Vacuum purification crystallization furnace and method for purifying ultra-pure manganese by using same

Abstract

The invention relates to a vacuum purification crystallization furnace and an ultra-pure manganese purification method using the same. The vacuum purification crystallization furnace comprises a furnace body and a hearth, and a distillation part and a condensation part are arranged in the hearth from bottom to top; the hearth is provided with a first baffle at the top height of the distillation component and around the peripheral side of the distillation component; a second baffle is arranged at the position, close to the top of the condensation part, of the hearth and surrounds the peripheral side of the condensation part. The first baffle and the second baffle divide the hearth into a first temperature field, a second temperature field and a third temperature field which are independently controlled in temperature from bottom to top. According to the present invention, the temperature of the distillation region and the condensation region can be independently and accurately controlled, the impurities in the manganese raw material can be completely removed, the ultra-pure manganese product with the purity of more than 5N and the density of more than 7.40 g / cm < 3 > can be obtained, the product distribution is centralized, the stripping is easy, and the yield of the product is more than 85.9%.

Description

Technical Field

[0001] The present invention relates to the technical field of metal purification, and in particular to a vacuum purification crystallization furnace and a method for purifying ultra-high purity manganese using the same. Background Art

[0002] Ultra-high purity manganese is mainly used to produce copper-manganese alloy sputtering targets for large-scale integrated circuits. It is a key raw material for chip manufacturing processes below 14μm. Adding manganese to high-purity copper can better control the grain size and uniformity of the target material and improve the strength and stability of the target material itself. With the rapid development of semiconductor process technology, the requirements for raw materials have become more stringent, and the purity of ultra-high purity manganese materials is required to reach 5N or above.

[0003] At present, common manganese is prepared by electrolysis of sulfuric acid or chloride system, but it generally contains hundreds of ppm of metal impurities and thousands of ppm of non-metallic impurities, which cannot meet the requirements of semiconductor target raw materials. Therefore, researchers are committed to developing methods for purifying metallic manganese, such as purifying metallic manganese by vacuum distillation process. However, the existing vacuum distillation process has the following defects: (1) Using electrolytic manganese in sulfuric acid system as raw material for purification, the sulfur element in the product exceeds the standard and the product purity is unqualified; (2) The condensation mold in the vacuum crystallization furnace is a traditional split structure, that is, a multi-layer condensation plate is used for multi-stage condensation, and the product is relatively dispersed, causing difficulty in stripping; (3) During the vacuum distillation process, only the temperature of the crucible is controlled, resulting in insufficient temperature control to completely remove impurity gases, high / low melting point impurities, etc. in the manganese raw material, resulting in the purity of the product still below 5N, which does not meet the purity requirements of the semiconductor industry for ultra-high purity manganese materials.

[0004] For example, CN102494534B discloses an energy-saving vacuum distillation furnace system, including a distillation crucible, a condensation crystallization tube, a secondary condensation chamber and a spiral resistance heating wire. The distillation crucible and the condensation crystallization tube of the distillation furnace system are independent of each other, and a secondary condensation chamber is provided at the upper end of the condensation crystallization tube; however, the condensation device of the distillation furnace system is a straight-cylindrical type, which is not conducive to the adhesion of the product, causing the product to easily fall off from the wall of the condensation tube to the distillation device, causing the product to be contaminated by the raw materials and impurities remaining in the distillation chamber.

[0005] For example, CN113897501A discloses a method for purifying metallic manganese by vacuum distillation, wherein the raw manganese is heated under vacuum conditions, the distilled manganese vapor is collected by a condensing device, and the metallic manganese is condensed; wherein the vacuum degree of the vacuum condition needs to be strictly controlled to be 10 -5-1Pa, the target temperature of the heating is 1250-1400℃; this method can only purify the manganese raw material to 4N5-5N, and there is still a lot of room for improvement; and the condensing device of the vacuum purification furnace used in this method includes 8-10 levels of steam channel openings stacked alternately on the condensation tray; the final product is dispersed on the 3-6 level condensation tray, there are problems of product dispersion and difficulty in stripping.

[0006] Based on this, how to develop a new vacuum purification crystallization furnace and purification method for purifying metallic manganese raw materials to ultra-high purity manganese, and obtain ultra-high purity manganese materials with a purity of more than 5N to meet the needs of the semiconductor industry has become a problem that needs to be solved urgently. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a vacuum purification crystallization furnace and a method for purifying ultra-high purity manganese using the same, which can realize independent temperature control of the distillation area and the condensation area, thereby improving the purity and yield of the product; avoiding the technical problems of residual impurity elements in the ultra-high purity manganese product due to inaccurate temperature control in the prior art, and the traditional straight-cylinder split condensing device causing product dispersion, difficulty in stripping, and low yield.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a vacuum purification crystallization furnace, the vacuum purification crystallization furnace comprising a furnace body and a furnace chamber, wherein a distillation component and a condensation component are arranged from bottom to top inside the furnace chamber;

[0010] The furnace is provided with a first baffle plate around the distillation component at the height of the top of the distillation component; the furnace is provided with a second baffle plate around the condensation component at a position close to the top of the condensation component;

[0011] The first baffle and the second baffle divide the furnace into a first temperature field, a second temperature field and a third temperature field which are independently controlled from bottom to top.

[0012] The vacuum purification crystallization furnace of the present invention divides the furnace from bottom to top into a first temperature field, a second temperature field and a third temperature field with independent temperature control by designing a first baffle and a second baffle, thereby achieving precise temperature control of the distillation component and the condensation component according to the product impurities and their purity requirements, thereby avoiding unclear division of distillation and condensation work, resulting in excessively high burnout rate of metallic manganese or insufficient volatilization of metallic impurities affecting the purification effect.

[0013] The vacuum purification crystallization furnace of the present invention can control the temperature in different zones, so that the molten metal in the first temperature field maintains a relatively stable evaporation rate. Moreover, when the metal vapor passes through the condensation section, the low-melting-point impurities cannot condense due to the high temperature and evaporate directly to the third temperature field, while the manganese vapor condenses in the condensation section, thereby obtaining a high-purity and high-density product.

[0014] Preferably, the condensing component comprises a tapered tube which is wider at the top and narrower at the bottom, and a first cooling component arranged around the outer wall of the tapered tube.

[0015] Preferably, the angle between the side wall of the tapered tube and the vertical direction is 0-10°, but does not include 0°, for example, it can be 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9° or 10°, etc., preferably 2-5°.

[0016] The vacuum purification crystallization furnace of the present invention further arranges the condensation component to include a tapered tube that is wide at the top and narrow at the bottom, and further preferably, the angle between the side wall of the tapered tube and the vertical direction is 2-5°; this avoids the problem that the adhesion of the traditional straight-cylinder condensation component to the straight-cylinder wall decreases as the product output increases, causing it to fall back to the distillation component, resulting in the product being contaminated by undistilled raw materials and high-melting-point impurities; if the angle between the side wall of the tapered tube and the vertical direction is too large, the condensation component will be heated unevenly, resulting in lower product purity.

[0017] Preferably, the first temperature field and the second temperature field are respectively provided with a first heating component and a second heating component with independent temperature control.

[0018] Preferably, the first heating component is arranged on the inner wall of the furnace in the first temperature field.

[0019] Preferably, the second heating component is arranged on the inner wall of the furnace in the second temperature field. Preferably, the furnace is connected to a vacuum system.

[0020] Preferably, an impurity collecting component is further provided inside the furnace on the upper side of the condensing component.

[0021] Preferably, the impurity collecting component comprises an arc-shaped outer shell opening downward and a mesh collecting member arranged on a side of the arc-shaped outer shell close to the condensing component.

[0022] The present invention further preferably provides the mesh collecting member to collect low melting point impurities to prevent a large amount of impurities from entering the vacuum system and causing equipment failure.

[0023] Preferably, a second cooling component is provided on a side of the arc-shaped housing away from the condensing component.

[0024] Preferably, the second cooling component comprises a water chiller.

[0025] In a second aspect, the present invention provides a method for purifying ultra-high purity manganese, wherein the purification method is carried out using the vacuum purification crystallization furnace described in the first aspect.

[0026] The method for purifying ultra-high purity manganese provided by the present invention adopts the vacuum purification crystallization furnace described in the first aspect, and obtains ultra-high purity manganese with a purity of more than 5N through its three independently controlled temperature fields and a tapered tube that is wide at the top and narrow at the bottom, and has a smooth surface, low oxygen content, high density and yield, which meets the purity requirements of the semiconductor industry for ultra-high purity manganese; the purification method has a simple process flow and is easy to industrialize.

[0027] Preferably, under vacuum conditions, the manganese raw material is distilled to obtain manganese vapor, and the manganese vapor is condensed to obtain ultra-high purity manganese; the distillation includes independently performing a first heating, a first heat preservation, a second heating, a second heat preservation, a third heating, a third heat preservation, a fourth heating and a fourth heat preservation on the first temperature field and the second temperature field; the condensation includes independently performing a first cooling and a second cooling on the first temperature field and the second temperature field.

[0028] The present invention further preferably performs gradient heating on the first insulation field and the second insulation field independently during the distillation process, which is beneficial to sequentially remove non-metallic impurity elements and low melting point / high melting point impurity elements in the manganese raw material, and then cooperates with the condensation process to obtain ultra-high purity manganese with higher purity.

[0029] Preferably, the purity of the manganese raw material is 3N-4N, for example, it can be 3N, 3N2, 3N5, 3N8 or 4N.

[0030] Preferably, the metal impurities in the manganese raw material include any one of Al, Cu, Fe, Ti, Zn or Sn, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of Al, Ti and Sn, a combination of Al, Cu, Fe and Ti, or a combination of Al, Cu, Fe, Ti, Zn and Sn, etc.

[0031] Preferably, the non-metallic impurities in the manganese raw material include any one or a combination of at least two of C, H, O, N or Cl, wherein typical but non-limiting combinations include a combination of C, H and O, a combination of C, H, O and Cl, or a combination of C, H, O, N and Cl, etc.

[0032] Preferably, the vacuum degree of the vacuum condition is ≤3.2×10 -1 Pa, for example, can be 3.2×10 -1 Pa, 3.0×10 -1 Pa, 2.9×10 -1 Pa, 2.8×10 -1 Pa or 2.5×10 -1Pa, etc., preferably 1.8×10 -1 Pa-2.5×10 -1 Pa.

[0033] Preferably, the first heating rate is 1.7-2°C / min, for example, 1.7°C / min, 1.8°C / min, 1.9°C / min or 2°C / min.

[0034] Preferably, the end point of the first heating is 180-220°C, for example, 180°C, 190°C, 200°C, 210°C or 220°C.

[0035] Preferably, the first insulation time is 1.5-2.5 h, for example, 1.5 h, 1.8 h, 2 h, 2.2 h or 2.5 h.

[0036] The present invention further prefers that the end point of the first heating is 180-220° C., in order to dry the water vapor in the distillation part, the condensation part and the manganese raw material.

[0037] Preferably, the second heating rate is 1.7-2°C / min, for example, 1.7°C / min, 1.8°C / min, 1.9°C / min or 2°C / min.

[0038] Preferably, the endpoint temperature of the second heating is 450-500°C, 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, etc.

[0039] Preferably, the second insulation time is 14-18 hours, for example, it can be 14 hours, 15 hours, 16 hours, 17 hours or 18 hours.

[0040] The present invention further preferably sets the end point temperature of the second heating to 450-500°C. In the second heating stage, the non-metallic impurity elements C, H, O, N and Cl in the manganese raw material are removed in the form of gas. If the end point temperature of the second heating is too low, the non-metallic impurity elements cannot be completely removed and remain in the subsequent manganese vapor, resulting in reduced purity of the final product. If the temperature is too high, voids will be included in the product, affecting the product density.

[0041] Preferably, the heating rate of the third heating is 2-2.5°C / min, for example, it can be 2°C / min, 2.1°C / min, 2.2°C / min, 2.3°C / min, 2.4°C / min or 2.5°C / min.

[0042] Preferably, the terminal temperature of the third heating is 700-800°C, for example, 700°C, 720°C, 750°C, 780°C or 800°C.

[0043] Preferably, the third insulation time is 20-30 hours, for example, it can be 20 hours, 22 hours, 24 hours, 26 hours, 28 hours or 30 hours.

[0044] The present invention further preferably has the terminal temperature of the third heating up to be 700-800°C and the third insulation to be 20-30h, in order to remove the low melting point metal impurity elements in the manganese raw material, which otherwise will remain in the manganese vapor during the distillation stage, resulting in lower product purity.

[0045] Preferably, during the fourth heating, the temperature of the second temperature field is lower than the temperature of the first temperature field.

[0046] It is worth noting that, during the fourth heating step of the present invention, the temperature of the first temperature field is higher than the melting point of manganese so that the metallic manganese can remain in liquid state and continue to evaporate. Secondly, the temperature of the second temperature field is lower than the temperature of the first temperature field so that the manganese vapor can effectively condense on the condensation component.

[0047] Preferably, the heating rate of the fourth heating in the first temperature field is 3-3.5°C / min, for example, it can be 3°C / min, 3.1°C / min, 3.2°C / min, 3.3°C / min, 3.4°C / min or 3.5°C / min.

[0048] Preferably, the terminal temperature of the fourth heating in the first temperature field is 1250-1350°C, for example, it can be 1250°C, 1280°C, 1300°C, 1320°C or 1350°C.

[0049] Preferably, the insulation time for the fourth insulation in the first temperature field is 100-150 hours, for example, it can be 100 hours, 110 hours, 120 hours, 130 hours, 140 hours or 150 hours.

[0050] Preferably, the heating rate of the fourth heating in the second temperature field is 1.2-1.5°C / min, for example, 1.2°C / min, 1.3°C / min, 1.4°C / min or 1.5°C / min.

[0051] Preferably, the terminal temperature of the fourth heating in the second temperature field is 800-900°C, for example, 800°C, 820°C, 850°C, 880°C or 900°C.

[0052] Preferably, the insulation time for the fourth insulation in the second temperature field is 100-150 hours, for example, it can be 100 hours, 110 hours, 120 hours, 130 hours, 140 hours or 150 hours.

[0053] The present invention further preferably independently controls the temperatures of the first temperature field and the second temperature field within a certain range during the fourth heating. Specifically, the terminal temperature of the first temperature field for the fourth heating is 1250-1350°C, and the terminal temperature of the second temperature field for the fourth heating is 800-900°C, which is beneficial to improving product purity. If the second temperature field is not heated for the fourth time, low melting point impurities will also condense in this area. If the terminal temperature of the second temperature field for the fourth heating is too high, manganese vapor will not be able to effectively condense and crystallize, and the burn-out rate will be too high.

[0054] Preferably, the first cooling rate is 1.8-2.2°C / min, for example, 1.8°C / min, 1.9°C / min, 2.0°C / min, 2.1°C / min or 2.2°C / min.

[0055] Preferably, the terminal temperature of the first cooling is 420-480°C, for example, 420°C, 440°C, 460°C or 480°C.

[0056] Preferably, after the second cooling, protective gas is filled into the furnace.

[0057] Preferably, the protective gas comprises nitrogen and / or argon.

[0058] Preferably, the pressure of the furnace after the protective gas is filled is 2.2×10 4 ~2.8×10 4 Pa, for example, can be 2.2×10 4 Pa, 2.4×10 4 Pa, 2.5×10 4 Pa, 2.7×10 4 Pa or 2.8×10 4 Pa et al.

[0059] Preferably, the cooling rate of the second cooling is 2.5-3°C / min, for example, 2.5°C / min, 2.6°C / min, 2.7°C / min, 2.8°C / min, 2.9°C / min or 3°C / min.

[0060] Preferably, the end point temperature of the second cooling is ≤50°C, for example, it may be 50°C, 45°C, 40°C, 35°C or 30°C.

[0061] As a further preferred technical solution of the present invention, the purification method comprises the following steps:

[0062] At vacuum degree ≤3.2×10 -1 Under the vacuum condition of 1.3 Pa, the manganese raw material with purity of 3N-4N is distilled and condensed to obtain ultra-high purity manganese;

[0063] The distillation comprises: the first temperature field and the second temperature field are independently heated to 180-220°C at a heating rate of 1.7-2°C / min for a first time, and then kept warm for 1.5-2.5h; then heated to 450-500°C at a heating rate of 1.7-2°C / min for a second time, and then kept warm for 14-18h; then heated to 700-800°C at a heating rate of 2-2.5°C / min for a third time, and then kept warm for 20-30h; then the first temperature field is heated to 1250-1350°C at a heating rate of 3-3.5°C / min for a fourth time, and kept warm for 100-150h; the second temperature field is heated to 800-900°C at a heating rate of 1.2-1.5°C / min for a fourth time, and then kept warm for 100-150h;

[0064] The condensation comprises: first cooling the temperature to 420-480°C at a cooling rate of 1.8-2.2°C / min, then filling the furnace with protective gas until the pressure in the furnace is 2.2×10 4 ~2.8×10 4 Pa, and then cool down the temperature to an end point temperature ≤50°C at a cooling rate of 2.5-3°C / min.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] (1) The vacuum purification crystallization furnace provided by the present invention divides the furnace of the vacuum purification crystallization furnace into three temperature fields by designing the first baffle and the second baffle, so that the distillation area and the condensation area are independently temperature-controlled, which is beneficial to fully remove the non-metallic impurity elements and low-melting point / high-melting point metal impurities in the manganese raw material; thereby improving the treatment effect of the raw material; in addition, by optimizing the structure of the condensation component, it is preferred to use a tapered tube that is wide at the top and narrow at the bottom, and it is further preferred that the angle between the side wall of the tapered tube and the vertical direction is 2-5°, so as to further avoid the problem of product contamination caused by the product falling from the tube wall to the distillation component; and the vacuum purification crystallization furnace has a compact structure and occupies a small area.

[0067] (2) The method for purifying ultra-high purity manganese provided by the present invention is carried out by using the above-mentioned vacuum purification crystallization furnace, and the purification effect is improved by independently controlling the temperature of the distillation and condensation areas in combination with gradient heating; especially in the fourth heating stage, the distillation area and the condensation area are controlled separately for temperature control, so that the molten metal in the first temperature field maintains a relatively stable evaporation rate. When the fierce steam passes through the condensation section, the low melting point impurities cannot condense due to the high temperature and directly volatilize to the third temperature field, and are collected by the collector. The manganese steam condenses on the conical ceramic tube wall at a suitable condensation temperature, and the thickness gradually increases, thereby obtaining a high-purity and high-density product; the purity is as high as 5N or more, and the density is as high as 7.40g / cm 3 The above preparation of ultra-high purity manganese, with a yield preferably as high as 85.9% or more, provides high-quality raw materials for manganese-copper alloy sputtering targets for semiconductor chips; the purification method has a simple operation process and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 is a schematic structural diagram of a vacuum purification crystallization furnace provided in Example 1 of the present invention;

[0069] In the figure: 1. furnace body; 2. furnace; 3. distillation component; 4. condensation component; 5. first baffle; 6. second baffle; 7. first temperature field; 8. second temperature field; 9. third temperature field; 10. first heating component; 11. second heating component; 12. first cooling component; 13. impurity capture component. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0071] 1. Implementation

[0072] Example 1

[0073] This embodiment provides a vacuum purification crystallization furnace, such as Figure 1 As shown, the vacuum purification crystallization furnace comprises a furnace body 1 and a furnace chamber 2, wherein a distillation component 3 and a condensation component 4 are arranged from bottom to top inside the furnace chamber 2; the distillation component 3 is a crucible; the condensation component 4 is a conical ceramic tube and a first cooling component 12 arranged around the conical ceramic tube; the angle between the side wall of the conical ceramic tube and the vertical direction is 3°; the first cooling component 12 is a water-cooled coil;

[0074] The furnace 2 is provided with a first baffle 5 around the distillation component 3 at the height of the top of the distillation component 3; the furnace 2 is provided with a second baffle 6 around the condensation component 4 at a position close to the top of the condensation component 4;

[0075] The first baffle 5 and the second baffle 6 divide the furnace 2 from bottom to top into a first temperature field 7, a second temperature field 8 and a third temperature field 9 with independent temperature controls; the first temperature field 7 and the second temperature field 8 are respectively provided with a first heating component 10 and a second heating component 11 with independent temperature controls; the first heating component 10 and the second heating component 11 are both resistance heating wires;

[0076] An impurity collecting component 13 is also provided inside the furnace 2 on the upper side of the condensing component 4;

[0077] The impurity collecting component 13 comprises an arc-shaped shell opening downward and a mesh collecting member arranged on a side of the arc-shaped shell close to the condensing component 4;

[0078] The side of the arc-shaped housing away from the condensing component 4 is connected to a chiller.

[0079] This embodiment also provides a method for purifying ultra-high purity manganese, which is carried out using the above-mentioned vacuum purification crystallization furnace; the purification method comprises the following steps:

[0080] At a vacuum degree of 3.2×10 -1 Under the vacuum condition of 1.5 Pa, the manganese raw material with a purity of 99.95% is distilled and condensed to obtain ultra-high purity manganese;

[0081] The distillation comprises: the first temperature field and the second temperature field are both heated to 200°C at a heating rate of 1.8°C / min for the first time and then kept warm for 2 hours; then heated to 480°C at a heating rate of 1.9°C / min for the second time and then kept warm for 16 hours; then heated to 750°C at a heating rate of 2.2°C / min for the third time and then kept warm for 24 hours; then the first temperature field is heated to 1300°C at a heating rate of 3.2°C / min for the fourth time and then kept warm for 120 hours, and the second temperature field is heated to 850°C at a heating rate of 1.4°C / min for the fourth time and then kept warm for 130 hours;

[0082] The condensation comprises: first cooling the temperature to 450°C at a cooling rate of 2°C / min, then filling the furnace with nitrogen until the pressure in the furnace is 2.5×10 4 Pa, and then cooled to 50°C at a cooling rate of 2.8°C / min.

[0083] The components and corresponding contents of the manganese raw materials described in this embodiment (the sum of the contents is 100wt%) are shown in Table 1;

[0084] Table 1

[0085]

[0086] Note: "Others" in Table 1 indicates impurity elements that are difficult to measure, and "-" indicates no relevant data.

[0087] Example 2

[0088] The present embodiment provides a vacuum purification crystallization furnace, the vacuum purification crystallization furnace comprises a furnace body and a furnace chamber, a distillation component and a condensation component are arranged from bottom to top inside the furnace chamber; the distillation component is a crucible; the condensation component is a conical ceramic tube and a first cooling component arranged around the conical ceramic tube; the angle between the side wall of the conical ceramic tube and the vertical direction is 5°; the first cooling component is a water cooling coil;

[0089] The furnace is provided with a first baffle plate around the distillation component at the height of the top of the distillation component; the furnace is provided with a second baffle plate around the condensation component at a position close to the top of the condensation component;

[0090] The first baffle and the second baffle divide the furnace from bottom to top into a first temperature field, a second temperature field and a third temperature field with independent temperature controls; the first temperature field and the second temperature field are respectively provided with a first heating component and a second heating component with independent temperature controls; the first heating component and the second heating component are both resistance heating wires;

[0091] An impurity collecting component is also arranged inside the furnace on the upper side of the condensing component;

[0092] The impurity collecting component comprises an arc-shaped shell opening downward and a mesh collecting member arranged on a side of the arc-shaped shell close to the condensing component;

[0093] The side of the arc-shaped housing away from the condensing component is connected to a chiller.

[0094] This embodiment also provides a method for purifying ultra-high purity manganese, which is carried out using the above-mentioned vacuum purification crystallization furnace; the purification method comprises the following steps:

[0095] At a vacuum degree of 3.0×10 -1 Under the vacuum condition of Pa, the manganese raw material with a purity of 99.99wt% is distilled and condensed to obtain ultra-high purity manganese;

[0096] The distillation comprises: the first temperature field and the second temperature field are both heated to 220°C at a heating rate of 1.7°C / min for a first time and then kept warm for 1.5 hours; then heated to 450°C at a heating rate of 1.7°C / min for a second time and then kept warm for 18 hours; then heated to 800°C at a heating rate of 2°C / min for a third time and then kept warm for 20 hours; then the first temperature field is heated to 1250°C at a heating rate of 3°C / min for a fourth time and then kept warm for 150 hours, and the second temperature field is heated to 900°C at a heating rate of 1.2°C / min for a fourth time and then kept warm for 100 hours;

[0097] The condensation comprises: first cooling the temperature to 420°C at a cooling rate of 1.8°C / min, then filling the furnace with nitrogen until the pressure in the furnace is 2.2×10 4 Pa, and then cooled to 40°C at a cooling rate of 2.5°C / min.

[0098] The components and corresponding contents of the manganese raw materials described in this embodiment (the sum of the contents is 100wt%) are shown in Table 2;

[0099] Table 2

[0100]

[0101]

[0102] Note: "Others" in Table 2 indicates impurity elements that are difficult to measure, and "-" indicates no relevant data.

[0103] Example 3

[0104] The present embodiment provides a vacuum purification crystallization furnace, the vacuum purification crystallization furnace comprises a furnace body and a furnace chamber, a distillation component and a condensation component are arranged from bottom to top inside the furnace chamber; the distillation component is a crucible; the condensation component is a conical ceramic tube and a first cooling component arranged around the conical ceramic tube; the angle between the side wall of the conical ceramic tube and the vertical direction is 2°; the first cooling component is a water cooling coil;

[0105] The furnace is provided with a first baffle plate around the distillation component at the height of the top of the distillation component; the furnace is provided with a second baffle plate around the condensation component at a position close to the top of the condensation component;

[0106] The first baffle and the second baffle divide the furnace from bottom to top into a first temperature field, a second temperature field and a third temperature field with independent temperature controls; the first temperature field and the second temperature field are respectively provided with a first heating component and a second heating component with independent temperature controls; the first heating component and the second heating component are both resistance heating wires;

[0107] An impurity collecting component is also arranged inside the furnace on the upper side of the condensing component;

[0108] The impurity collecting component comprises an arc-shaped shell opening downward and a mesh collecting member arranged on a side of the arc-shaped shell close to the condensing component;

[0109] The side of the arc-shaped housing away from the condensing component is connected to a chiller.

[0110] This embodiment also provides a method for purifying ultra-high purity manganese, which is carried out using the above-mentioned vacuum purification crystallization furnace; the purification method comprises the following steps:

[0111] At a vacuum degree of 2.8×10 -1 Under the vacuum condition of Pa, the manganese raw material with a purity of 99.99wt% is distilled and condensed to obtain ultra-high purity manganese;

[0112] The distillation comprises: the first temperature field and the second temperature field are both heated to 180°C at a heating rate of 2°C / min for a first time and then kept warm for 2.5 hours; then heated to 500°C at a heating rate of 2°C / min for a second time and then kept warm for 14 hours; then heated to 700°C at a heating rate of 2.5°C / min for a third time and then kept warm for 30 hours; then the first temperature field is heated to 1350°C at a heating rate of 3.5°C / min for a fourth time and then kept warm for 100 hours, and the second temperature field is heated to 800°C at a heating rate of 1.5°C / min for a fourth time and then kept warm for 150 hours;

[0113] The condensation comprises: first cooling the temperature to 480°C at a cooling rate of 2.2°C / min, then filling the furnace with nitrogen until the pressure in the furnace is 2.8×10 4 Pa, and then cooled to 45°C at a cooling rate of 3°C / min.

[0114] The components and corresponding contents of the manganese raw materials described in this embodiment (the sum of the contents is 100wt%) are shown in Table 3;

[0115] Table 3

[0116]

[0117] Note: "Others" in Table 3 indicates impurity elements with very low content that are difficult to measure, and "-" indicates no relevant data.

[0118] Example 4

[0119] This embodiment provides a vacuum purification crystallization furnace, which is the same as that of Embodiment 1 except that the angle between the side wall of the conical ceramic tube and the vertical direction is 8°.

[0120] This embodiment also provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the vacuum purification crystallization furnace provided in this embodiment is used.

[0121] Example 5

[0122] This embodiment provides a vacuum purification crystallization furnace, which is the same as Embodiment 1 except that the condensation component adopts a cylindrical ceramic tube.

[0123] This embodiment also provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the vacuum purification crystallization furnace provided in this embodiment is used.

[0124] Example 6

[0125] This embodiment provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the end temperature of the second heating is 420°C.

[0126] Example 7

[0127] This embodiment provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the terminal temperature of the second heating is 600°C.

[0128] Example 8

[0129] This embodiment provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the end temperature of the third heating is 650°C.

[0130] Example 9

[0131] This embodiment provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the end temperature of the third heating is 850°C.

[0132] Example 10

[0133] This embodiment provides a method for purifying ultra-high purity manganese. The purification method is the same as that of Embodiment 1 except that the end temperature of the fourth heating in the second temperature field is 1000° C.

[0134] 2. Comparison

[0135] Comparative Example 1

[0136] This comparative example provides a vacuum purification crystallization furnace, which is the same as Example 1 except that the first baffle is not provided.

[0137] This comparative example also provides a method for purifying ultra-high purity manganese. The purification method is carried out using the vacuum purification crystallization furnace provided in this comparative example, that is, the distillation area and the condensation area cannot be independently temperature-controlled, and the rest is the same as Example 1.

[0138] Comparative Example 2

[0139] This comparative example provides a method for purifying ultra-high purity manganese. The purification method is the same as Example 1 except that the first heating is not performed.

[0140] Comparative Example 3

[0141] This comparative example provides a method for purifying ultra-high purity manganese. The purification method is carried out by using the method for purifying metallic manganese by vacuum distillation and the purification device disclosed in Example 1 of CN113897501A.

[0142] The condensing device in the purification device described in this comparative example is a split condensation plate, and the product is dispersed in 3-6 level condensation plates, which is difficult to peel off, and the product is prone to secondary contamination during the peeling process.

[0143] 3. The impurity content of the ultra-high purity manganese obtained in the above examples and comparative examples was analyzed to calculate its purity and yield, and its density was tested. The results are shown in Table 4;

[0144] Table 4

[0145]

[0146]

[0147] From Table 4 we can see that:

[0148] (1) It can be seen from Examples 1 to 3 that the vacuum purification method for ultra-high purity manganese provided by the present invention successfully prepares ultra-high purity manganese with a purity of up to 99.999% (i.e., above 5N) and a density of up to 7.40 g / cm by using the vacuum purification crystallization furnace provided by the present invention in combination with a gradient heating method. 3 The above ultra-high purity manganese products have a yield of over 85.9%, which meets the purity requirements of semiconductor targets for raw materials.

[0149] (2) It can be seen from Example 1 and Example 4 to Example 5 that the angle between the side wall of the tapered ceramic tube in the vacuum purification crystallization furnace described in Example 4 and the vertical direction is too large, resulting in the purity of the ultra-high purity manganese product decreasing to 99.9991% and the yield decreasing to 85.2%; the condensation component in the vacuum purification crystallization furnace described in Example 5 adopts a cylindrical ceramic tube, resulting in the yield of the ultra-high purity manganese product decreasing to 73.8%; this shows that the present invention further preferably adopts a tapered tube with a wide top and a narrow bottom for the condensation component of the vacuum purification crystallization furnace, and further preferably the angle between the side wall of the tapered tube and the vertical direction is 2-5°, which further improves the purity and yield of the ultra-high purity manganese.

[0150] (3) It can be seen from Example 1 and Examples 6 to 10 that the end temperature of the second heating in Example 6 is too low, resulting in the inability to completely remove the non-metallic impurity elements in the manganese raw material, the product purity is reduced to 99.9930%, and the yield is reduced to 80.6%; the end temperature of the second heating in Example 7 is too high, resulting in the purity being reduced to 99.9950%, and the yield being reduced to 78.1%; the end temperature of the third heating in Example 8 is too low, resulting in the inability to completely remove the low-melting-point impurity elements in the manganese raw material, which remain in the manganese raw material, resulting in the product purity being reduced to 99.9910%, and the yield being reduced to 79.4%; the end temperature of the third heating in Example 9 is too low, resulting in the yield being reduced to 79.4%; this shows that the present invention further preferably sets the end temperature of the second heating to 450-500°C, and further preferably sets the end temperature of the third heating to 700-800°C, which further improves the purity and yield of the obtained product.

[0151] (4) It can be seen from Example 1 and Comparative Examples 1 to 3 that since the vacuum purification crystallization furnace described in Comparative Example 1 does not have a first baffle, that is, the distillation area and the condensation area cannot form an independent temperature field, resulting in the inability to independently control the temperature, resulting in the purity of the product being reduced to 99.9900%, and the yield being reduced to 62.5%; the purification method described in Comparative Example 2 does not perform the first heating, resulting in the density of the product being reduced to 7.36 g / cm 3 , the product purity dropped to 99.9940%: the condensing device in the purification device adopted by the purification method described in Comparative Example 3 is a split condensing plate, and its product is dispersed in 3-6 level condensing plates, which is difficult to strip, and the yield is only 72.1%. In addition, the product is prone to secondary contamination during the stripping process, and the purity of the prepared product is only 99.9930%, which cannot meet the demand for semiconductor target raw materials.

[0152] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A vacuum purification crystallization furnace, characterized in that: The vacuum purification crystallization furnace comprises a furnace body and a furnace, wherein a distillation component and a condensation component are arranged inside the furnace from bottom to top; The furnace is provided with a first baffle plate around the distillation component at the height of the top of the distillation component; the furnace is provided with a second baffle plate around the condensation component at a position close to the top of the condensation component; The first baffle and the second baffle divide the furnace into a first temperature field, a second temperature field and a third temperature field which are independently controlled from bottom to top.

2. The vacuum purification crystallization furnace according to claim 1, characterized in that: The condensing component comprises a tapered tube that is wide at the top and narrow at the bottom, and a first cooling component arranged around the outer wall of the tapered tube; Preferably, the angle between the side wall of the tapered tube and the vertical direction is 0-10°, but not including 0°, and preferably 2-5°.

3. The vacuum purification crystallization furnace according to claim 1 or 2, characterized in that: The first temperature field and the second temperature field are respectively provided with a first heating component and a second heating component with independent temperature control; Preferably, an impurity collecting component is further provided inside the furnace on the upper side of the condensing component; Preferably, the impurity collecting component comprises an arc-shaped outer shell opening downward and a mesh collecting member arranged on a side of the arc-shaped outer shell close to the condensing component.

4. A method for purifying ultra-high purity manganese, characterized in that: The purification method is carried out using the vacuum purification crystallization furnace as described in any one of claims 1 to 3.

5. The purification method according to claim 4, characterized in that The purification method comprises the following steps: Under vacuum conditions, the manganese raw material is distilled to obtain manganese vapor, and the manganese vapor is condensed to obtain ultra-high purity manganese; The distillation comprises independently performing a first temperature increase, a first heat preservation, a second temperature increase, a second heat preservation, a third temperature increase, a third heat preservation, a fourth temperature increase and a fourth heat preservation on the first temperature field and the second temperature field; The condensation includes independently performing a first temperature reduction and a second temperature reduction on the first temperature field and the second temperature field.

6. The purification method according to claim 4 or 5, characterized in that: The purity of the manganese raw material is 3N-4N; Preferably, the metal impurities in the manganese raw material include any one or a combination of at least two of Al, Cu, Fe, Ti, Zn, Sn, Mg or As; Preferably, the non-metallic impurities in the manganese raw material include any one of C, H, O, N or Cl, or a combination of at least two of them.

7. The purification method according to any one of claims 4 to 6, characterized in that: The vacuum degree of the vacuum condition is ≤3.2×10 -1 Pa, preferably 1.8×10 -1 Pa-2.5×10 -1 Pa; Preferably, the first heating rate is 1.7-2°C / min; Preferably, the end point of the first heating is 180-220°C; Preferably, the first heat preservation time is 1.5-2.5h; Preferably, the second heating rate is 1.7-2°C / min; Preferably, the end temperature of the second heating is 450-500°C; Preferably, the second insulation time is 14-18h; Preferably, the heating rate of the third heating is 2-2.5°C / min; Preferably, the end temperature of the third heating step is 700-800°C; Preferably, the third insulation time is 20-30 hours.

8. The purification method according to any one of claims 4 to 7, characterized in that: The heating rate of the fourth heating in the first temperature field is 3-3.5°C / min; Preferably, the end temperature of the fourth heating of the first temperature field is 1250-1350°C; Preferably, the insulation time of the fourth insulation in the first temperature field is 100-150h; Preferably, the heating rate of the fourth heating in the second temperature field is 1.2-1.5°C / min; Preferably, the end temperature of the fourth heating of the second temperature field is 800-900°C; Preferably, the fourth insulation time of the second temperature field is 100-150 hours.

9. The purification method according to any one of claims 4 to 8, characterized in that: The first cooling rate is 1.8-2.2°C / min; Preferably, the endpoint temperature of the first cooling is 420-480°C; Preferably, after the second cooling, a protective gas is filled into the furnace; Preferably, the protective gas comprises nitrogen and / or argon; Preferably, the pressure of the furnace after the protective gas is filled is 2.2×10 4 ~2.8×10 4 Pa; Preferably, the cooling rate of the second cooling is 2.5-3°C / min; Preferably, the end point temperature of the second cooling is ≤50°C.

10. The purification method according to any one of claims 5 to 9, characterized in that: The purification method comprises the following steps: At vacuum degree ≤3.2×10 -1 Under the vacuum condition of 1.3 Pa, the manganese raw material with purity of 3N-4N is distilled and condensed to obtain ultra-high purity manganese; The distillation comprises: the first temperature field and the second temperature field are independently heated to 180-220°C at a heating rate of 1.7-2°C / min for a first time, and then kept warm for 1.5-2.5h; then heated to 450-500°C at a heating rate of 1.7-2°C / min for a second time, and then kept warm for 14-18h; then heated to 700-800°C at a heating rate of 2-2.5°C / min for a third time, and then kept warm for 20-30h; then the first temperature field is heated to 1250-1350°C at a heating rate of 3-3.5°C / min for a fourth time, and kept warm for 100-150h; the second temperature field is heated to 800-900°C at a heating rate of 1.2-1.5°C / min for a fourth time, and then kept warm for 100-150h; The condensation comprises: first cooling the temperature to 420-480°C at a cooling rate of 1.8-2.2°C / min, then filling the furnace with protective gas until the pressure in the furnace is 2.2×10 4 ~2.8×10 4 Pa, and then cool down the temperature to an end point temperature ≤50°C at a cooling rate of 2.5-3°C / min.

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