CN106467312A - A kind of purification process of beryllium oxide and its product - Google Patents

Abstract

The invention discloses a method for purifying beryllium oxide and its product. The purification method comprises the steps of dissolving beryllium oxide with oxalic acid, treating Ba(OH) ₂ solution, feeding N ₂ and H ₂ mixed gas for calcination, and the like. This purification method is beneficial to the protection of beryllium, will not pose a threat to the health of the operator and the environment, and will not introduce new impurity ions. At the same time, this purification method adopts two desulfurization processes, which can effectively remove the most difficult sulfur impurities in industrial beryllium oxide, and also has the advantages of simple operation and relatively easy realization of industrial production. The beryllium oxide product prepared by the invention meets the standard of nuclear pure grade beryllium oxide and has a wide range of applications.

Description

A kind of purification method of beryllium oxide and product thereof

technical field

The invention belongs to the field of chemistry, and in particular relates to a method for purifying beryllium oxide and its product.

Background technique

Due to the unique nuclear, thermal, electrical, mechanical and physical and chemical properties of beryllium oxide, beryllium oxide can not only be used as a raw material for the production of metal beryllium, beryllium copper alloy and beryllium oxide ceramics, but also in the fields of reactor engineering, aerospace and electronics industries. a wide range of applications. For the application of beryllium in these high-tech fields, only nuclear-grade beryllium oxide can meet the technical requirements, so the purification of beryllium oxide has become a very urgent problem that must be solved.

There are two industrial beryllium smelting methods, one is to extract beryllium after dissolving beryllium ore in sulfuric acid, and the other is to mix and sinter sodium fluorosilicate, sodium carbonate and sodium ferric fluoride to generate soluble sodium fluoroberyllate , thereby extracting beryllium. The latter is poisonous due to both fluorine and beryllium, and the product quality is also inferior to the sulfuric acid method, so the current mainstream beryllium smelting method is the sulfuric acid method. Beryllium oxide produced by sulfuric acid smelting of beryllium often contains impurities such as Al, S, Si, Fe, and Cu. Using beryllium oxide containing these impurities to produce beryllium-containing downstream products will definitely affect the melting point, thermal conductivity, electrical conductivity and mechanical properties of beryllium-containing components. When beryllium is used in a reactor, it also affects the neutron economy of the reactor and enhances corrosion of piping materials in molten salt reactors. In order to prepare nuclear-pure beryllium oxide, American Brash Beryllium Industry Company (ASFM, 1955) used sulfuric acid to dissolve beryllium oxide, then added excess ammonium sulfate to recrystallize ammonium aluminum alum, and then crystallized very pure beryllium sulfate. Calcining beryllium sulfate to obtain relatively pure beryllium oxide. The disadvantage of this method is that when using beryllium sulfate calcination, sulfur residues are unavoidable in beryllium oxide. It is used as an intermediate product for smelting beryllium, and there is a certain amount of sulfur impurities remaining in it. Milford Harwin Plant (Inst.of Min.andMetallurgy, 1957) in the United Kingdom proposed to use caustic soda to dissolve beryllium hydroxide, then hydrolyze beryllium hydroxide to obtain beryllium hydroxide precipitation, and then calcinate beryllium hydroxide to obtain beryllium oxide. The disadvantage of this method is that the purified product obtained contains more sodium. Therefore, how to remove impurities in beryllium oxide without introducing new impurities has become the key to purify beryllium oxide.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects that the purity of beryllium oxide obtained by the existing beryllium oxide purification method is not high, contains various impurities, especially sulfur impurities, the purification method has relatively large environmental pollution, and is not suitable for industrial production, etc., and provides A new method for purifying beryllium oxide is proposed. The obtained beryllium oxide has high purity, simple operation process, environmental protection, and is suitable for industrial production.

The inventors found that due to the complex source and preparation process of beryllium oxide and impurities in the preparation process of beryllium oxide, it is difficult to prepare beryllium oxide that meets the nuclear purity level by referring to the existing purification methods of beryllium oxide. In addition, new impurities may be introduced during the purification of beryllium oxide. The purification and preparation process of the existing beryllium oxide described in the background art is complex, and it is difficult to meet the needs of large-scale industrial production. In order to reduce the content of impurities in beryllium oxide, the inventors found that it is not possible to follow the conventional thinking, that is, to screen and improve only from the purification method of beryllium oxide, but also to consider the combination of acidic dissolution conditions, subsequent alkali washing and calcination processes. Specifically, the present invention analyzes and screens a series of technical parameters in the beryllium oxide purification process: including the selection of the type and amount of acid and alkali, the type of mixed gas in the calcination process, the pressure of the mixed gas and different gas The limitation of the molar ratio, the limitation of calcination temperature and calcination time, and the combination of various technical parameters have been carefully screened, and finally the purity of the obtained beryllium oxide has been greatly improved, and the impurity content has been significantly reduced, which meets the standard of nuclear-grade beryllium oxide. technical effect.

In order to solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is: a purification method of beryllium oxide, the purification method comprising the following steps:

(1) beryllium oxide is dissolved in oxalic acid solution, and beryllium oxalate solution is obtained by filtration; Gained beryllium oxalate solution is mixed with barium hydroxide solution, and beryllium hydroxide precipitation and barium oxalate precipitation are obtained by filtration;

(2) step (1) gained beryllium hydroxide precipitation and barium oxalate precipitation are dissolved in oxalic acid solution, filter to obtain beryllium oxalate solution;

(3) The beryllium oxalate solution obtained in step ( ₂ ) is evaporated and crystallized under vacuum conditions to obtain beryllium oxalate containing crystal water, and the gained beryllium oxalate containing crystal water is heated under vacuum conditions, and calcined in N and H _mixed gas , that is.

Wherein the step (1) is dissolving beryllium oxide in oxalic acid solution, filtering to obtain beryllium oxalate solution; mixing the obtained beryllium oxalate solution with barium hydroxide solution, and filtering to obtain beryllium hydroxide precipitate and barium oxalate precipitate.

Wherein the molar ratio of beryllium oxide to oxalic acid in the oxalic acid solution is preferably 1:1 to 1:1.4, more preferably 1:1.2 to 1:1.3, preferably 1:1.2.5, and the time for dissolution is better Preferably it is 25 to 35 minutes, more preferably 28 to 32 minutes, preferably 30 minutes. When the mol ratio of oxalic acid in described beryllium oxide and oxalic acid solution dissolves when the mol ratio of described beryllium oxide and oxalic acid in oxalic acid solution is greater than 1:1, can cause beryllium oxide excessive, can not be dissolved by oxalic acid completely; When mole When the ratio is less than 1:1.4, it will lead to too much oxalic acid, which is uneconomical. When the molar ratio is between 1:1 and 1.4, the beryllium oxide can be fully dissolved without wasting oxalic acid.

In the production process of beryllium oxide, sulfuric acid is usually used in the field to dissolve beryllium ore, and the resulting beryllium sulfate is evaporated and crystallized and then calcined to obtain beryllium oxide, which contains more sulfur impurities. In order to further purify beryllium oxide, it is necessary to choose a suitable acid to dissolve beryllium oxide. The choice of the type of acid used to dissolve beryllium oxide ore requires that the beryllium salt corresponding to the acid has high solubility and the acid ion of the beryllium salt after evaporation and crystallization can be removed by calcination. The oxalic acid of the present invention can meet these two conditions simultaneously. If sulfuric acid is used, it is easy to further introduce impurity sulfur into beryllium oxide, so that it is impossible to purify and prepare nuclear-grade beryllium oxide.

Wherein the molar ratio of the beryllium oxalate in the beryllium oxalate solution to the barium hydroxide in the barium hydroxide solution is preferably 1:1～1:1.5, more preferably 1:1.2～1:1.4, preferably 1:1. 1.3. The dissolution time is preferably 25-35 minutes, more preferably 28-32 minutes, and preferably 30 minutes. The alkali selected in the present invention is carefully selected by the inventor. The inventor has found that barium hydroxide can effectively remove free sulfate ions in the beryllium oxide solution, and has the technical effect of removing sulfate pollution. If other alkaline The solution is difficult to remove sulfate ions, and it is impossible to prepare nuclear pure grade beryllium oxide. When the molar ratio and dissolving time of the oxalic acid in the beryllium hydroxide to the oxalic acid solution exceed the scope claimed in the present invention, the technical effect obtained by the present invention cannot be obtained, and nuclear-grade beryllium oxide cannot be prepared.

Step (2) is dissolving beryllium hydroxide precipitate and barium oxalate precipitate obtained in step (1) in oxalic acid solution, and filtering to obtain beryllium oxalate solution.

Wherein the molar ratio of the beryllium hydroxide in the beryllium hydroxide precipitation to the oxalic acid in the oxalic acid solution is preferably 1:1.4～1:1.6, more preferably 1:1.5, and the time for the dissolution is preferably 28～ 32 minutes, more preferably 30 minutes.

Step (3) is to obtain beryllium oxalate containing water of crystallization by evaporating and crystallizing the beryllium oxalate solution gained in step (2) under vacuum conditions, heating the beryllium oxalate containing water of crystallization with gained under vacuum conditions, under N ₂ and H ₂ mixed gas Calcined, that is.

Wherein the temperature of evaporative crystallization under vacuum conditions is preferably 40°C-70°C, more preferably 50°C-60°C, preferably 55°C; the time of evaporative crystallization is preferably 110-130 minutes , more preferably 115 to 125 minutes, preferably 120 minutes; the temperature of heating the resulting beryllium oxalate containing crystal water under vacuum conditions is preferably 300°C to 450°C, more preferably 350°C to 420°C , preferably 400°C; the heating time is preferably 110-130 minutes, more preferably 115-125 minutes, preferably 120 minutes. The molar ratio of _N2 and _H2 in the mixed gas is preferably 1:1 to 1:4, more preferably 1:1.1 to 1:3, preferably 1:2, and the pressure of the mixed gas is preferably 0.1Mpa～0.3Mpa, more preferably 0.15Mpa～0.28Mpa, preferably 0.2Mpa, the temperature of the calcination is preferably 600°C～1000°C, more preferably 700°C～800°C, preferably The temperature is 750°C, and the calcination time is preferably 2 hours to 5 hours, more preferably 2.5 hours to 3.5 hours, and preferably 3 hours. When the technical parameters of evaporation, crystallization and heating of the beryllium oxalate containing crystal water under vacuum conditions exceed the scope of protection claimed by the present invention, the technical effect obtained by the present invention cannot be obtained, and nuclear-grade beryllium oxide cannot be prepared. The unit of the pressure value of the _N2 and _H2 mixed gas in the present invention is Mpa, and Mpa is a conventional pressure unit in this field. The Chinese name of this pressure unit is MPa, and the full name is MPa. 1 Pascal is 1N/m ² . When the molar ratio of the _N2 and _H2 mixed gas, the pressure value, and the temperature and time of calcination exceed the scope of protection claimed by the present invention, the technical effect obtained by the present invention cannot be obtained, and nuclear pure grade beryllium oxide cannot be prepared.

In order to solve the above technical problems, the second technical solution adopted by the present invention is: a beryllium oxide product prepared by the purification method of beryllium oxide described in the present invention.

The beryllium oxide product is a conventional beryllium oxide product in the field, preferably nuclear-grade beryllium oxide, that is, the impurity content in the beryllium oxide product is extremely low, meeting the impurity content standard of nuclear-grade beryllium oxide. The impurity content of the sub-poisons of the beryllium oxide product fully meets the application requirements of the beryllium oxide in reactors, especially the fourth-generation molten salt reactors. Therefore, the beryllium oxide prepared by the present invention can be widely used in the fields of rocket technology, aviation technology, nuclear industry technology and high-end beryllium oxide ceramics manufacturing, and its derivative products can be used in the manufacture of beryllium alloys.

On the basis of conforming to common knowledge in the field, the above-mentioned 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 progress effect of the present invention is:

(1) All the steps of the purification method are carried out in solution or in a vacuum condition, which is conducive to the protection of beryllium and will not pose a threat to the health of the operator.

(2) This purification method will not introduce new impurity ions. Although Ba(OH) ₂ is used in the alkaline washing process, barium ions can be effectively removed in the subsequent process.

(3) In this purification method, two desulfurization processes are adopted, that is, using Ba(OH) ₂ alkali washing and passing N ₂ and H ₂ for calcination, effectively removing the most difficult sulfur impurities in industrial beryllium hydroxide , improve the purity of beryllium oxide, and prepare nuclear pure grade beryllium oxide.

(4) The purification method is simple to operate and relatively easy to realize industrial production.

Description of drawings

Fig. 1 is the comparison of the impurity content of beryllium oxide obtained after being treated by the beryllium oxide purification method of the present invention and the nuclear pure grade beryllium oxide impurity content.

Fig. 2 is the relationship between reaction energy and temperature in the hydrogen desulfurization reaction in the beryllium oxide purification method of the present invention.

Fig. 3 is the relationship between the reaction constant and the temperature in the hydrogen desulfurization reaction in the beryllium oxide purification method of the present invention.

Fig. 4 is the relationship curve between sulfur impurity content and temperature in beryllium oxide after hydrogen desulfurization after treatment with oxalic acid and barium hydroxide in the beryllium oxide purification method of the present invention.

detailed description

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples. For the experimental methods that do not specify specific conditions in the following examples, select according to conventional methods and conditions, or according to the product instructions. In the present invention, unless otherwise specified, the room temperature is about 20°C, usually 18-25°C. The reagents used in the examples are of analytical grade unless otherwise specified, and were purchased from Sinopharm Group.

The purification of embodiment 1 beryllium oxide

Take 2.5g BeO, add it to 0.5L oxalic acid solution (concentration is 0.2mol/L), dissolve at 20°C for 25 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.55L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 25 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.6L oxalic acid solution (concentration is 0.2mol/L), dissolve 30 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 45°C for 130 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 450°C, react for 120 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:1), keep the pressure of the vacuum furnace at 0.15Mpa, and keep the temperature of the reaction system 800 ° C, react for 3 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 2 beryllium oxide

Take 2.5g BeO, add it to 0.55L oxalic acid solution (concentration is 0.2mol/L), dissolve at 18°C for 35 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.6L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 25 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.65L oxalic acid solution (concentration is 0.2mol/L), dissolve 30 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 40°C for 120 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 300°C, react for 120 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:2), keep the pressure of the vacuum furnace at 0.25Mpa, and keep the temperature of the reaction system 800 ° C, react for 2 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 3 beryllium oxide

Take 2.5g BeO, add it to 0.6L oxalic acid solution (concentration is 0.2mol/L), dissolve at 25°C for 28 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.9L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 25 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.7L oxalic acid solution (concentration is 0.2mol/L), dissolve 30 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 60°C for 120 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 400°C, react for 115 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:3), keep the pressure of the vacuum furnace at 0.3Mpa, and keep the temperature of the reaction system 600 ° C, react for 2.5 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 4 beryllium oxide

Take 2.5g BeO, add it to 0.65L oxalic acid solution (concentration is 0.2mol/L), dissolve at 20°C for 32 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.7L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 28 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.75L oxalic acid solution (concentration is 0.2mol/L), dissolve 30 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 55°C for 125 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 350°C, react for 130 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:4), keep the pressure of the vacuum furnace at 0.28Mpa, and keep the temperature of the reaction system 1000°C, react for 3.5 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 5 beryllium oxide

Take 2.5g BeO, add it to 0.7L oxalic acid solution (concentration is 0.2mol/L), dissolve at 20°C for 30 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.7L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 32 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.85L oxalic acid solution (concentration is 0.2mol/L), dissolve 28 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution into a vacuum furnace, evaporate and crystallize at 65°C for 120 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 450°C, react for 110 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:1.1), keep the pressure of the vacuum furnace at 0.1Mpa, and keep the temperature of the reaction system 950 ° C, react for 4 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 6 beryllium oxide

Take 2.5g BeO, add it to 0.65L oxalic acid solution (concentration is 0.2mol/L), dissolve at 20°C for 30 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.7L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (Concentration is 0.2mol/L), 30 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.8L oxalic acid solution (concentration is 0.2mol/L), dissolve 32 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 50°C for 125 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 420°C, react for 125 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:2), keep the pressure of the vacuum furnace at 0.18Mpa, and keep the temperature of the reaction system 700 ° C, react for 3 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

The purification of embodiment 7 beryllium oxide

Take 2.5g BeO, add it to 0.6L oxalic acid solution (concentration is 0.2mol/L), dissolve at 20°C for 35 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.65L Ba(OH) ₂ solution after filtering the beryllium oxalate solution (concentration is 0.2mol/L), 35 minutes, after reaction is complete, filter this solution to obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.75L oxalic acid solution (concentration is 0.2mol/L), dissolves 30 minutes , after the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution in a vacuum furnace, evaporate and crystallize at 70°C for 110 minutes, and obtain beryllium oxalate containing crystal water, put the beryllium oxalate containing crystal water in a vacuum furnace Heat to 380°C, react for 120 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:3), keep the pressure of the vacuum furnace at 0.2Mpa, and keep the temperature of the reaction system 880 ° C, react for 5 hours, after the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide has reached the standard of nuclear pure grade beryllium oxide.

Effect Example 1

The beryllium oxide obtained in Example 1 was analyzed by the ICP-OES method, and the results showed that the impurity content in the obtained beryllium oxide fully reached the impurity content standard of nuclear pure grade beryllium oxide. The analysis and test results are shown in Table 1 and Figure 1:

Table 1 Comparison of the impurity content of BeO obtained by the purification method of beryllium oxide and the content of nuclear pure BeO

The results of Table 1 and Fig. 1 show that the impurity content of the obtained beryllium oxide prepared by the beryllium oxide purification method of the present invention fully reaches the standard of nuclear pure grade beryllium oxide, and the content of some impurities is significantly lower than that of nuclear pure grade beryllium oxide. Therefore, the impurity content of beryllium oxide sub-poisons obtained after this purification treatment fully meets the application requirements of beryllium oxide in reactors, especially the fourth-generation molten salt reactors. In addition, the obtained beryllium oxide can also be used in the fields of rocket technology, aviation technology and high-end beryllium oxide ceramic manufacturing, and its derivative products can be used in the manufacture of beryllium alloys.

Detect the reaction energy and temperature in the hydrogen desulfurization reaction in the embodiments of the present invention, and use the ORIGIN drawing software to process the obtained results, and show the relationship between the two as shown in Figure 2. As can be seen from Figure 2, the higher the calcination temperature, the more It is beneficial to the hydrogen desulfurization reaction. Detect the reaction constant and temperature in the hydrogen desulfurization reaction in the embodiment of the present invention, and process the obtained results using ORIGIN drawing software, which shows the relationship between the neutralization temperature of the present invention as shown in Figure 3, and it can be seen from Figure 3 that the calcination temperature rises to a certain extent The rear reaction constant tends to be constant, and too high calcination temperature is not conducive to the economy of hydrogen desulfurization, so the calcination temperature can only achieve the best desulfurization effect within the range limited by the present invention.

Detect the S impurity content and temperature in the hydrogen desulfurization experiment of the embodiment of the present invention, and use the ORIGIN drawing software to process the obtained results. Higher, more conducive to the removal of sulfur impurities in beryllium oxide. Combining the economy of the beryllium oxide purification method and the subsequent application range of the obtained beryllium oxide, it can be determined that the calcination temperature range defined by the present invention is a more suitable hydrogen desulfurization temperature range.

Comparative example 1

Take 2.5g BeO, add it to 2L oxalic acid solution (concentration is 0.2mol/L), dissolve at 40°C for 50 minutes, filter the obtained beryllium oxalate solution after the dissolution is complete, add 0.65L Ba(OH) ₂ solution after the beryllium oxalate solution is filtered ( Concentration is 0.2mol/L), 30 minutes, after reaction is complete, filter this solution and obtain the mixture of beryllium hydroxide and barium oxalate precipitation, the gained mixture is added 0.75L oxalic acid solution (concentration is 0.2mol/L), dissolves 30 minutes, After the dissolution is complete, filter the obtained beryllium oxalate solution, put the filtered beryllium oxalate solution into a vacuum furnace, evaporate and crystallize at 100°C for 200 minutes, and obtain beryllium oxalate containing crystal water, and heat the beryllium oxalate containing crystal water in a vacuum furnace To 380°C, react for 120 minutes, feed N ₂ and H ₂ mixed gas into the vacuum furnace (the molar ratio of N ₂ /H ₂ is 1:5), keep the pressure of the vacuum furnace at 0.28Mpa, and keep the temperature of the reaction system at React at 880°C for 4 hours. After the purification process is completed, close the vacuum furnace and cool to room temperature. The obtained beryllium oxide does not meet the impurity content standard of nuclear pure grade beryllium oxide in Table 1. The results of the comparative example show that when the parameter values of the beryllium oxide purification method are not within the scope of protection claimed by the present invention, the purity of the obtained beryllium oxide will be significantly reduced, which does not meet the impurity content standard of nuclear pure grade beryllium oxide.

It should be understood that after reading the above content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. a kind of purification process of beryllium oxide is it is characterised in that described purification process comprises the following steps：

(1) beryllium oxide is dissolved in oxalic acid solution, is filtrated to get beryllium oxalate solution；By gained oxalic acid Beryllium solution is mixed with barium hydroxide solution, is filtrated to get beryllium hydroxide precipitation and oxalic acid precipitated barium；

(2) step (1) gained beryllium hydroxide precipitation and barium oxalate are precipitated and dissolved in oxalic acid solution, mistake Filter obtains beryllium oxalate solution；

(3) by step (2) gained beryllium oxalate solution, evaporative crystallization obtains containing crystallization under vacuum The beryllium oxalate of water, the beryllium oxalate that gained is contained water of crystallization heats under vacuum, in N₂And H₂Mixed Close in gas and calcine, obtain final product.

2. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (1) is described Beryllium oxide is 1 with the mol ratio of oxalic acid solution mesoxalic acid:1～1:1.4, the time of dissolving is 25～35 minutes, Described beryllium oxalate solution mesoxalic acid beryllium is 1 with the mol ratio of barium hydroxide in barium hydroxide solution:1～1:1.5, The time of described mixing is 25～35 minutes.

3. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (1) is described Beryllium oxide is 1 with the mol ratio of oxalic acid solution mesoxalic acid:1.2～1:1.3, the time of dissolving is 28～32 minutes, Described beryllium oxalate solution mesoxalic acid beryllium is 1 with the mol ratio of barium hydroxide in barium hydroxide solution:1.2～1:1.4, The time of described mixing is 28～32 minutes.

4. the purification process of beryllium oxide as claimed in claim 2 is it is characterised in that described beryllium oxide one The mol ratio of oxalic acid solution mesoxalic acid is 1:1.25, the time of dissolving is 30 minutes, described beryllium oxalate solution Mesoxalic acid beryllium is 1 with the mol ratio of barium hydroxide in barium hydroxide solution:1.3, the time of described mixing is 30 minutes.

5. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (1) is described Beryllium oxalate solution mesoxalic acid beryllium is 1 with the mol ratio of barium hydroxide in barium hydroxide solution:1～1:1.5, described The time of mixing is 25～35 minutes.

6. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (2) is described Beryllium hydroxide in beryllium hydroxide precipitation is 1 with the mol ratio of oxalic acid solution mesoxalic acid:1.4～1:1.6, described The time of dissolving is 28～32 minutes.

7. the purification process of beryllium oxide as claimed in claim 6 is it is characterised in that described beryllium hydroxide Beryllium hydroxide in precipitation is 1 with the mol ratio of oxalic acid solution mesoxalic acid:1.5, described dissolution time is 30 Minute.

8. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (3) is described The temperature of evaporative crystallization is 40 DEG C～70 DEG C, and the time of evaporative crystallization is 110～130 minutes, and gained is contained The temperature that the beryllium oxalate having water of crystallization heats under vacuum is 300 DEG C～450 DEG C, and the time of heating is 110～130 minutes；N in described mixed gas₂And H₂Mol ratio be 1:1～1:4, the pressure of mixed gas Power is 0.1Mpa～0.3Mpa, and the temperature of described calcining is 600 DEG C～1000 DEG C, and the time of calcining is 2 Hour～5 hours.

9. the purification process of beryllium oxide as claimed in claim 1 is it is characterised in that step (3) is described The temperature of evaporative crystallization is 50 DEG C～60 DEG C, and the time of evaporative crystallization is 115～125 minutes, and gained is contained The temperature that the beryllium oxalate having water of crystallization heats under vacuum is 350 DEG C～420 DEG C, and the time of heating is 115～125 minutes；N in described mixed gas₂And H₂Mol ratio be 1:1.1～1:3, mixed gas Pressure is 0.15Mpa～0.28Mpa, and the temperature of described calcining is 650 DEG C～800 DEG C, and the time of calcining is 2.5 hours～3.5 hours.

10. as described in a kind of any one as claim 1～9, the purification process of beryllium oxide prepares the oxidation of gained Beryllium product.