Dry preparation method of sodium perborate and preparation device thereof

Abstract

The invention discloses a dry preparation method of sodium perborate and a preparation device thereof, and belongs to the field of dry preparation of sodium perborate. The preparation method comprises the following steps: S1, hydrogen peroxide pretreatment: adding a stabilizer into a hydrogen peroxide solution; s2, preparing a reactant precursor, putting solid borax pentahydrate and solid sodium hydroxide into a horizontal reactor according to a certain molar ratio, and stirring; titanium dioxide is added, and an ultraviolet light beam emitter is turned on; then adding a weakly alkaline pH buffer regulator to obtain a reactant precursor; s3, spraying the hydrogen peroxide solution added with the stabilizer in the step S1 into the reactant precursor in the step S2, stirring, and increasing the power of an ultraviolet beam emitter when spraying begins; and after the reaction is finished, drying to obtain a sodium perborate solid. According to the method, solid-liquid separation is not needed, and the process link of centrifugation is omitted, so that a large amount of production time is saved, and the overall production efficiency is improved by more than 30%.

Description

Technical Field

[0001] The invention relates to the field of dry preparation of sodium perborate, and more specifically to a dry preparation method of sodium perborate and a preparation device thereof. Background Art

[0002] Sodium perborate has advantages in many fields such as detergents, textile bleaching, sewage treatment, agricultural disinfection, medical disinfection and battery materials. However, the existing sodium perborate preparation technology adopts wet preparation, adding sodium perborate mother liquor as a base medium before the reaction, the basic raw materials are borax pentahydrate, sodium hydroxide and hydrogen peroxide, and finally reacting to form a saturated suspension of sodium perborate, and then obtaining a solid product through centrifugation, drying and other steps. However, this process has the following defects: 1. The wet process is complicated, and the sodium perborate suspension needs to be centrifuged, the reaction steps are many, the time is long, and the overall production efficiency is low; 2. A large amount of wastewater is generated after the reaction is completed; and the wastewater contains unreacted alkali, borate and other components, which require complex wastewater treatment before discharge, which increases environmental pressure and processing costs. In addition, the loss of some active substances in the wastewater also reduces the effective utilization rate of raw materials; 3. The method obtains sodium perborate as crystal particles precipitated from a supersaturated solution, which are small, have a relatively low active oxygen content, and have poor active storage stability.

[0003] Therefore, it is necessary to provide a method for preparing sodium perborate which can solve the above problems of large amount of wastewater, complicated process, small prepared sodium perborate particles, low active oxygen content and poor activity stability. Summary of the invention

[0004] In view of the problems existing in the prior art, the first purpose of the present invention is to provide a dry preparation method of sodium perborate, which has a simple process, no wastewater is generated during the reaction process, and the particles of the prepared sodium perborate are larger and the active oxygen content is significantly improved; in addition, the sodium perborate prepared by the method has high activity stability; the second purpose of the present invention is to provide a dry preparation device of sodium perborate.

[0005] To solve the above problems, the present invention adopts the following technical solutions.

[0006] A dry preparation method of sodium perborate, the preparation method is as follows: S1: Hydrogen peroxide pretreatment: adding stabilizer to the hydrogen peroxide solution; S2: Preparation of reactant precursor: solid borax pentahydrate and solid sodium hydroxide are added into a horizontal reactor according to a certain molar ratio and stirred; titanium dioxide is added and the ultraviolet beam emitter is turned on; then a weakly alkaline pH buffer regulator is added to obtain a reactant precursor; S3: spray the hydrogen peroxide solution with stabilizer added in S1 into the reactant precursor of step S2, stir, and increase the power of the ultraviolet light beam emitter at the beginning of spraying; after the reaction is completed, dry to obtain sodium perborate solid.

[0007] Furthermore, in step S1, the concentration of the hydrogen peroxide solution is 30-40%, the stabilizer is one of citric acid, sodium silicate, hydroxyethylidene diphosphonic acid and hydroxypropyl methacrylate; and the mass ratio of the stabilizer to the hydrogen peroxide in the hydrogen peroxide solution is 0.1-0.3:100.

[0008] Furthermore, the initial wavelength of the ultraviolet light emitted by the ultraviolet light beam emitter in step S2 is 300-500 nm, and the power is 300-600 W.

[0009] Furthermore, in step S2, the molar ratio of solid sodium hydroxide to solid borax pentahydrate is 2-2.5:1.

[0010] Furthermore, in the step S2, the mass ratio of titanium dioxide to solid borax pentahydrate is 0.09-0.13:100.

[0011] Furthermore, in the step S2, the weakly alkaline pH buffer regulator is a sodium phosphate buffer, a borax-calcium chloride buffer solution or a tris(hydroxymethyl)aminomethane hydrochloride buffer solution; the sodium phosphate buffer is composed of sodium monohydrogen phosphate, sodium dihydrogen phosphate and water, and the mass percentage of sodium monohydrogen phosphate is 9.3%; the mass percentage of sodium dihydrogen phosphate is 0.7%; the tris(hydroxymethyl)aminomethane hydrochloride buffer solution is composed of tris(hydroxymethyl)aminomethane, hydrochloric acid and water, and the mass percentage of tris(hydroxymethyl)aminomethane is 12%, and the mass percentage of hydrochloric acid is 4%.

[0012] Furthermore, in step S2, a weakly alkaline pH buffer regulator is used to adjust the pH during the reaction to 8-9.

[0013] Furthermore, the molar ratio of hydrogen peroxide to borax pentahydrate in the hydrogen peroxide solution sprayed in step S3 is 3-5:1.

[0014] Furthermore, in step S3, the power of the ultraviolet light beam emitter (3) is increased to 600 W; the reaction temperature is 30-35° C., and the reaction time is 50-60 min.

[0015] The invention also provides a preparation device for dry preparation of sodium perborate, which is used for the dry preparation method of sodium perborate.

[0016] Furthermore, the preparation device includes a high-pressure spray system, a horizontal reactor, an ultraviolet beam emitter, a motor and an integrated control device; an agitator is rotatably installed inside the horizontal reactor, and the agitator is fixedly connected to the motor; the high-pressure spray system, the ultraviolet beam emitter, the motor and the integrated control device are electrically connected, a base is fixedly connected to the lower end of the horizontal reactor, and the upper side of the horizontal reactor is detachably connected to the high-pressure spray system; a plurality of ultraviolet beam emitters are detachably connected to the side of the horizontal reactor, a cooling jacket is detachably connected to the outer end of the horizontal reactor, the cooling jacket is electrically connected to the integrated control device, and the horizontal reactor is located on one side of the integrated control device; the base is detachably connected to the motor.

[0017] Furthermore, the stirrer is a spiral stirrer.

[0018] Furthermore, the diameter of the nozzle hole of the high-pressure sprayer is 50~150 μm; the high-pressure sprayer is in high-pressure mode, and the spray pressure is 0.2~0.6 Mpa.

[0019] The specific preparation process is as follows: (1) Hydrogen peroxide pretreatment: prepare a 30-40% concentration of hydrogen peroxide solution in advance, add a stabilizer accounting for 0.1-0.3% of the mass fraction of hydrogen peroxide in the hydrogen peroxide solution, and the stabilizer used is one of citric acid, sodium silicate, hydroxyethylidene diphosphonic acid and hydroxypropyl methacrylate. Add the accurately weighed stabilizer to the above hydrogen peroxide solution and stir thoroughly to mix evenly; (2) Preparation of sodium hydroxide and borax pentahydrate: prepare solid borax pentahydrate and solid sodium hydroxide in advance, the molar ratio of solid sodium hydroxide to solid borax pentahydrate being 2-2.5:1, put the solid borax pentahydrate and solid sodium hydroxide into a horizontal reactor, install a spiral stirrer inside the horizontal reactor, and adjust the rotation speed to 60-150 r / min to obtain a mixture of sodium hydroxide and borax pentahydrate; (3) Titanium dioxide photocatalysis: At the initial stage of the reaction, the ultraviolet beam emitter is turned on to irradiate the input ultraviolet beam of 300-500 nm. At the same time, titanium dioxide accounting for about 0.1% of the mass fraction of borax pentahydrate is added to the mixture of sodium hydroxide and borax pentahydrate in step (2) for photocatalysis during the reaction. The photocatalytic effect of titanium dioxide under specific wavelength conditions will generate a large number of hydroxyl radicals (·OH) and superoxide radicals (·O 2- ), such active free radicals enable hydrogen peroxide to react with borax pentahydrate and sodium hydroxide in the presence of a very small amount of water to generate a sodium perborate wet solid with a qualified content; (4) Weakly alkaline buffer: Add a weakly alkaline pH buffer regulator to the mixture to which titanium dioxide is added in step (3), using a specific ratio of sodium phosphate buffer (composed of sodium monohydrogen phosphate, sodium dihydrogen phosphate and water), borax-calcium chloride buffer solution or tris(hydroxymethyl)aminomethane hydrochloride buffer solution, to adjust the pH value of the dry process for preparing sodium perborate to 8-9, provide a weakly alkaline environment, allow the reaction to proceed smoothly, and obtain the reactant precursor; (5) Hydrogen peroxide spray feeding: prepare hydrogen peroxide with a molar amount of 4 times that of borax pentahydrate, feed the hydrogen peroxide solution with stabilizer added through the high-pressure spray system, and evenly install 3 high-pressure sprayers on the top of the reactor to ensure that the hydrogen peroxide can be completely and evenly sprayed into the material system. The diameter of the spray hole is controlled between 50 and 150 μm. The high-pressure spray system adopts high-pressure mode, and the pressure is usually set within 0.2~0.6 Mpa. Through high-pressure transmission, hydrogen peroxide is quickly atomized at the nozzle to form fine droplets, and the hydrogen peroxide droplets are evenly sprayed into the reactant precursor that is already being stirred. The hydrogen peroxide spray time is 30~60 minutes; (6) After the addition of hydrogen peroxide is completed, the reaction materials are evenly sent to the fluidized bed dryer for drying.

[0020] Compared with the prior art, the advantages of the present invention are: 1. This scheme installs a UV beam emitter in the reactor to excite titanium dioxide within a specific wavelength range of 300-500 nm, causing water molecules to generate free radicals (such as active oxygen free radicals • OH and superoxide anion free radicals • O 2- ), these active free radicals make up for the problem of insufficient reaction power of sodium peroxide in dry reaction, so that hydrogen peroxide can react quickly with borax pentahydrate and sodium hydroxide under dry conditions to produce wet sodium perborate with qualified content. In addition, compared with the wet process, this method does not require solid-liquid separation and eliminates the process link of centrifugation, thus saving a lot of production time and improving the overall production efficiency by more than 30%.

[0021] 2. The dry preparation process of this scheme does not need to use a large amount of mother liquor water as a solvent medium, thus avoiding the generation of a large amount of wastewater containing salt and active ingredients.

[0022] 3. The content of effective active oxygen in the sodium perborate prepared by this scheme is better than that prepared by the wet method, and the sodium perborate prepared by this method has better storage stability.

[0023] 4. During the reaction process of this scheme, the regulating effect of the buffer enables the reaction to proceed under weak alkaline conditions, which is conducive to the smooth progress of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of a device for preparing sodium perborate by dry method of the present invention; Figure 2 It is a partial structural schematic diagram of the dry method for preparing sodium perborate of the present invention; Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure of part A; Figure 4 The present invention is a schematic diagram of the material discharge structure of the dry method for preparing sodium perborate.

[0025] Description of the numbers in the figure: 1 high-pressure spray system, 11 liquid storage tank, 12 hose, 13 high-pressure sprayer, 2 horizontal reactor, 21 shell, 22 feeding port, 23 stirring device, 231 main shaft, 232 rotating blade, 24 unloading device, 241 unloading space, 242 unloading sheet, 243 rotating shaft, 244 rotating gear, 245 rack, 246 connecting plate, 247 reversible motor, 248 limit block, 3 ultraviolet beam emitter, 4 cooling jacket, 5 motor, 6 base, 7 integrated control device. DETAILED DESCRIPTION

[0026] See also Figure 1-Figure 4 A dry process sodium perborate preparation device comprises a high pressure spray system 1, a horizontal reactor 2, an ultraviolet beam emitter 3, a cooling jacket 4, a motor 5, a base 6 and an integrated control device 7. The high pressure spray system 1, the ultraviolet beam emitter 3, the cooling jacket 4 and the motor 5 are electrically connected to the integrated control device 7 to realize the centralized control of the dry process preparation device and reduce the control difficulty of the reaction device. The base 6 is fixedly connected to the lower side of the horizontal reactor 2; the base 6 is detachably connected to the motor 5.

[0027] The horizontal reactor 2 includes a shell 21 and a stirring device 23. A storage space for storing reaction materials is provided in the shell 21. A feed port 22 is fixedly connected to the top of the shell 21. A plurality of discharge ports are provided at the bottom of the shell 21. The feed port 22 and the discharge ports are connected to the internal space of the shell 21. The stirring device 23 is rotatably installed in the shell 21 at the center line. The stirring device 23 includes a main shaft 231 and a rotating blade 232. The main shaft 231 is fixedly connected to the rotating blade 232. The main shaft 231 passes through the shell 21, and one end of the main shaft 231 is fixedly connected to the motor 5, and the other end is rotatably connected to the base 6. A sealing ring is installed at the connection between the main shaft 231 and the shell 21 to prevent the reaction materials in the shell 21 from leaking out.

[0028] A feeding device 24 is fixedly connected to the feeding port, and the feeding device 24 completely covers the feeding port. The feeding device 24 includes a feeding space 241, a feeding piece 242, and a rotating device; the feeding piece 242 is embedded and rotatably connected in the feeding space 241. The rotating device includes a rotating shaft 243 extending outward from the two sides of the feeding piece 242 and the center line, a rotating gear 244 fixedly connected to the outer end of the rotating shaft 243, a pair of racks 245 matched with the rotating gear 244, a reversible motor 247, and a limit block 248. A pair of racks 245 are embedded and slidably connected to the inner wall of the lower end of the housing 21, and a connecting plate 246 is fixedly connected between the pair of racks 245, so that the racks 245 can move synchronously. Such a design prevents the racks 245 from deviating during movement. One end of a pair of racks 245 extends to the outside of the outer shell 21, and is embedded and slidably connected to the inside of the limit block 248, so that the racks 245 can move inside the limit block 248; a gear matching a pair of racks 245 is detachably connected to the output shaft of the reversible motor 247, and the distance between the pair of gears is equal to the distance between the pair of racks 245; the reversible motor 247 can control the pair of racks 245 to move repeatedly, thereby controlling the opening and closing of the lower sheet, and the reversible motor 247 is electrically connected to the integrated control device 7.

[0029] The high-pressure spray system 1 includes a liquid storage tank 11, a hose 12 and a high-pressure sprayer 13, and the high-pressure sprayer 13 is detachably connected to the liquid storage tank 11 through the hose 12. The high-pressure sprayer 13 is detachably connected to the upper side of the horizontal reactor 2 and communicates with the internal storage space of the housing 21. The high-pressure spray system 1 effectively increases the surface area of ​​the reaction material by dropletizing the reaction material, thereby significantly improving the reaction efficiency and reaction speed.

[0030] The side wall of the housing 21 is detachably connected with a plurality of groups of ultraviolet light beam emitting devices, the distance between each two adjacent groups of ultraviolet light beam emitting devices is equal, and the first group of ultraviolet light beam emitting devices and the last group of ultraviolet light beam emitting devices are respectively installed at the ends of the side wall of the housing 21. Each group of ultraviolet light beam emitting devices includes 10 ultraviolet light beam emitters 3, and the distance between any adjacent ultraviolet light beam emitters 3 in each group of ultraviolet light beam emitting devices is equal.

[0031] A cooling jacket 4 is detachably mounted on the outside of the housing 21 to maintain the temperature in the reactor and prevent overheating, thereby ensuring the stability of the reaction.

[0032] During the reaction process, the lowering sheet 242 completely covers the lowering space 241 to prevent the reaction materials from leaking from the lowering space 241, thereby causing waste of the reaction materials. After the reaction is completed, the reversible motor 247 drives the rack 245 to slide in the direction close to the lowering sheet 247, thereby driving the lowering sheet 242 to rotate clockwise, so that the lowering space 241 is unblocked and the reaction materials can flow out of the lowering space 241. When the reaction materials have completely flowed out, the reversible motor 247 drives the rack 245 to slide in the direction away from the lowering sheet 247, thereby driving the lowering sheet 242 to rotate counterclockwise, so that the lowering space 241 is completely blocked and the reaction materials cannot flow out of the lowering space 241.

[0033] Embodiment 1:

[0034] Preparation process of sodium perborate: (1) Hydrogen peroxide pretreatment: add 453 kg of 30% hydrogen peroxide solution and 0.242 kg of stabilizer citric acid into the liquid storage tank 11, and stir until the citric acid is completely dissolved; then place it in a cool place, avoid direct sunlight, and avoid decomposition of hydrogen peroxide in a high temperature environment.

[0035] (2) Preparation of sodium hydroxide and borax pentahydrate: 291 kg of borax pentahydrate solid and 80 kg of sodium hydroxide solid were added into the horizontal reactor 2 and mixed together. To ensure uniform mixing, stirring was performed during the mixing process. The stirring rate of the stirring device 23 was 150 r / min. The stirring was performed for 10 min to ensure that the sodium hydroxide and borax pentahydrate were completely mixed, thereby obtaining a mixture of sodium hydroxide and borax pentahydrate.

[0036] (3) Titanium dioxide photocatalytic reaction: 0.375 kg of titanium dioxide was added to the mixture of sodium hydroxide and borax pentahydrate prepared in step (2); all ultraviolet beam emitters 3 were turned on, and the ultraviolet beam emitters 3 were controlled so that the wavelength of the emitted ultraviolet beam was 300 nm and the power was 300 W.

[0037] (4) Weakly alkaline buffer: add 0.291 kg of sodium phosphate buffer solution (buffer composition: 9.3% sodium monohydrogen phosphate, 0.7% sodium dihydrogen phosphate, and the remainder water) to the mixture to which titanium dioxide is added in step (3); stir thoroughly to obtain a reaction precursor mixture.

[0038] (5) Spraying of hydrogen peroxide: Use a high-pressure sprayer 13 with a nozzle diameter of 100 μm and a spray pressure of 0.5 MPa to evenly spray the pretreated hydrogen peroxide in the liquid storage tank 11 into the reaction precursor mixture of step (4), and stir and control the reaction temperature to 30-35 °C. During the spraying process, the power of the ultraviolet beam emitter 3 is continuously increased to 600 w and the stirring rate of the stirring device 23 is controlled to 80 r / min, and the spraying time is 40 min; after the spraying is completed, the stirring rate of the stirring device 23 is reduced to 30 r / min, and stirred for 10 min.

[0039] (6) Material drying and finished product processing: After the reaction is completed, the unloading device 24 of the horizontal reactor 2 is opened to transport all the materials after the reaction in step (5) to the fluidized bed dryer, and the outlet temperature of the dryer is set to 70°C, the inlet air temperature is set to 90°C, and the drying lasts for 60 min.

[0040] (7) Reaction summary: Total reaction time: 20 min for raw material and precursor preparation, 50 min for hydrogen peroxide spraying, 60 min for finished product drying, a total of 2 h 10 min. Finished product: 410 kg of sodium perborate finished product was obtained, and the active oxygen content in the sodium perborate finished product was 15.7%.

[0041] Example 2: Preparation process of sodium perborate: (1) Hydrogen peroxide pretreatment: add 340 kg of 40% hydrogen peroxide solution and 0.242 kg of stabilizer hydroxyethylidene diphosphonic acid into the liquid storage tank 11, and stir until the hydroxyethylidene diphosphonic acid is completely dissolved; then place it in a cool place to avoid direct sunlight to prevent the decomposition of hydrogen peroxide in a high temperature environment.

[0042] (2) Preparation of sodium hydroxide and borax pentahydrate: 291 kg of borax pentahydrate solid and 100 kg of sodium hydroxide solid were added into the horizontal reactor 2 and mixed together. To ensure the mixing uniformity, the mixing process was stirred. The stirring rate of the stirring device 23 was 150 r / min. The stirring was performed for 10 min to ensure that the sodium hydroxide and borax pentahydrate were completely mixed, thereby obtaining a mixture of sodium hydroxide and borax pentahydrate.

[0043] (3) Titanium dioxide photocatalytic reaction: 0.375 kg of titanium dioxide was added to the mixture of sodium hydroxide and borax pentahydrate prepared in step (2); after mixing evenly, all ultraviolet beam emitters 3 were turned on, and the ultraviolet beam emitters 3 were controlled so that the wavelength of the emitted ultraviolet beam was 350 nm and the power was 300 W.

[0044] (4) Weakly alkaline buffer: Add 0.291 kg of tris(hydroxymethyl)aminomethane hydrochloride buffer solution (buffer composition: 12% tris(hydroxymethyl)aminomethane, 4% hydrochloric acid, and the remainder water) to the mixture to which titanium dioxide is added in step (3); stir thoroughly to obtain a reaction precursor mixture.

[0045] (5) Spraying of hydrogen peroxide: Use a high-pressure sprayer 13 with a nozzle diameter of 100 μm and a spray pressure of 0.6 MPa to evenly spray the pretreated hydrogen peroxide in the liquid storage tank 11 into the reaction precursor mixture of step (4), and stir and control the reaction temperature to 30-35 °C. During the spraying process, the power of the ultraviolet beam emitter 3 is continuously increased to 600 W and the stirring rate of the stirring device 23 is controlled to 90 r / min, and the stirring is continued for 40 min; after the spraying is completed, the stirring rate of the stirring device 23 is reduced to 30 r / min, and the stirring is continued for 10 min.

[0046] (6) Material drying and finished product processing: After the reaction is completed, open the unloading device 24 of the horizontal reactor 2 to transport all the materials after the reaction in step (5) to the fluidized bed dryer, and set the outlet temperature of the dryer to 70°C and the inlet air temperature to 90°C for drying for 60 min.

[0047] (7) Response summary: Total reaction time: 20 min for raw material and precursor preparation, 50 min for hydrogen peroxide spraying, 60 min for finished product drying, a total of 2 h 10 min. Finished product: 405 kg of sodium perborate finished product was obtained, and the active oxygen content in the sodium perborate finished product was 15.5%.

[0048] Comparative Example 1: (1) Add 0.242 kg of stabilizer hydroxyethylidene diphosphonic acid to 340 kg of 40% hydrogen peroxide solution and stir until the hydroxyethylidene diphosphonic acid is completely dissolved; then place it in a cool place away from direct sunlight to prevent the decomposition of hydrogen peroxide in a high temperature environment.

[0049] (2) Weigh 500 kg of saturated sodium perborate mother liquor and add it into the reactor as the reaction medium. At the same time, slowly add 80 kg of sodium hydroxide and 291 kg of borax pentahydrate into the reactor and stir evenly for later use.

[0050] (3) Slowly add the hydrogen peroxide solution with stabilizer added in step (1) into the reactor. After reacting for 60 min, transfer the material into a centrifuge for solid-liquid separation. The centrifugation time is 30 min. After centrifugation, transfer all the materials to a fluidized bed dryer, and set the outlet temperature of the dryer to 70 °C, the inlet air temperature to 90 °C, and the drying time to 60 min.

[0051] (4) Reaction summary: Total reaction time: raw material preparation time is 20 min; reaction time is 60 min; centrifugation time is 30 min; finished product drying time is 60 min; total is 2 h 50 min. Finished product: 398 kg of sodium perborate finished product was obtained, and the active oxygen content in the sodium perborate finished product was 14.6%.

[0052] The experimental data of Example 1, Example 2 and Comparative Example 1 are compared, and the data comparison is shown in Table 1.

[0053] Table 1 Experimental data of Example 1, Example 2 and Comparative Example 1

[0054] As shown in Table 1, the production efficiency of sodium perborate prepared by dry method is significantly higher than that of sodium perborate prepared by wet method, and the active oxygen content of sodium perborate prepared by dry method is higher than that of sodium perborate prepared by wet method. The particle size of sodium perborate prepared by dry method is significantly larger than that of sodium perborate prepared by wet method; no wastewater is generated in the process of preparing sodium perborate by dry method, which meets the requirements of green chemistry and sustainable development.

[0055] Test Example 1: The sodium perborate involved in Example 1, Example 2 and Comparative Example 1 was tested for activity stability (the percentage data of activity stability was calculated by calculating the change before and after the active oxygen content, and the calculation formula was: activity stability = test active oxygen content / initial active oxygen content), and the test results are shown in Table 2.

[0056] Table 2 Activity stability test results of sodium perborate involved in Example 1, Example 2 and Comparative Example 1

[0057] It can be seen from Table 2 that within thirty days, the activity stability of sodium perborate prepared by the dry method decreased by about 0.7%, while the activity stability of sodium perborate prepared by the wet method decreased by 1.52%. Therefore, the activity stability of sodium perborate prepared by the dry method is higher than that of sodium perborate prepared by the wet method.

Claims

1. A dry method for preparing sodium perborate, characterized in that: The preparation method is as follows: S1: Hydrogen peroxide pretreatment: adding stabilizer to the hydrogen peroxide solution; S2: Preparation of reactant precursor: solid borax pentahydrate and solid sodium hydroxide are added into a horizontal reactor (2) according to a certain molar ratio and stirred; titanium dioxide is added and the ultraviolet beam emitter (3) is turned on; then a weakly alkaline pH buffer regulator is added to obtain a reactant precursor; S3: spraying the hydrogen peroxide solution with the stabilizer added in S1 into the reactant precursor of step S2, stirring, and increasing the power of the ultraviolet beam emitter (3) at the beginning of spraying; drying after the reaction is completed to obtain sodium perborate solid.

2. A dry method for preparing sodium perborate according to claim 1, characterized in that: The concentration of the hydrogen peroxide solution in step S1 is 30-40%, and the stabilizer is one of citric acid, sodium silicate, hydroxyethylidene diphosphonic acid and hydroxypropyl methacrylate; the mass ratio of the stabilizer to the hydrogen peroxide in the hydrogen peroxide solution is 0.1-0.3:

100.

3. A dry method for preparing sodium perborate according to claim 1, characterized in that: In step S2, the wavelength of the ultraviolet light beam emitted by the ultraviolet light beam emitter (3) is 300-500 nm, and the power is 300-600 W.

4. A dry method for preparing sodium perborate according to claim 1, characterized in that: In the step S2, the molar ratio of solid sodium hydroxide to solid borax pentahydrate is 2-2.5:1; and the mass ratio of titanium dioxide to solid borax pentahydrate is 0.09-0.13:

100.

5. A dry method for preparing sodium perborate according to claim 1, characterized in that: In the step S2, the weakly alkaline pH buffer regulator is a sodium phosphate buffer, a borax-calcium chloride buffer solution or a tris(hydroxymethyl)aminomethane hydrochloride buffer solution; the sodium phosphate buffer is composed of sodium monohydrogen phosphate, sodium dihydrogen phosphate and water, and the mass percentage of sodium monohydrogen phosphate is 9.3%, and the mass percentage of sodium dihydrogen phosphate is 0.7%; the tris(hydroxymethyl)aminomethane hydrochloride buffer solution is composed of tris(hydroxymethyl)aminomethane, hydrochloric acid and water, and the mass percentage of tris(hydroxymethyl)aminomethane is 12%, and the mass percentage of hydrochloric acid is 4%.

6. A dry method for preparing sodium perborate according to claim 1, characterized in that: In the step S2, a weakly alkaline pH buffering agent is used to adjust the pH during the reaction to 8-9.

7. A dry method for preparing sodium perborate according to claim 1, characterized in that: The molar ratio of hydrogen peroxide to borax pentahydrate in the hydrogen peroxide solution sprayed in step S3 is 3-5:

1.

8. A dry method for preparing sodium perborate according to claim 1, characterized in that: In step S3, the power of the ultraviolet light beam emitter (3) is increased to 600 W; the reaction temperature is 30-35° C., and the reaction time is 50-60 min.

9. A preparation device for dry preparation of sodium perborate, characterized in that: A dry preparation method for sodium perborate according to any one of claims 1 to 8.

10. A preparation device for dry preparation of sodium perborate according to claim 9, characterized in that: The preparation device comprises a high-pressure spray system (1), a horizontal reactor (2), an ultraviolet light beam emitter (3), a motor (5) and an integrated control device (7); a stirrer is rotatably installed inside the horizontal reactor (2), and the stirrer is fixedly connected to the motor (5); the high-pressure spray system (1), the ultraviolet light beam emitter (3), the motor (5) and the integrated control device (7) are electrically connected, a base (6) is fixedly connected to the lower end of the horizontal reactor (2), and the upper side of the horizontal reactor (2) is detachably connected to the high-pressure spray system (1); a plurality of ultraviolet light beam emitters (3) are detachably connected to the side of the horizontal reactor (2), a cooling jacket (4) is detachably connected to the outer end of the horizontal reactor (2), and the cooling jacket (4) is electrically connected to the integrated control device (7), and the horizontal reactor (2) is located on one side of the integrated control device (7); the base (6) is detachably connected to the motor (5).

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