Method for purifying sodium fluoride from amines

Abstract

The invention discloses a method for purifying sodium fluoride from amines. The method comprises the following steps: S1, preparing a sodium fluoride solution from a raw material containing sodium fluoride; s2, adding a seed crystal into the sodium fluoride solution, wherein the seed crystal is a pure sodium fluoride crystal; s3, adding an amine solvent with the volume 0.5-5 times that of the sodium fluoride solution into the sodium fluoride solution; s4, controlling the temperature of the solution within the range of 25-10 DEG C, so that sodium fluoride is crystallized and separated out on the seed crystal; and S5, carrying out solid-liquid separation on sodium fluoride separated out by crystallization to obtain purified sodium fluoride. According to the method, sodium fluoride can be efficiently and fully purified in an environment-friendly and low-cost manner.

Description

Technical Field

[0001] The invention relates to the technical field of sodium fluoride purification and processing, in particular to a method for purifying sodium fluoride using amines. Background Art

[0002] Sodium fluoride is an important inorganic salt, widely used in metallurgy, ceramics, glass, electronics and other industrial fields. The purity of sodium fluoride is of great significance to its application in various fields.

[0003] In the production and use of sodium fluoride, various impurities are often mixed in, thus affecting the purity and use effect of sodium fluoride. At present, the purification of sodium fluoride can be achieved by distillation, melt crystallization, zone smelting, precipitation of impurities, recrystallization, extraction and ion exchange. However, most of them have problems such as complex operation, difficulty in three waste treatment, poor economic efficiency and unsatisfactory purification effect.

[0004] Therefore, the research purpose of the present invention is to design a method for purifying sodium fluoride with amines that can fully purify sodium fluoride in an efficient, environmentally friendly and low-cost manner. Summary of the invention

[0005] In view of the technical problems existing in the above-mentioned prior art, the present invention provides a method for purifying sodium fluoride with amines, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is: A method for purifying sodium fluoride from amines comprises the following specific steps: S1, preparing a sodium fluoride solution from a raw material containing sodium fluoride; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 0.5-5 times the volume of an amine solvent to the sodium fluoride solution; S4, controlling the temperature of the solution within a range of 25° C. to −10° C. to allow sodium fluoride to crystallize on the seed crystal; S5, separating the crystallized sodium fluoride into solid and liquid to obtain purified sodium fluoride.

[0007] The method further comprises step S6 after step S5, wherein the purified sodium fluoride is dried to remove residual solvent and obtain a high-purity sodium fluoride product.

[0008] The drying process in step S6 is vacuum heating drying, and the heating temperature is 70°C-120°C.

[0009] The concentration of the sodium fluoride solution prepared in step S1 is not less than 50%, and the sodium fluoride solution in step S1 is prepared by stirring.

[0010] The sodium fluoride in step S4 is crystallized under an ultrasonic environment.

[0011] The solid-liquid separation in step S5 is centrifugal separation.

[0012] The method is implemented by a sodium fluoride purification device, which comprises: A purification tank body is fixedly mounted on the corresponding support legs, and a corresponding solution preparation container is fixedly connected to the upper side of the purification tank body through an annular plate, and the solution preparation container includes a bottom side container, and the top of the bottom side container is fixedly connected to a circle of side baffles connected to the annular plate and tilted outward; The sealing cover is driven by a telescopic oil cylinder fixedly mounted on the purification tank body. A corresponding material receiving container is arranged in a liftable manner in the solution preparation container. The bottom and side walls of the material receiving container are respectively provided with corresponding liquid permeable holes. A corresponding connecting guide shaft is fixedly connected upwardly to the material receiving container. A corresponding driving tube is rotatably mounted in the middle of the sealing cover. The driving tube is driven by a driving motor mounted on the sealing cover. A cover body matching the upper end of the material receiving container is arranged on the bottom side of the driving tube. The connecting guide shaft is movably inserted into the driving tube by a keyway matching method, and the connecting guide shaft is rotatably mounted to the piston rod end of the corresponding lifting cylinder. An ultrasonic transducer is fixedly mounted on the bottom side of the bottom container, and the ultrasonic transducer is connected to an external ultrasonic generator; The heat exchange mechanism comprises a heat exchange medium inlet pipe and a heat exchange medium outlet pipe connected to the purification tank body.

[0013] A feeding pipe for adding sodium fluoride raw material and solvent into the solution preparation container is fixedly connected to the sealing cover, and a discharging pipe for discharging liquid is arranged at the bottom side of the solution preparation container.

[0014] The liquid permeable holes on the side wall of the material receiving container are arranged inwardly and tilted, and a protrusion for sealing the liquid permeable holes at the bottom of the material receiving container is arranged upward at the bottom of the bottom container.

[0015] The amine solvent is one of N-methyldiethanolamine, ethylenediamine, monoethanolamine and isopropylamine.

[0016] Advantages of the present invention: 1) The present invention purifies sodium fluoride by crystallization of amines, and the crystallization effect can be optimized by controlling the crystallization conditions and the crystallization solvent; the method can produce high-quality products that meet the purity requirements of sodium fluoride in various industrial fields, while improving production efficiency and reducing costs. Therefore, the present invention has broad market application prospects and important economic value.

[0017] 2) The present invention also introduces auxiliary means such as stirring and ultrasound to further improve the purification efficiency and product quality. Stirring is used to ensure the preparation efficiency and effect of the sodium fluoride solution, and ultrasound is used to cause the solid solute in the solution to precipitate rapidly and gently, and to strengthen crystal growth, thereby improving the crystallization efficiency and effect of the product.

[0018] 3) The purification process of the present invention is realized by a newly designed sodium fluoride purification device. The sodium fluoride solution can be directly prepared by the sodium fluoride purification device. During the preparation process, the sodium fluoride raw material and the relevant solvent can be added to the solution preparation container, and then the driving motor is started to drive the receiving container to stir the sodium fluoride raw material and the relevant solvent in the area where the side baffle is located to ensure the preparation efficiency of the sodium fluoride solution; after the sodium fluoride solution is prepared, the piston rod end of the lifting cylinder extends to drive the receiving container to be located in the bottom container of the solution preparation container; then the external heat exchange medium is circulated into the purification tank and the solution The crystallization temperature is precisely controlled between the preparation containers; during the crystallization process, the external ultrasonic transducer is started, and the ultrasonic transducer transmits ultrasonic waves to the material, thereby accelerating the crystallization efficiency; the crystallized sodium fluoride is collected in the receiving container, and after the crystallization is completed, the piston rod of the lifting cylinder retracts, so that the cover body is covered on the receiving container; finally, the driving motor is started to drive the receiving container to rotate in the area where the side baffle is located, thereby realizing centrifugal solid-liquid separation; after the solid-liquid separation, the telescopic cylinder drives the cover to lift up, and the piston rod of the lifting cylinder extends, so that the purified materials in the receiving container can be uniformly collected.

[0019] Therefore, the preparation of sodium fluoride solution, crystallization, solid-liquid separation and other processes can be completed by a set of equipment, which can effectively ensure the controllability of the purification process and realize ultrasonic intervention during the crystallization process, thereby ensuring the practical effect of the present invention and further ensuring the crystallization efficiency and effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the sodium fluoride purification equipment of the present invention.

[0021] Figure 2 It is a cross-sectional view of a sodium fluoride purification device of the present invention.

[0022] Figure 3 It is a process flow chart of the purification process of the present invention. DETAILED DESCRIPTION

[0023] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments in conjunction with the accompanying drawings: Example 1 refer to Figure 1-2 , a sodium fluoride purification device, comprising: The purification tank body 1 is fixedly mounted on the corresponding support leg 2. The upper side of the purification tank body 1 is sealed and fixedly connected with a corresponding solution preparation container 4 through an annular plate 3. The solution preparation container 4 comprises a bottom side container 401. The top of the bottom side container 401 is tilted outward and fixedly connected with a circle of side baffles 402 connected to the annular plate 3. The sealing cover 5 is driven by a telescopic oil cylinder 6 fixedly mounted on the purification tank body 1. A corresponding material receiving container 7 is arranged in the solution preparation container 4 so as to be liftable. The bottom and side walls of the material receiving container 7 are respectively provided with corresponding liquid permeable holes 8. The material receiving container 7 is upwardly fixedly connected with a corresponding connecting guide shaft 9. A corresponding driving tube 10 is rotatably mounted in the middle of the sealing cover 5. The driving tube 10 is driven by a driving motor 11 mounted on the sealing cover 5. A cover body 1001 matching the upper end of the material receiving container 7 is arranged on the bottom side of the driving tube 10. The connecting guide shaft 9 is movably inserted into the driving tube 10 by keyway matching, and the connecting guide shaft 9 is rotatably mounted to the piston rod end of the corresponding lifting cylinder 12. An ultrasonic transducer 13 is fixedly mounted on the bottom side of the bottom container 401, and the ultrasonic transducer 13 is connected to an external ultrasonic generator; The heat exchange mechanism comprises a heat exchange medium inlet pipe 1401 and a heat exchange medium outlet pipe 1402 connected to the purification tank body 1 .

[0024] A feed pipe 15 for adding sodium fluoride raw material and solvent into the solution preparation container 4 is fixedly connected to the cover 5, and a discharge pipe 16 for discharging liquid is arranged at the bottom side of the solution preparation container 4.

[0025] The liquid permeable hole 8 on the side wall of the material receiving container 7 is tilted inwardly, and a protrusion 17 for closing the liquid permeable hole 8 at the bottom of the material receiving container 7 is upwardly provided at the bottom of the bottom container 401 .

[0026] The sodium fluoride purification equipment provided in this embodiment can directly prepare the sodium fluoride solution. During the preparation process, the sodium fluoride raw material and the relevant solvent can be added into the solution preparation container 4, and then the driving motor is started to drive the receiving container 7 to stir the sodium fluoride raw material and the relevant solvent in the area where the side baffle 402 is located, so as to ensure the preparation efficiency of the sodium fluoride solution; after the sodium fluoride solution is prepared, the piston rod end of the lifting cylinder 12 is extended to drive the receiving container 7 to be located in the bottom container 401 of the solution preparation container 4; then the external heat exchange medium is circulated between the purification tank body 1 and the solution preparation container 4 to accurately control the crystal analysis temperature; during the crystallization process, the external ultrasonic transducer is started, and the ultrasonic transducer 13 transmits ultrasonic waves to the material, thereby accelerating the crystallization efficiency; the crystallized sodium fluoride is collected in the receiving container 7, and after the crystallization is completed, the piston rod of the lifting cylinder 12 retracts, so that the cover body 1001 is covered on the receiving container 7; finally, the driving motor is started to drive the receiving container 7 to rotate in the area where the side baffle 402 is located, thereby realizing centrifugal solid-liquid separation; after the solid-liquid separation, the telescopic cylinder 6 drives the sealing cover 5 to lift up, and the piston rod of the lifting cylinder 12 extends, so that the purified materials located in the receiving container 7 can be uniformly collected.

[0027] A set of equipment can be used to complete the processes of sodium fluoride solution preparation, crystallization, solid-liquid separation, etc., and ultrasonic intervention can be achieved during the crystallization process to ensure the crystallization efficiency and effect.

[0028] Example 2 refer to Figure 3 , a method for purifying sodium fluoride from amines, comprising the following specific steps: S1, adding sodium fluoride raw materials and deionized water into the sodium fluoride purification equipment in Example 1 to prepare a sodium fluoride solution with a concentration of 50%; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 4 volumes of N-methyldiethanolamine to the sodium fluoride solution; S4, controlling the temperature of the solution at -5°C to allow sodium fluoride to crystallize on the seed crystal; S5, performing solid-liquid separation on the crystallized sodium fluoride to obtain purified sodium fluoride; S6, vacuum drying the purified sodium fluoride to remove residual solvent and obtain a high-purity sodium fluoride product, wherein the heating temperature is 120°C.

[0029] After testing, the high-purity sodium fluoride product with a total amount of metal cations as low as 14.3136 ppm was obtained through purification according to Example 2 of the present invention.

[0030] Example 3 refer to Figure 3, a method for purifying sodium fluoride from amines, comprising the following specific steps: S1, adding sodium fluoride raw materials and deionized water into the sodium fluoride purification equipment in Example 1 to prepare a saturated sodium fluoride solution; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 2 volumes of ethylenediamine to the sodium fluoride solution; S4, controlling the temperature of the solution at -3°C to allow sodium fluoride to crystallize on the seed crystal; S5, performing solid-liquid separation on the crystallized sodium fluoride to obtain purified sodium fluoride; S6, vacuum drying the purified sodium fluoride to remove residual solvent and obtain a high-purity sodium fluoride product, wherein the heating temperature is 110°C.

[0031] After testing, the high-purity sodium fluoride product with a total amount of metal cations as low as 13.6257 ppm was obtained through purification according to Example 2 of the present invention.

[0032] Example 4 refer to Figure 3 , a method for purifying sodium fluoride from amines, comprising the following specific steps: S1, adding sodium fluoride raw materials and deionized water into the sodium fluoride purification equipment in Example 1 to prepare a saturated sodium fluoride solution; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 1 volume of monoethanolamine to the sodium fluoride solution; S4, controlling the temperature of the solution at 5°C to allow sodium fluoride to crystallize on the seed crystal; S5, performing solid-liquid separation on the crystallized sodium fluoride to obtain purified sodium fluoride; S6, vacuum drying the purified sodium fluoride to remove residual solvent and obtain a high-purity sodium fluoride product, wherein the heating temperature is 115°C.

[0033] After testing, the high-purity sodium fluoride product with a total amount of metal cations as low as 13.0307 ppm was obtained through purification in Example 2 of the present invention.

[0034] Example 5 refer to Figure 3 , a method for purifying sodium fluoride from amines, comprising the following specific steps: S1, adding sodium fluoride raw materials and deionized water into the sodium fluoride purification equipment in Example 1 to prepare a saturated sodium fluoride solution; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 1 volume of isopropylamine to the sodium fluoride solution; S4, controlling the temperature of the solution at -5°C to allow sodium fluoride to crystallize on the seed crystal; S5, performing solid-liquid separation on the crystallized sodium fluoride to obtain purified sodium fluoride; S6, vacuum drying the purified sodium fluoride to remove residual solvent and obtain a high-purity sodium fluoride product, wherein the heating temperature is 100°C.

[0035] After testing, the high-purity sodium fluoride product with a total amount of metal cations as low as 9.6357 ppm was obtained through purification in Example 2 of the present invention.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for purifying sodium fluoride from amines, characterized in that: The specific steps include: S1, preparing a sodium fluoride solution from a raw material containing sodium fluoride; S2, adding seed crystals to the sodium fluoride solution, wherein the seed crystals are pure sodium fluoride crystals; S3, adding 0.5-5 times the volume of an amine solvent to the sodium fluoride solution; S4, controlling the temperature of the solution within a range of 25° C. to −10° C. to allow sodium fluoride to crystallize on the seed crystal; S5, separating the crystallized sodium fluoride into solid and liquid to obtain purified sodium fluoride.

2. A method for purifying sodium fluoride from amines according to claim 1, characterized in that: The method further comprises step S6 after step S5, wherein the purified sodium fluoride is dried to remove residual solvent and obtain a high-purity sodium fluoride product.

3. A method for purifying sodium fluoride from amines according to claim 2, characterized in that: The drying process in step S6 is vacuum heating drying, and the heating temperature is 70°C-120°C.

4. A method for purifying sodium fluoride from amines according to claim 1, characterized in that: The concentration of the sodium fluoride solution prepared in step S1 is not less than 50%, and the sodium fluoride solution in step S1 is prepared by stirring.

5. A method for purifying sodium fluoride from amines according to claim 4, characterized in that: The sodium fluoride in step S4 is crystallized under an ultrasonic environment.

6. The method for purifying sodium fluoride from amines according to claim 5, characterized in that: The solid-liquid separation in step S5 is centrifugal separation.

7. The method for purifying sodium fluoride from amines according to claim 5, characterized in that: The method is implemented by a sodium fluoride purification device, which comprises: A purification tank body is fixedly mounted on the corresponding support legs, and a corresponding solution preparation container is fixedly connected to the upper side of the purification tank body through an annular plate, and the solution preparation container includes a bottom side container, and the top of the bottom side container is fixedly connected to a circle of side baffles connected to the annular plate and tilted outward; The sealing cover is driven by a telescopic oil cylinder fixedly mounted on the purification tank body. A corresponding material receiving container is arranged in a liftable manner in the solution preparation container. The bottom and side walls of the material receiving container are respectively provided with corresponding liquid permeable holes. A corresponding connecting guide shaft is fixedly connected upwardly to the material receiving container. A corresponding driving tube is rotatably mounted in the middle of the sealing cover. The driving tube is driven by a driving motor mounted on the sealing cover. A cover body matching the upper end of the material receiving container is arranged on the bottom side of the driving tube. The connecting guide shaft is movably inserted into the driving tube by a keyway matching method, and the connecting guide shaft is rotatably mounted to the piston rod end of the corresponding lifting cylinder. An ultrasonic transducer is fixedly mounted on the bottom side of the bottom container, and the ultrasonic transducer is connected to an external ultrasonic generator; The heat exchange mechanism comprises a heat exchange medium inlet pipe and a heat exchange medium outlet pipe connected to the purification tank body.

8. The method for purifying sodium fluoride from amines according to claim 7, characterized in that: A feeding pipe for adding sodium fluoride raw material and solvent into the solution preparation container is fixedly connected to the sealing cover, and a discharging pipe for discharging liquid is arranged at the bottom side of the solution preparation container.

9. The method for purifying sodium fluoride from amines according to claim 8, characterized in that: The liquid permeable holes on the side wall of the material receiving container are arranged inwardly and tilted, and a protrusion for sealing the liquid permeable holes at the bottom of the material receiving container is arranged upward at the bottom of the bottom container.

10. The method for purifying sodium fluoride from amines according to claim 1, characterized in that: The amine solvent is one of N-methyldiethanolamine, ethylenediamine, monoethanolamine and isopropylamine.

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