CN112891973B - A kind of method for reducing oxygen content in halide molten salt - Google Patents

Abstract

The invention discloses a method for reducing the oxygen content in halide molten salt. The method comprises the following steps: under vacuum conditions, the halide molten salt is subjected to distillation treatment; wherein, the vacuum degree of the vacuum conditions is ^10-5 to 10 ³ Pa; in the distillation treatment, the distillation temperature is at least 200°C higher than the condensation temperature , the distillation temperature is 400 ~ 1200 ℃. The method for reducing the oxygen content in the halide molten salt in the present invention can effectively reduce the oxygen content in the halide molten salt by more than 70%; the oxygen content in the treated distillation product can be as low as 560 mg/Kg or less, even as low as 200 mg/Kg. Kg or less; and the treatment efficiency is high, and the corrosiveness to the equipment is weak.

Description

A kind of method for reducing oxygen content in halide molten salt

technical field

The present invention relates to a method for reducing the oxygen content in halide molten salt.

Background technique

The molten salt energy storage technology can be combined with the solar thermal power generation system to meet the peak regulation needs of the power grid. Among them, halide molten salt has certain application potential. For example, chloride molten salt is cheap and has a large latent heat of phase transition; fluoride molten salt has a high melting point and large latent heat of fusion, and has good heat transfer performance. However, the halide may absorb water and deliquescence to produce oxygen during the production process, or it may be contaminated by oxygen during the storage process, so that the halide molten salt inevitably contains oxygen, and the corrosion of the halide molten salt with high oxygen content Sex will be significantly enhanced.

In the research of nuclear energy reactors, the dry reprocessing technology using molten salt as a medium has the advantages of radiation resistance, compact equipment, low criticality risk, non-nuclear proliferation and less amount of radioactive waste. The high temperature molten salt electrolysis technology mainly uses halide molten salt as the medium to electrolyze the fuel element at high temperature. During the electrolysis process, if the oxygen content of the molten salt medium is too high, the electrolysis efficiency of the electrolysis process will be affected, and the alkaline earth fission products or rare earth fission products will also be converted into corresponding oxides or oxyhalides, which cannot be electrolytically purified and recovered.

Halide molten salt system can also be used as the nuclear fuel carrier and coolant for molten salt reactors. If the oxygen content in the carrier salt is too high, part of the fission products generated by the fission of nuclear fuel will be converted into low-solubility oxygen-containing compounds, which will cause the fission in the molten salt. Precipitation occurs in the reactor, forming a fixed-point exothermic source and radiation source, threatening the safety of reactor operation and increasing the difficulty of reactor maintenance.

Therefore, the oxygen content in the halide molten salt is effectively reduced, which is more beneficial to the application of the halide molten salt.

At present, methods for reducing the oxygen content in halide molten salts include H ₂ -hydrogen halide method, electrochemical method or transpiration method. Among them, although the H ₂ -hydrogen halide method can remove water, oxides, etc. in the molten salt, the treatment time is also long. At the same time, during the operation process, the hydrogen halide has certain risks and is more corrosive to the equipment. Especially when dealing with halide molten salts with higher oxygen content, it takes longer processing time and is correspondingly more corrosive to equipment; compared with H ₂ -hydrogen halide method, although electrochemical The method can treat molten salt with low oxygen content and slightly alleviate the corrosiveness of the equipment, but its treatment capacity per unit time is small and the treatment efficiency is low; the treatment process of the transpiration method is relatively simple, although it can reduce the oxygen content. High halide molten salt is processed, but it is heated under normal pressure, which takes a long time and has low processing efficiency.

Therefore, there is an urgent need to provide a method that can effectively reduce the oxygen content in the halide molten salt and has high treatment efficiency.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is that the method for reducing the oxygen content in the halide molten salt in the prior art has strong corrosiveness to equipment and low processing efficiency, especially when the halide molten salt with high oxygen content is processed. The problem of taking a long time, and providing a method to reduce the oxygen content in the halide molten salt. The method for reducing the oxygen content in the halide molten salt in the present invention can effectively reduce the oxygen content in the halide molten salt, has high treatment efficiency, and is less corrosive to equipment.

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

A method for reducing oxygen content in a halide molten salt, comprising the steps of: under vacuum conditions, distilling the halide molten salt to obtain a distillation product;

Wherein, in the vacuum condition, the vacuum degree is 10 ^-5 -10 ³ Pa; in the distillation treatment, the distillation temperature is at least 200°C higher than the condensation temperature, and the distillation temperature is 400-1200°C.

In the present invention, the halide molten salt may be a halide molten salt commonly used in the field of molten salt energy storage or in the field of nuclear energy reactors, including at least halide. The source of the halide molten salt may be the halide molten salt used in the molten salt battery, the halide molten salt fuel carrier, the halide molten salt used in the molten salt reactor, or the source of the halide molten salt used in the dry reprocessing of the reactor spent fuel. of waste salt. Among them, the dry reprocessing of the spent reactor fuel can be conventional in the art, such as a high temperature electrochemical treatment process or a fission product separation process.

The oxygen content in the halide molten salt may be 500-40000 mg/Kg, preferably 500-15000 mg/Kg, for example 1000-15000 mg/Kg, and for example 1370 mg/Kg or 10000 mg/Kg.

The oxygen content in the halide molten salt refers to the content of oxygen existing in the form of oxides or oxyhalides in the halide molten salt.

Wherein, the halide generally refers to one or more of fluoride, chloride, bromide and iodide, preferably fluoride or chloride.

Wherein, the fluoride can be one or more of LiF, NaF, KF and BeF ₂ .

The fluoride is preferably LiF.

The fluorides are preferably LiF and BeF ₂ ; more preferably 67 mol % LiF and 33 mol % BeF ₂ .

The fluorides are preferably LiF, NaF and KF; more preferably 46.5 mol % LiF, 11.5 mol % NaF and 42 mol % KF.

Wherein, the chloride can be one or more of LiCl, NaCl, KCl and BeCl ₂ .

The chloride is preferably LiCl.

The chloride is preferably NaCl.

The chloride is preferably KCl.

The chlorides are preferably LiCl and KCl.

The chlorides are preferably NaCl and KCl.

Wherein, when the halide molten salt includes two halides, the molar ratio of the two halides may be any ratio, for example (1-2):1. The halogen atoms in the two halides may be the same or different halogen atoms, preferably the same halogen atoms.

When the halide molten salt includes three halides, the molar percentage ratio of the three halides can be any ratio, for example, 1:(3~4):(4~5), for example, 1:3.65:4 . The halogen atoms in the three halides may be the same or different halogen atoms, preferably the same halogen atoms.

In the present invention, the distillation product is the halide molten salt after distillation treatment. Wherein, the oxygen content in the distillation product may be below 560 mg/Kg, for example, 100-480 mg/Kg, and for example, 180 mg/Kg, 190 mg/Kg, 320 mg/Kg, 450 mg/Kg or 560 mg/Kg.

In the present invention, the degree of vacuum is preferably 10 ^-2 to 10 ³ Pa, more preferably 10 ^-1 to 10 ³ Pa, for example, 5 to 15 Pa or 90 to 110 Pa.

In the present invention, the distillation treatment is preferably performed under an inert atmosphere.

In the distillation treatment, the temperature difference between the distillation temperature and the condensation temperature is preferably 200 to 500°C, for example, 230°C or 300°C.

The distillation temperature is preferably 400-1200°C, more preferably 700-1000°C, such as 730°C, 900°C or 950°C.

The time for the distillation treatment may be 0.5 to 5 hours, preferably 1 to 4 hours, for example, 3 hours.

The processing capacity of the distillation treatment may be 5-500 g, preferably 10-350 g, more preferably 100 g or 200 g.

The distillation equipment can be conventional distillation equipment in the field, and the distillation equipment generally includes an evaporation unit, a condensation unit and a collection unit; preferably, it also includes an inert atmosphere unit. The inert atmosphere unit is used to provide an inert environment for the distillation process, so as to ensure that the halide molten salt in the distillation process and the distillation product after the distillation process will not be polluted by the atmosphere with high oxygen content again; at the same time, the inert atmosphere unit The inert gas required to restore the distillation equipment to normal pressure can also be provided.

Wherein, the evaporation unit may include an evaporation furnace body and an evaporation container. The evaporation container may be placed in a furnace cavity of the evaporation furnace body. The evaporation vessel may be an evaporation crucible. The size of the evaporation crucible can be the size conventional in the field, such as

The collection unit may be a collection crucible.

In a preferred embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt comprises the following steps: under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product;

Wherein, the halide in the halide molten salt is 67mol% LiF and 33mol% BeF ₂ ; the oxygen content in the halide molten salt is 500-12000mg/Kg;

In the vacuum condition, the vacuum degree is 5～30Pa;

In the distillation treatment, the distillation temperature and the condensation temperature are respectively 800-1000°C and 500-700°C; the temperature difference between the distillation temperature and the condensation temperature is 250-350°C,

The oxygen content in the distillation product is 480 mg/Kg or less.

In this preferred embodiment, the time for the distillation treatment is preferably 2 to 5 hours. The treatment amount of the distillation treatment is preferably 100 to 400 g.

In a preferred embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt comprises the following steps: under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product;

Wherein, the halide in the halide molten salt is lithium halide, preferably LiCl or LiF; the oxygen content in the halide molten salt is 1000-15000 mg/Kg;

In the vacuum condition, the vacuum degree is 5～150Pa;

In the distillation treatment, the distillation temperature and the condensation temperature are respectively 700-1000°C and 500-800°C; the temperature difference between the distillation temperature and the condensation temperature is 200-350°C,

The oxygen content in the distillation product is 400 mg/Kg or less.

In this preferred embodiment, the time for the distillation treatment is preferably 0.5 to 4 hours. The treatment amount of the distillation treatment is preferably 50 to 200 g.

In a preferred embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt comprises the following steps: under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product;

Wherein, the halide in the halide molten salt is 46.5mol% LiF, 11.5mol% NaF and 42mol% KF; the oxygen content in the halide molten salt is 30000～40000mg/Kg;

In the vacuum condition, the vacuum degree is 5～30Pa;

In the distillation treatment, the distillation temperature and the condensation temperature are respectively 800-1000°C and 500-700°C; the temperature difference between the distillation temperature and the condensation temperature is 200-350°C,

The oxygen content in the distillation product is 560 mg/Kg or less.

In this preferred embodiment, the time for the distillation treatment is preferably 0.5 to 2 hours. The treatment amount of the distillation treatment is preferably 50 to 200 g.

In a specific embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt preferably includes the following steps:

(1) under an inert atmosphere, make the inert gas fill the furnace cavity of the evaporation furnace body, and place the halide molten salt in the evaporation container of the distillation equipment, and seal it;

Wherein, the oxygen content in the halide molten salt is 600mg/Kg; the halide in the halide molten salt is 67mol% LiF and 33mol% BeF ₂ ; the processing capacity of the halide molten salt is 200g;

(2) the vacuum tightness of described distillation equipment is set to 10Pa;

(3) the distillation temperature and condensation temperature of the distillation equipment are respectively set to 950 ° C and 650 ° C, and the halide is subjected to distillation treatment;

Wherein, the time of described distillation treatment is 3h;

(4) after described distillation process finishes, oxygen-containing impurities remain in described distillation vessel, and obtain distillation product in collection unit;

Wherein, the oxygen content in the distillation product is 180 mg/Kg.

In a specific embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt preferably includes the following steps:

(1) under an inert atmosphere, make the inert gas fill the furnace cavity of the evaporation furnace body, and place the halide molten salt in the evaporation container of the distillation equipment, and seal it;

Wherein, the oxygen content in the halide molten salt is 1370mg/Kg; the halide in the halide molten salt is LiCl; the processing capacity of the halide molten salt is 10g;

(2) the vacuum tightness of described distillation equipment is set to 100Pa;

(3) the distillation temperature and condensation temperature of the distillation equipment are respectively set to 730 ° C and 500 ° C, and the halide is subjected to distillation treatment;

Wherein, the time of described distillation treatment is 1h;

(4) after described distillation process finishes, oxygen-containing impurities remain in described distillation vessel, and obtain distillation product in collection unit;

Wherein, the oxygen content in the distillation product is 320 mg/Kg.

In a specific embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt preferably includes the following steps:

(1) under an inert atmosphere, make the inert gas fill the furnace cavity of the evaporation furnace body, and place the halide molten salt in the evaporation container of the distillation equipment, and seal it;

Wherein, the oxygen content in the halide molten salt is 10000mg/Kg; the halide in the halide molten salt is LiF; the processing capacity of the halide molten salt is 100g;

(2) the vacuum tightness of described distillation equipment is set to 10Pa;

(3) the distillation temperature and condensation temperature of the distillation equipment are respectively set to 950 ° C and 650 ° C, and the halide is subjected to distillation treatment;

Wherein, the time of described distillation treatment is 3h;

(4) after described distillation process finishes, oxygen-containing impurities remain in described distillation vessel, and obtain distillation product in collection unit;

Wherein, the oxygen content in the distillation product is 190 mg/Kg.

In a specific embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt preferably includes the following steps:

(1) under an inert atmosphere, make the inert gas fill the furnace cavity of the evaporation furnace body, and place the halide molten salt in the evaporation container of the distillation equipment, and seal it;

Wherein, the oxygen content in the halide molten salt is 40000mg/Kg; the halide in the halide molten salt is 46.5mol% LiF, 11.5mol% NaF and 42mol% KF; the treatment of the halide molten salt The amount is 100g;

(2) the vacuum tightness of described distillation equipment is set to 10Pa;

(3) the distillation temperature and condensation temperature of the distillation equipment are respectively set to 900°C and 600°C, and the halide is subjected to distillation treatment;

Wherein, the time of described distillation treatment is 1h;

(4) after described distillation process finishes, oxygen-containing impurities remain in described distillation vessel, and obtain distillation product in collection unit;

Wherein, the oxygen content in the distillation product is 560 mg/Kg.

In a specific embodiment of the present invention, the method for reducing the oxygen content in the halide molten salt preferably includes the following steps:

(1) under an inert atmosphere, make the inert gas fill the furnace cavity of the evaporation furnace body, and place the halide molten salt in the evaporation container of the distillation equipment, and seal it;

Wherein, the oxygen content in the halide molten salt is 10000mg/Kg; the halide in the halide molten salt is 67mol% LiF and 33mol% BeF ₂ ; the processing capacity of the halide molten salt is 350g;

(2) the vacuum tightness of described distillation equipment is set to 10Pa;

(3) the distillation temperature and condensation temperature of the distillation equipment are respectively set to 950 ° C and 650 ° C, and the halide is subjected to distillation treatment;

Wherein, the time of described distillation treatment is 5h;

(4) after described distillation process finishes, oxygen-containing impurities remain in described distillation vessel, and obtain distillation product in collection unit;

Wherein, the oxygen content in the distillation product is 450 mg/Kg.

On the basis of conforming to common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain preferred examples of the present invention.

The reagents and raw materials used in the present invention are all commercially available.

The positive progressive effect of the present invention is:

1. The method for reducing the oxygen content in the halide molten salt in the present invention can effectively reduce the oxygen content in the halide molten salt by more than 70%, and even reduce the oxygen content by more than 98%; the oxygen content in the treated distillation product can be low. To below 560mg/Kg, even as low as below 200mg/Kg.

2. The method for reducing the oxygen content in the halide molten salt in the present invention has high treatment efficiency, wherein the evaporation ratio of the halide molten salt is as high as 99% or more, and the evaporation recovery rate is as high as 80% or more.

3. At the same time, the method for reducing the oxygen content in the halide molten salt in the present invention is less corrosive to equipment.

Description of drawings

Fig. 1 is the appearance photo of the distillation product obtained after the halide molten salt is treated by distillation in Example 1;

2 is a photo of the internal section (cut) of the obtained distillation product after the halide molten salt in Example 1 is treated by distillation;

3 is a photograph of oxygen-containing impurities remaining in the distillation vessel after the halide molten salt in Example 1 is subjected to distillation.

Detailed ways

The present invention is further described below by way of examples, but the present invention is not limited to the scope of the described examples. In the following examples, the experimental methods without specific conditions are selected according to conventional methods and conditions, or according to the commercial instructions.

Examples 1 to 5

The halide molten salt in Examples 1, 3 and 4 is a self-made simulated molten salt reactor fuel carrier salt; the halide molten salt in Example 2 is the halide molten salt used in molten salt batteries; the halogenated salt in Example 5 Molten salt is the halide molten salt used in molten salt reactors.

In Embodiments 1 to 5, the method for reducing the oxygen content in the halide molten salt comprises the following steps:

中，密封；(1) After the halide molten salt is pulverized, under an inert atmosphere, the inert gas is filled into the furnace cavity of the evaporation furnace body, and the pulverized halide molten salt is placed in the evaporation crucible of the distillation equipment

medium, sealed;

(2) the vacuum degree of distillation equipment is set;

(3) distillation temperature, condensation temperature and distillation time of distillation equipment are set, and halide molten salt is carried out distillation treatment;

(4) after the distillation treatment finishes, oxygen-containing impurities remain in the evaporation crucible, and the distillation product is collected in the collection crucible;

The parameter conditions in steps (1) to (4) are shown in Table 1.

Table 1

Effect Example 1

(1) After the distillation treatment in Example 1 was completed, the distillation product was cooled to room temperature, and a white molten salt product as shown in Figure 1 was obtained in a collection crucible, with a clean appearance. When the molten salt product shown in Figure 1 is cut, it can be seen that its internal section is also white, as shown in Figure 2. The remaining product in the evaporation crucible in Figure 3 is an oxide impurity, which is gray-green. It can be seen that the distillation process has separated oxide impurities from the white halide molten salt.

(2) Calculate the evaporation ratio and distillation recovery rate of the halide molten salt in Examples 1-5.

Among them, the evaporation ratio = (m _total - m _remaining ) / m _total × 100%;

Evaporation recovery = m _collected / (m _total - m _remaining ) x 100%;

m is _always the total mass of the halide molten salt to be distilled, that is, the halide molten salt treatment amount described in Table 1;

m _remaining is the mass of the remaining molten salt in the evaporation crucible after the distillation treatment;

m _collection is the mass of the white molten salt product collected in the collection crucible after distillation treatment.

The results are shown in Table 2.

(3) The oxygen content of the halide molten salt and the oxygen content of the halide molten salt after distillation were measured with an oxygen content analyzer (model 0836) from LECO, USA, and the average value was obtained by measuring twice.

The results are shown in Table 2.

Table 2

As can be seen from the data in Table 2, the method for reducing the oxygen content in the halide molten salt in Examples 1 to 5, the evaporation ratio of the halide molten salt is as high as more than 99%, and the distillation recovery rate can reach more than 80%, and can effectively The oxygen content in the halide molten salt is reduced by more than 70%, and the treatment efficiency is high. The oxygen content in the treated distillation product can be as low as 560 mg/Kg or less, or even as low as 200 mg/Kg. At the same time, it is more corrosive to equipment. weak.

Claims (39)

1. a method for reducing oxygen content in halide molten salt, is characterized in that, it comprises the following steps: under inert atmosphere and vacuum condition, halide molten salt is carried out distillation process, promptly obtains distillation product; Wherein, in the vacuum condition, the vacuum degree is 0.1-10 ³ Pa; in the distillation treatment, the distillation temperature is at least 200°C higher than the condensation temperature, and the distillation temperature is 730-1200°C; the distillation treatment equipment includes Evaporation unit, condensation unit and collection unit; the time of the distillation treatment is 0.5-5h; the treatment capacity of the distillation treatment is 5-500g. 2 . The method for reducing the oxygen content in the halide molten salt according to claim 1 , wherein the oxygen content in the halide molten salt is 500-40000 mg/Kg. 3 . 3 . The method for reducing the oxygen content in the halide molten salt according to claim 2 , wherein the oxygen content in the halide molten salt is 500-15000 mg/Kg. 4 . 4. The method for reducing the oxygen content in the halide molten salt according to claim 3, wherein the oxygen content in the halide molten salt is 1000-15000 mg/Kg. 5 . The method for reducing the oxygen content in the halide molten salt according to claim 4 , wherein the oxygen content in the halide molten salt is 1370 mg/Kg or 10000 mg/Kg. 6 . 6. The method for reducing oxygen content in halide molten salt according to claim 2, wherein the halide is one or more of fluoride, chloride, bromide and iodide. 7. The method for reducing oxygen content in halide molten salt according to claim 6, wherein the halide is fluoride or chloride. 8. The method for reducing oxygen content in halide molten salt according to claim 7, wherein the fluoride is one or more of LiF, NaF, KF and BeF ₂ . 9. The method for reducing oxygen content in halide molten salt according to claim 8, wherein the fluoride is LiF. 10 . The method for reducing the oxygen content in halide molten salt according to claim 8 , wherein the fluorides are LiF and BeF ₂ . 11 . 11. The method for reducing oxygen content in halide molten salt according to claim 10, wherein when the fluoride is LiF and _BeF2 , the fluoride is 67 mol% LiF and 33 mol% _BeF2 . 12. The method for reducing oxygen content in halide molten salt according to claim 8, wherein the fluorides are LiF, NaF and KF. 13. The method for reducing oxygen content in halide molten salt according to claim 12, wherein when the fluoride is LiF, NaF and KF, the fluoride is 46.5mol% LiF, 11.5mol% NaF and 42 mol% KF. 14. The method for reducing oxygen content in halide molten salt according to claim 7, wherein the chloride is one or more of LiCl, NaCl, KCl and BeCl ₂ . 15. The method for reducing oxygen content in halide molten salt according to claim 14, wherein the chloride is LiCl. 16. The method for reducing oxygen content in halide molten salt according to claim 14, wherein the chloride is NaCl. 17. The method for reducing oxygen content in halide molten salt according to claim 14, wherein the chloride is KCl. 18. The method for reducing oxygen content in halide molten salt according to claim 14, wherein the chlorides are LiCl and KCl. 19. The method for reducing oxygen content in halide molten salt according to claim 14, wherein the chlorides are NaCl and KCl. 20. The method for reducing oxygen content in a halide molten salt according to claim 1, wherein when the halide molten salt includes two halides, the molar percentage ratio of the two halides is an arbitrary ratio ; Alternatively, when the halide molten salt includes three halides, the molar percentage ratio of the three halides is arbitrary. 21. The method for reducing the oxygen content in a halide molten salt according to claim 20, wherein when the halide molten salt includes two halides, the ratio of the two halides in molar percentage is (1 ~2):1; Alternatively, when the halide molten salt includes three halides, the molar percentage ratio of the three halides is 1:(3-4):(4-5). 22. The method for reducing oxygen content in a halide molten salt according to claim 21, wherein when the halide molten salt includes two halides, the halogen atoms in the two halides are the same halogen atom; Alternatively, when three halides are included in the halide molten salt, the halogen atoms in the three halides are the same halogen atom. 23. The method for reducing the oxygen content in a molten halide salt according to any one of claims 1 to 22, wherein the oxygen content in the distillation product is 560 mg/Kg or less. 24. The method for reducing the oxygen content in the halide molten salt according to claim 23, wherein the oxygen content in the distillation product is 100-480 mg/Kg. 25. The method for reducing oxygen content in halide molten salt as claimed in claim 24, wherein the oxygen content in the distillation product is 180 mg/Kg, 190 mg/Kg, 320 mg/Kg, 450 mg/Kg or 560mg/Kg. 26. The method for reducing the oxygen content in a halide molten salt according to any one of claims 1 to 22, wherein in the distillation treatment, the temperature difference between the distillation temperature and the condensation temperature is 200 to 500°C. 27. The method for reducing the oxygen content in halide molten salt according to claim 26, wherein in the distillation treatment, the temperature difference between the distillation temperature and the condensation temperature is 230°C or 300°C. 28. The method for reducing oxygen content in halide molten salt according to any one of claims 1 to 9, wherein the distillation temperature is 730°C, 900°C or 950°C. 29. The method for reducing the oxygen content in a halide molten salt according to any one of claims 1 to 22, wherein the distillation treatment time is 1 to 4 hours. 30. The method for reducing the oxygen content in the halide molten salt according to claim 29, wherein the distillation treatment time is 3h. 31. The method for reducing the oxygen content in a halide molten salt according to any one of claims 1 to 22, wherein the distillation treatment has a treatment amount of 10 to 350 g. 32. The method for reducing the oxygen content in the halide molten salt according to claim 31, wherein the treatment amount of the distillation treatment is 100 g or 200 g. 33. The method for reducing the oxygen content in halide molten salt according to any one of claims 1 to 22, wherein the distillation treatment equipment comprises an inert atmosphere unit. 34. The method for reducing oxygen content in halide molten salt according to any one of claims 1 to 22, wherein the evaporation unit comprises an evaporation furnace body and an evaporation vessel. 35. The method for reducing oxygen content in halide molten salt according to claim 34, wherein the evaporation vessel is an evaporation crucible. 36. The method of claim 35, wherein the evaporation crucible has a size of

37. The method for reducing oxygen content in halide molten salt according to any one of claims 1 to 22, wherein the collection unit is a collection crucible. 38. The method for reducing oxygen content in halide molten salt according to any one of claims 1 to 22, characterized in that it comprises the steps of: Under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product; wherein, the halide in the halide molten salt is 67 mol% LiF and 33 mol% BeF ₂ ; In the vacuum condition, the vacuum degree is 5～30Pa; In the distillation treatment, the distillation temperature and the condensation temperature are respectively 800-1000°C and 500-700°C; the temperature difference between the distillation temperature and the condensation temperature is 250-350°C, The oxygen content in the distillation product is below 480mg/Kg; The time of the distillation treatment is 2～5h; The processing capacity of the distillation treatment is 100-400 g; Alternatively, the method for reducing the oxygen content in the halide molten salt comprises the steps of: Under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product; wherein, the halide in the halide molten salt is lithium halide; In the vacuum condition, the vacuum degree is 5～150Pa; In the distillation treatment, the distillation temperature and the condensation temperature are respectively 700-1000°C and 500-800°C; the temperature difference between the distillation temperature and the condensation temperature is 200-350°C, The oxygen content in the distillation product is below 400mg/Kg; The time of the distillation treatment is 0.5～4h; The processing capacity of the distillation treatment is 50-200 g; Alternatively, the method for reducing the oxygen content in the halide molten salt comprises the steps of: Under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product; wherein, the halides in the halide molten salt are 46.5mol% LiF, 11.5mol% NaF and 42mol% KF; In the vacuum condition, the vacuum degree is 5～30Pa; In the distillation treatment, the distillation temperature and the condensation temperature are respectively 800-1000°C and 500-700°C; the temperature difference between the distillation temperature and the condensation temperature is 200-350°C, The oxygen content in the distillation product is below 560 mg/Kg; The time of the distillation treatment is 0.5～2h; The processing capacity of the distillation treatment is 50-200 g. 39. The method for reducing the oxygen content in the halide molten salt according to claim 38, wherein the method for reducing the oxygen content in the halide molten salt comprises the steps of: Under inert atmosphere and vacuum conditions, the halide molten salt is subjected to distillation treatment to obtain a distillation product; wherein, the lithium halide is LiCl or LiF.

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