 10, 20, 30, 40, 50° C. and ranges therebetween.

[0024] Any of the above is preferably that the mass ratio of sodium chloride to water in the sodium chloride aqueous solution obtained in step 1 is 1.2:10 to 3.5:10. Further, the mass ratio of sodium chloride to water in the sodium chloride aqueous solution is preferably 1.2:10, 1.6:10, 2.0:10, 2.5:10, 3.0:10, 3.5:10 and the range therebetween.

[0025] Any of the above is preferably that in step 2, the mass ratio of the amount of ammonium bicarbonate added to the amount of sodium chloride added in step 1 is 0.7:1 to 1.5:1. Further, the mass ratio of the amount of ammonium bicarbonate added to the amount of sodium chloride added in step 1 is preferably 0.7:1, 1.0:1, 1.2:1, 1.5:1 and the range therebetween.

[0026] Any one of the above is preferably that in step 3, the sodium bicarbonate seed D 50 >50 μm, the mass of the sodium bicarbonate seed crystals added is 0.01-0.5% of the mass of the sodium chloride added in step 1. More preferably, 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.5% and ranges therebetween.

[0027] Any one of the above is preferably that in step 4, ammonium bicarbonate is added in 2 to 8 portions on average.

[0028] In any of the above, the mass ratio of the total mass of ammonium bicarbonate added in step 2 and step 4 to the mass ratio of sodium chloride in step 1 is 0.6:1 to 1.5:1. More preferably, it is 0.6:1, 1.0:1, 1.5:1 and the range therebetween.

[0029] Preferably, in any of the above items, in step 5, the solution cooling rate is 5°C / h to 20°C / h, and more preferably, 5, 10, 15, 20°C / h and the range therebetween.

[0030] Preferably, in any of the above items, in step 6, the washing method is: washing the filtered product with a washing liquid, wherein the washing liquid comprises at least one of anhydrous ethanol, a saturated sodium bicarbonate solution, and ice water. The ice water is preferably 0-5°C ice water, and more preferably 0, 1, 2, 3, 4, 5°C and ice water in the range therebetween.

[0031] Preferably, in any of the above items, in step 7, the drying temperature is 35-55° C. More preferably, it is 35, 40, 45, 50, 55° C. and the range therebetween.

[0032] Preferably, in any of the above items, in step 7, the drying time is 2 to 6 hours, more preferably 2, 3, 4, 5, 6 hours and the range therebetween.

[0033] Any of the above is preferably that the particle size D of the large-particle sodium bicarbonate crystals prepared by the preparation method provided by the present invention is 50 Not less than 200 μm, further preferably D 50 200μm~300μm, preferably D 50 250μm~300μm, preferably D 50 200, 250, 300 μm and ranges therebetween.

[0034] In a preferred embodiment of the present invention, the method for preparing the large particle crystals of the present invention is as follows:

[0035] (1) Dissolve a certain amount of sodium chloride (NaCl) in deionized water and stir continuously for 30 to 60 minutes to fully dissolve;

[0036] (2) First add a certain amount of ammonium bicarbonate (NH4HCO3) and allow it to react until it no longer dissolves;

[0037] (3) Add a certain amount of seed crystals (NaHCO3) and continue stirring for 15 to 30 minutes;

[0038] (4) Add a certain amount of ammonium bicarbonate in batches and allow to react for 30 to 60 minutes;

[0039] (5) Cooling the solution to 0-10°C;

[0040] (6) filtering the product and washing it with a washing liquid;

[0041] (7) Drying the product in a vacuum drying oven;

[0042] (8) obtaining a large-particle sodium bicarbonate product after drying;

[0043] In step (1) of the method, the reaction temperature is 10-50° C., and the mass ratio of sodium chloride to water is (1.2-3.5):10;

[0044] In step (2) of the method, the ratio of the amount of ammonium bicarbonate added to the amount of sodium chloride is (0.7-1.5):1;

[0045] In step (3) of the method, the sodium bicarbonate D 50 >50μm;

[0046] In step (4) of the method, ammonium bicarbonate is added in 2 to 8 portions on average, and the total mass ratio of ammonium bicarbonate added in step (2) and step (4) to sodium chloride is (0.6 to 1.5):1;

[0047] In step (5) of the method, the solution temperature rise and fall rate is 5°C / h to 20°C / h;

[0048] In step (6) of the method, the washing liquid is one or more of anhydrous ethanol, saturated sodium bicarbonate solution, and 0-5°C ice water;

[0049] In step (7) of the method, the drying temperature is 35 to 55° C. and the drying time is 2 to 6 hours;

[0050] In the method, the crystallization method is reactive crystallization, which is carried out under stirring conditions, and the mother liquor after filtration can be subsequently treated to separate the ammonium chloride and then recycled.

[0051] The large-particle sodium bicarbonate crystal preparation process of the present invention is simple, the process is stable, the energy consumption is low, the economy is high, the reproducibility is high, and no complicated equipment and additional additives are required. The one-time yield of the crystal product reaches more than 60%, the cycle yield reaches more than 98%, and the product purity reaches more than 99.5%. Compared with the powdered sodium bicarbonate available on the market, the large-particle sodium bicarbonate obtained by the present invention is spherical, has a uniform particle size distribution, a high bulk density, good fluidity, and is easy to filter and dry. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 : is the particle size distribution curve of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0053] Figure 2 It is the X-ray powder diffraction pattern of the large-particle sodium bicarbonate crystals in the preferred embodiment of the present invention.

[0054] Figure 3 This is a SEM image of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0055] Figure 4 This is a polarized light microscope image of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0056] Figure 5 It is a SEM picture of commercially available powdered sodium bicarbonate product in the prior art.

[0057] Figure 6 This is the X-ray powder diffraction pattern of the preferred embodiment 1 of the present invention.

[0058] Figure 7 This is the X-ray powder diffraction pattern of the preferred embodiment 2 of the present invention.

[0059] Figure 8 This is the X-ray powder diffraction pattern of the preferred embodiment 3 of the present invention.

[0060] Fig. 9 This is the X-ray powder diffraction pattern of the preferred embodiment 4 of the present invention.

[0061] Fig.10 This is the X-ray powder diffraction pattern of the preferred embodiment 5 of the present invention. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below through the accompanying drawings and specific embodiments.

[0063] Figure 1 : is the particle size distribution curve of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0064] Figure 2 It is the X-ray powder diffraction pattern of the large-particle sodium bicarbonate crystals in the preferred embodiment of the present invention.

[0065] Figure 3 This is a SEM image of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0066] Figure 4 This is a polarized light microscope image of large-particle sodium bicarbonate crystals in a preferred embodiment of the present invention.

[0067] Figure 5 The SEM image of the powdered sodium bicarbonate product available in the prior art is shown in Figure 1. The commercially available product is purchased from Tianjin Xiensiopude Technology Co., Ltd., CAS: 144-55-8, purity> 99%.

[0068] Example 1

[0069] (1) Dissolve 30 g of NaCl in 100 ml of deionized water at 20 °C and stir for 1 h to fully dissolve the NaCl solution; (2) Add 5 g of NH4HCO3 and react for 30 min; (3) Add 0.03 g of NaHCO3; (4) Add 30 g of NH4HCO3 in 5 portions with an interval of 40 min; (5) Cool to 5 °C at a cooling rate of 5 °C / h; (6) Filter the precipitated crystals, wash the filter cake with anhydrous ethanol, and filter with vacuum extraction; (7) Dry under vacuum at 45 °C for 3 h; (8) The final product is tested by PXRD. Figure 6As shown, at 2θ = 15.0 ± 0.2, 18.3 ± 0.2, 21.9 ± 0.2, 23.8 ± 0.2, 25.6 ± 0.2, 27.2 ± 0.2, 27.6 ± 0.2, 28.9 ± 0.2, 29.2 ± 0.2, 30.2 ± 0.2, 31.7 ± 0.2, 33.4 ± 0.2, 34.5 ± 0.2, 35.5 ± 0.2, 36.8 ± 0.2, 37.3 ± 0.2, 38.0 ± 0.2, 39. There are characteristic peaks at 9.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3 and 54.3±0.2 degrees, proving to be sodium bicarbonate crystal product.

[0070] Example 2

[0071] (1) Dissolve 50 g of NaCl in 200 ml of deionized water at 50 °C and stir for 1 h to fully dissolve the NaCl solution; (2) Add 15 g of NH4HCO3 and react for 30 min; (3) Add 0.04 g of NaHCO3; (4) Add 40 g of NH4HCO3 in two portions with an interval of 60 min; (5) Cool to 5 °C at a cooling rate of 10 °C / h; (6) Filter the precipitated crystals, wash the filter cake with anhydrous ethanol, and filter with vacuum extraction; (7) Dry under vacuum at 35 °C for 5 h; (8) The final product is tested by PXRD. Figure 7 As shown, at 2θ = 15.0 ± 0.2, 18.3 ± 0.2, 21.9 ± 0.2, 23.8 ± 0.2, 25.6 ± 0.2, 27.2 ± 0.2, 27.6 ± 0.2, 28.9 ± 0.2, 29.2 ± 0.2, 30.2 ± 0.2, 31.7 ± 0.2, 33.4 ± 0.2, 34.5 ± 0.2, 35.5 ± 0.2, 36.8 ± 0.2, 37.3 ± 0.2, 38.0 ± 0.2, 39. There are characteristic peaks at 9.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3 and 54.3±0.2 degrees, proving to be sodium bicarbonate crystal product.

[0072] Example 3

[0073] (1) Dissolve 20 g of NaCl in 100 ml of deionized water at 30 °C and stir for 1 h to fully dissolve the NaCl solution; (2) Add 3 g of NH4HCO3 and react for 30 min; (3) Add 0.02 g of NaHCO3; (4) Add 20 g of NH4HCO3 in three portions with an interval of 60 min; (5) Cool to 10 °C at a cooling rate of 5 °C / h; (6) Filter the precipitated crystals, wash the filter cake with saturated sodium bicarbonate solution, and filter with vacuum suction; (7) Dry under vacuum at 50 °C for 2 h; (8) The final product is tested by PXRD. Figure 8 As shown, at 2θ = 15.0 ± 0.2, 18.3 ± 0.2, 21.9 ± 0.2, 23.8 ± 0.2, 25.6 ± 0.2, 27.2 ± 0.2, 27.6 ± 0.2, 28.9 ± 0.2, 29.2 ± 0.2, 30.2 ± 0.2, 31.7 ± 0.2, 33.4 ± 0.2, 34.5 ± 0.2, 35.5 ± 0.2, 36.8 ± 0.2, 37.3 ± 0.2, 38.0 ± 0.2, 39. There are characteristic peaks at 9.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3 and 54.3±0.2 degrees, proving to be sodium bicarbonate crystal product.

[0074] Example 4

[0075] (1) Dissolve 150 g of NaCl in 500 ml of deionized water at 40 °C and stir for 1 h to fully dissolve the NaCl solution; (2) Add 25 g of NH4HCO3 and react for 30 min; (3) Add 0.5 g of NaHCO3; (4) Add 120 g of NH4HCO3 in 5 portions with an interval of 60 min; (5) Cool to 10 °C at a cooling rate of 10 °C / h; (6) Filter the precipitated crystals, wash the filter cake with 5 °C deionized water, and filter with vacuum suction; (7) Dry under vacuum at 55 °C for 2 h; (8) The final product is tested by PXRD. Fig. 9As shown, at 2θ = 15.0 ± 0.2, 18.3 ± 0.2, 21.9 ± 0.2, 23.8 ± 0.2, 25.6 ± 0.2, 27.2 ± 0.2, 27.6 ± 0.2, 28.9 ± 0.2, 29.2 ± 0.2, 30.2 ± 0.2, 31.7 ± 0.2, 33.4 ± 0.2, 34.5 ± 0.2, 35.5 ± 0.2, 36.8 ± 0.2, 37.3 ± 0.2, 38.0 ± 0.2, 39. There are characteristic peaks at 9.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3 and 54.3±0.2 degrees, proving to be sodium bicarbonate crystal product.

[0076] Example 5

[0077] (1) Dissolve 15 g of NaCl in 100 ml of deionized water at 10 °C and stir for 1 h to fully dissolve the NaCl solution; (2) Add 3 g of NH4HCO3 and react for 30 min; (3) Add 0.015 g of NaHCO3; (4) Add 20 g of NH4HCO3 in three portions with an interval of 60 min; (5) Cool to 5 °C at a cooling rate of 5 °C / h; (6) Filter the precipitated crystals, wash the filter cake with anhydrous ethanol, and filter with vacuum extraction; (7) Dry under vacuum at 55 °C for 2 h; (8) The final product is tested by PXRD. Fig.10 As shown, at 2θ = 15.0 ± 0.2, 18.3 ± 0.2, 21.9 ± 0.2, 23.8 ± 0.2, 25.6 ± 0.2, 27.2 ± 0.2, 27.6 ± 0.2, 28.9 ± 0.2, 29.2 ± 0.2, 30.2 ± 0.2, 31.7 ± 0.2, 33.4 ± 0.2, 34.5 ± 0.2, 35.5 ± 0.2, 36.8 ± 0.2, 37.3 ± 0.2, 38.0 ± 0.2, 39. There are characteristic peaks at 9.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3 and 54.3±0.2 degrees, proving to be sodium bicarbonate crystal product.

[0078] The above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A large-particle sodium bicarbonate crystal, characterized in that: The X-ray powder diffraction pattern of the large-particle sodium bicarbonate crystals is at diffraction angles 2θ=15.0±0.2, 18.3±0.2, 21.9±0.2, 23.8±0.2, 25.6±0.2, 27.2±0.2, 27.6±0.2, 28.9±0.2, 29.2±0.2, 30.2±0.2, 31.7±0.2, 33.4±0.2, 34.5±0.2, 35.5±0.2, 36.8±0.2, 37 There are characteristic peaks at .3±0.2, 38.0±0.2, 39.0±0.2, 40.8±0.2, 43.5±0.2, 44.5±0.2, 45.6±0.2, 46.1±0.2, 46.9±0.2, 47.5±0.2, 48.6±0.2, 48.6±0.2, 49.7±0.2, 50.0±0.2, 51.3±0.2, 52.6±0.2, 53.2±0.3, and 54.3±0.2 degrees.

2. The large-particle sodium bicarbonate crystal according to claim 1, characterized in that The molecular formula of the large-particle sodium bicarbonate crystal is NaHCO3, and the particle size of the large-particle sodium bicarbonate crystal is D 50 >200μm.

3. The method for preparing large-particle sodium bicarbonate crystals according to claim 1 or 2, comprising the steps of: Step 1: Dissolve sodium chloride fully in deionized water; Step 2: Add ammonium bicarbonate and allow to react until it no longer dissolves; Step 3: Add sodium bicarbonate seed crystals and continue stirring for 15 to 30 minutes; Step 4: Add ammonium bicarbonate in batches to fully react; Step 5: Cool the solution to 0-10°C; Step 6: Filter and wash the product obtained in step 5; Step 7: Dry the product obtained in step 6; after drying, a large-particle sodium bicarbonate product is obtained, namely the large-particle sodium bicarbonate crystals.

4. The preparation method according to claim 3, characterized in that: In step 1, the dissolution temperature is 10 to 50° C., and the mass ratio of sodium chloride to water in the sodium chloride aqueous solution obtained in step 1 is 1.2:10 to 3.5:

10.

5. The preparation method according to claim 3, characterized in that: In step 2, the mass ratio of the amount of ammonium bicarbonate added to the amount of sodium chloride added in step 1 is 0.7:1 to 1.5:

1.

6. The preparation method according to claim 3, characterized in that: In step 3, the sodium bicarbonate seed D 50 >50μm, the mass of the sodium bicarbonate seed crystals added is 0.01-0.5% of the mass of the sodium chloride added in step 1.

7. The preparation method according to claim 3, characterized in that: In step 4, ammonium bicarbonate is added in 2 to 8 portions on average, and the mass ratio of the total mass of ammonium bicarbonate added in steps 2 and 4 to the mass ratio of sodium chloride in step 1 is 0.6:1 to 1.5:

1.

8. The preparation method according to claim 3, characterized in that: In step 5, the solution cooling rate is 5°C / h to 20°C / h.

9. The preparation method according to claim 3, characterized in that: In step 6, the washing method is: washing the filtered product with a washing liquid, wherein the washing liquid includes at least one of anhydrous ethanol, a saturated sodium bicarbonate solution, and 0-5° C. ice water.

10. The preparation method according to claim 3, characterized in that: In step 7, the drying temperature is 35 to 55° C., and the drying time is 2 to 6 hours.

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