Method for producing high-purity manganese and high-purity manganese

Abstract

To provide a method for producing a high-purity manganese with reduced concentrations of specific impurity elements, and to provide high-purity manganese.SOLUTION: A method for producing a high-purity manganese comprises: a first purifying step of accommodating a raw material manganese with a purity of 3 N or higher in a crucible, and heating the crucible under vacuum at a first heating temperature and condensing the resulting first manganese vapor at a first recovery temperature of 800°C or more and 960°C or less at a recovery section to obtain a primary refined manganese; and a second purifying step of accommodating the resulting primary refined manganese in the recovery section in the crucible and heating the crucible under vacuum at a second heating temperature lower than the first heating temperature and condensing the resulting second manganese vapor at a second recovery temperature of 800°C or more and 960°C or less at the recovery section to obtain a secondary refined manganese.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing high-purity manganese and high-purity manganese.

Background Art

[0002] In recent years, the opportunity to use an Mn-Cu alloy in which manganese is added to copper (Cu), which is a wiring material for semiconductor devices, has been increasing. This is because adding manganese to copper can suppress the diffusion of copper into silicon (Si), which is a semiconductor material. High-purity manganese may be employed as a raw material for such a manganese evaporation source or an alloy sputtering target. As methods for producing high-purity manganese, there are a method of subjecting raw material manganese to electrolysis (for example, Patent Document 1), a method of sublimating manganese after performing electrolytic purification on raw material manganese (for example, Patent Document 2), and further, a method of producing manganese with reduced chlorine, nitrogen, and sulfur by performing filtration before electrolysis of raw material manganese (for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using an Mn-Cu alloy as a semiconductor material, even if chlorine and sulfur are contained in high-purity manganese as impurities, it is required that the concentrations of these elements in the high-purity manganese are very low. However, in the prior art, as can be seen from Patent Document 3, when acid leaching is performed for electrolysis, acid components (for example, chlorine (Cl) and sulfur (S)) are contained in the manganese after electrolytic purification. Therefore, even when using a method of removing the dissolved and floating slag or a sublimation method for purification with respect to the raw material manganese and the manganese after electrolytic purification of the raw material manganese, these impurity elements could not be sufficiently removed. Thus, an object of the present invention is to provide a method for producing high-purity manganese and high-purity manganese in which the concentrations of specific impurity elements, including chlorine (Cl) and sulfur (S), are reduced.

Means for Solving the Problems

[0005] As a result of intensive research to achieve the above-described problems, the present inventors have found that the concentration of specific impurity elements can be reduced by purifying manganese through multiple stages of the sublimation method, and the present inventors have completed the present invention described below.

[0006] <1> A first purification step of accommodating raw material manganese having a purity of 3N or more in a crucible, heating the crucible at a first heating temperature under vacuum, and condensing the obtained first manganese vapor in a recovery section having a first recovery temperature of 800°C or higher and 960°C or lower to obtain primary purified manganese. A second purification step of accommodating the primary purified manganese obtained in the recovery section in the crucible, heating the crucible at a second heating temperature lower than the first heating temperature under vacuum, and condensing the obtained second manganese vapor in the recovery section having a second recovery temperature of 800°C or higher and 960°C or lower to obtain secondary purified manganese. A method for producing high-purity manganese, including the above steps.

[0007] <2> The method for producing high-purity manganese according to <1>, wherein the first heating temperature is 1110°C or higher and 1300°C or lower, and the second heating temperature is 960°C or higher and less than 1110°C.

[0008] <3> After the second purification step, the secondary purified manganese obtained in the recovery section is accommodated in the crucible, and the crucible is heated under vacuum at a third heating temperature lower than the first heating temperature, and the obtained third manganese vapor is condensed in the recovery section at a third recovery temperature different from the second recovery temperature to obtain tertiary purified manganese. The manufacturing method of high-purity manganese according to any one of <1> or <2>, further comprising a third purification step.

[0009] <4> The manufacturing method of high-purity manganese according to any one of <1> to <3>, further comprising a washing step of washing the raw material manganese with pure water prior to the first purification step.

[0010] <5> High-purity manganese in which, among the impurity elements measured by GD-MS analysis, the content of Cl is 0.3 ppm or less, and the total content of elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 4.0 ppm or less.

[0011] <6> The high-purity manganese according to <5>, wherein the content of Cl is 0.05 ppm or less.

[0012] <7> The high-purity manganese according to any one of <5> or <6>, wherein the total content of elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 1.0 ppm or less.

[0013] <8> The high-purity manganese according to any one of <6> or <7>, wherein the content of each element excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 0.3 ppm or less.

Advantages of the Invention

[0014] In the present invention, it is possible to provide a method for manufacturing high-purity manganese with reduced concentrations of specific impurity elements and high-purity manganese.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0016] Prior to the description of the embodiment of the method for producing high-purity manganese according to the present invention, terms used in this specification will be described.

[0017] <Impurities of Manganese (Mn)> In the high-purity manganese according to the present invention, among the impurity elements measured by GD-MS analysis (glow discharge mass spectrometer), in particular, the total content of elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is used as an index of the impurity content. Note that C, N, O, F, and noble gases are excluded because they are elements contained in the background in the GD-MS analyzer or in Ar gas, He gas, etc. used for measurement, and these elements are not evaluated by GD-MS analysis from the viewpoint of accuracy. Cu is excluded because it does not need to be considered as an impurity in the Mn-Cu alloy. B is excluded because it is a non-metal element. Also, in the present invention, attention is paid to the content of chlorine (Cl) among the impurity elements measured by GD-MS analysis. By the method for producing high-purity manganese according to the present invention, it is possible to obtain high-purity manganese with a very low Cl content and a low total content of elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94.

[0018] ―GD-MS Analysis― In the GD-MS analysis (Astrum ES manufactured by Nu Instruments) carried out for measuring the impurity content in the present invention, the discharge gas species was measured under the analysis conditions using argon and high-purity In as a binder. Also, the ratio of impurities means mass ppm, and may be simply indicated as "ppm" for convenience in this specification. In the GD-MS analysis, impurity elements from atomic number 3 to 94 excluding C, N, O, and noble gases are measured for the above reasons.

[0019] - IGA analysis - In the present invention, for the analysis of carbon and oxygen, which are difficult to evaluate in the GD-MS analysis, the IGA (Instrumental Gas Analysis) analysis method was used. Regarding the analysis of carbon (C), a carbon and sulfur analyzer (EMIA-920V2 manufactured by Horiba, Ltd.) was used. The carbon content was measured under the analysis conditions with N2 as the carrier gas species and Fe, W, and Sn added as auxiliary agents. Regarding the analysis of oxygen (O), an oxygen, nitrogen, and hydrogen simultaneous analyzer (ONH836 manufactured by LECO) was used. The oxygen content was measured under the analysis conditions with He as the carrier gas species and no auxiliary agent added. Also, the ratio of impurities means mass ppm, and may be simply indicated as "ppm" for convenience in this specification.

[0020] (Method for manufacturing high-purity manganese) Hereinafter, the details of the method for manufacturing high-purity manganese according to the present embodiment will be described.

[0021] The method for producing high-purity manganese according to this embodiment includes at least a first purification step and a second purification step. First, in the first purification step, raw material manganese with a purity of 3N or more is placed in a crucible, and the crucible is heated at a first heating temperature under vacuum. The obtained first manganese vapor is condensed in a recovery section at a first recovery temperature of 800°C or higher and 960°C or lower to obtain primary purified manganese. Then, in the second purification step, the primary purified manganese obtained in the recovery section is placed in a crucible, and the crucible is heated at a second heating temperature lower than the first heating temperature under vacuum. The obtained second manganese vapor is condensed in a recovery section at a second recovery temperature of 800°C or higher and 960°C or lower to obtain secondary purified manganese. It is also preferable to place the secondary purified manganese in a crucible, heat the crucible at a third heating temperature lower than the first heating temperature under vacuum, and condense the obtained third manganese vapor in a recovery section at a third recovery temperature different from the second recovery temperature to obtain tertiary purified manganese. Further, it is also preferable to further include a washing step of washing the raw material manganese with pure water prior to the first purification step.

[0022] [Structure of Vacuum Purification Furnace] Prior to the description of each step of this embodiment, a schematic diagram of an example of a vacuum purification furnace applicable to the method for producing high-purity manganese according to this embodiment is shown with reference to FIG. 1. The vacuum purification furnace 10 in FIG. 1 includes at least a vacuum pump 20, a raw material crucible 80 for storing raw materials, a recovery crucible 90 for recovering purified manganese, an inner cylinder 30, a raw material section heater 60 for heating the raw material crucible 80, and a recovery section heater 70 for heating the recovery crucible 90.

[0023] As the housing of the vacuum purification furnace 10, for example, stainless steel or the like can be used. It has heat insulation properties and preferably has a water cooling mechanism. The inside of the vacuum purification furnace 10 can be maintained under vacuum by the vacuum pump 20. The raw material crucible 80 and the recovery crucible 90 are installed inside the inner cylinder 30 in the housing. As the materials of the inner cylinder 30, the raw material crucible 80, and the recovery crucible 90, it is preferable that they do not cause chemical changes such as dissolution and reaction through a series of purification steps. For example, alumina can be used.

[0024] Around the raw material crucible 80, a raw material section heater 60 is arranged, and around the recovery crucible 90, a recovery section heater 70 is arranged, and each can heat the raw material crucible 80 and the recovery crucible 90 to a desired temperature. The heat generation method of each heater is not limited, and for example, a carbon heater can be used.

[0025] In FIG. 1, a vertical vacuum refining furnace is shown as an example. However, the shape of the vacuum refining furnace may be horizontal with the recovery crucible 90 arranged horizontally with respect to the raw material crucible 80, or the recovery crucible 90 may be arranged obliquely downward with respect to the raw material crucible 80. When arranged vertically or obliquely downward, not only the upper part can be the raw material section and the lower part can be the recovery section, but also the upper part can be the recovery section and the lower part can be the raw material section. Vacuum evacuation may be performed not only from the upper part but also from the lower part. In order to achieve a high vacuum degree, a rotary pump and a turbo molecular pump may be used in combination. Further, in this embodiment, after the refining process, the refined manganese is taken out from the recovery crucible 90 and put into the raw material crucible 80 again to perform the next refining process. However, a valve that can be opened and closed is provided between the crucibles of the furnace, and by adjusting the temperature so as to move the zone where refining is performed along with the opening and closing of the valve, a continuous method of changing the recovery crucible 90 into the raw material crucible 80 to perform the next refining may be adopted.

[0026] Next, with reference to FIG. 2, the details of each step of the method for producing high-purity manganese will be described. Here, the heating temperature is the temperature at the center of the inner bottom of the raw material crucible 80 during heating. By arranging a temperature measuring device (for example, a measuring ring: manufactured by Lead Hammer Japan) at the center of the inner bottom of the raw material crucible 80 and measuring the relationship with the set output of the raw material section heater 60 in advance, the first to third heating temperatures can be adjusted by the raw material section heater 60. Further, the recovery temperature is the temperature at the center of the inner bottom of the recovery crucible 90 during heating. By arranging a temperature measuring device at the center of the inner bottom of the recovery crucible 90 and measuring the relationship with the set output of the recovery section heater 70 in advance, the first to third recovery temperatures can be adjusted by the recovery section heater 70.

[0027] <First Refining Step> In the first purification step, first, raw manganese with a manganese purity of 3N (99.9%) or higher is placed in a crucible. Next, the space inside the crucible is evacuated to make the raw manganese under vacuum. Here, in the present invention, the vacuum preferably has a degree of vacuum of 1×10 2 Pa or less, more preferably a degree of vacuum of 1×10 1 ~1×10 -4 Pa, and most preferably 3×10 0 ~1×10 -2 Pa. The higher the degree of vacuum, the more preferably the sublimation of manganese, which is the target element, can be promoted, and the oxidation of the metal during purification can also be suppressed. Next, after evacuating the inside of the purification apparatus, the raw material crucible 80 is heated, particularly by the contribution of the raw material heater 60. The heating by the raw material heater 60 only needs to be able to heat the raw material crucible 80 to the first heating temperature. From the point of promoting the sublimation of manganese while suppressing the sublimation of impurities, it is preferably 1110°C or higher and 1300°C or lower, and more preferably 1120°C or higher and 1200°C or lower.

[0028] The manganese vapor sublimated at the first heating temperature is heated by the contribution of the recovery unit heater 70 and condensed in the recovery crucible 90 which is the recovery unit at a first recovery temperature of 800 °C or higher and 960 °C or lower to become primary purified manganese. The first recovery temperature is at least lower than the first heating temperature. In order to deposit manganese on the recovery crucible 90, the first recovery temperature is preferably 810 °C or higher and 850 °C or lower, and more preferably 820 °C or higher and 840 °C or lower. At this time, the manganese sublimated by heating in the raw material crucible 80 is recovered in the recovery crucible 90, thereby increasing the manganese purity. Impurity elements with a higher vapor pressure than manganese diffuse into the system, and most of the impurities with a lower vapor pressure in the raw material manganese are concentrated and recovered in the raw material manganese remaining in the raw material crucible 80. The heating time for maintaining the heating after raising the temperature to the first heating temperature and the first recovery temperature is not particularly limited, but it may be determined depending on the capacity and the sublimation rate. In order to sublime a sufficient amount of raw material manganese and recover primary purified manganese, it is preferably 10 hours or more, and more preferably 50 hours or more. Also, from the viewpoint of efficiency improvement, it is preferably 100 hours or less.

[0029] After a desired amount of primary purified manganese is recovered in the recovery crucible 90, all heaters are stopped and the entire purification apparatus including the recovery crucible 90 is naturally cooled. Then, the primary purified manganese is taken out. When taking it out of the vacuum purification furnace 10, from the viewpoints of suppressing oxidation of manganese and safety, it is preferably naturally cooled until the recovery crucible 90 reaches 80 °C or lower, and more preferably cooled until it reaches 40 °C or lower. Note that in the raw material crucible 80, manganese with a higher impurity concentration than the raw material manganese accommodated at the beginning of this process remains after passing through the first purification step.

[0030] <Second Purification Step> In the second purification step, the primary purified manganese recovered from the recovery section in the first purification step is further purified. First, the primary purified manganese obtained in the first purification step is placed in the raw material crucible 80. Next, in order to place the primary purified manganese under vacuum, the space inside the crucible is evacuated. At this time, the higher the degree of vacuum, the better. For example, it is preferably 1 Pa or less, and it may be the same as or different from the degree of vacuum in the first purification step. Next, after evacuating the inside of the purification apparatus, the raw material section heater 60 is heated to a second heating temperature lower than the first heating temperature. The second heating temperature is preferably 960°C or higher and 1110°C or lower, and more preferably 1000°C or higher and 1100°C or lower from the viewpoint of suppressing the sublimation of impurities while promoting the sublimation of manganese. At this time, the second heating temperature is set lower than the first heating temperature. By changing the heating temperature, the elements sublimated from the raw material crucible 80 can be limited. In particular, the impurity Si concentration after recovery by secondary purification can be reduced, and the purity of manganese can be increased. The heating time for maintaining the heating after raising the temperature to the second heating temperature and the second recovery temperature is not particularly limited, but it may be determined depending on the capacity and the sublimation rate. In order to sublime a sufficient amount of raw material manganese and recover the secondary purified manganese, it is preferably 10 hours or more, and more preferably 50 hours or more. Also, from the viewpoint of efficiency improvement, it is preferably 100 hours or less. When the raw material manganese accommodated in the raw material crucible 80 in the first purification step is electrolytic manganese with a purity of about 3N obtained by electrolytic purification, the surface of the raw material is covered with a thick oxide film. On the other hand, in the second purification step, since the primary purified manganese purified through the first purification step is used as the raw material, the oxide film of the manganese serving as the raw material exists only in the very surface portion of the raw material, and a metallic luster is observed visually. Also from the viewpoint of the difference in sublimation rate due to the difference in the oxidation state of each raw material at the start of such purification, it is preferable that the second heating temperature is lower than the first heating temperature.

[0031] The second manganese vapor sublimated at the second heating temperature is condensed in a recovery section at a second recovery temperature of 800°C or higher and 960°C or lower to become secondary purified manganese. The second recovery temperature may be the same as or different from the first recovery temperature. From the viewpoint of separating Mn and impurities, the second recovery temperature is preferably 810°C or higher and 850°C or lower, and more preferably 820°C or higher and 840°C or lower.

[0032] After all the primary purified manganese stored in the raw material crucible 80 has sublimated or after a desired amount of secondary purified manganese has been recovered in the recovery crucible 90, all the heaters are stopped and the entire purification apparatus including the recovery crucible 90 is naturally cooled, and then the secondary purified manganese is taken out. Similar to the first purification step, the time required for natural cooling is not particularly limited.

[0033] <Third Purification Step> Furthermore, following the above-described first purification step and second purification step, it is preferable to further perform a third purification step. Specifically, the secondary purified manganese obtained in the recovery section in the second purification step is accommodated in the raw material crucible 80, and the raw material crucible 80 is heated under vacuum at a third heating temperature lower than the first heating temperature, and the obtained third manganese vapor is condensed in a recovery section having a third recovery temperature different from the second recovery temperature to obtain tertiary purified manganese. The degree of vacuum may be the same as or different from that in the first purification step and the second purification step. For the same reason as in the second purification step, by setting the third heating temperature lower than the first heating temperature, the elements sublimating from the crucible can be limited, and the purity of the recovered manganese can be increased. The third heating temperature is preferably 960°C or higher and 1110°C or lower, and more preferably 1000°C or higher and 1100°C or lower from the viewpoint of promoting the sublimation of manganese while suppressing the sublimation of impurities. Also, by setting the third heating temperature lower than the second heating temperature, the purity of the further recovered manganese can be increased. The third manganese vapor sublimated at the third heating temperature is condensed in a recovery section having a third recovery temperature of 800°C or higher and 960°C or lower to become tertiary purified manganese. The third recovery temperature may be the same as or different from the first recovery temperature and the second recovery temperature. Also, in order to obtain tertiary purified manganese with higher purity, it is preferable to set the third recovery temperature higher than the first recovery temperature and the second recovery temperature, preferably 850°C or higher and 900°C or lower, and more preferably 860°C or higher and 880°C or lower. This is because by lowering the heating temperature and raising the recovery temperature, the amount of types of impurities moving together with the manganese vapor and the aggregation ratio in the recovery crucible can be reduced. The heating time for maintaining the heating after raising the temperature to the third heating temperature and the third recovery temperature is not particularly limited, but may be determined depending on the capacity and the sublimation rate. In order to sublime a sufficient amount of raw material manganese and recover tertiary purified manganese, it is preferably 10 hours or more, and more preferably 50 hours or more. Also, from the viewpoint of efficiency, the maintenance time is preferably 100 hours or less.

[0034] After all the secondary purified manganese stored in the raw material crucible 80 has sublimated or after the desired amount of tertiary purified manganese has been recovered in the recovery crucible 90, all the heaters are stopped and the entire purification apparatus including the recovery crucible 90 is allowed to cool naturally, and then the tertiary purified manganese is taken out. Similar to the first purification step, the time required for natural cooling is not particularly limited.

[0035] <<Washing>> Also, it is preferable that this manufacturing method further includes a washing step of washing the raw material manganese with pure water prior to the first purification step. By washing the raw material manganese with pure water, dirt and fine powder adhering to the raw material surface during transportation from the electrolytic manganese supplier can be floated and removed. As the washing method, it is preferable to perform ultrasonic washing, for example, it is preferable to perform ultrasonic washing for 1 hour. After the raw material manganese washed with pure water is separated into solid and liquid by an arbitrary method, it is also preferable to perform vacuum drying. Thereby, the washed raw material manganese in a dry state can be obtained. Note that the washing method in this step is not limited to ultrasonic washing using pure water, and any washing method such as manual stirring and washing can be adopted.

[0036] (High-purity manganese) Next, the high-purity manganese obtained by the manufacturing method of high-purity manganese described so far will be described. The high-purity manganese according to this embodiment is manganese in which the content of Cl is 0.3 ppm or less among the impurity elements measured by GD-MS analysis, and the total content of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 4.0 ppm or less. From the viewpoints of corrosion during Mn-Cu alloy formation, electrical conductivity, reactivity with other elements, etc., the content of Cl is preferably 0.05 ppm or less. Further, for the high-purity manganese according to this embodiment, it is more preferable that the total content of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 1.0 ppm or less, and it is even more preferable that the content of each of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 0.3 ppm or less.

Example

[0037] Hereinafter, a method for producing high-purity manganese according to this embodiment and examples of high-purity manganese produced by the production method will be described.

[0038] (Comparative Example 1) As the raw material manganese, 10 kg of a commercially available product of flaky electrolytic manganese with a purity of 3N was used. The surface of the raw material was oxidized and turned brown, and there was no metallic luster. By washing with ultrasonic waves in pure water, surface dirt was removed. Next, 10 kg of the washed raw material manganese was placed in an alumina raw material crucible, and the raw material crucible was stored in a vacuum refining furnace. Then, after evacuating the inside of the vacuum refining furnace to a vacuum degree of 1 Pa using a vacuum pump, the raw material crucible was heated to 1130 °C by a raw material heater. The raw material manganese sublimated into a gas of manganese vapor and flowed in the direction of the recovery part in the furnace. Also, in the vicinity of the alumina recovery crucible maintained at 820 °C by the recovery heater, the gaseous manganese was cooled, contacted the inner wall surface of the recovery crucible, and condensed and precipitated. After heating each part in the furnace to the above respective temperatures, the heating was stopped after 65 hours, and natural cooling was performed. In this way, the first purification by the sublimation method was carried out, and the purified manganese was recovered from the recovery crucible to obtain manganese after primary purification. This is taken as Comparative Example 1. In the visual observation of the obtained manganese, metallic luster was observed on the surface.

[0039] (Example 1) In Example 1, the manganese after primary purification obtained in the same manner as in Comparative Example 1 was placed in a raw material crucible made of alumina. The inside of the vacuum purification furnace was evacuated until the vacuum reached 1 Pa, and then the raw material crucible was heated to 1090 °C by the raw material section heater. After the raw material manganese sublimated into a gas of manganese vapor, it was cooled near the alumina recovery crucible maintained at 820 °C by the recovery section heater, contacted and condensed on the inner wall surface of the recovery crucible, and manganese was deposited in the recovery crucible. After the temperatures of each part in the furnace were raised to the above temperatures, heating was stopped after 46 hours passed, and natural cooling was performed. The purified manganese thus obtained was recovered from the recovery crucible to obtain the manganese after secondary purification according to Example 1. When observing the appearance of the obtained manganese, a metallic luster was observed on the surface.

[0040] (Example 2) In Example 2, the manganese after secondary purification obtained in the same manner as in Example 1 was placed in a raw material crucible made of alumina. Similar to the secondary purification in Example 1, the inside of the vacuum purification furnace was evacuated until the vacuum reached 1 Pa, and then the raw material crucible was heated to 1090 °C by the raw material section heater. However, the temperature of the recovery crucible was changed from 820 °C to 870 °C by the recovery section heater. After the temperatures of each part in the furnace were raised to the above temperatures, heating was stopped after 46 hours passed, and natural cooling was performed. The purified manganese thus obtained was recovered from the recovery crucible to obtain the manganese after secondary purification according to Example 1. When observing the appearance of the obtained manganese, a metallic luster was observed on the surface.

[0041] The conditions of the manufacturing methods of high-purity manganese according to Comparative Example 1, Example 1, and Example 2 above are shown in Table 1 below.

[0042]

Table 1

[0043] <Trace element analysis> Elemental analysis was performed on the high-purity manganese according to Comparative Example 1, Example 1, and Example 2 obtained by the above method. For each trace element contained in manganese, analysis was performed by the methods shown below, respectively.

[0044] <<GD-MS Analysis>> For the quantitative analysis of trace elements of impurity elements with atomic numbers from 3 to 94, excluding C, N, O and noble gases, among the impurity elements contained in manganese, GD-MS analysis measurement (Astrum ES manufactured by Nu Instruments) was used. In the analysis, the discharge gas type was argon, and the measurement was carried out under the analysis conditions using high-purity In as a binder. The measurement results are shown in Table 2 (Table 2-1 and Table 2-2), and at the same time, the lower limit values of measurement in the measurement of each trace element are shown.

[0045] <<IGA Analysis>> In addition, for the quantitative analysis of carbon and oxygen contained in manganese, the following IGA analysis method was used for analysis. The measurement results are shown in Table 2-1, and at the same time, the lower limit values of measurement in the measurement of each trace element are shown. Regarding the analysis of carbon (C), a carbon and sulfur analyzer (EMIA-920V2 manufactured by Horiba, Ltd.) was used. The sample weight was about 0.5 g, and the carbon content was measured under the analysis conditions where the carrier gas type was N2, and 0.5 g of Fe, 1.8 g of W, and 0.3 g of Sn were added as auxiliary agents. Regarding the analysis of oxygen (O), an oxygen, nitrogen, and hydrogen simultaneous analyzer (ONH836 manufactured by LECO) was used. The sample weight was 1 g, and the oxygen content was measured under the analysis conditions where the carrier gas type was He and no auxiliary agent was added.

[0046]

Table 2-1

Table 2-2

[0047] Among the obtained analysis results, in Comparative Example 1 where only one purification was performed, the contents of chlorine (Cl) and sulfur (S) were high, and the total amount of impurity elements was also large. In Examples 1 and 2 that underwent the purification process according to the present invention, in both cases, the Cl content became 0.3 ppm or less, and the total content of metal elements (excluding B, F, and Cu) from impurity elements with atomic numbers from 3 to 94 (GD-MS analysis results) excluding C, N, O, and noble gases (i.e., the value of "total metal elements" shown in Table 2-2) was reduced to 4.0 ppm or less. In particular, in Example 2, the Cl content was 0.05 ppm or less, and the total content of metal elements (excluding B, F, and Cu) from impurity elements with atomic numbers from 3 to 94 (GD-MS analysis results) excluding C, N, O, and noble gases (i.e., the value of "total metal elements" shown in Table 2-2) became 1.0 ppm or less, and each content was also 0.3 ppm or less.

Industrial Applicability

[0048] According to the present invention, a method for producing high-purity manganese with a reduced concentration of specific impurity elements and high-purity manganese can be provided.

Explanation of Symbols

[0049] 10 Vacuum purification furnace 20 Vacuum pump 30 Inner cylinder 60 Raw material section heater 70 Recovery section heater 80 Raw material crucible 90 Recovery crucible

Claims

1. Raw manganese with a purity of 3N or higher is placed in a crucible, and the crucible is heated at a first heating temperature under vacuum. The obtained first manganese vapor is condensed in a recovery section at a first recovery temperature of 800°C or higher and 960°C or lower to obtain primary purified manganese, and a first purification step; The primary purified manganese obtained in the recovery section is placed in the crucible, and the crucible is heated at a second heating temperature lower than the first heating temperature under vacuum. The obtained second manganese vapor is condensed in the recovery section at a second recovery temperature of 800°C or higher and 960°C or lower to obtain secondary purified manganese, and a second purification step; A method for producing high-purity manganese, including the above steps.

2. The first heating temperature is 1110°C or higher and 1300°C or lower, and The second heating temperature is 960°C or higher and less than 1110°C. The method for producing high-purity manganese according to claim 1.

3. After the second purification step, the secondary purified manganese obtained in the recovery section is placed in the crucible, and the crucible is heated at a third heating temperature lower than the first heating temperature under vacuum. The obtained third manganese vapor is condensed in the recovery section at a third recovery temperature different from the second recovery temperature to obtain tertiary purified manganese, and a third purification step. The method for producing high-purity manganese according to claim 1, further including the above step.

4. Before the first purification step, a washing step of washing the raw manganese with pure water is further included. The method for producing high-purity manganese according to any one of claims 1 to 3.

5. Among the impurity elements measured by GD-MS analysis, the content of Cl is 0.3 ppm or less, and the total content of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 4.0 ppm or less. High-purity manganese.

6. The content of Cl is 0.05 ppm or less. The high-purity manganese according to claim 5.

7. The total content of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 1.0 ppm or less. The high-purity manganese according to claim 6.

8. The content of the elements excluding B, C, N, O, F, noble gases, and Cu from the impurity elements with atomic numbers from 3 to 94 is 0.3 ppm or less respectively. The high-purity manganese according to any one of claims 6 or 7.

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