A sublimation purification method of electronic-grade molybdenum-based compounds

Abstract

This application provides a method for the sublimation purification of electronic-grade molybdenum-based compounds, belonging to the field of electronic specialty gas purification technology. The method includes the following steps: S1. A solid raw material is placed in a sublimation tube, and high-purity inert gas is supplied into the sublimation tube until the pressure is not lower than 0.1 MPa. High-purity inert gas is continuously supplied under heating conditions to purge the solid raw material in the sublimation tube. The processing temperature is higher than the sublimation point of low-sublimation-point impurities at this pressure but lower than the sublimation point of the molybdenum-based compound at this pressure, yielding an intermediate. S2. The temperature of the sublimation tube is lowered to room temperature, and the supply of high-purity inert gas is stopped. The sublimation tube is evacuated until the pressure drops below 100 Pa. Then, the intermediate in the sublimation tube is heated, wherein the processing temperature is not lower than the sublimation point of the molybdenum-based compound at this pressure. The molybdenum-based compound prepared by this method has both high purity and high yield.

Description

Technical Field

[0001] This application relates to the field of electronic specialty gas purification technology, and more specifically, to a method for the sublimation purification of electronic-grade molybdenum-based compounds. Background Technology

[0002] In existing technologies, the sublimation purification of molybdenum-based compounds typically employs atmospheric pressure sublimation. Specifically, relying on the difference in sublimation points between various impurities in the feed gas and the molybdenum-based compound at atmospheric pressure, the temperature in the sublimation tube is sequentially increased. This allows low-sublimation-point impurities, the molybdenum-based compound, and high-sublimation-point impurities to sublimate sequentially, effectively removing various impurities from the feed gas to collect electronic-grade molybdenum-based compounds. However, this sublimation purification method results in low purity and yield of the molybdenum-based compounds, thus limiting their widespread application. Therefore, there is an urgent need for a new sublimation purification method to prepare molybdenum-based compounds with high purity and high yield. Summary of the Invention

[0003] The purpose of this application is to provide a method for the sublimation purification of electronic-grade molybdenum-based compounds, which yields molybdenum-based compounds with both high purity and high yield.

[0004] The embodiments of this application are implemented as follows: In a first aspect, embodiments of this application provide a method for the sublimation purification of electronic-grade molybdenum-based compounds, comprising the following steps: S1. A solid raw material, including a molybdenum-based compound and low-sublimation-point impurities with a sublimation point lower than that of the molybdenum-based compound, is placed in a sublimation tube. High-purity inert gas is introduced into the sublimation tube until the pressure is not lower than 0.1 MPa. This pressure is maintained, and high-purity inert gas is continuously introduced under heating conditions to purge the solid raw material in the sublimation tube. The processing temperature is higher than the sublimation point of the low-sublimation-point impurities at this pressure but lower than the sublimation point of the molybdenum-based compound at this pressure, so that the low-sublimation-point impurities are sublimated and removed, yielding an intermediate. S2. The temperature of the sublimation tube is lowered to room temperature, and the supply of high-purity inert gas is stopped. The sublimation tube is evacuated until the pressure drops below 100 Pa. The intermediate in the sublimation tube is then heated at a temperature not lower than the sublimation point of the molybdenum-based compound at this pressure, so that the molybdenum-based compound sublimates. The gaseous molybdenum-based compound is then collected to obtain an electronic-grade molybdenum-based compound.

[0005] In the above technical solution, firstly, during the removal of low-sublimation-point impurities, the pressure inside the sublimation tube is increased by conveying an inert atmosphere. Since the sublimation point of the molybdenum-based compound and the sublimation point of the low-sublimation-point impurities increase at different rates with increasing pressure—specifically, the rate of increase for the molybdenum-based compound is greater than that for the low-sublimation-point impurities—this increases the difference in sublimation points between the molybdenum-based compound and the low-sublimation-point impurities. Then, based on the sublimation point of the low-sublimation-point impurities at this pressure, the solid material inside the sublimation tube is heated, and simultaneously, high-purity inert gas is used to heat the solid material inside the sublimation tube. Firstly, by purging the material, low-sublimation-point impurities can be effectively removed while retaining as much of the molybdenum-based compound as possible, thus obtaining a high-purity and high-yield molybdenum-based compound. Secondly, during the subsequent collection of the molybdenum-based compound, the sublimation tube is evacuated until the pressure is reduced to the aforementioned pressure. Since the sublimation point of the molybdenum-based compound decreases synchronously with the decrease in pressure, the molybdenum-based compound can be sublimated and collected at a lower processing temperature, thereby effectively reducing the risk of decomposition of the molybdenum-based compound at high temperatures, and thus obtaining a high-purity and high-yield molybdenum-based compound. Through the combined effect of these two aspects, a high-purity and high-yield molybdenum-based compound can ultimately be obtained.

[0006] In some alternative implementations, high-purity inert gas is supplied into the sublimation tube until the pressure reaches 0.1 MPa to 0.5 MPa.

[0007] In the above technical solution, increasing the pressure inside the sublimation tube to the aforementioned range enables the molybdenum-based compound and the low-sublimation-point impurities to have a significant difference in sublimation point. This facilitates the subsequent removal of the low-sublimation-point impurities more thoroughly while preserving the molybdenum-based compound as much as possible. At the same time, it can effectively reduce the risk of decomposition of the molybdenum-based compound during the removal of low-sublimation-point impurities.

[0008] In some alternative implementations, high-purity inert gas is supplied into the sublimation tube until the pressure reaches 0.2 MPa to 0.4 MPa.

[0009] In the above technical solution, increasing the pressure inside the sublimation tube to the aforementioned range enables the molybdenum-based compound and the low-sublimation-point impurities to have a significant difference in sublimation point. This facilitates the more thorough removal of the low-sublimation-point impurities while preserving the molybdenum-based compound as much as possible. At the same time, it can also more effectively reduce the risk of decomposition of the molybdenum-based compound during the removal of low-sublimation-point impurities.

[0010] In some alternative implementations, in step S1, the processing temperature is not higher than the melting point of the molybdenum-based compound.

[0011] In the above technical solution, limiting the processing temperature in step S1 to a range not exceeding the melting point of the molybdenum-based compound can effectively reduce the risk of melting of the molybdenum-based compound during the removal of low sublimation point impurities, so that the low sublimation point impurities in the solid raw material are exposed more thoroughly, so as to remove the low sublimation point impurities more thoroughly, thereby preparing a molybdenum-based compound with higher purity.

[0012] In some alternative embodiments, the molybdenum-based compound is molybdenum pentachloride, and the low-sublimation-point impurities include aluminum trichloride and vanadium trichloride, with a processing temperature of 170°C to 190°C.

[0013] In the above technical solution, when the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, and the pressure inside the sublimation tube is 0.2 MPa to 0.4 MPa, limiting the processing temperature in step S1 within the above range allows aluminum trichloride and vanadium trichloride to sublimate more thoroughly and be carried out of the sublimation tube by the inert gas flow. At the same time, the processing temperature is also lower than the melting point of molybdenum pentachloride and its sublimation point at the corresponding pressure, thereby enabling the removal of low sublimation point impurities such as aluminum trichloride and vanadium trichloride more thoroughly while retaining molybdenum pentachloride as much as possible.

[0014] In some alternative implementations, the high-purity inert gas used in the purging step is delivered at a flow rate of 0.2 L / min to 0.4 L / min and for a purging time of 1 h to 3 h.

[0015] In the above technical solution, the inert gas flow rate and duration in the purging step are limited to the above range, which can remove low sublimation point impurities more thoroughly.

[0016] In some alternative embodiments, step S2 further includes preheating the intermediate in the sublimation tube after vacuuming and before heating the intermediate in the sublimation tube, wherein the temperature of the preheating treatment is not higher than the sublimation point of the molybdenum-based compound at that pressure.

[0017] In the above technical solution, after vacuuming and before heating the intermediate in the sublimation tube, the intermediate in the sublimation tube is preheated at the above-mentioned treatment temperature, which can further remove the residual low sublimation point impurities, thereby further improving the purity of the prepared molybdenum-based compound.

[0018] In some alternative embodiments, the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, the preheating temperature is 50°C to 80°C, and the preheating time is 0.5 h to 1.5 h.

[0019] In the above technical solution, when the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, and the pressure inside the sublimation tube is below 100 Pa, limiting the temperature and duration of the preheating treatment to the above ranges can more thoroughly remove low sublimation point impurities such as aluminum trichloride and vanadium trichloride while retaining molybdenum pentachloride as much as possible.

[0020] In some alternative implementations, the step of heating the intermediate in the sublimation tube is carried out at a temperature of 90°C to 150°C until the solid material in the sublimation tube is emptied.

[0021] In the above technical solution, when the molybdenum-based compound is molybdenum pentachloride and the pressure inside the sublimation tube is below 100 Pa, limiting the heating temperature within the above range allows molybdenum pentachloride to sublimate more thoroughly and be collected, while high-sublimation-point impurities remain in the sublimation tube as much as possible, thereby preparing molybdenum pentachloride with high purity and high yield.

[0022] In some alternative implementations, during the step of evacuating the sublimation tube, the pressure inside the sublimation tube decreases at a rate of 0.03 MPa / min to 0.08 MPa / min.

[0023] In the above technical solution, during the step of evacuating the sublimation tube, the rate of pressure reduction inside the sublimation tube is limited to the aforementioned range, so that the pressure change is relatively gradual and the structural stability of molybdenum pentachloride can be better maintained. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of a sublimation purification method for electronic-grade molybdenum-based compounds provided in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", all refer to the three cases of "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".

[0028] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two endpoints "a" and "b"; and "unit of measurement" in "numerical value a to numerical value b + unit of measurement" represents the "unit of measurement" of both "numerical value a" and "numerical value b".

[0029] The inventors found that the existing atmospheric pressure sublimation method (i.e., the pressure inside and outside the sublimation tube is the same, and no special pressure or vacuum is applied) produces molybdenum-based compounds with low purity and yield. The main reasons are twofold: (1) The entire process is carried out under a single pressure, and the adjustable window of the processing temperature is small, making it difficult to effectively separate low-sublimation-point impurities that are close to the sublimation point of the molybdenum-based compound from the molybdenum-based compound. That is, they are easily removed or collected together, resulting in low purity or yield of the prepared molybdenum-based compound; (2) The processing temperature required for atmospheric pressure sublimation is high, and the molybdenum-based compound is easy to decompose at high temperatures, resulting in low yield and purity of the prepared molybdenum-based compound.

[0030] Based on this, the applicant innovatively provides a pressure swing sublimation purification method. In the stage of removing low-sublimation-point impurities, increasing the pressure can increase the difference in sublimation points between the low-sublimation-point impurities and the molybdenum-based compound. This allows for the effective removal of low-sublimation-point impurities while retaining as much of the molybdenum-based compound as possible, thereby preparing a high-purity and high-yield molybdenum-based compound. Furthermore, after the low-sublimation-point impurities are removed, decreasing the pressure can lower the sublimation point of the molybdenum-based compound. This allows the molybdenum-based compound to sublimate and be collected at a lower processing temperature, thereby preparing a high-purity and high-yield molybdenum-based compound.

[0031] The following is a detailed description of a method for sublimation purification of an electronic-grade molybdenum-based compound according to an embodiment of this application.

[0032] In a first aspect, embodiments of this application provide a method for the sublimation purification of electronic-grade molybdenum-based compounds, comprising the following steps: S1. A solid raw material, including a molybdenum-based compound and low-sublimation-point impurities with a sublimation point lower than that of the molybdenum-based compound, is placed in a sublimation tube. High-purity inert gas is introduced into the sublimation tube until the pressure is not lower than 0.1 MPa. This pressure is maintained, and high-purity inert gas is continuously introduced under heating conditions to purge the solid raw material in the sublimation tube. The processing temperature is higher than the sublimation point of the low-sublimation-point impurities at this pressure but lower than the sublimation point of the molybdenum-based compound at this pressure, so that the low-sublimation-point impurities are sublimated and removed, yielding an intermediate. S2. The temperature of the sublimation tube is lowered to room temperature, and the supply of high-purity inert gas is stopped. The sublimation tube is evacuated until the pressure drops below 100 Pa. The intermediate in the sublimation tube is then heated at a temperature not lower than the sublimation point of the molybdenum-based compound at this pressure, so that the molybdenum-based compound sublimates. The gaseous molybdenum-based compound is then collected to obtain an electronic-grade molybdenum-based compound.

[0033] In this application, firstly, during the removal of low-sublimation-point impurities, the pressure inside the sublimation tube is increased by conveying an inert atmosphere. Since the sublimation point of the molybdenum-based compound and the sublimation point of the low-sublimation-point impurities increase at different rates with increasing pressure—specifically, the rate of increase for the molybdenum-based compound is greater than that for the low-sublimation-point impurities—this increases the difference in sublimation points between the molybdenum-based compound and the low-sublimation-point impurities. Then, based on the sublimation point of the low-sublimation-point impurities at this pressure, the solid material inside the sublimation tube is heated, and simultaneously, high-purity inert gas is used to treat the solid raw material inside the sublimation tube. Firstly, by performing a purging process, low-sublimation-point impurities can be effectively removed while preserving as much of the molybdenum-based compound as possible, thus obtaining a high-purity and high-yield molybdenum-based compound. Secondly, during the subsequent collection of the molybdenum-based compound, the sublimation tube is evacuated until the pressure is reduced to the aforementioned pressure. Since the sublimation point of the molybdenum-based compound decreases synchronously with the decrease in pressure, the molybdenum-based compound can be sublimated and collected at a lower processing temperature. This effectively reduces the risk of decomposition of the molybdenum-based compound at high temperatures, thereby obtaining a high-purity and high-yield molybdenum-based compound. Through the combined effect of these two aspects, a high-purity and high-yield molybdenum-based compound can ultimately be obtained.

[0034] It should be noted that the first stage of pressurization and the second stage of depressurization are essential key steps in the preparation of high-purity and high-yield molybdenum-based compounds. They are also the core difference between the technical solution provided in this application and the existing single-pressure system.

[0035] During the pressurization phase, the sublimation point and boiling point of the same substance usually increase simultaneously. To better understand how pressurization can increase the difference in sublimation points between low-sublimation-point impurities and molybdenum-based compounds, we will use the change in the boiling point difference of two specific substances as an auxiliary explanation: the molybdenum-based compound is molybdenum pentachloride, whose boiling point at atmospheric pressure is around 268℃; a common low-sublimation-point impurity in molybdenum pentachloride is aluminum trichloride, whose boiling point at atmospheric pressure is around 180℃, meaning the difference in their boiling points is approximately 90℃. When the pressure increases from atmospheric pressure to 0.3 MPa, according to the Clausius-Clapeyron equation, the increase in the boiling point of a substance is positively correlated with its enthalpy of vaporization (ΔH_vap). The enthalpy of vaporization of molybdenum pentachloride is approximately 171 kJ / mol, and that of aluminum trichloride is approximately 50 kJ / mol. kJ / mol was used to raise the boiling point of molybdenum pentachloride to about 330℃ and the boiling point of aluminum trichloride to 210℃, that is, the difference in their boiling points was 120℃, which is an increase of 30℃. Similarly, the difference in their sublimation points also increased simultaneously.

[0036] It should be noted that the type of inert gas is not limited; for example, it can be at least one of argon and nitrogen.

[0037] As an example, high-purity inert gas is supplied into the sublimation tube until the pressure is 0.1 MPa to 0.5 MPa, such as, but not limited to, any one of the pressures of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa and 0.5 MPa or any range between two of them.

[0038] In this embodiment, increasing the pressure inside the sublimation tube to the aforementioned range allows for a significant difference in sublimation points between the molybdenum-based compound and the low-sublimation-point impurities. This facilitates the more thorough removal of the low-sublimation-point impurities while preserving the molybdenum-based compound as much as possible. Simultaneously, it effectively reduces the risk of decomposition of the molybdenum-based compound during the removal of low-sublimation-point impurities.

[0039] As an example, high-purity inert gas is supplied into the sublimation tube until the pressure reaches 0.2 MPa to 0.4 MPa, such as, but not limited to, any one of the pressures of 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa and 0.4 MPa or any range between two of them.

[0040] In this embodiment, increasing the pressure inside the sublimation tube to the aforementioned range allows for a significant difference in sublimation points between the molybdenum-based compound and the low-sublimation-point impurities. This facilitates a more thorough removal of the low-sublimation-point impurities while preserving the molybdenum-based compound as much as possible. Furthermore, it more effectively reduces the risk of decomposition of the molybdenum-based compound during the removal of low-sublimation-point impurities.

[0041] As an example, in step S1, the processing temperature is not higher than the melting point of the molybdenum-based compound.

[0042] In this embodiment, limiting the processing temperature in step S1 to a range not exceeding the melting point of the molybdenum-based compound can effectively reduce the risk of melting of the molybdenum-based compound during the removal of low sublimation point impurities, so that the low sublimation point impurities in the solid raw material are exposed more thoroughly, so as to remove the low sublimation point impurities more thoroughly, thereby preparing a molybdenum-based compound with higher purity.

[0043] As an example, the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, and the processing temperature is 170°C to 190°C, for example, but not limited to any one of 170°C, 175°C, 180°C, 185°C and 190°C or a range between any two.

[0044] It should be noted that when the molybdenum-based compound is molybdenum pentachloride, it usually contains low-sublimation-point impurities such as aluminum trichloride and vanadium trichloride, as well as high-sublimation-point impurities such as ferric chloride.

[0045] It should be noted that the melting point of a substance usually does not change with pressure. For example, the melting point of molybdenum pentachloride is approximately 194°C.

[0046] In this embodiment, when the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, and the pressure inside the sublimation tube is 0.2 MPa to 0.4 MPa, limiting the processing temperature in step S1 within the above range allows aluminum trichloride and vanadium trichloride to sublimate more thoroughly and be carried out of the sublimation tube by the inert gas flow. At the same time, the processing temperature is also lower than the melting point of molybdenum pentachloride and its sublimation point at the corresponding pressure, thereby enabling the removal of low sublimation point impurities such as aluminum trichloride and vanadium trichloride more thoroughly while retaining molybdenum pentachloride as much as possible.

[0047] As an example, in the purging step, the high-purity inert gas is delivered at a flow rate of 0.2 L / min to 0.4 L / min (e.g., but not limited to any one of 0.2 L / min, 0.25 L / min, 0.3 L / min, 0.35 L / min and 0.4 L / min or any range between two), and the purging time is 1 h to 3 h (e.g., but not limited to any one of 1 h, 1.5 h, 2 h, 2.5 h and 3 h or any range between two).

[0048] In this embodiment, the inert gas flow rate and duration in the purging step are limited to the above-mentioned ranges, which can more thoroughly remove low sublimation point impurities.

[0049] As an example, in step S2, after vacuuming and before heating the intermediate in the sublimation tube, a preheating treatment of the intermediate in the sublimation tube is also included, wherein the temperature of the preheating treatment is not higher than the sublimation point of the molybdenum-based compound at that pressure.

[0050] In this embodiment, after vacuuming and before heating the intermediate in the sublimation tube, the intermediate in the sublimation tube is preheated at the above-mentioned treatment temperature. This can further remove residual low sublimation point impurities, thereby further improving the purity of the prepared molybdenum-based compound.

[0051] As an example, the molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, the preheating temperature is 50°C to 80°C (e.g., but not limited to any one of 50°C, 60°C, 70°C and 80°C or any range between two), and the preheating time is 0.5 h to 1.5 h (e.g., but not limited to any one of 0.5 h, 0.8 h, 1.0 h, 1.2 h and 1.5 h or any range between two).

[0052] In this embodiment, when the molybdenum-based compound is molybdenum pentachloride, the low-sublimation-point impurities include aluminum trichloride and vanadium trichloride, and the pressure inside the sublimation tube is below 100 Pa, the temperature and duration of the preheating treatment are limited to the above ranges, which can remove low-sublimation-point impurities such as aluminum trichloride and vanadium trichloride more thoroughly while retaining molybdenum pentachloride as much as possible.

[0053] It should be noted that the specific magnitude of the pressure is not limited. For example, it can be any one of 1 Pa, 2 Pa, 5 Pa, 10 Pa, 20 Pa, 50 Pa, 80 Pa, and 90 Pa, or any range between two of them.

[0054] As an example, in the step of heating the intermediate in the sublimation tube, the treatment temperature is 90°C to 150°C (for example, but not limited to any one of 90°C, 100°C, 110°C, 120°C, 130°C, 140°C and 150°C or any range between two of the treatment temperatures) until the solid raw material in the sublimation tube is emptied.

[0055] In this embodiment, when the molybdenum-based compound is molybdenum pentachloride and the pressure inside the sublimation tube is below 100 Pa, limiting the heating temperature within the above range allows the molybdenum pentachloride to sublimate more thoroughly and be collected, while high-sublimation-point impurities (such as ferric chloride and zinc chloride) remain in the sublimation tube as much as possible, thereby preparing molybdenum pentachloride with high purity and high yield.

[0056] As an example, in the step of evacuating the sublimation tube, the pressure decrease rate inside the sublimation tube is 0.03 MPa / min to 0.08 MPa / min (e.g., but not limited to any one of 0.03 MPa / min, 0.04 MPa / min, 0.05 MPa / min, 0.06 MPa / min, 0.07 MPa / min and 0.08 MPa / min or any range between two of these rates).

[0057] In this embodiment, during the step of evacuating the sublimation tube, the rate of pressure reduction inside the sublimation tube is limited to the aforementioned range so that the pressure change is relatively gradual, which can better maintain the structural stability of molybdenum pentachloride.

[0058] It should be noted that, for the sublimation purification of electronic-grade molybdenum-based compounds, any processes or steps not specifically described or limited can be carried out according to conventional processes in this field.

[0059] As an example, a process flow diagram of the sublimation purification method for electronic-grade molybdenum-based compounds is exemplarily provided. Figure 1 .

[0060] It should be noted that the sublimation purification method provided in this application is not limited to any particular object. In addition to being applicable to molybdenum pentachloride raw material, it is also applicable to molybdenum dichlorodioxide raw material; and in addition to being applicable to molybdenum-based compounds, it is also applicable to other metal salt systems with similar separation characteristics.

[0061] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0062] Example 1 This application provides a method for the sublimation purification of electronic-grade molybdenum-based compounds, comprising the following steps: S1. Solid raw material of molybdenum pentachloride is placed in a sublimation tube. The solid raw material includes molybdenum pentachloride, low sublimation point impurities (aluminum trichloride and vanadium trichloride), and high sublimation point impurities (ferric trichloride). High-purity argon gas (purity of 99.99%) is introduced into the sublimation tube until the pressure inside the sublimation tube rises to 0.3 MPa. This pressure is maintained, and high-purity argon gas is continuously introduced under heating conditions to purge the solid raw material in the sublimation tube. The flow rate of high-purity argon gas is 0.3 L / min, the processing temperature is 180℃, and the purging time is 2 h, so that the low sublimation point impurities (aluminum trichloride and vanadium trichloride) are sublimated and removed, and an intermediate is obtained.

[0063] S2. Once the temperature inside the sublimation tube has decreased to room temperature and the supply of high-purity argon to the sublimation tube has stopped, the sublimation tube is evacuated until the pressure inside the sublimation tube decreases to 10 Pa, with a pressure decrease rate of 0.05 MPa / min. Then, the remaining solid raw material (i.e., intermediate) in the sublimation tube is preheated at a temperature of 70°C for 1 hour to remove remaining low-sublimation-point impurities (aluminum trichloride and vanadium trichloride), which are further removed by sublimation. The temperature is then raised to 110°C and held for sublimation to allow molybdenum pentachloride to sublimate, and the gaseous molybdenum pentachloride is collected until the solid raw material in the sublimation tube is emptied. Finally, the gaseous molybdenum pentachloride is condensed and stored.

[0064] Comparative Example 1 This application provides a comparative example of a method for the sublimation purification of an electronic-grade molybdenum-based compound, comprising the following steps: S1. Solid raw material of molybdenum pentachloride is placed in a sublimation tube. The solid raw material includes molybdenum pentachloride, low sublimation point impurities (aluminum trichloride and vanadium trichloride), and high sublimation point impurities (ferric trichloride). The gas in the sublimation tube is replaced with high-purity argon gas to make the pressure inside and outside the sublimation tube the same (i.e., atmospheric pressure). Under atmospheric pressure conditions and heating conditions, high-purity argon gas is continuously supplied to purge the solid raw material in the sublimation tube. The supply flow rate of high-purity argon gas is 0.3 L / min, the processing temperature is 130℃, and the purging time is 2 h, so that the low sublimation point impurities (aluminum trichloride and vanadium trichloride) are sublimated and removed to obtain an intermediate.

[0065] S2. Once the temperature inside the sublimation tube has decreased to room temperature and the supply of high-purity argon to the sublimation tube has stopped, the sublimation tube is evacuated until the pressure inside the sublimation tube decreases to 10 Pa, with a pressure decrease rate of 0.05 MPa / min. Then, the remaining solid raw material (i.e., intermediate) in the sublimation tube is preheated at a temperature of 70°C for 1 hour to remove remaining low-sublimation-point impurities (aluminum trichloride and vanadium trichloride), which are further removed by sublimation. The temperature is then raised to 110°C and held for sublimation to allow molybdenum pentachloride to sublimate, and the gaseous molybdenum pentachloride is collected until the solid raw material in the sublimation tube is emptied. Finally, the gaseous molybdenum pentachloride is condensed and stored.

[0066] Comparative Example 2 This application provides a comparative example of a method for the sublimation purification of an electronic-grade molybdenum-based compound, comprising the following steps: S1. Solid raw material of molybdenum pentachloride is placed in a sublimation tube. The solid raw material includes molybdenum pentachloride, low sublimation point impurities (aluminum trichloride and vanadium trichloride), and high sublimation point impurities (ferric trichloride). High-purity argon gas (purity of 99.99%) is introduced into the sublimation tube until the pressure inside the sublimation tube rises to 0.3 MPa. This pressure is maintained, and high-purity argon gas is continuously introduced under heating conditions to purge the solid raw material in the sublimation tube. The flow rate of high-purity argon gas is 0.3 L / min, the processing temperature is 180℃, and the purging time is 2 h, so that the low sublimation point impurities (aluminum trichloride and vanadium trichloride) are sublimated and removed, and an intermediate is obtained.

[0067] S2. Once the temperature inside the sublimation tube has decreased to room temperature and the supply of high-purity argon to the sublimation tube has stopped, the sublimation tube is evacuated until the pressure inside the sublimation tube decreases to the same level as the external pressure (i.e., atmospheric pressure). The pressure decrease rate inside the sublimation tube is 0.05 MPa / min. Then, the remaining solid raw material (i.e., intermediate) in the sublimation tube is preheated at a temperature of 130°C for 1 hour to remove the remaining low-sublimation-point impurities (aluminum trichloride and vanadium trichloride). Sublimation is then further removed. The temperature is then raised to 160°C and held for sublimation to allow molybdenum pentachloride to sublimate. The gaseous molybdenum pentachloride is collected until the solid raw material inside the sublimation tube is emptied. Finally, the gaseous molybdenum pentachloride is condensed and stored.

[0068] Comparative Example 3 This application provides a comparative example of a method for the sublimation purification of an electronic-grade molybdenum-based compound, comprising the following steps: S1. Solid raw material of molybdenum pentachloride is placed in a sublimation tube. The solid raw material includes molybdenum pentachloride, low sublimation point impurities (aluminum trichloride and vanadium trichloride), and high sublimation point impurities (ferric trichloride). The gas in the sublimation tube is replaced with high-purity argon gas to make the pressure inside and outside the sublimation tube the same (i.e., atmospheric pressure). Under atmospheric pressure conditions and heating conditions, high-purity argon gas is continuously supplied to purge the solid raw material in the sublimation tube. The supply flow rate of high-purity argon gas is 0.3 L / min, the processing temperature is 130℃, and the purging time is 2 h, so that the low sublimation point impurities (aluminum trichloride and vanadium trichloride) are sublimated and removed to obtain an intermediate.

[0069] S2. Once the temperature inside the sublimation tube has decreased to room temperature and the supply of high-purity argon to the sublimation tube has stopped, the sublimation tube is evacuated until the pressure inside the sublimation tube decreases to the same level as the external pressure (i.e., atmospheric pressure). The pressure decrease rate inside the sublimation tube is 0.05 MPa / min. Then, the remaining solid raw material (i.e., intermediate) in the sublimation tube is preheated at a temperature of 130°C for 1 hour to remove the remaining low-sublimation-point impurities (aluminum trichloride and vanadium trichloride). Sublimation is then further removed. The temperature is then raised to 160°C and held for sublimation to allow molybdenum pentachloride to sublimate. The gaseous molybdenum pentachloride is collected until the solid raw material inside the sublimation tube is emptied. Finally, the gaseous molybdenum pentachloride is condensed and stored.

[0070] Test case Molybdenum pentachloride was prepared according to the sublimation purification process of Example 1 and Comparative Examples 1-3, respectively. Then, the content of impurity metal elements in each sample was tested by ICP-MS, and the corresponding yield was calculated by the mass of molybdenum pentachloride before and after sublimation. The test results are summarized in Table 1.

[0071] Table 1

[0072] Referring to Table 1, the test results of Example 1 and Comparative Example 3 show that the pressure swing sublimation purification method provided in this application, which uses high pressure in the first stage and low pressure in the second stage, can produce molybdenum pentachloride with higher purity and yield than the existing atmospheric pressure sublimation purification method.

[0073] As can be seen from the test results of Example 1 and Comparative Examples 1-2, the pressure swing sublimation purification method provided in this application, which uses high pressure in the first stage and low pressure in the second stage, can produce molybdenum pentachloride with higher purity and yield than using high pressure only in the first stage or low pressure only in the second stage.

[0074] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for sublimation purification of electronic-grade molybdenum-based compounds, characterized in that, Includes the following steps: S1. A solid raw material is placed in a sublimation tube. The solid raw material includes a molybdenum-based compound and low-sublimation-point impurities with a sublimation point lower than that of the molybdenum-based compound. High-purity inert gas is supplied into the sublimation tube until the pressure is not lower than 0.1 MPa. This pressure is maintained, and the high-purity inert gas is continuously supplied under heating conditions to purge the solid raw material in the sublimation tube. The processing temperature is higher than the sublimation point of the low-sublimation-point impurities at this pressure but lower than the sublimation point of the molybdenum-based compound at this pressure, so that the low-sublimation-point impurities are sublimated and removed, resulting in an intermediate. S2. The temperature of the sublimation tube is reduced to room temperature and the supply of the high-purity inert gas is stopped. The sublimation tube is evacuated until the pressure is reduced to below 100 Pa. Then, the intermediate in the sublimation tube is heated, wherein the heating temperature is not lower than the sublimation point of the molybdenum-based compound at the pressure, so as to sublimate the molybdenum-based compound. Then, the gaseous molybdenum-based compound is collected to obtain an electronic-grade molybdenum-based compound.

2. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 1, characterized in that, High-purity inert gas is supplied into the sublimation tube until the pressure reaches 0.1 MPa to 0.5 MPa.

3. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 2, characterized in that, High-purity inert gas is supplied into the sublimation tube until the pressure reaches 0.2 MPa to 0.4 MPa.

4. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 3, characterized in that, In step S1, the processing temperature is not higher than the melting point of the molybdenum-based compound.

5. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 4, characterized in that, The molybdenum-based compound is molybdenum pentachloride, and the low sublimation point impurities include aluminum trichloride and vanadium trichloride. The processing temperature is 170℃~190℃.

6. The method for sublimation purification of the electronic-grade molybdenum-based compound according to any one of claims 1 to 5, characterized in that, In the purging process, the flow rate of the high-purity inert gas used is 0.2 L / min to 0.4 L / min, and the purging time is 1 h to 3 h.

7. The method for sublimation purification of the electronic-grade molybdenum-based compound according to any one of claims 1 to 5, characterized in that, In step S2, after the vacuuming and before the heating treatment of the intermediate in the sublimation tube, the intermediate in the sublimation tube is further subjected to a preheating treatment, wherein the temperature of the preheating treatment is not higher than the sublimation point of the molybdenum-based compound under the pressure.

8. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 7, characterized in that, The molybdenum-based compound is molybdenum pentachloride, the low sublimation point impurities include aluminum trichloride and vanadium trichloride, the preheating treatment temperature is 50℃~80℃, and the preheating treatment duration is 0.5 h~1.5 h.

9. The method for sublimation purification of electronic-grade molybdenum-based compounds according to claim 8, characterized in that, In the step of heating the intermediate in the sublimation tube, the treatment temperature is 90℃~150℃ until the solid raw material in the sublimation tube is emptied.

10. The method for sublimation purification of the electronic-grade molybdenum-based compound according to any one of claims 1 to 5, characterized in that, During the step of evacuating the sublimation tube, the pressure inside the sublimation tube decreases at a rate of 0.03 MPa / min to 0.08 MPa / min.

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