Preparation method of metal selenium and ultrasonic enhanced impinging stream reaction system and method

Abstract

The invention belongs to the technical field of material preparation, and particularly relates to a preparation method of metal selenium and an ultrasonic enhanced impinging stream reaction system and method. According to the invention, an ultrasonic wave and impinging stream combined process is utilized, two reaction solution flow columns collide with each other, so that the contact specific surface area of the two reaction solutions and the effective collision probability between molecules are obviously increased, interphase transfer and micro-mixing of fluids are strengthened, the mass transfer rate is increased, and ultrasonic waves are introduced to strengthen the reduction reaction of selenium dioxide; pure selenium powder with good research prospects is obtained through one-step reduction of selenium dioxide, the preparation method provided by the invention realizes normal-temperature and normal-pressure reduction, the reduction efficiency is high, products are not easy to agglomerate, the reaction conditions are simple, the reaction process is short, and industrial production and application are very easily realized on the whole. According to the device, the impinging stream is adopted for preparing the pure selenium powder, and the pure selenium powder with higher purity can be more efficiently prepared through non-contact ultrasonic treatment, closed reaction equipment and no introduction of impurities.

Description

Technical Field

[0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing metallic selenium and an ultrasonically enhanced impinging flow reaction system and method. Background Art

[0002] As a rare non-metallic element with extremely dispersed distribution, selenium mainly comes from copper anode mud. It has good conductivity and has broad development prospects in the fields of chemical industry, electronics industry, metallurgical industry and agriculture. With the continuous maturity of metallurgical technology, the demand for selenium products in various fields is also increasing, and the purification of selenium is crucial to its subsequent application.

[0003] Chinese patent CN 112897475A discloses a method for producing high-purity selenium by ultrasonic enhanced reduction, wherein the reaction process is carried out under ultrasonic conditions and local stirring is used to achieve a greater reduction potential, and selenious acid is reduced to generate selenium powder. However, the disadvantage of this method is that the concentration of the reducing agent is instantly reduced when the reducing agent is added to the selenious acid solution, and as the reaction proceeds, the volume of the reaction system becomes larger and larger, and the concentration of selenious acid becomes lower and lower, resulting in a slower and slower chemical reaction and a longer reaction cycle. At the same time, an open system may introduce new impurities, thereby affecting the purity of selenium. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method of metallic selenium and an ultrasonic enhanced impinging stream reaction system and method. The purity of metallic selenium obtained by the preparation method provided by the present invention is above 99.99%.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing metallic selenium, comprising the following steps:

[0007] The impinging stream of the selenious acid solution and the impinging stream of the reducing agent solution collide and mix to generate a reduction reaction, and then the reduction reaction is continued under ultrasonic conditions to obtain metallic selenium with a purity of more than 99.99%.

[0008] Preferably, the mass concentration of the selenious acid solution is 5-25%.

[0009] Preferably, the reducing agent solution comprises a reducing agent and water; the reducing agent comprises one or more of sulfurous acid, sodium hyposulfite, sodium thiosulfate, hydroxylamine hydrochloride, hydrazine, glucose, ascorbic acid, borohydride, hypophosphorous acid and phosphorous acid; and the mass concentration of the reducing agent solution is 10 to 30%.

[0010] Preferably, the flow rates of the selenious acid solution impingement flow and the reducing agent solution impingement flow are independently 8 to 24 mL / min.

[0011] Preferably, the temperature of the reduction reaction is room temperature, the pressure is normal pressure, and the reaction time is 5 to 30 minutes; the ultrasonic conditions of the reduction reaction are: ultrasonic frequency is 25 to 60 kHz, ultrasonic power is 0 to 120 W, and ultrasonic time is 5 to 30 minutes.

[0012] Preferably, the collision is a countercurrent collision.

[0013] The present invention also provides an ultrasonic enhanced impinging flow reaction system, comprising a first peristaltic pump, a second peristaltic pump, an impinging flow reactor, an ultrasonic reactor, an ultrasonic generator and a product container; the impinging flow reactor is provided with two inlets, and the two inlets are respectively connected to the first peristaltic pump and the second peristaltic pump through pipelines; the ultrasonic reactor comprises a shell, an ultrasonic vibrator and a reactor; an ultrasonic vibrator is provided at the bottom of the shell, and the ultrasonic vibrator is connected to the ultrasonic generator; the reactor is installed in the shell, the feed inlet of the reactor is connected to the outlet of the impinging flow reactor through a pipeline, and the discharge port of the reactor is connected to the product container through a discharge pipe.

[0014] Preferably, the impinging stream reactor is a three-way structure reactor; the two end ports of the three-way structure reactor are inlets; the diameter of the two end ports is 9 to 15 mm; the middle port of the three-way structure reactor is an outlet; the diameter of the middle port is 10 to 16 mm.

[0015] Preferably, the pipeline connecting the first peristaltic pump and the inlet of the impinging stream reactor is a first rubber tube; the pipeline connecting the second peristaltic pump and the inlet of the impinging stream reactor is a second rubber tube; the inner diameters of the first rubber tube and the second rubber tube are independently 9 to 15 mm.

[0016] The present invention also provides a method for preparing metallic selenium using the ultrasonic enhanced impinging stream reaction system described in the above scheme, comprising the following steps:

[0017] The selenous acid solution and the reducing agent solution are simultaneously pumped into the impinging flow reactor by a first peristaltic pump and a second peristaltic pump to collide and perform a reduction reaction. The reduction reaction is continuously performed in the ultrasonic reactor to obtain metallic selenium.

[0018] The present invention provides a method for preparing metallic selenium. The present invention utilizes a combined process of ultrasonic and impinging flow, and through the mutual collision of two reaction solution streams, the specific surface area of ​​the two reaction solutions in contact and the effective collision probability between molecules are significantly increased, the microscopic mixing effect of the collision zone is significant, the phase transfer and microscopic mixing of the fluid are enhanced, the mass transfer rate is increased, and ultrasonic waves are introduced to enhance the reduction reaction of selenium dioxide, and pure selenium powder is obtained from selenium dioxide by one-step reduction, the reaction efficiency is high, the process flow is short, the product particle size is small, it is not easy to agglomerate, it is conducive to further processing and manufacturing, less equipment is required, the cost is low, and it is easy to industrialize and apply.

[0019] Furthermore, the temperature of the reduction reaction is room temperature, the pressure is normal pressure, and the reaction time is 5 to 30 minutes; the ultrasonic conditions of the reduction reaction are: ultrasonic frequency is 25 to 60 kHz, ultrasonic power is 0 to 120 W, and ultrasonic time is 5 to 30 minutes. The preparation method provided by the present invention has the advantages of: reduction at room temperature and pressure, high reduction efficiency, the product is not easy to agglomerate, simple reaction conditions, short reaction process, and overall very easy to realize industrial production and application, and pure selenium powder with good research prospects is obtained from selenium dioxide by one-step reduction.

[0020] The present invention also provides an ultrasonic enhanced impinging stream reaction system. The ultrasonic enhanced impinging stream reaction system provided by the present invention adopts impinging stream to prepare pure selenium powder, uses non-contact ultrasound, and the reaction equipment is closed, and no impurities are introduced. Compared with general ultrasonic devices, pure selenium powder with higher purity can be prepared more efficiently. In addition, the ultrasonic enhanced impinging stream reaction system provided by the present invention has a simple structure, is easy to disassemble, and has replaceable components.

[0021] When the ultrasonic enhanced impinging stream reaction system provided by the present invention is working, two peristaltic pumps maintain the same speed operation, and two reaction solutions (selenious acid solution and reducing agent solution) flow into the impinging stream reactor through two peristaltic pumps respectively, collide, mix and react in the impinging stream reactor, and then pass through the reactor, and continuously generate products (selenium) in the reactor under the action of ultrasonic vibration, and then collect the products from the discharge pipe. The ultrasonic enhanced impinging stream reaction system provided by the present invention utilizes the ultrasonic wave and the impinging stream combined process, which can significantly increase the specific surface area of ​​the reaction solution contact and the effective collision probability between molecules, is suitable for liquid-liquid reaction process, has significant microscopic mixing effect in the impact zone, fast reaction rate, small product particle size, and is not easy to form agglomerates, which is conducive to further processing and manufacturing, and is very suitable for different powder manufacturing and industrial production.

[0022] The present invention also provides a method for preparing metallic selenium using the ultrasonic enhanced impinging flow reaction system described in the above scheme. The present invention introduces ultrasonic enhanced selenium dioxide reduction reaction, the ultrasonic impinging flow reactor reaction channel is spiral, the reaction efficiency is high, the product particle size is uniform, not easy to agglomerate, and the channel is a closed channel, no impurities are introduced, the device structure is simple, and it is conducive to manufacturing and maintenance, as well as further processing and modification. The method provided by the present invention has a high degree of automation, ensures the stability of the reaction process and product quality, has high production efficiency, low labor costs, simple maintenance, and is very suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of the ultrasonic enhanced impinging stream reaction system provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the connection structure between the ultrasonic vibrator and the shell in the ultrasonic enhanced impinging stream reaction system of the present invention;

[0026] Figure 3 It is a front view of an ultrasonic reactor in the ultrasonic enhanced impinging stream reaction system of the present invention;

[0027] Figure 4 It is a top view of the connection structure of the ultrasonic reactor, the impinging stream reactor and the discharge pipe in the ultrasonic enhanced impinging stream reaction system of the present invention;

[0028] Figure 5 It is a schematic diagram of the impingement zone formed by the internal fluid of the impinging stream reactor in the ultrasonic enhanced impinging stream reaction system of the present invention;

[0029] Figure 6 The XRD pattern of the metallic selenium prepared by the present invention;

[0030] Figure 7 This is a SEM image of the metallic selenium prepared by the present invention;

[0031] Figure 8 The particle size distribution diagram of the metallic selenium prepared by the present invention;

[0032] Figure numerals: 1-first peristaltic pump, 2-impinging flow reactor, 3-ultrasonic reactor, 4-ultrasonic generator, 5-shell, 6-ultrasonic vibrator, 7-reactor, 8-discharge pipe, 9-bolt, 10-first rubber tube, 11 is product container, 12-second rubber tube, 13-third rubber tube, 14-fourth rubber tube, 15 is second peristaltic pump. DETAILED DESCRIPTION

[0033] The present invention provides a method for preparing metallic selenium, comprising the following steps:

[0034] The impinging stream of the selenious acid solution and the impinging stream of the reducing agent solution collide and mix to generate a reduction reaction, and then the reduction reaction is continued under ultrasonic conditions to obtain metallic selenium with a purity of more than 99.99%.

[0035] In the present invention, the mass concentration of the selenious acid solution is preferably 5-25%, specifically 5%, 10%, 15%, 18%, 20%, 22% or 25%.

[0036] In the present invention, the method for preparing the selenious acid solution is preferably: mixing selenium dioxide powder with water (referred to as the first mixing), performing a reduction reaction (referred to as the second reduction reaction), and then performing solid-liquid separation (referred to as the first solid-liquid separation), collecting the filtrate, and obtaining the selenious acid solution.

[0037] The present invention has no special requirements on the purity of the selenium dioxide powder, which is preferably not less than 95%, and specifically can be 95%, 96%, 97%, 98% or 99%.

[0038] In the present invention, the water is preferably deionized water or pure water.

[0039] In the present invention, the mass ratio of selenium dioxide to water is preferably 1-5:4-17, specifically 1:4, 1:7, 1:10, 1:14, 1:17, 2:4, 2:7, 2:10, 2:14, 2:17, 3:4, 3:7, 3:10, 3:14, 3:17, 4:4, 4:7, 4:10, 4:14, 4:17, 5:4, 5:7, 5:10, 5:14 or 5:17.

[0040] In the present invention, the first mixing is preferably stirring and mixing; the first solid-liquid separation is preferably filtering or suction filtration. The present invention removes impurities through the first solid-liquid separation.

[0041] In the present invention, the temperature of the second reduction reaction is preferably 25-75°C, specifically 25°C, 35°C, 45°C, 55°C, 65°C, 70°C or 75°C.

[0042] In the present invention, the reducing agent solution preferably includes a reducing agent and water; the reducing agent preferably includes one or more of sulfurous acid, sodium hyposulfite, sodium thiosulfate, hydroxylamine hydrochloride, hydrazine, glucose, ascorbic acid, boron hydride, hypophosphorous acid and phosphorous acid, more preferably hydrazine, sodium thiosulfate or SO 2 ; The water is preferably deionized water; the mass concentration of the reducing agent solution is preferably 10-30%, specifically 10%, 14%, 16%, 20%, 24% or 30%.

[0043] In the present invention, the reducing agent solution is preferably prepared by mixing the reducing agent and water.

[0044] In the present invention, the flow rates of the selenious acid solution impinging stream and the reducing agent solution impinging stream are independently preferably 8 to 24 mL / min, specifically 8 mL / min, 12 mL / min, 16 mL / min, 20 mL / min or 24 mL / min. The present invention ensures that the reduction reaction is carried out thoroughly by using an excess of reducing agent.

[0045] In the present invention, the collision is preferably a countercurrent collision.

[0046] In the present invention, the temperature of the reduction reaction is preferably room temperature, specifically 22-25° C., the pressure is preferably normal pressure, and the reaction time is preferably 5-30 min (starting from the collision), specifically 5 min, 10 min, 15 min, 20 min or 30 min. The preparation method of metallic selenium provided by the present invention can react at normal temperature and pressure, and the reaction time is short.

[0047] In the present invention, the ultrasonic conditions for the reduction reaction are preferably: the ultrasonic frequency is preferably 25-60 kHz, specifically 25 kHz, 28 kHz, 40 kHz, 50 kHz or 60 kHz, the ultrasonic power is preferably 0-120 W, specifically 10 W, 30 W, 50 W, 70 W, 90 W, 100 W or 120 W, and the ultrasonic time is preferably 5-30 min.

[0048] In the present invention, after the reduction reaction, the reduction reaction preferably further comprises sequentially performing solid-liquid separation (referred to as the second solid-liquid separation) and vacuum drying of the solid on the reduction reaction liquid obtained by the reduction reaction.

[0049] In the present invention, the second solid-liquid separation is preferably filtration.

[0050] In the present invention, before the solid is vacuum-dried, the solid obtained by the second solid-liquid separation is preferably washed; the number of washings is preferably 3 to 5 times; the washing is preferably flushing; the washing solvent is preferably deionized water; the mass ratio of the washing solvent to the solid each time is preferably not less than 3:1, specifically 3:1, 4:1, 5:1 or 10:1.

[0051] In the present invention, the temperature for vacuum drying of the solid is preferably 10-60°C, specifically 10°C, 20°C, 30°C, 40°C, 50°C or 60°C, the vacuum degree is preferably 0.01-10Pa, specifically 0.01Pa, 0.05Pa, 0.1Pa, 0.5Pa, 1Pa, 3Pa, 5Pa, 8Pa and 10Pa, and the vacuum drying time is preferably 1-32h, specifically 1h, 5h, 8h, 12h, 15h, 18h, 21h, 24h, 27h, 30h or 32h.

[0052] The present invention also provides an ultrasonic enhanced impinging stream reaction system, comprising a first peristaltic pump 1, a second peristaltic pump 15, an impinging stream reactor 2, an ultrasonic reactor 3, an ultrasonic generator 4 and a product container 11; the impinging stream reactor 2 is provided with two inlets, and the two inlets are respectively connected to the first peristaltic pump 1 and the second peristaltic pump 15 through pipelines; the ultrasonic reactor 3 comprises a shell 5, an ultrasonic vibrator 6 and a reactor 7; an ultrasonic vibrator 6 is provided at the bottom of the shell 5, and the ultrasonic vibrator 6 is connected to the ultrasonic generator 4; the reactor 7 is installed in the shell 5, the feed port of the reactor 7 is connected to the outlet of the impinging stream reactor 2 through a pipeline, and the discharge port of the reactor 7 is connected to the product container 11 through a discharge pipe 8 (the specific structure is as shown in FIG. Figure 1 shown).

[0053] The ultrasonic enhanced impinging flow reaction system provided by the present invention comprises a first peristaltic pump 1 and a second peristaltic pump 15; the first peristaltic pump 1 and the second peristaltic pump 15 are preferably placed at the same level. The present invention utilizes the first peristaltic pump 1 and the second peristaltic pump 15 to realize the feeding of the reaction solution and provide the power for the collision of the two reaction solutions.

[0054] The ultrasonic enhanced impinging stream reaction system provided by the present invention comprises an impinging stream reactor 2; the impinging stream reactor 2 is preferably a three-way structure reactor (the specific structure is as follows Figure 5 As shown); the three-way structure reactor is preferably a T-shaped glass tube; the two end ports of the three-way structure reactor are preferably inlets; the diameter of the two end ports is preferably 9-15mm, specifically 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm; the middle port of the three-way structure reactor is preferably an outlet; the diameter of the middle port is preferably 10-16mm, specifically 10mm, 11mm, 12mm, 13mm, 14mm, 15mm or 16mm. When working, the middle part of the impinging flow reactor 2 forms an impingement zone.

[0055] In the present invention, the pipeline connecting the first peristaltic pump 1 and the inlet of the impinging stream reactor 2 is preferably a first rubber tube 10; the pipeline connecting the second peristaltic pump 15 and the inlet of the impinging stream reactor 2 is preferably a second rubber tube 12; the inner diameters of the first rubber tube 10 and the second rubber tube 12 are independently preferably 9 to 15 mm, specifically 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm. The present invention adopts the first rubber tube 10 and the second rubber tube 12, which is convenient and quick to connect.

[0056] The ultrasonic enhanced impinging stream reaction system provided by the present invention comprises an ultrasonic reactor 3; the material of the ultrasonic reactor 3 is preferably a corrosion-resistant material with good thermal conductivity, and specifically can be an inert material.

[0057] In the present invention, the frequency of the ultrasonic reactor 3 is preferably 25 to 60 kHz, specifically 25 kHz, 28 kHz, 40 kHz, 50 kHz or 60 kHz.

[0058] In the present invention, the power of the ultrasonic reactor 3 is preferably 0-120W, specifically 10W, 30W, 50W, 70W, 90W, 100W or 120W.

[0059] In the present invention, the housing 5 is preferably a housing with an open top structure; the material of the housing 5 is preferably stainless steel. The present invention adopts the above-mentioned structural housing to facilitate the installation of the ultrasonic vibrator 6 and the reactor 7, reduce the use and maintenance costs of the ultrasonic reactor 3, and improve the use efficiency of the ultrasonic reactor 3.

[0060] In the present invention, the ultrasonic vibrator 6 is preferably fixed to the bottom of the housing 5 by means of a bolt 9, and the bottom of the housing 5 is provided with a bolt hole corresponding to the bolt 9 (the specific structure is as follows Figure 2 and Figure 3 The gap between the ultrasonic vibrator 6 and the housing 5 is preferably filled with fixing glue. The present invention facilitates the disassembly and maintenance of the ultrasonic vibrator 6 through the above installation, reduces the maintenance difficulty of the ultrasonic vibrator 6, and ensures the fixing effect while also playing a waterproof role.

[0061] In the present invention, the frequency of the ultrasonic vibrator 6 is preferably 25-60kHZ, specifically 25kHz, 28kHz, 40kHz, 50kHz or 60kHz, the power is preferably 0-120W, specifically 10W, 30W, 50W, 70W, 90W, 100W or 120W, the number is preferably 4-8, specifically 4, 5, 6, 7 or 8, and the 6 ultrasonic vibrators 6 are preferably connected in parallel and connected to the circuit board; each of the ultrasonic vibrators 6 is preferably provided with a wiring terminal, and the positive electrode of each of the ultrasonic vibrators 6 is preferably connected to the positive electrode of the ultrasonic generator 4, and the negative electrode is preferably connected to the negative electrode of the ultrasonic generator 4; each of the ultrasonic vibrators 6 is preferably arranged equidistantly to ensure the uniformity of the force on the shell 5 when the ultrasonic vibrator 6 vibrates.

[0062] In the present invention, the reactor 7 is preferably an impinging stream reactor; the impinging stream reactor is preferably horizontally and obliquely placed in the shell 5, and the inner tube of the impinging stream reactor is preferably a spiral reaction passage; the feed port and the discharge port of the inner tube of the impinging stream reactor are preferably passed through the shell 5, and are wrapped with a third rubber tube 13 and a fourth rubber tube 14 to protect the feed port and the discharge port and to achieve an extension effect; the feed port of the inner tube of the impinging stream reactor is preferably connected to the outlet of the impinging stream reactor 2 through a pipeline; the pipeline connecting the feed port of the inner tube of the impinging stream reactor and the outlet of the impinging stream reactor 2 is preferably a third rubber tube 13; the discharge port of the inner tube of the impinging stream reactor is preferably connected to the discharge pipe 8 (the specific structure is as shown in FIG. 1 ). Figure 4 The reaction system can be condensed by the reactor 7.

[0063] In the present invention, when the ultrasonic reactor 3 is working, it is preferred to immerse the ultrasonic probe in the reduction reaction system, or use an ultrasonic reaction tank. The bottom of the ultrasonic reaction tank is provided with an ultrasonic device, which can perform ultrasonic treatment on the reduction reaction system.

[0064] In a specific embodiment of the present invention, the product container 11 is preferably a glass container.

[0065] The ultrasonic enhanced impinging stream reaction system provided by the present invention comprises an ultrasonic generator 4. The present invention utilizes the ultrasonic generator 4 to generate ultrasonic waves for ultrasonic enhanced reduction reaction.

[0066] The ultrasonic enhanced impinging stream reaction system provided by the present invention can prepare a variety of powder products, and the powder products preferably include one or more of magnesium hydroxide, calcium hydroxide, calcium phosphate salt, iron phosphate, tungsten powder, selenium powder, tellurium powder and barium sulfate, as well as nanoparticles of the above powder products.

[0067] The present invention also provides a method for preparing metallic selenium using the ultrasonic enhanced impinging stream reaction system described in the above scheme, comprising the following steps:

[0068] The selenious acid solution and the reducing agent solution are simultaneously pumped into the impinging flow reactor 2 by the first peristaltic pump 1 and the second peristaltic pump 15 to collide and perform a reduction reaction. The reduction reaction is continuously performed in the ultrasonic reactor 3 to obtain metallic selenium.

[0069] In the present invention, the method for preparing metallic selenium using the ultrasonic enhanced impinging stream reaction system described in the above scheme preferably has the same specific parameters as the method for preparing metallic selenium described in the above scheme, which will not be repeated here.

[0070] In the present invention, the solution flow rates of the first peristaltic pump 1 and the second peristaltic pump 15 are independently preferably 8 to 24 mL / min, specifically 8 mL / min, 12 mL / min, 16 mL / min, 20 mL / min or 24 mL / min.

[0071] In order to further illustrate the present invention, the scheme of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be understood as limiting the protection scope of the present invention.

[0072] Example 1

[0073] The ultrasonic enhanced impinging stream reaction system used in this embodiment is as follows Figure 1 As shown, selenium dioxide with a purity of 99% is mixed and dissolved with deionized water in a mass ratio of 1:5. After being fully dissolved, the solution is filtered with a vacuum filter, and the filtrate is collected to obtain a pure selenious acid solution;

[0074] 100 mL of the above-mentioned pure selenious acid solution is taken, and under ultrasonic conditions, the first peristaltic pump 1 and the second peristaltic pump 15 are operated simultaneously, so that the selenious acid solution and the hydrazine hydrate solution collide, react and pass through the tee, and ultrasonic reduction is performed for 20 minutes under the conditions of a reduction temperature of 25° C., an ultrasonic frequency of 28 kHz, and an ultrasonic power of 50 W to obtain a reduction reaction liquid;

[0075] The reduction reaction liquid was separated into solid and liquid, and the solid product obtained by the solid-liquid separation was rinsed 5 times with deionized water. The solid product obtained by rinsing was dried at 25° C. for 24 hours to obtain pure selenium powder with a purity of 99.99152%.

[0076] The pure selenium powder obtained in this example was subjected to XRD and SEM detection, and the results are as follows: Figure 6 and Figure 7 As shown. Figure 6 and Figure 7 It can be seen that metallic selenium was prepared in this embodiment.

[0077] Example 2

[0078] The ultrasonic enhanced impinging stream reaction system used in this embodiment is as follows Figure 1 As shown, selenium dioxide with a purity of 99% is mixed and dissolved with deionized water in a mass ratio of 1:8. After being fully dissolved, the solution is filtered with a vacuum filter, and the filtrate is a pure selenious acid solution;

[0079] Take 100 mL of the above-mentioned pure selenious acid solution, and operate the first peristaltic pump 1 and the second peristaltic pump 15 simultaneously under ultrasonic conditions, so that the selenious acid solution and the hydrazine hydrate solution collide, react and pass through the tee, and perform ultrasonic reduction for 30 minutes under the conditions of reduction temperature of 25° C., ultrasonic frequency of 28 kHz, and ultrasonic power of 80 W to obtain a reduction reaction liquid;

[0080] The reduction reaction liquid was separated into solid and liquid, and the solid product obtained by the solid-liquid separation was rinsed 5 times with deionized water. The solid product obtained by rinsing was dried at 25° C. for 24 hours to obtain pure selenium powder with a purity of 99.99328%.

[0081] Example 3

[0082] The ultrasonic enhanced impinging stream reaction system used in this embodiment is as follows Figure 1 As shown, selenium dioxide with a purity of 96% is mixed and dissolved with deionized water in a mass ratio of 3:20. After being fully dissolved, the solution is filtered with a vacuum filter, and the filtrate is a pure selenious acid solution;

[0083] 100 mL of the above-mentioned pure selenious acid solution is taken, and under ultrasonic conditions, the first peristaltic pump 1 and the second peristaltic pump 15 are operated simultaneously, so that the selenious acid solution and the hydrazine hydrate solution collide, react and pass through the tee, and ultrasonic reduction is performed for 60 minutes under the conditions of a reduction temperature of 25° C., an ultrasonic frequency of 28 kHz, and an ultrasonic power of 100 W to obtain a reduction reaction liquid;

[0084] The reduction reaction liquid was separated into solid and liquid, and the solid product obtained by the solid-liquid separation was rinsed 5 times with deionized water. The solid product obtained by rinsing was dried at 50° C. for 12 h to obtain pure selenium powder with a purity of 99.99516%.

[0085] The pure selenium powder of Example 1 was tested for particle size, and the results were as follows: Figure 8 As shown. Figure 8 It can be seen that when the cumulative distribution in the particle size distribution curve of the product metallic selenium is 10%, 50% and 90%, the corresponding equivalent diameters are 2.496 μm, 6.076 μm and 12.819 μm, respectively, and the average particle size of metallic selenium is 6.076 μm.

[0086] The test results of the pure selenium powder of Examples 2-3 are similar to those of Example 1.

[0087] It can be seen from the above embodiments that the purity of metallic selenium obtained by the preparation method provided by the present invention is above 99.99%, the purity is higher, and the preparation process is efficient, metallic selenium is prepared in one step, the process flow is short, the product particle size is small, it is not easy to agglomerate, which is conducive to further processing and manufacturing, less equipment is required, the cost is low, and it is easy to industrialize and apply.

[0088] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing metallic selenium, characterized in that: The following steps are involved: The impinging stream of the selenious acid solution and the impinging stream of the reducing agent solution collide and mix to generate a reduction reaction, and then the reduction reaction is continued under ultrasonic conditions to obtain metallic selenium with a purity of more than 99.99%.

2. The preparation method according to claim 1, characterized in that: The mass concentration of the selenous acid solution is 5-25%.

3. The preparation method according to claim 1 or 2, characterized in that: The reducing agent solution comprises a reducing agent and water; The reducing agent includes one or more of sulfurous acid, sodium hyposulfite, sodium thiosulfate, hydroxylamine hydrochloride, hydrazine, glucose, ascorbic acid, boron hydride, hypophosphorous acid and phosphorous acid; The mass concentration of the reducing agent solution is 10-30%.

4. The preparation method according to claim 1, characterized in that: The flow rates of the selenious acid solution impingement flow and the reducing agent solution impingement flow are independently 8-24 mL / min.

5. The preparation method according to claim 1 or 4, characterized in that: The temperature of the reduction reaction is room temperature, the pressure is normal pressure, and the reaction time is 5 to 30 minutes; The ultrasonic conditions for the reduction reaction are as follows: ultrasonic frequency is 25-60 kHz, ultrasonic power is 0-120 W, and ultrasonic time is 5-30 min.

6. The preparation method according to claim 1, characterized in that: The collision is a countercurrent collision.

7. An ultrasonic enhanced impinging stream reaction system, characterized in that: It comprises a first peristaltic pump (1), a second peristaltic pump (15), an impinging flow reactor (2), an ultrasonic reactor (3), an ultrasonic generator (4) and a product container (11); The impinging stream reactor (2) is provided with two inlets, and the two inlets are respectively connected to the first peristaltic pump (1) and the second peristaltic pump (15) through pipelines; The ultrasonic reactor (3) comprises a housing (5), an ultrasonic vibrator (6) and a reactor (7); An ultrasonic vibrator (6) is provided at the bottom of the housing (5), and the ultrasonic vibrator (6) is connected to the ultrasonic generator (4); The reactor (7) is installed in the shell (5), the feed port of the reactor (7) is connected to the outlet of the impinging flow reactor (2) through a pipeline, and the discharge port of the reactor (7) is connected to the product container (11) through a discharge pipe (8).

8. The ultrasonic enhanced impinging stream reaction system according to claim 7, characterized in that: The impinging stream reactor (2) is a three-way structure reactor; The two end ports of the three-way structure reactor are inlets; the diameter of the two end ports is 9 to 15 mm; The middle port of the three-way structure reactor is an outlet; the diameter of the middle port is 10 to 16 mm.

9. The ultrasonic enhanced impinging stream reaction system according to claim 7 or 8, characterized in that: The pipeline connecting the first peristaltic pump (1) and the inlet of the impinging stream reactor (2) is a first rubber tube (10); The pipeline connecting the second peristaltic pump (15) and the inlet of the impinging stream reactor (2) is a second rubber tube (12); The inner diameters of the first rubber tube (10) and the second rubber tube (12) are independently 9 to 15 mm.

10. A method for preparing metallic selenium using the ultrasonic enhanced impinging stream reaction system according to any one of claims 7 to 9, characterized in that: The following steps are involved: The selenious acid solution and the reducing agent solution are simultaneously pumped into the impinging flow reactor (2) by means of a first peristaltic pump (1) and a second peristaltic pump (15) to collide and perform a reduction reaction. The reduction reaction is continuously performed in the ultrasonic reactor (3) to obtain metallic selenium.

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