Method and device for preparing high-purity manganese metal through vacuum sublimation

Abstract

The invention belongs to the technical field of high-purity metal preparation, and particularly relates to a method and device for preparing high-purity metal manganese through vacuum sublimation. The method comprises the following steps: pretreating a raw material manganese; carrying out vacuum sublimation and condensation treatment on the pretreated raw material manganese; the pretreatment comprises ultrasonic cleaning, surface chemical cleaning with diluted hydrochloric acid and vacuum drying; the target sublimation temperature of the vacuum sublimation is below the melting point of manganese, and the temperature of a condensation area of the condensation treatment is controlled to be 850-980 DEG C. According to the method, trace elements which are high in melting point and difficult to volatilize in the manganese metal can be effectively removed, the purity of a high-purity manganese sample reaches 5N, the total content of non-gas element impurities is lower than 10ppm, the total content of gas elements is lower than 50ppm, the purity of the manganese metal is remarkably improved, and the method has the advantages of being simple in technological process, low in energy consumption, high in product collection rate, free of pollution and the like.

Description

Technical Field

[0001] This invention belongs to the field of high-purity metal preparation technology, specifically relating to a method and apparatus for preparing high-purity metallic manganese by vacuum sublimation. Background Technology

[0002] With the rapid development of the microelectronics industry, high-purity manganese has become a key basic material in fields such as electronic chips. Adding high-purity manganese to high-purity copper can effectively suppress copper electromigration and improve the lifespan and reliability of integrated circuits. The microelectronics industry has very high purity requirements for high-purity manganese, requiring strict control of non-gaseous impurities such as B, Si, Al, Na, and Mg, with their contents needing to be at the ppm level or even lower. The contents of gaseous impurities such as C, H, O, and N also need to be precisely controlled; otherwise, the application performance and product quality of high-purity manganese will be seriously affected, leading to problems such as chip short circuits and open circuit failures. Traditional electrolytic manganese or metallurgical manganese preparation processes have technological limitations, resulting in products with high impurity content, which cannot meet the current market demand for high-purity manganese. Further purification processes are necessary.

[0003] Currently, high-purity manganese preparation methods mainly fall into two categories: electrolytic refining and vacuum distillation. Electrolytic refining utilizes an electrochemical reaction in an electrolyte system to precipitate manganese ions at the cathode, while some impurity ions are removed because they cannot deposit or dissolve at the corresponding potential, thus achieving the separation and purification of manganese from impurities. Its limitations include a complex process, high energy consumption, and poor performance in removing low-melting-point metal impurities such as Na and Mg, making it difficult to achieve a purity of 5N or higher. Vacuum distillation, on the other hand, relies on the differences in vapor pressure changes with temperature among different substances. Manganese is distilled and purified in a vacuum environment, causing differences in the volatilization and condensation behaviors of manganese and impurities within a specific temperature range, thereby achieving separation. This method offers advantages such as simple process, no pollution, and low energy consumption.

[0004] Current vacuum distillation processes lack sufficient differentiation between heating and condensation temperatures, making it difficult to consider the different condensation characteristics of low-melting-point impurities and metallic manganese. This results in some low-melting-point impurities, such as Na, Mg, and Ca, becoming mixed and remaining during condensation, while solid impurities such as B, Si, and Fe easily mix into high-purity manganese during heating, affecting the purity of the final product. Traditional equipment lacks a targeted gas venting mechanism, allowing gaseous impurities such as C, H, O, and N to remain in the manganese lattice, affecting its key properties, such as electrical performance, as interstitial atoms, thus limiting the application of high-purity manganese in high-end fields.

[0005] In summary, the products obtained by existing high-purity manganese preparation methods are significantly different from the needs of high-end industries, and there is an urgent need to develop new high-purity manganese preparation processes that have better purification effects, higher efficiency, and better economic benefits. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method and apparatus for preparing high-purity manganese by vacuum sublimation. This invention effectively removes high-melting-point, non-volatile trace elements from metallic manganese, achieving a high-purity manganese sample purity of 5N (excluding gaseous elements). The total content of non-gaseous element impurities is below 10 ppm, and the total content of gaseous elements is below 50 ppm, significantly improving the purity of metallic manganese. Furthermore, the process is simple, energy-efficient, has a high product collection rate, and is pollution-free.

[0007] In a first aspect, the present invention provides a method for preparing high-purity metallic manganese by vacuum sublimation, comprising: 1) Pre-treat the raw manganese.

[0008] 2) The pretreated raw manganese is subjected to vacuum sublimation and condensation treatment.

[0009] The pretreatment includes ultrasonic cleaning, surface chemical cleaning with dilute hydrochloric acid, and vacuum drying. The target sublimation temperature for vacuum sublimation is below the melting point of manganese, and the condensation zone temperature is controlled between 850 and 980°C. In this invention, raw manganese is pretreated through ultrasonic cleaning, acid chemical cleaning, and drying. Subsequently, a vacuum sublimation process is performed, placing the treated raw manganese in a crucible. By controlling the heating, holding, and condensation conditions, manganese sublimation and high-purity collection are achieved. Dilute hydrochloric acid solution is used for chemical cleaning, and the target sublimation temperature and condensation zone temperature of the manganese material are controlled within specific ranges during the heating process to ensure the preparation effect of high-purity manganese. This invention can effectively remove high-melting-point, non-volatile trace elements from metallic manganese, achieving a high-purity manganese sample purity of 5N (excluding gaseous elements), with a total non-gaseous element impurity content of less than 10 ppm and a total gaseous element content of less than 50 ppm. This significantly improves the purity of metallic manganese and has advantages such as simple process flow, low energy consumption, high product collection rate, and no pollution.

[0010] Preferably, in step 1), the purity of the raw manganese is 2N~3N5. In this invention, the raw manganese is commercially available electrolytic manganese flakes, and its purity is tested according to the metallurgical industry standard YB / T051-2015 to be 2N~3N5, for example, 2N (99%), 3N (99.5%) or 3N5 (99.95%), etc.

[0011] Preferably, in step 1), the acid used for surface chemical cleaning is a dilute hydrochloric acid solution with a concentration of 5-15 wt%.

[0012] According to the present invention, some commercially available electrolytic manganese sheets undergo passivation treatment, and a dense oxide layer is formed on the surface of the manganese sheet after the addition of a passivating agent. Through a preferred surface pretreatment process, the oxide layer on the surface of the raw material manganese sheet can be removed, while the organic impurities remaining from the passivating agent are washed away, and the carbonization and decomposition of organic matter during heating is prevented, thereby significantly reducing the C and O element content of the distillation product.

[0013] Preferably, in step 1), the vacuum drying time is 30-60 minutes, and the drying temperature is 60-80°C. In this invention, the vacuum conditions can be implemented in a vacuum drying oven or other equipment capable of achieving the same function. Under the preferred vacuum drying conditions, drying can be carried out at a suitable temperature, making it more suitable for the drying of manganese raw materials in this invention.

[0014] Further preferred, in step 1), the pretreatment includes sequentially performing ultrasonic cleaning, a first water wash, surface chemical cleaning with dilute hydrochloric acid, a second water wash, and vacuum drying.

[0015] Further preferably, the ultrasonic cleaning time is 4-6 minutes.

[0016] Preferably, the surface chemical cleaning time is 1 to 3 minutes.

[0017] Preferably, the first water washing time is 20~40s.

[0018] Preferably, the second water wash is performed to remove residual acid.

[0019] Preferably, in step 2), the target sublimation temperature is 1150~1240℃.

[0020] In this invention, the target sublimation temperature for the heat treatment is preferably 1150~1240℃, below the melting point of manganese. Compared with the vaporization process, although the volatilization rate is slower during low-temperature sublimation, it is more conducive to the separation of manganese from high-melting-point elements. If the target sublimation temperature is set too low, the difference between the saturated vapor pressure and the actual vapor pressure of manganese will decrease. This requires a high vacuum level from the vacuum system to sublimate metallic manganese into a gaseous state; at the same time, the volatilization rate of the raw material manganese will be significantly reduced, resulting in decreased production efficiency. Both of these points are detrimental to the actual production process.

[0021] Further preferred, in step 2), the temperature of the condensation zone is controlled at 850~950℃; in this invention, if the target condensation temperature of the condensation zone is too low, it will be detrimental to the separation of manganese from easily volatile trace elements such as Na, Mg, and Ca.

[0022] Further optimization involves heating to the target sublimation temperature and condensation zone temperature at a rate of 8~15℃ / min. For example, 8℃ / min, 9℃ / min, 10℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, etc.

[0023] According to a preferred embodiment of the present invention, a method for preparing high-purity metallic manganese by vacuum sublimation includes: cleaning the raw manganese material: ultrasonically cleaning the raw manganese material with isopropanol as the cleaning solution; then rinsing with flowing pure water for 25-40 seconds to remove residual isopropanol from the surface of the raw material; then performing surface chemical cleaning in dilute hydrochloric acid until the surface of the electrolytic manganese sheet exhibits a silvery-white metallic luster, the surface chemical cleaning time being 1-3 minutes; then rinsing with pure water to remove residual acid from the surface; and drying the cleaned raw manganese material. The cleaned and dried raw manganese material is then evenly placed in a crucible; after loading the furnace, the vacuum furnace is sealed, and the furnace cavity is evacuated to an absolute pressure of 10. -4 ~10 -3 High vacuum on the order of Pa; during heating and heat preservation, the vacuum system maintains the absolute pressure at 10 Pa. -5 The temperature is on the order of ~1 Pa. The condensation zone is heated at a rate of 10 °C / min until the target temperature is reached and then held. After the temperature of the condensation zone stabilizes, the crucible is heated at a rate of 10 °C / min until it reaches the target sublimation temperature, which is below the melting point of metallic manganese. After the temperature inside the crucible stabilizes, it is held for 3-6 hours. Driven by the vapor pressure difference, manganese vapor enters the collection zone and condenses into a solid, depositing on the side of the collection zone. After the holding period, the crucible is stopped from heating and cooled. When the crucible temperature cools to 700 °C, the condensation zone is stopped from heating and then cooled. The high-purity manganese in the condensation zone is collected. According to the present invention, the high-purity manganese collected in the condensation zone has a purity of 5N, with a total non-gaseous element impurity content of less than 10 ppm and a total gaseous element content of less than 50 ppm. This method is effective in removing high-melting-point, non-volatile trace elements from metallic manganese, reducing the content of major high-melting-point elements such as B, Si, Al, Cr, Fe, Co, Ni, Mo, and W to below 0.3 ppm.

[0024] Secondly, the present invention provides an apparatus suitable for vacuum sublimation purification of metallic manganese, the apparatus comprising: A crucible for loading raw material manganese.

[0025] An isolation mesh plate is disposed between the crucible and the condensation zone.

[0026] Condensation zone; the condensation zone is used to condense and collect manganese vapor.

[0027] Top cover; the top cover is provided with a hole for discharging gaseous impurities.

[0028] Preferably, the isolation mesh is a porous wire mesh or a porous plate; the isolation mesh is used to limit the volatilization rate and vapor flow rate of manganese, and reduce the entry of high-melting-point impurities into the condensation zone. Preferably, the porous wire mesh is made of high-purity W, Ti or Mo, with a mesh size of 200-300 mesh; the porous plate is made of alumina, with an opening rate of 30-40%.

[0029] Preferably, the condensation zone is a cylindrical condensation zone.

[0030] Preferably, the top cover has a hole at its center, and the diameter of the hole is 0.5~2cm.

[0031] Preferably, heating devices are provided around both the crucible and the condensation zone. In this invention, the heating devices around the crucible are used to adjust the target heating temperature and heating rate of the raw manganese; the heating devices around the condensation zone are used to adjust the target condensation temperature and heating rate of the condensation zone.

[0032] The beneficial effects of this invention are at least as follows: This invention pre-treats the raw manganese through steps such as ultrasonic cleaning, acid chemical cleaning, and drying; subsequently, a vacuum sublimation process is performed, placing the treated raw manganese in a crucible; by controlling the conditions of heating, heat preservation, and condensation, the sublimation and high-purity collection of manganese are achieved. The chemical cleaning uses a dilute hydrochloric acid solution, and the target sublimation temperature and condensation zone temperature of the manganese material are controlled within specific ranges during the heating process to ensure the preparation effect of high-purity manganese. This invention can effectively remove high-melting-point, non-volatile trace elements from metallic manganese, enabling the high-purity manganese sample to reach a purity of 5N (excluding gaseous elements), with the total content of non-gaseous element impurities below 10 ppm and the total content of gaseous elements below 50 ppm, significantly improving the purity of metallic manganese. It has advantages such as simple process flow, low energy consumption, high product collection rate, and no pollution. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is an apparatus for vacuum sublimation purification of metallic manganese provided in this embodiment of the invention.

[0035] In the diagram, 1-crucible, 2-isolation mesh plate, 3-condensation zone, 4-top cover, 5-heating device. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0038] Unless otherwise specified, the techniques or conditions described in the embodiments of this invention shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Devices, instruments, reagents, etc., without specified manufacturers, are all conventional products that can be purchased through legitimate channels. All experimental reagents and raw materials involved are commercially available products, and all reagents are analytical grade products.

[0039] In this embodiment of the invention, the apparatus provided is suitable for vacuum sublimation purification of metallic manganese, such as... Figure 1 As shown, the (cylindrical condenser) device includes: a crucible 1 for loading raw manganese; a separating mesh plate 2 positioned between the crucible 1 and a condensation zone 3; a condensation zone 3 for condensing and collecting manganese vapor; and a top cover 4 with holes for discharging gaseous impurities. The separating mesh plate 2 is a porous wire mesh or a porous plate; it limits the volatilization rate and vapor flow of manganese, reducing the entry of high-melting-point impurities into the condensation zone. The porous wire mesh is made of high-purity W, Ti, or Mo with a mesh size of 200-300 mesh; the porous plate is made of alumina with an opening rate of 30-40%; the condensation zone 3 is cylindrical; and the top cover 4 has a hole in its center with a diameter of 0.5-2 cm. Heating devices 5 are arranged around both the crucible 1 and the condensation zone 3. The heating device 5 arranged around the crucible is used to adjust the target heating temperature and heating rate of the raw material manganese; the heating device 5 arranged around the condensation zone is used to adjust the target condensation temperature and heating rate of the condensation zone.

[0040] Example 1 This embodiment provides a specific method for preparing high-purity metallic manganese by vacuum sublimation, the method comprising: Commercially available electrolytic manganese with a purity of 3N5 was placed in an ultrasonic cleaning device, and isopropanol (electronic grade) was added as the cleaning solution to immerse the manganese material. Ultrasonic cleaning was performed for 5 minutes. Subsequently, it was rinsed with running pure water for 30 seconds to remove residual isopropanol from the surface. Next, the manganese material was placed in a 5wt% dilute hydrochloric acid solution for surface chemical cleaning until the surface of the electrolytic manganese sheet exhibited a silvery-white metallic luster; the cleaning time was approximately 3 minutes. Afterward, it was rinsed with pure water to remove any remaining acid. Finally, the cleaned manganese material was placed in a vacuum oven for drying at 80℃ for 120 minutes.

[0041] 1 kg of cleaned and dried raw manganese was evenly placed in a crucible, placed inside a vacuum furnace and sealed. The furnace was then evacuated to 10 °C. -4 A high vacuum at the Pa level is then applied, followed by heating and heat preservation.

[0042] During heating and heat preservation, the vacuum system maintains the absolute pressure at 10. -5 The pressure is on the order of ~1 Pa. High-purity metallic manganese is obtained by collecting the sublimated manganese vapor using a cylindrical condenser. The cylindrical condenser is as follows: Figure 1 As shown. The crucible is cylindrical, and its size is adapted to the condensation device. A porous wire mesh made of high-purity W with a mesh size of 300 is placed between the crucible and the condensation device.

[0043] The condensation zone was heated from room temperature to the target condensation temperature of 900℃ at a rate of 10℃ / min and held at that temperature. After the temperature of the condensation zone stabilized, the crucible was heated at a rate of 10℃ / min to reach the target sublimation temperature of 1220℃. After the temperature inside the crucible stabilized, it was held at that temperature for 4 hours.

[0044] After the heating and holding process is completed, the crucible begins to cool. When the crucible cools to 700°C, the condensation zone stops holding the temperature and begins to cool.

[0045] After the experiment, the product from the condensation zone was collected and weighed, yielding 854.3g of high-purity manganese, with a yield of 85.43%.

[0046] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 1. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0047] Table 1

[0048] As shown in Table 1, this embodiment uses electrolytic manganese sheets with a purity of 3N5 as raw material, and the total content of non-gaseous impurity elements in the prepared high-purity manganese is less than 10 ppm, with a purity exceeding 5N. The content of the main impurity element S in the raw material is reduced to below 0.5 ppm, the content of Al and Si elements is below 0.3 ppm, and the content of high-melting-point metal elements such as Cr, Fe, Co, Ni, and Mo is below the detection limit. At the same time, the content of gaseous elements C, H, O, and N does not exceed 5 ppm, which can meet the manganese purity requirements of integrated circuits.

[0049] Example 2 This embodiment provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The only difference between this method and Embodiment 1 is that the target sublimation temperature is changed from 1220℃ to 1200℃, and the holding time is extended from 4h to 5h.

[0050] After the experiment, the product from the condensation zone was collected and weighed, yielding 910.8g of high-purity manganese, with a yield of 91.08%.

[0051] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 2. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0052] Table 2

[0053] As shown in Table 2, this embodiment uses electrolytic manganese sheets with a purity of 3N5 as raw material, and the total content of non-gaseous impurities in the prepared high-purity manganese is less than 10 ppm, with a purity exceeding 5N. The content of the main impurity S element in the raw material is reduced to below 0.5 ppm, the content of Al and Si elements is below 0.3 ppm, and the content of high-melting-point metal elements such as Cr, Fe, Co, Ni, and Mo is below the detection limit. At the same time, the content of gaseous elements C, H, O, and N does not exceed 5 ppm, which can meet the manganese purity requirements of integrated circuits.

[0054] Example 3 This embodiment provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The only difference between this method and Embodiment 1 is that the target condensation temperature is increased from 900℃ to 930℃.

[0055] After the experiment, the product from the condensation zone was collected and weighed, yielding 834.6g of high-purity manganese, with a yield of 83.46%.

[0056] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 3. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0057] Table 3

[0058] As shown in Table 3, this embodiment uses electrolytic manganese sheets with a purity of 3N5 as raw material, and the total content of non-gaseous impurities in the prepared high-purity manganese is less than 10 ppm, with a purity exceeding 5N. The content of the main impurity S element in the raw material is reduced to below 0.5 ppm, the content of Al and Si elements is below 0.3 ppm, and the content of high-melting-point metal elements such as Cr, Fe, Co, Ni, and Mo is below the detection limit. At the same time, the content of gaseous elements C, H, O, and N does not exceed 5 ppm, which can meet the manganese purity requirements of integrated circuits.

[0059] Example 4 This embodiment provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The only difference between this method and Embodiment 1 is that the 300-mesh high-purity W wire mesh is replaced with a porous plate made of alumina with an opening rate of 30%.

[0060] After the experiment, the product from the condensation zone was collected and weighed, yielding 900.5g of high-purity manganese, with a yield of 90.05%.

[0061] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 4. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0062] Table 4

[0063] As shown in Table 4, this embodiment uses electrolytic manganese sheets with a purity of 3N5 as raw material, and the total content of non-gaseous impurities in the prepared high-purity manganese is less than 10 ppm, with a purity exceeding 5N. The content of the main impurity S element in the raw material is reduced to below 0.5 ppm, the content of Al and Si elements is below 0.4 ppm, and the content of high-melting-point metal elements such as Cr, Fe, Co, Ni, and Mo is below the detection limit. At the same time, the content of gaseous elements C, H, O, and N does not exceed 5 ppm, which can meet the manganese purity requirements of integrated circuits.

[0064] Comparative Example 1 This comparative example provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The main difference from Example 1 is that the target condensation temperature is reduced from 900°C to 700°C.

[0065] After the experiment, the product from the condensation zone was collected and weighed, yielding 894.5g of high-purity manganese, with a yield of 89.45%.

[0066] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 5. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0067] Table 5

[0068] As shown in Table 5, the total content of non-gaseous impurities in the high-purity manganese prepared in this comparative example is less than 10 ppm, and the purity can reach 5N. However, the target temperature of the condensation zone was set too low, resulting in poor separation of low-melting-point metal elements such as Na, Mg, and Ca, all of which were significantly higher than in Example 1. Among them, the highest content of Mg exceeded 1 ppm, which had a significant impact on the purity. The high content of low-melting-point metal elements is not conducive to the promotion and application of this product in the field of integrated circuits.

[0069] Comparative Example 2 This comparative example provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The main difference from Example 1 is that the raw manganese flakes are not cleaned before the vacuum sublimation process.

[0070] After the experiment, the product from the condensation zone was collected and weighed, yielding 814.6g of high-purity manganese, with a yield of 81.46%.

[0071] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 6. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0072] Table 6

[0073] As shown in Table 6, the high-purity manganese prepared in this comparative example has a non-gaseous impurity element content of less than 10 ppm and a purity of up to 5N. However, the contents of gaseous impurity elements C and O both exceed 5 ppm, failing to meet application requirements. The cleaning process aims to remove the passivation layer and some oxides from the surface of the raw manganese sheet. Manganese oxides easily form green manganese slag during subsequent heating, adhering to the surface of the raw material and the inner wall of the crucible. On the one hand, the solid oxide layer on the surface restricts the volatilization process of manganese, reducing the yield; on the other hand, small solid oxide particles may enter the condensation zone and deposit with the manganese vapor flow when the porosity of the porous wire mesh or porous plate is large. The C impurities contained in the passivation layer may cause the high-purity manganese in the condensation zone to be contaminated by carbide impurities during heating.

[0074] Comparative Example 3 This comparative example provides a specific method for preparing high-purity metallic manganese by vacuum sublimation. The main difference from Example 2 is that the condensation zone was not preheated and kept at a certain temperature, and the crucible was cooled before the temperature dropped to 700°C.

[0075] After the experiment, the product from the condensation zone was collected and weighed, yielding 914.9g of high-purity manganese, with a yield of 91.49%.

[0076] In this invention, for the purity analysis of high-purity manganese, escape gas analysis (EGA) was used to detect four gaseous elements: C, H, O, and N. Other non-gaseous elements were detected using glow discharge mass spectrometry (GDMS). The analytical results of trace element content are summarized in Table 7. It is assumed that the sum of the mass fractions of solid trace elements B, Na, Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Se, Mo, Sb, and W with the main metal Mn is 100%.

[0077] Table 7

[0078] As shown in Table 7, the high-purity manganese prepared in this comparative example has a non-gaseous impurity element content of less than 10 ppm and a purity of 5N. However, compared with the high-purity manganese sample obtained in Example 2, the contents of low-melting-point metals Na, Mg, and Ca are significantly increased. This is because during the heating and cooling process of the crucible, low-melting-point elements are more likely to undergo vaporization / sublimation than metallic manganese. If the temperature of the condensation zone is low at this time, the gaseous low-melting-point elements after sublimation are more likely to deposit in the condensation zone, ultimately leading to an increase in the content of low-melting-point elements on the surface of the product in the condensation zone.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-purity metallic manganese by vacuum sublimation, comprising: 1) Pre-treat the raw manganese; 2) The pretreated raw manganese is subjected to vacuum sublimation and condensation treatment; The pretreatment includes ultrasonic cleaning, surface chemical cleaning with dilute hydrochloric acid, and vacuum drying; the target sublimation temperature of the vacuum sublimation is below the melting point of manganese, and the temperature of the condensation zone of the condensation treatment is controlled at 850~980℃.

2. The method according to claim 1, characterized in that, In step 1), the purity of the raw material manganese is 2N~3N5.

3. The method according to claim 1, characterized in that, In step 1), the acid used for surface chemical cleaning is a dilute hydrochloric acid solution with a concentration of 5~15wt%.

4. The method according to any one of claims 1-3, characterized in that, In step 1), the vacuum drying time is 30-60 minutes and the drying temperature is 60-80°C.

5. The method according to any one of claims 1-3, characterized in that, In step 1), the pretreatment includes sequentially performing ultrasonic cleaning, a first water wash, surface chemical cleaning with dilute hydrochloric acid, a second water wash, and vacuum drying. Preferably, the ultrasonic cleaning time is 4-6 minutes; And / or, the surface chemical cleaning time is 1~3 min; And / or, the first water wash lasts for 20 to 40 seconds; And / or, the second water wash continues until residual acid is removed.

6. The method according to any one of claims 1-3, characterized in that, In step 2), the target sublimation temperature is 1150~1240℃.

7. The method according to claim 6, characterized in that, In step 2), the temperature of the condensation zone is controlled at 850~950℃; And / or, heat to the target sublimation temperature and condensation zone temperature at a rate of 8~15℃ / min.

8. An apparatus for vacuum sublimation purification of metallic manganese using the method described in any one of claims 1-7, characterized in that, include: A crucible for loading raw material manganese; Isolation mesh panels; The isolation mesh plate is disposed between the crucible and the condensation zone; Condensation zone; the condensation zone is used to condense and collect manganese vapor; Top cover; the top cover is provided with a hole for discharging gaseous impurities.

9. The apparatus according to claim 8, characterized in that, The isolation mesh is a porous wire mesh or a porous plate; the porous wire mesh is made of high-purity W, Ti, or Mo, with a mesh size of 200-300 mesh; the porous plate is made of alumina, with an opening rate of 30-40%. And / or, the condensation zone is a cylindrical condensation zone; And / or, the top cover has a hole at its center, the diameter of which is 0.5~2cm.

10. The apparatus according to claim 8 or 9, characterized in that, Heating devices are provided around the crucible and the condensation zone.

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