Method for preparing 5N ammonium rhenate

Abstract

The invention relates to the field of metallurgical materials, in particular to a method for purifying ammonium rhenate. The method specifically comprises the following steps: by taking ammonium rhenate containing impurities as a raw material, adding the raw material and ultrapure water into a reaction container, and obtaining an ammonium rhenate solution with a certain concentration for later use after the ammonium rhenate containing impurities and ultrapure water are completely dissolved; carrying out adsorption and impurity removal on the dissolved ammonium rhenate solution through an adsorption tube filled with attapulgite, precisely filtering the ammonium rhenate subjected to adsorption and impurity removal, and then carrying out refrigerated centrifugal crystallization on the ammonium rhenate filtrate to obtain mixed slurry; filtering the mixed slurry to obtain pre-crystallized powder and ammonium rhenate refined filtrate; and carrying out low-temperature slow recrystallization on the obtained ammonium rhenate refined filtrate, filtering the recrystallized slurry, washing and recrystallizing with ultrapure water, freeze-drying to obtain 5N ammonium rhenate, evaporating and concentrating the residual ammonium rhenate filtrate to a certain concentration, adsorbing and removing impurities again, and recycling.

Description

Technical Field

[0001] The invention relates to the field of metallurgical materials, and in particular to a method for preparing 5N ammonium rhenate. Background Art

[0002] Rhenium is a rare metal. At high temperatures, rhenium and rhenium alloys have excellent thermal vibration resistance and creep resistance, which is the so-called "rhenium effect". Generally, rhenium products with a purity of 4N can meet the requirements, while some aviation-grade rhenium products have higher requirements for their purity. In the process of using mainstream hydrogen reduction to prepare high-purity rhenium powder, high-purity ammonium rhenate is required as a prerequisite. Therefore, as a raw material for preparing 5N rhenium powder, ammonium rhenate with a higher purity than 2N and 4N is required, and its impurity content must meet the established requirements before a high-purity rhenium product that meets the requirements can be prepared. Therefore, the purification of ammonium rhenate is of great significance for the preparation of high-purity rhenium products.

[0003] Recrystallization is currently the most mature process for purifying high-purity ammonium rhenate, especially for ammonium rhenate raw materials with low impurities. Recrystallization can achieve the removal of specific impurities. The principle is to use the different solubility of the solvent to the purified substance and impurities, while allowing the purified substance to precipitate from the supersaturated solution while leaving all or most of the impurities in the solution. If the solubility of the impurity in the solvent is extremely low, it will be filtered out after being prepared into a saturated solution, thereby achieving the purpose of purification. Macroscopically, the impurities with high solubility in the raw material are redistributed between the solution and the crystals, and the impurities with low solubility are filtered out; microscopically, during crystallization, the purified substance is orderly arranged and crystallized.

[0004] Regarding the purification of 5N ammonium rhenate, the process for extracting 5N ammonium rhenate involved in patent CN 110527854 B is complicated and the steps are cumbersome. Therefore, how to prepare 5N ammonium rhenate through simple process control is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The present invention discloses a method for preparing 5N ammonium rhenate, so as to solve any of the above and other potential problems in the prior art.

[0006] To achieve the above object, the technical solution of the present invention is: a method for preparing 5N ammonium rhenate, the method specifically comprising the following steps:

[0007] S1) using mixed ammonium rhenate as a raw material, mixing the raw material with ultrapure water, heating to a certain temperature, and keeping the temperature for a period of time to obtain an ammonium rhenate solution of a certain concentration for standby use;

[0008] S2) passing the ammonium rhenate solution obtained in S1) through an adsorption tube filled with attapulgite to remove impurities by adsorption, and then finely filtering to obtain an ammonium rhenate filtrate after adsorption and removal of impurities;

[0009] S3) placing the ammonium rhenate filtrate of S2) into a refrigerated centrifuge, setting a certain temperature and centrifugal rate, and obtaining a mixed slurry of centrifugal crystals after the refrigerated centrifugation is completed;

[0010] S4) filtering the mixed slurry containing centrifugal crystals in S3) to obtain pre-crystallized powder and ammonium rhenate refined filtrate, and re-recrystallizing the ammonium rhenate refined filtrate at low temperature and slowly;

[0011] S5) filtering the recrystallized slurry obtained in S4), washing the recrystallized product with ultrapure water and freeze-drying it to obtain 5N ammonium rhenate, and evaporating and concentrating the filtrate and returning it to the attapulgite for adsorption and impurity removal.

[0012] Further, the purity of the ammonium rhenate raw material in S1) is 2N-4N:

[0013] The reaction temperature is 40-80° C., and the insulation time is 1-4 hours; the concentration of the ammonium rhenate solution is 30 g / L-60 g / L.

[0014] Further, the adsorption and impurity removal parameters in S2) are:

[0015] The adsorption and impurity removal temperature of the adsorption tube filled with attapulgite is controlled to be 30°C-50°C, and the volume ratio of the solution to the attapulgite is controlled to be 20 / 1-50 / 1;

[0016] Furthermore, the precision filtration in S2) controls the precision filtration pore size to be 0.5-10 microns.

[0017] Further, the freezing centrifugation parameters in S3) are:

[0018] The refrigerated centrifugation temperature was controlled at 5°C-10°C, the refrigerated centrifugation speed was controlled at 2000-6000 r / min, and the refrigerated centrifugation time was controlled at 30s-180s.

[0019] Furthermore, the low temperature slow recrystallization temperature in S4) is -5°C-5°C, and the low temperature slow recrystallization temperature is 12h-24h.

[0020] Furthermore, the recrystallization freeze-drying pressure in S5) is 10-300 Pa, the drying temperature is -10°C-0°C, and the drying time is 8h-12h.

[0021] Furthermore, the container used for drying the ammonium rhenate in S5) is a high-purity quartz plate.

[0022] Furthermore, the filtrate in S5) is evaporated and concentrated to a concentration of 30 g / L-60 g / L and then returned to adsorption and impurity removal.

[0023] A 5N ammonium rhenate is prepared by the above method.

[0024] The beneficial effects of the present invention are as follows: due to the adoption of the above technical scheme, the method of the present invention has the advantages of simple control process for preparing 5N ammonium rhenate, most of the heavy metals, alkali metals and alkaline earth metals in the raw materials can be removed by adsorption removal and two-stage crystallization, an effective open circuit is formed for impurities, and the raw materials can be stably purified from 3N-4N to 5N level, and the complicated steps of multiple recrystallizations are avoided, the energy consumption is small, the rhenium loss is small, and the yield is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic flow diagram of a method for preparing 5N ammonium rhenate.

[0026] Figure 2 This is a third-party GDMS test report for the 5N ammonium rhenate prepared in the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below through the accompanying drawings and specific embodiments of the present invention.

[0028] like Figure 1 As shown, the present invention provides a method for preparing 5N ammonium rhenate, and the method specifically comprises the following steps:

[0029] S1) using mixed ammonium rhenate as a raw material, mixing the raw material with ultrapure water, heating to a certain temperature, and keeping the temperature for a period of time to obtain an ammonium rhenate solution of a certain concentration for standby use;

[0030] S2) passing the ammonium rhenate solution obtained in S1) through an adsorption tube filled with attapulgite to remove impurities by adsorption, and then finely filtering to obtain an ammonium rhenate filtrate after adsorption and removal of impurities;

[0031] S3) placing the ammonium rhenate filtrate of S2) into a refrigerated centrifuge, setting a certain temperature and centrifugal rate, and obtaining a mixed slurry of centrifugal crystals after the refrigerated centrifugation is completed;

[0032] S4) filtering the mixed slurry containing centrifugal crystals in S3) to obtain pre-crystallized powder and ammonium rhenate refined filtrate, and re-recrystallizing the ammonium rhenate refined filtrate at low temperature and slowly;

[0033] S5) filtering the recrystallized slurry obtained in S4), washing the recrystallized product with ultrapure water and freeze-drying it to obtain 5N ammonium rhenate, and evaporating and concentrating the filtrate and returning it to the attapulgite for adsorption and impurity removal.

[0034] The purity of the ammonium rhenate raw material in S1) is 2N-4N:

[0035] The reaction temperature is 40-80° C., and the insulation time is 1-4 hours. The concentration of the ammonium rhenate solution is 30 g / L-60 g / L, and a certain concentration of ammonium rhenate solution is fully dissolved to avoid the precipitation of ammonium rhenate crystals during the adsorption of attapulgite, thereby ensuring the adsorption effect of attapulgite.

[0036] The adsorption and impurity removal parameters in S2) are:

[0037] The adsorption and impurity removal temperature of the adsorption tube filled with attapulgite is controlled to be 30°C-50°C, and the volume ratio of the solution to the attapulgite is controlled to be 20 / 1-50 / 1. Most of the heavy metal ions and some alkali metal and alkaline earth metal impurities are removed during the adsorption process of the attapulgite.

[0038] The precision filtration in S2) controls the precision filtration pore size to be 0.5-10 microns, and the precision filtration prevents fine attapulgite debris from entering the filtrate after impurity removal and introducing new impurities.

[0039] The freezing centrifugation parameters in S3) are:

[0040] The freezing centrifugation temperature is controlled to be 5°C-10°C, the freezing centrifugation speed is 2000-6000r / min, and the freezing centrifugation time is 30s-180s. The crystals obtained by freezing centrifugation contain most of the alkali metal and alkaline earth metal impurities. After filtering the impurity-containing pre-crystallization, an ammonium rhenate solution with higher purity is obtained.

[0041] The low temperature slow recrystallization temperature in S4) is -5°C to 5°C, and the low temperature slow recrystallization temperature is 12h to 24h.

[0042] The recrystallization freeze drying pressure in S5) is 10-300 Pa, the drying temperature is -10°C-0°C, the drying time is 8h-12h, and the sealed freeze drying avoids the introduction of air impurities during the drying process.

[0043] The container used for drying the ammonium rhenate in S5) is a high-purity quartz plate.

[0044] The filtrate in S5) is concentrated by evaporation to a concentration of 30 g / L-60 g / L and then returned to the adsorption and impurity removal stage.

[0045] Embodiment 1:

[0046] First, 400g of 2N ammonium rhenate at a concentration of 30g / L and ultrapure water were added to a glass container, heated to 50°C, and the temperature was maintained and stirred for 2h after the solution was clarified; the clarified ammonium rhenate solution was passed through an adsorption tube at 40°C with a solution volume to attapulgite volume ratio of 20, and the solution after adsorption and impurity removal was finely filtered through a 2-micron filter pore size, and the filtered liquid was placed in a refrigerated centrifuge, with the temperature set to 10°C, the speed set to 5000r / min, and the centrifugal time set to 60s. After the centrifugation, the mixed slurry was filtered, and the obtained ammonium rhenate filtrate was slowly recrystallized at 0°C for 12h, the recrystallized slurry was filtered, washed with ultrapure water, and freeze-dried and recrystallized for 12h using a high-purity quartz disk as a container at a pressure of 50Pa and a temperature of -5°C, and finally 147g of 5N ammonium rhenate was obtained, and the remaining ammonium rhenate filtrate was evaporated and concentrated and used as a return material for further adsorption and impurity removal. The test data of 5N ammonium rhenate is shown in Table 1.

[0047] Table 1 5N ammonium rhenate test data

[0048]

[0049] Embodiment 2:

[0050] First, 320g of 3N ammonium rhenate at a concentration of 50g / L and ultrapure water were added to a glass container, heated to 60°C, and the temperature was maintained and stirred for 2h after the solution was clarified; the clarified ammonium rhenate solution was passed through an adsorption tube at 40°C with a solution volume to attapulgite volume ratio of 30, and the solution after adsorption and impurity removal was finely filtered through a 1-micron filter pore size, and the filtered liquid was placed in a refrigerated centrifuge, with the temperature set to 5°C, the speed set to 6000r / min, and the centrifugal time set to 60s. After the centrifugation, the mixed slurry was filtered, and the obtained ammonium rhenate filtrate was slowly recrystallized at 0°C for 18h, the recrystallized slurry was filtered, washed with ultrapure water, and freeze-dried and recrystallized for 12h using a high-purity quartz disk as a container at a pressure of 100Pa and a temperature of -5°C, and finally 176g of 5N ammonium rhenate was obtained, and the remaining ammonium rhenate filtrate was evaporated and concentrated and used as a return material for further adsorption and impurity removal. The test data of 5N ammonium rhenate is shown in Table 2.

[0051] Table 2 5N ammonium rhenate test data

[0052]

[0053] Embodiment 3:

[0054] First, 500g of 4N ammonium rhenate at a concentration of 60g / L and ultrapure water were added to a glass container, heated to 80℃, and stirred for 2h after the solution was clarified; the clarified ammonium rhenate solution was passed through an adsorption tube at 50℃ with a solution volume to attapulgite volume ratio of 50, and the solution after adsorption and impurity removal was finely filtered through a 0.5 micron filter pore size, and the filtered liquid was placed in a refrigerated centrifuge, with the temperature set to 0℃, the speed set to 4000r / min, and the centrifugation time set to 60s. After the centrifugation, the mixed slurry was filtered, and the obtained ammonium rhenate filtrate was slowly recrystallized at -5℃ for 24h, the recrystallized slurry was filtered, washed with ultrapure water, and freeze-dried and recrystallized for 12h using a high-purity quartz disk as a container at a pressure of 50Pa and a temperature of -5℃, and finally 294g of 5N ammonium rhenate was obtained, and the remaining ammonium rhenate filtrate was evaporated and concentrated and used as a return material for further adsorption and impurity removal. The test data of 5N ammonium rhenate is shown in Table 3.

[0055] Table 3 5N ammonium rhenate test data

[0056]

[0057] The above is a detailed introduction to a method for preparing 5N ammonium rhenate provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and its core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present application.

[0058] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0059] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0060] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0061] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A method for preparing 5N ammonium rhenate, characterized in that: The method specifically comprises the following steps: S1) using mixed ammonium rhenate as a raw material, mixing the raw material with ultrapure water, heating to a certain temperature, and keeping the temperature for a period of time to obtain an ammonium rhenate solution of a certain concentration for standby use; S2) passing the ammonium rhenate solution obtained in S1) through an adsorption tube filled with attapulgite to remove impurities by adsorption, and then finely filtering to obtain an ammonium rhenate filtrate after adsorption and removal of impurities; S3) placing the ammonium rhenate filtrate of S2) into a refrigerated centrifuge, setting a certain temperature and centrifugal rate, and obtaining a mixed slurry of centrifugal crystals after the refrigerated centrifugation is completed; S4) filtering the mixed slurry containing centrifugal crystals in S3) to obtain pre-crystallized powder and ammonium rhenate refined filtrate, and re-recrystallizing the ammonium rhenate refined filtrate at low temperature and slowly; S5) filtering the recrystallized slurry obtained in S4), washing the recrystallized product with ultrapure water and freeze-drying it to obtain 5N ammonium rhenate, and evaporating and concentrating the filtrate and returning it to the attapulgite for adsorption and impurity removal.

2. The method according to claim 1, characterized in that: The purity of the impurity ammonium rhenate in S1) is 2N-4N, the reaction temperature is 40-80°C, and the insulation time is 1-4h; the concentration of the ammonium rhenate solution is 30g / L-60g / L.

3. The method according to claim 1, characterized in that In said S2): The adsorption and impurity removal temperature of the adsorption tube filled with attapulgite is controlled to be 30° C.-50° C., the volume ratio of the solution to the volume of attapulgite is controlled to be 20 / 1-50 / 1; and the precision filtration pore size is controlled to be 0.5-10 microns.

4. The method according to claim 1, characterized in that: In said S3), the temperature of the refrigerated centrifuge is controlled to be 5°C-10°C, the speed of the refrigerated centrifuge is controlled to be 2000-6000 r / min, and the time of the refrigerated centrifuge is controlled to be 30s-180s.

5. The method according to claim 1, characterized in that The low temperature slow recrystallization temperature in S4) is -5°C to 5°C, and the low temperature recrystallization time is 12h to 24h.

6. The method according to claim 1, characterized in that The recrystallization freeze drying pressure in S5) is 10-300 Pa, the drying temperature is -10°C-0°C, the drying time is 8h-12h, and the container used for drying the ammonium rhenate is a high-purity quartz plate.

7. The method according to claim 1, characterized in that The filtrate in S5) is evaporated and concentrated to a concentration of 30 g / L-60 g / L and then returned to the attapulgite for adsorption and impurity removal.

8. A 5N ammonium rhenate, characterized in that The 5N ammonium rhenate is prepared by the method according to any one of claims 1 to 7.

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