CN108441651B - Preparation method for improving purity and yield of molybdenum - Google Patents
Preparation method for improving purity and yield of molybdenum Download PDFInfo
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- CN108441651B CN108441651B CN201810275898.1A CN201810275898A CN108441651B CN 108441651 B CN108441651 B CN 108441651B CN 201810275898 A CN201810275898 A CN 201810275898A CN 108441651 B CN108441651 B CN 108441651B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/30—Obtaining chromium, molybdenum or tungsten
- C22B34/34—Obtaining molybdenum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/16—Remelting metals
- C22B9/22—Remelting metals with heating by wave energy or particle radiation
- C22B9/228—Remelting metals with heating by wave energy or particle radiation by particle radiation, e.g. electron beams
Abstract
The invention discloses a preparation method for improving the purity and yield of molybdenum, which comprises the following steps: 1) taking an ammonium molybdate raw material with the total content of potassium and/or sodium lower than 10ppm and the tungsten content lower than 10 ppm; 2) calcining and reducing the ammonium molybdate raw material to obtain molybdenum powder; 3) pressing molybdenum powder into a molybdenum blank, and then performing two-stage presintering on the molybdenum blank under the vacuum condition or the protective condition of a reducing atmosphere to obtain a low-oxygen molybdenum blank with the oxygen content of below 30 ppm; 4) and performing vacuum electron beam melting on the low-oxygen molybdenum blank twice, and removing the surface of the obtained cast ingot after performing peeling treatment after each vacuum electron beam melting to obtain a molybdenum product. The preparation method has the advantages of simple process, high yield and good purification effect, and can be applied to industrial production.
Description
Technical Field
The invention relates to a purification process of refractory metals, in particular to a preparation method for improving the purity and yield of molybdenum.
Background
Molybdenum is a non-renewable strategic resource, has a plurality of excellent physical and chemical properties, and is widely applied to the fields of steel, chemical industry, nonferrous metallurgy, aerospace and the like. With the development of semiconductor manufacturing technologies such as large-scale integrated circuits, ion implantation, vapor deposition and the like, higher requirements are put on the purity and performance of molybdenum.
At present, the purity of the mainstream product of the molybdenum material in China is 99.95 percent, and the requirement of the field on the purity of the molybdenum cannot be met. For example, MoSix or molybdenum sputtering targets for producing integrated circuits, and related metal heating and vacuum system elements applied to high-end sapphire crystals, such as crucibles, heat shields, heating rods, and the like, all require a purity of 99.99-99.999%.
The molybdenum prepared by the currently adopted powder metallurgy method has low cost, but the prepared molybdenum has high W, O content, and the quality requirement of high-purity molybdenum used in the industries such as electronics and the like is difficult to meet.
Electron beam melting is an effective method for increasing the purity of molybdenum and has been used industrially to purify refractory metals containing impurities with high saturated vapor pressure. The electron beam with high energy density is used to bombard metal to generate high temperature for melting metal, and this process is performed in vacuum to evaporate impurity and obtain high purifying effect. Meanwhile, the basic mode of removing impurities by electron beam melting is to utilize the difference of vapor pressures of different impurity elements and molybdenum at high temperature, namely, the removal rate with large vapor pressure difference is higher, and the removal rate with large vapor pressure difference is smaller. The low vapor pressure element, such as W, has a lower vapor pressure than Mo, and in electron beam melting of Mo, W cannot be removed once it exists in the raw material rod, limiting further improvement of molybdenum purity.
JP1993-009617 discloses a method for separating tungsten impurity from ammonium molybdate by adjusting the solution of ammonium molybdate containing tungsten to acidity (pH 2.5-4.5) with inorganic acid to crystallize ammonium molybdate. By adopting the method, the content of tungsten in the molybdenum oxide is reduced to below 10ppm, but the content of other impurities such as K is still above 10ppm after three times of circulating treatment, meanwhile, the problem that the content of C, O in the molybdenum is higher is difficult to solve, and the recovery rate of Mo is seriously influenced by multiple times of circulating treatment.
Patent CN1253865A discloses binding molybdenum strips and molybdenum scrap into rods by molybdenum wires, and then purifying and manufacturing metal molybdenum rods for producing molybdenum electrode blanks and molybdenum runner blanks by electron beam melting.
In patent CN102127741A, ammonium molybdate as a raw material is roasted and reduced into Mo, the Mo is formed by isostatic pressing, the Mo is sintered at the high temperature of 1950-2000 ℃, and then the Mo is smelted by a high-power electron beam, wherein the oxygen content of the molybdenum target obtained by the method is less than or equal to 0.004%, the Mo content is more than or equal to 99.97% (metal content), but the W content in the molybdenum is higher, and the K content is not detected.
The patent CN103114213A adopts electron beam vacuum melting, zone melting purification and electromagnetic field purification methods to prepare high-purity molybdenum for the sapphire growth furnace, and the purity of the molybdenum prepared by the method reaches 99.99 percent, but the method has complex process and high production cost.
Disclosure of Invention
The invention aims to provide a preparation method for improving the purity and yield of molybdenum, and solves the problem that the purity and yield of molybdenum are difficult to further improve by the existing molybdenum purification technology.
The invention discloses a preparation method for improving the purity and yield of molybdenum, which comprises the following steps:
1) taking an ammonium molybdate raw material with the total content of potassium and/or sodium lower than 10ppm and the tungsten content lower than 10 ppm;
2) calcining and reducing the ammonium molybdate raw material to obtain molybdenum powder;
3) pressing the molybdenum powder into a molybdenum blank, and then performing two-stage presintering on the molybdenum blank under the vacuum condition or the protective condition of a reducing atmosphere to obtain a low-oxygen molybdenum blank with the oxygen content of below 30 ppm;
4) and performing vacuum electron beam melting on the low-oxygen molybdenum blank twice, and peeling the surface of the obtained cast ingot after each vacuum electron beam melting to obtain a molybdenum product.
In the present invention, the total content of K and/or Na, the W content, the Mo content and the O content are each in parts per million by mass (ppm).
In the prior art, after molybdenum powder obtained through calcination treatment and reduction treatment, the content of gas atoms (O, N and the like) is increased, the oxygen content may reach as high as 800ppm, and although the gas atoms can be removed through electron beam melting, the removal efficiency of the gas atoms impurities of the electron beam melting is general, multiple times of electron beam melting is often required, the energy consumption is additionally increased, and the molybdenum yield is low.
Based on the findings, the invention is subjected to a large number of tests, molybdenum powder is pressed and subjected to two-stage presintering before electron beam melting, molybdenum blanks are further purified, the gas atom content, particularly the oxygen content, in molybdenum is reduced, low-oxygen molybdenum blanks with the oxygen content of below 30ppm are obtained, and the low-oxygen molybdenum blanks are applied to electron beam melting, so that the contents of impurities such as Co, Cr, La, Ni, Fe and the like are greatly reduced.
The applicant has found that the high and low potassium and sodium contents are directly linked to the high and low molybdenum oxide content produced during the pre-sintering/sintering, the higher the potassium and sodium contents, the higher the molybdenum oxide content in the molybdenum blank after the pre-sintering/sintering and vice versa.
Presumably, potassium and sodium are more than K2MoO4、Na2MoO4When the alkali metal composite oxide exists in the form of equal alkali metal composite oxide, impurity oxygen of molybdenum blank and reduced molybdenum are recombined into molybdenum oxide during presintering/sintering, and the molybdenum oxide and metal molybdenum have large melting point difference and are removed in the form of steam during electron beam melting, so that the molybdenum yield is low.
It should be noted that, in step 2), the temperature and time control of the calcination and reduction treatments is a routine choice in the industry, and therefore, in the examples, the temperature and time of the calcination treatment and the range of the temperature and time of the reduction treatment were not tested and verified. For example, the precipitate B may be calcined at 900 ℃ to 1100 ℃ for 2h to 6h to obtain molybdenum oxide powder, and the molybdenum oxide powder may be put into a reduction vessel and, after introducing hydrogen gas, reduced at 900 ℃ to 1400 ℃ for 3h to 6 h.
The numerical ranges disclosed herein include all point values within that range.
Detailed Description
In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the following examples, and experimental methods in which specific conditions are not specified in the following examples are generally performed under conventional conditions.
In a preferred embodiment, the total potassium and/or sodium content of the ammonium molybdate is preferably below 8 ppm.
In a preferred embodiment, the ammonium molybdate is prepared by: 1) adjusting the pH of the ammonium molybdate solution A containing impurities to be acidic by using inorganic acid to obtain a precipitated ammonium molybdate precipitate A; 2) dissolving the ammonium molybdate precipitate A with ammonia water to obtain an ammonium molybdate solution B, and then adjusting the pH of the ammonium molybdate solution B to be acidic with inorganic acid to obtain a precipitated ammonium molybdate precipitate B; 3) and drying the ammonium molybdate precipitate B to obtain ammonium molybdate. The method adopts a secondary purification technology, can greatly reduce the contents of alkali metal elements such as Na, K and the like and W, and obtains the ammonium molybdate crystal with extremely low alkali metal content and tungsten content.
In a recommended embodiment, the pressing pressure is 80MPa-95MPa, the dwell time is 3min-8min, and the oxygen content of the low-oxygen molybdenum blank is below 20 ppm. By the mode, a loose and porous structure can be formed in the molybdenum blank, so that a large number of pore passages in the molybdenum blank are prevented from being blocked, and the improvement on the reduction of the content of gas atoms (O, N and the like) in the molybdenum in the pre-sintering process is more beneficial.
In a preferred embodiment, the reducing atmosphere is hydrogen.
In a recommended embodiment, the two-stage pre-sintering comprises a first-stage pre-sintering and a second-stage pre-sintering, wherein the first-stage pre-sintering comprises raising the temperature from room temperature to 1200 ℃ and keeping the temperature for more than 1.5h within 4.5h-5.5h, and the second-stage pre-sintering comprises raising the temperature from 1200 ℃ to 1350 ℃ and keeping the temperature for 2h-3h within 1.5h-2 h. The selection of the sintering time and sintering temperature for the first stage of pre-sintering and the second stage of pre-sintering is also a routine choice in the industry and the above ranges are not tested and verified in the examples.
In a preferred embodiment, the vacuum electron beam melting comprises a furnace pressure of 10-2Pa below, the pressure in the electron gun chamber is 10-3Pa below, electron gun power above 20kW, and smelting temperature of 2700-3500 ℃. The selection of the pressure in the furnace body, the pressure in the electron gun chamber, the electron gun power and the melting temperature is also a routine choice in the industry, and the ranges are not tested and verified in the embodiment.
In a preferred embodiment, the ammonium molybdate solution a is prepared by dissolving at least one selected from molybdenum dioxide, molybdenum trioxide and molybdenum disulfide as a raw material with ammonia water.
In a preferred embodiment, the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, or boric acid. This is because the inorganic acid is more easily removed in a subsequent step.
In a recommended embodiment, the ammonium molybdate solution A is adjusted to have a pH value within the range of 3.0-3.5 by using inorganic acid, and the temperature is controlled to be 30-40 ℃; and adjusting the pH value of the ammonium molybdate solution B to be within the range of 3.5-4.0 by using inorganic acid, controlling the temperature to be 25-35 ℃, and controlling the total content of potassium and/or sodium in the ammonium molybdate to be lower than 8 ppm. The invention adopts secondary separation and filtration, and unexpectedly finds that ammonium molybdate with extremely low potassium and/or sodium content and tungsten content can be obtained by respectively adjusting the pH value and the temperature of the solution in the two-time separation.
In a preferred embodiment, the molybdenum dioxide, trioxide or disulfide is more than 95.0% pure. The molybdenum dioxide, the molybdenum trioxide or the molybdenum disulfide may contain W and K impurities.
Example one
1) The total content of potassium and sodium and the tungsten content of each of the four ammonium molybdate raw materials, 300g, are shown in Table 1.
2) Respectively calcining the four ammonium molybdate raw materials at 900 ℃ for 6 hours to obtain molybdenum oxide powder; putting the molybdenum oxide powder into a reduction container, introducing hydrogen for reduction treatment, wherein the reduction temperature is 1400 ℃, and the reduction time is 3 hours to obtain molybdenum powder;
3) pressing by a cold isostatic pressing method, pressing molybdenum powder into a molybdenum blank, wherein the pressing pressure is 80MPa, the pressure maintaining time is 8min, then placing the molybdenum blank into a sintering furnace, performing two-stage presintering under the vacuum condition, performing the first-stage presintering, raising the temperature from room temperature to 1200 ℃ over 4.5h, preserving the heat for 1.5h, performing the second-stage presintering, raising the temperature from 1200 ℃ over 2h to 1350 ℃, and preserving the heat for 2h to obtain the low-oxygen molybdenum blank.
4) Placing the low-oxygen molybdenum blank into an electron beam smelting furnace, exhausting and vacuumizing to ensure that the pressure in the furnace body is 10-2Pa, the pressure in the electron gun chamber is 10-3Pa; and starting an electron gun, controlling the power of the electron gun to be 20kW, controlling the smelting temperature to be 2700 ℃, carrying out vacuum electron beam smelting twice, carrying out scalping treatment on the surface of the obtained cast ingot after each vacuum electron beam smelting, and cleaning with water to obtain the molybdenum product.
TABLE 1 analysis of the composition of part of ammonium molybdate raw material for each of examples and comparative examples (unit: ppm)
| Serial number | Total content of potassium and sodium | Tungsten content |
| Example 1 | 8 | 8 |
| Example 2 | 10 | 10 |
| Comparative example 1 | 15 | 25 |
| Comparative example 2 | 20 | 50 |
Example two
1) Respectively dissolving 6 groups of 300g molybdenum dioxide (purity is 95%) by using 1mol/L ammonia water, filtering to remove insoluble substances to form an ammonium molybdate solution A, adjusting the pH value of the solution A by using 3mol/L hydrobromic acid, slowly dropwise adding the solution A at a controlled temperature, wherein the pH value and the temperature are shown in table 2, and filtering to obtain a precipitated ammonium molybdate precipitate A; dissolving the ammonium molybdate precipitate A with 1mol/L ammonia water to form an ammonium molybdate solution B, adjusting the pH value of the solution B with 3mol/L hydrochloric acid, slowly dropwise adding the solution B with the temperature controlled, wherein the pH value and the temperature are shown in table 2, filtering to obtain the ammonium molybdate precipitate B, and drying to obtain ammonium molybdate.
2) Respectively calcining 6 groups of ammonium molybdate at 1000 ℃ for 4 hours to obtain molybdenum oxide powder; putting molybdenum oxide powder into a reduction container, introducing hydrogen for reduction treatment, wherein the reduction temperature is 1200 ℃, and the reduction time is 4 hours to obtain molybdenum powder;
3) pressing by a cold isostatic pressing method, pressing molybdenum powder into a molybdenum blank, wherein the pressing pressure is 90MPa, the pressure maintaining time is 5min, then placing the molybdenum blank into a sintering furnace, performing two-stage presintering under the vacuum condition, performing the first-stage presintering, raising the temperature from room temperature to 1200 ℃ through 5.5h, preserving the heat for 2h, performing the second-stage presintering, raising the temperature from 1200 ℃ through 1.5h to 1350 ℃, and preserving the heat for 3h to obtain the low-oxygen molybdenum blank.
4) Placing the low-oxygen molybdenum billet in an electron beam melting furnace, exhausting and vacuumizing to ensure that the pressure in the furnace body is 5 × 10-3Pa, pressure in the electron gun chamber of 5 × 10-4Pa; starting an electron gun, controlling the power of the electron gun to be 100kW, controlling the smelting temperature to be 3200 ℃, carrying out vacuum electron beam smelting twice, carrying out scalping treatment on the surface of the obtained cast ingot after each vacuum electron beam smelting, and cleaning with water to obtain a molybdenum product.
TABLE 2 pH and temperature control in step 1 of the examples
EXAMPLE III
1) Dissolving 4 groups of 500g molybdenum trioxide (purity is 95%) with 1.5mol/L ammonia water, filtering to remove insoluble substances to form an ammonium molybdate solution A, adjusting the pH value of the solution A to 3.5 with 2mol/L hydrochloric acid and 1mol/L boric acid mixed acid, and controlling the temperature to be 40 ℃ to obtain a precipitated ammonium molybdate precipitate A; dissolving the ammonium molybdate precipitate A with 1.5mol/L ammonia water to form an ammonium molybdate solution B, adjusting the pH value of the solution B to 4.0 with 3mol/L hydrochloric acid, controlling the temperature to be 35 ℃, filtering to obtain an ammonium molybdate precipitate B, and drying to obtain ammonium molybdate.
2) Respectively calcining 4 groups of ammonium molybdate at 1100 ℃ for 2 hours to obtain molybdenum oxide powder; putting the molybdenum oxide powder into a reduction container, introducing hydrogen for reduction treatment, wherein the reduction temperature is 1400 ℃, and the reduction time is 3 hours to obtain molybdenum powder;
3) pressing by a cold isostatic pressing method, pressing molybdenum powder into molybdenum blanks, wherein the pressing pressure and pressure maintaining time of 4 groups of examples are shown in table 3, then placing the molybdenum blanks into a sintering furnace, performing two-stage presintering under a vacuum condition, performing the first-stage presintering, raising the temperature from room temperature to 1200 ℃ over 5h, preserving the temperature for 2h, performing the second-stage presintering, raising the temperature from 1200 ℃ over 1.5h to 1350 ℃, and preserving the temperature for 2.5h to obtain the low-oxygen molybdenum blanks.
4) Low oxygen molybdenum billetPlacing in an electron beam melting furnace, exhausting and vacuumizing to make the pressure in the furnace body be 10-3Pa, the pressure in the electron gun chamber is 10-4Pa; starting an electron gun, controlling the power of the electron gun to be 120kW, controlling the smelting temperature to be 3500 ℃, carrying out vacuum electron beam smelting twice, carrying out scalping treatment on the surface of the obtained cast ingot after each vacuum electron beam smelting, and cleaning with water to obtain a molybdenum product.
TABLE 3 pressure and dwell time for pressing in the examples
| Serial number | Pressure (MPa) | Dwell time (min) |
| Example 9 | 75 | 10 |
| Example 10 | 80 | 8 |
| Example 11 | 95 | 3 |
| Example 12 | 105 | 2.5 |
The following performance tests were performed for each of the examples and comparative examples:
1) the molybdenum powders and molybdenum products of the examples and comparative examples were weighed, wherein the examples and comparative examples in example one are shown in table 4. And calculating the yield of molybdenum according to the following formula:
2) the molybdenum powder obtained by reduction in each example and comparative example and the molybdenum product after electron beam melting were subjected to Glow Discharge Mass Spectrometry (GDMS) test and the purity of molybdenum (formula below) was calculated, and the results of the contents of elements K, Na, O, W and other impurities (Co, Cr, La, Ni, Fe, Mn, V, P, Si, etc.), the yield of molybdenum, and the purity of molybdenum were shown in tables 5 and 6.
TABLE 4 quality of molybdenum products of examples and comparative examples
| Serial number | Molybdenum product quality (g) |
| Example 1 | 146.78 |
| Example 2 | 144.56 |
| Comparative example 1 | 129.60 |
| Comparative example 2 | 126.43 |
TABLE 5 Performance test results of molybdenum powders of examples and comparative examples
TABLE 6 Performance test results for each of the example and comparative molybdenum products
As can be seen from Table 4, the molybdenum product quality, i.e., the molybdenum yield, is higher for ammonium molybdate feedstocks having a total potassium and/or sodium content of less than 10ppm and a tungsten content of less than 10 ppm; as the total content of potassium and/or sodium increased, the yield of molybdenum decreased, and as can be further seen from table 6, the purity of molybdenum was much higher in examples 1 and 2 than in comparative examples 1 and 2, and the yield of molybdenum was also higher by more than 5%.
As can be seen from Table 5, the adjustment of the pH and temperature of the solutions in the two separations is more beneficial for obtaining low-potassium and low-tungsten precipitates, and further, the first pH is in the range of 3.0 to 3.5, the temperature is controlled to be 30 ℃ to 40 ℃, the second pH is in the range of 3.5 to 4.0, and the temperature is controlled to be 25 ℃ to 35 ℃, so that ammonium molybdate with the total content of potassium and sodium lower than 8ppm and the content of tungsten lower than 10ppm can be obtained.
As can be seen from Table 6, the pressing pressure is 80MPa to 95MPa, and the pressure maintaining time is 3min to 8min, which is more beneficial to the reduction of the O content in the molybdenum in the pre-sintering process.
As can also be seen from Table 6, the purity of the molybdenum product prepared in this example can reach more than 99.997% (i.e., the mass ratio of molybdenum is more than or equal to 99.997 wt%).
To conclude, we can conclude that:
the yield of molybdenum is higher for the ammonium molybdate raw material with the total content of potassium and/or sodium lower than 10ppm and the tungsten content lower than 10 ppm; as the total content of potassium and/or sodium increases, the yield of molybdenum decreases.
By adopting secondary separation and filtration, the method is more beneficial to obtaining ammonium molybdate precipitate with extremely low potassium and/or sodium content and tungsten content by adjusting the pH value and the temperature of the solution in the two-time separation (specifically, the first pH value is within the range of 3.0-3.5, the temperature is controlled within the range of 30-40 ℃, the second pH value is within the range of 3.5-4.0, and the temperature is controlled within the range of 25-35 ℃);
the pressing pressure is 80MPa-95MPa, the pressure maintaining time is 3min-8min, a loose and porous structure can be formed in the molybdenum blank, and the reduction of the oxygen content in the molybdenum in the pre-sintering process is more beneficial;
by controlling the total content of potassium and/or sodium and the content of tungsten in the raw materials and pressing molybdenum powder (80MPa-95MPa, maintaining the pressure for 3min-8min) before two times of electron beam melting, the purity of the obtained molybdenum product can reach more than 99.997%.
The above embodiments are only used for explaining the technical solutions provided by the present invention, and the present invention is not limited thereto, and any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention fall within the protection scope of the technical solutions of the present invention.
Claims (8)
1. The preparation method for improving the purity and yield of molybdenum is characterized by comprising the following steps:
1) taking an ammonium molybdate raw material with the total content of potassium and/or sodium lower than 8ppm and the tungsten content lower than 10 ppm; the ammonium molybdate is prepared by the following steps: 1) adjusting the pH of the ammonium molybdate solution A containing impurities to be acidic by using inorganic acid to obtain a precipitated ammonium molybdate precipitate A; 2) dissolving the ammonium molybdate precipitate A with ammonia water to obtain an ammonium molybdate solution B, and then adjusting the pH of the ammonium molybdate solution B to be acidic with inorganic acid to obtain a precipitated ammonium molybdate precipitate B; 3) drying the ammonium molybdate precipitate B to obtain ammonium molybdate; adjusting the pH value of the ammonium molybdate solution A to be within the range of 3.0-3.5 by using inorganic acid, and controlling the temperature to be 30-40 ℃; adjusting the pH value of the ammonium molybdate solution B to be within the range of 3.5-4.0 by using inorganic acid, and controlling the temperature to be 25-35 ℃;
2) calcining and reducing the ammonium molybdate raw material to obtain molybdenum powder;
3) pressing the molybdenum powder into a molybdenum blank, and then performing two-stage presintering on the molybdenum blank under the vacuum condition or the protective condition of a reducing atmosphere to obtain a low-oxygen molybdenum blank with the oxygen content of below 30 ppm;
4) and performing vacuum electron beam melting on the low-oxygen molybdenum blank twice, and peeling the surface of the obtained cast ingot after each vacuum electron beam melting to obtain a molybdenum product.
2. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the pressing pressure is 80MPa-95MPa, the dwell time is 3min-8min, and the oxygen content of the low-oxygen molybdenum blank is below 20 ppm.
3. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the reducing atmosphere is hydrogen.
4. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the two-stage presintering comprises a first stage presintering and a second stage presintering, wherein the first stage presintering comprises the steps of heating from room temperature to 1200 ℃ within 4.5-5.5 h, and preserving heat for more than 1.5h, and the second stage presintering comprises the steps of heating from 1200 ℃ to 1350 ℃ within 1.5-2 h, and preserving heat for 2-3 h.
5. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the vacuum electron beam melting comprises that the pressure in a furnace body is 10-2Pa below, the pressure in the electron gun chamber is 10-3Pa below, electron gun power above 20kW, and smelting temperature of 2700-3500 ℃.
6. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the ammonium molybdate solution A is prepared by taking at least one of molybdenum dioxide, molybdenum trioxide or molybdenum disulfide as a raw material and dissolving the raw material with ammonia water.
7. The preparation method for improving the purity and the yield of the molybdenum according to claim 1, wherein the preparation method comprises the following steps: the inorganic acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid or boric acid.
8. The preparation method for improving the purity and the yield of the molybdenum according to claim 6, wherein the method comprises the following steps: the purity of the molybdenum dioxide, the molybdenum trioxide or the molybdenum disulfide reaches more than 95.0 percent.
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| CN112320769A (en) * | 2020-11-19 | 2021-02-05 | 金川集团股份有限公司 | Method for inhibiting loss of metal tellurium during ingot casting in early stage of refining high-purity tellurium |
| CN114395700A (en) * | 2022-01-14 | 2022-04-26 | 宁波江丰钨钼材料有限公司 | Molybdenum blank and preparation method and application thereof |
| CN115261634B (en) * | 2022-07-25 | 2024-02-06 | 金堆城钼业股份有限公司 | Low-potassium molybdenum matrix, preparation method and application |
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| JPS60221538A (en) * | 1984-04-18 | 1985-11-06 | Mitsubishi Metal Corp | Method for refining molybdenum |
| CN101956159A (en) * | 2010-09-30 | 2011-01-26 | 金堆城钼业股份有限公司 | Method for preparing high-purity molybdenum titanium sputtering target |
| CN101966592A (en) * | 2010-11-01 | 2011-02-09 | 金堆城钼业股份有限公司 | Method for preparing molybdenum powder |
| CN102266943A (en) * | 2011-07-05 | 2011-12-07 | 金堆城钼业股份有限公司 | Method for preparing high-purity molybdenum electrode |
| CN103114213A (en) * | 2012-11-08 | 2013-05-22 | 宝鸡市博信金属材料有限公司 | Method for preparing high-purity molybdenum for sapphire growth furnace |
| CN107262733B (en) * | 2017-08-02 | 2019-02-26 | 北京科技大学 | A kind of method that two-part reduction prepares ultrafine molybdenum powder |
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