JP6039469B2 - Method for producing metal nitride - Google Patents

Description

  The present invention relates to a method for producing a metal nitride, particularly a metal nitride selected from lithium, magnesium, calcium, strontium and barium.

  In recent years, metal nitrides have attracted attention as one of materials such as aluminum nitride raw materials, metal sliding members, and electrode constituent materials used in semiconductor devices. In addition, many phosphors using metal nitrides have been found, and the demand as a raw material has been increasing. The metal nitride used for such applications is required to have a high purity.

As a conventional method for producing a metal nitride, there is a method of heating an alkaline earth metal such as calcium in a nitrogen stream (Non-Patent Documents 1 and 2).
However, with this method, only the metal surface is nitrided, and it is difficult to nitride the inside. Moreover, the obtained metal nitride aggregated firmly (patent document 1), and collection | recovery was difficult. Furthermore, when the aggregate is pulverized, trace components may be mixed due to excessive pulverization. Therefore, the metal nitride obtained by this method cannot be used for applications requiring a high-purity product such as the semiconductor device.
In addition, there is a method of heating calcium with ammonia, but this method has a problem that calcium hydride is by-produced (Non-patent Document 3), and there is also a method of heating tricalcium tetranitride to 250 ° C. However, there were problems of explosiveness and toxicity (Non-patent Document 4).
Further, a method for synthesizing calcium nitride in which a molten zinc-calcium alloy is reacted with a heated and pressurized nitrogen jet has been disclosed (Patent Document 1). However, this method requires a special apparatus. There is an industrially advantageous method.
In addition, the present inventors have found that an alkaline earth metal nitride can be obtained by pyrolyzing an alkaline earth metal amide obtained from an alkaline earth metal or an alkaline earth metal hydride at 800 to 1300 ° C. Reported (Patent Document 2).

JP 2005-531483 A Japanese Patent No. 4585043

Michinori Oki et al., “Chemical Dictionary” 1st edition, Tokyo Chemical Doujin, 1st edition, page 1413, 1989 The Chemical Society of Japan, “New Experimental Chemistry Course 8, Synthesis of Inorganic Compounds I” Maruzen Co., Ltd., p.414, 1976) “Chemical Dictionary 5”, reduced edition, Kyoritsu Shuppan Co., Ltd., page 880, 1987 “Inorganic Compound and Complex Dictionary” by Katsumi Nakahara, Kodansha, p. 476, 1997

  However, when the alkaline earth metal amide is used as a raw material, it is necessary to produce the alkaline earth metal amide from an alkaline earth metal or an alkaline earth metal hydride, which raises a problem of increased cost.

  Therefore, an object of the present invention is to provide a method for producing a metal nitride having a low yield and a high purity by an easy method with a good yield without the above-mentioned problems.

  In view of such circumstances, the present inventor has conducted intensive research, and as a result, metal amides such as alkaline earth metals and the same metals are used in combination at a constant molar ratio and heated to 100 to 1500 ° C. Surprisingly, not only amides such as alkaline earth metals but also alkaline earth metals do not agglomerate, and nitrogenation proceeds further to the inside, so that high-purity metal nitride can be obtained at low cost. The present invention has been completed.

  That is, the present invention provides the following [1] to [5].

[1] One or more metal amides (A) selected from lithium, magnesium, calcium, strontium and barium and one or more metals selected from lithium, magnesium, calcium, strontium and barium A composition comprising (B) and having a molar ratio (A: B) of the metal amide (A) to the metal (B) of 1: 0.01 to 1: 5 is heated to 100 to 1500 ° C. A method for producing a nitride of one or more metals selected from lithium, magnesium, calcium, strontium, and barium.
[2] The method for producing a metal nitride according to [1], wherein the molar ratio (A: B) between the metal amide (A) and the metal (B) is 1: 0.01 to 1: 2.
[3] The method for producing a metal nitride according to [1] or [2], wherein the heating is performed in an atmosphere of nitrogen gas or inert gas.
[4] The method for producing a metal nitride according to any one of [1] to [3], wherein the heating is performed in a nitrogen gas atmosphere.
[5] The metal amide (A) to be used is a particle having a particle diameter of 0.001 to 100 μm, and the metal (B) is a particle or a lump having a particle diameter of 0.1 mm to 200 mm [1] to [4] ] The manufacturing method of the metal nitride in any one of.

  According to the present invention, high-purity metal nitride can be produced by an easy method at a low cost and in a high yield. Since the obtained metal nitride does not agglomerate firmly, it can be easily recovered.

FIG. 3 is a diagram showing XRD results of calcium nitride obtained in Example 1. It is a figure which shows the XRD result of the calcium nitride obtained by Example 2. It is a figure which shows the XRD result of the calcium nitride obtained by Example 3. It is a figure which shows the XRD result of the strontium nitride obtained by Example 4.

  In the method of the present invention, as raw materials, one or more metal amides (A) selected from lithium, magnesium, calcium, strontium and barium and one selected from lithium, magnesium, calcium, strontium and barium are used. Alternatively, a composition comprising two or more metals (B) and having a molar ratio (A: B) of the metal amide (A) to the metal (B) of 1: 0.01 to 1: 5 is used. . By using the metal (B) in this molar ratio in addition to the metal amide (A), the production cost is reduced.

  Lithium amide, which is one of the raw materials of the present invention, is a known compound, and can be produced by a known method, for example, a method in which ammonia is allowed to act on lithium at a high temperature.

  The metal amide of magnesium, calcium, strontium, or barium, which is a raw material of the present invention, is a known compound that has applications such as a hydrogen storage material, and can be produced by a known method. For example, a method of producing hexaammine calcium (0) from calcium metal and ammonium and decomposing it in the presence of contact ("Chemical Dictionary", reprinted edition, Kyoritsu Shuppan Co., Ltd., calcium amide), these metal hydrogens And a method of reacting a compound with ammonia (Japanese Patent Laid-Open No. 2006-8440).

  In the present invention, these metal amides (A) may be used alone or in combination of two or more.

  Since the metal amide (A) is usually available as a powder, it is preferable to use particles having a particle size of 0.001 to 100 μm, more preferably particles having a particle size of 0.05 to 50 μm, and a particle size of 0.001. More preferably, 1-10 μm particles are used.

  One or more metals (B) selected from lithium, magnesium, calcium, strontium, and barium, which are the other raw materials, are usually available in the form of particles or lumps as commercial products, and should be used as they are. Can do. From the point of obtaining a high-purity metal nitride without agglomeration, it is preferable to use particles or lumps having a particle size of 0.1 to 200 mm, more preferably particles or lumps having a particle size of 0.5 to 50 mm, More preferably, particles or lumps having a particle diameter of 1 to 10 mm are used.

  One or more of the metal amide (A) and the metal (B) can be used, but it is desirable that the metal of the metal amide (A) and the metal (B) are the same.

  The use molar ratio (A: B) of the metal amide (A) to the metal (B) is 1: 0.01 to 1: 5 from the viewpoint of obtaining a high-purity metal nitride without agglomeration and economy. 1: 0.01-1: 3 is preferable, and 1: 0.01-1: 2 is more preferable. Further, from the point of obtaining a highly pure metal nitride, 1: 0.1 to 1: 3 is more preferable, and 1: 0.25 to 1: 2 is more preferable.

  Since the metal amide (A) and the metal (B) have large particle diameters, it is difficult to mix them uniformly, and it is only necessary that both exist in the reaction system. You can just put it on.

The heating temperature of the composition comprising the metal amide (A) and the metal (B) is 100 to 100% from the viewpoint that the metal nitride is not decomposed and a high-purity metal nitride is obtained in consideration of the reactor and economy. 1500 degreeC is preferable, 200-1300 degreeC is more preferable, and 300-1300 degreeC is further more preferable.
Moreover, 100-700 degreeC is preferable, as for the heating temperature in the case of using lithium amide and lithium as a raw material, 200-500 degreeC is more preferable, and 300-500 degreeC is further more preferable. On the other hand, the heating temperature when magnesium, calcium, strontium or barium amide and magnesium, calcium, strontium or barium are used as raw materials is preferably 510 to 1500 ° C, more preferably 600 to 1300 ° C, and 800 to 1200 ° C. Is more preferable.

Since the metal amide (A) as a starting material is easily oxidized in the air, the reaction is preferably performed in an inert gas atmosphere such as nitrogen gas or argon gas, and further, nitrogenation proceeds further to the inside, Since high-purity metal nitride can be obtained at low cost, it is more preferable to carry out in a nitrogen gas atmosphere. In addition, when the reaction is performed in a nitrogen gas atmosphere, if the molar ratio (A: B) of metal amide (A) to metal (B) is 1: 0.01 to 1: 2, the metal remains. All can be obtained as nitrides.
In addition, when the reaction is performed in a gas atmosphere, the pressure is not particularly limited, but it is economical and preferable to perform the reaction at normal pressure. The reaction may be a batch type or a continuous type, but the continuous type is advantageous for mass production.

  The reaction time may be appropriately determined depending on the apparatus, reaction temperature, and amount of raw material, but is usually preferably 10 minutes to 48 hours, more preferably 1 hour to 24 hours, and particularly preferably 3 hours to 12 hours.

  The reaction apparatus may be an apparatus that can withstand heat of about 1500 ° C., and for example, a tubular furnace, an electric furnace, a batch kiln, or a rotary kiln may be used.

After completion of the reaction, for example, in the case of a batch type, since only the target metal nitride remains in a powder form in the reaction apparatus, recovery is very easy.
On the other hand, in the case of a continuous type, for example, if a rotary kiln whose interior is filled with N ₂ or Ar is used, the metal nitride is easily recovered continuously.

  Depending on the conditions such as the molar ratio of metal amide (A) and metal (B) used, the reaction temperature, and time, the metal may remain. However, by using the method of the present invention, the metal nitride and the remaining metal can be easily recovered without agglomeration. When the obtained metal nitride and the remaining metal are appropriately pulverized, the metal nitride becomes a powder and the remaining metal remains in a granular form, and a pure metal nitride can be obtained. Separation can be performed, for example, by a general classification device such as sieving, specific gravity separation, and airflow classification device. The separated metal can be used again as the raw material metal (B), and can be made into a metal nitride by the method of the present invention.

The metal nitride obtained by the method of the present invention has high purity because the reaction easily proceeds to the inside by the thermal decomposition reaction of the metal amide (A). Moreover, even if the metal (B) is used in a lump, the reason for nitriding to the inside is not clear, but it is estimated that ammonia generated by the thermal decomposition of the metal amide is used for reduction and nitridation of the metal (B). Is done. The metal nitride obtained by the present invention is one or two selected from Li ₃ N, Mg ₃ N ₂ , Ca ₃ N ₂ , Ca ₂ N, Sr ₃ N ₂ , Sr ₂ N and Ba ₂ N. The above is preferable.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
The experiment was performed under the conditions of calcium metal: calcium amide of 0.4 mol: 1 mol. A mixture of 10 g of 5 mm lump calcium metal and 50 g of calcium amide powder having a particle diameter of 0.5 μm was heat-treated at 1000 ° C. for 4 hours under a nitrogen flow. Heating is carried on a furnace core tube (inner diameter 50mm, length 600mm) alumina board installed in the glove box, the furnace core tube is sealed with a silicon cap, and the furnace core tube taken out from the glove box is set in a tubular furnace. Up to 300 ° C./hour. The heat-treated product was collected in the glove box. When the mineral phase of the fired product after treatment was identified using XRD, it was all-phase calcium nitride, and no peak of calcium metal was confirmed (FIG. 1).

Example 2
The experiment was conducted under the conditions of 0.6 mol: 1 mol of calcium metal: calcium amide. A mixture of 10 g of a 5 mm lump of calcium metal and 30 g of calcium amide powder having a particle diameter of 0.5 μm was heated at 1000 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. When the mineral phase of the fired product after the treatment was identified using XRD, it was all-phase calcium nitride, and the peak of calcium metal was not confirmed (FIG. 2).

Example 3
The experiment was performed under the conditions of 1.8 mol: 1 mol of calcium metal: calcium amide. A mixture of 216 g of 10 mm lump calcium metal and 216 g of calcium amide powder having a particle size of 0.5 μm was heat-treated at 1100 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. When the mineral phase of the baked product after the treatment was identified using XRD, it was all-phase calcium nitride, and the peak of calcium metal was not confirmed (FIG. 3).

Example 4
Experiments were conducted under the conditions of 0.3 mol: 1 mol of strontium metal: strontium amide. A mixture of 10 g of 20 mm strontium metal mixed with 50 g of strontium amide having a particle diameter of 0.5 μm was heated at 900 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. When the mineral phase of the fired product after the treatment was identified using XRD, it was all-phase strontium nitride, and no strontium metal peak was confirmed (FIG. 4).

Example 5
The experiment was conducted under the conditions of 0.6 mol: 1 mol of calcium metal: calcium amide. A mixture of 10 g of 5 mm lump calcium metal and 30 g of calcium amide powder having a particle diameter of 0.5 μm was heat-treated at 1000 ° C. under argon gas. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. After recovery, about 0.5 g of calcium metal remained when pulverized and classified in an agate mortar for XRD measurement. When the mineral phase of the baked product after removing calcium metal was identified using XRD, it was all-phase calcium nitride.

Example 6
Strontium metal: Strontium amide was used at 1 mol: 1 mol, and the strontium metal and strontium amide were not mixed, and the experiment was carried out with the strontium metal on the strontium amide. A 20 mm lump of strontium metal 7.3 g and 10 g of strontium amide having a particle diameter of 0.5 μm were laid and heated at 800 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. When the mineral phase of the fired product after the treatment was identified using XRD, it was all-phase strontium nitride, and no strontium metal peak was confirmed.

Example 7
The experiment was conducted under the conditions of 2.1 mol: 1 mol of calcium metal: calcium amide. A mixture of 11.6 g of 10 mm lump calcium metal and 10 g of calcium amide powder having a particle diameter of 0.5 μm was heat-treated at 1100 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. After collection, about 0.8 g of calcium metal remained when pulverized and classified in an agate mortar for XRD measurement. When the mineral phase of the baked product after removing calcium metal was identified using XRD, it was all-phase calcium nitride. The remaining calcium metal was again mixed with calcium amide at 1 mol: 1 mol and heat-treated at 1100 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. There was no calcium metal in the recovered material, and the mineral phase of the fired product was identified using XRD. As a result, it was all-phase calcium nitride, and no peak of calcium metal was confirmed.

Example 8
An experiment was conducted under the conditions of 2.2 mol: 1 mol of strontium metal: strontium amide. A 20 mm lump of 16.1 g of strontium metal mixed with 10 g of strontium amide having a particle diameter of 0.5 μm was heated at 1000 ° C. under nitrogen gas. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. After collection, about 1.5 g of strontium metal remained after pulverization and classification in an agate mortar for XRD measurement. When the mineral phase of the fired product after strontium metal removal was identified using XRD, it was all-phase strontium nitride. The remaining strontium metal was again mixed with strontium amide and heat-treated at 900 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. There was no strontium metal in the recovered material, and the mineral phase of the fired product was identified using XRD. As a result, all phases were strontium nitride, and no strontium metal peak was confirmed.

Example 9
An experiment was conducted under the conditions of 3 mol: 1 mol of strontium metal: strontium amide. A mixture of 11.0 g of strontium metal having a mass of 20 mm and 5 g of strontium amide having a particle diameter of 0.5 μm was heated at 900 ° C. under nitrogen gas. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. After collection, about 2.5 g of strontium metal remained when pulverized and classified in an agate mortar for XRD measurement. When the mineral layer of the baked product after strontium metal removal was identified using XRD, it was all phase strontium nitride. The remaining strontium metal was again mixed with strontium amide at 1 mol: 1 mol, and heat-treated at 800 ° C. for 4 hours under a nitrogen flow. Heating was performed in the same manner as in Example 1. The heat-treated product was collected in the glove box. There was no strontium metal in the recovered material, and the mineral phase of the fired product was identified using XRD. As a result, all phases were strontium nitride, and no peak of strontium metal was confirmed.

Comparative Example 1
Experiments were carried out under the conditions of 10 mol: 1 mol of calcium metal: calcium amide. A mixture of 11.2 g of 5 mm lump calcium metal and 2 g of calcium amide powder having a particle size of 0.5 μm was heat-treated at 1000 ° C. under nitrogen gas. Heating was performed in the same manner as in Example 1. The heat-treated material is collected in the glove box. Aggregates of calcium metal and calcium amide were fixed and could not be recovered. In addition, calcium metal was eroded and cracked in the alumina boat used for the firing boat.

  As described above, the method for producing a metal nitride according to the present invention can obtain a high-purity metal nitride without agglomeration even when a granular metal is used as a raw material. Further, when the molar ratio (B / A) between the metal amide (A) and the metal (B) was 2 or less, all-phase metal nitride could be obtained.

Claims (5)

Magnesium, calcium, and one or more metal amide selected from strontium and barium (A), magnesium, calcium, from the one or more metals selected from strontium and barium (B) And a composition having a molar ratio (A: B) of the metal amide (A) to the metal (B) of 1: 0.01 to 1: 2 is heated to 800 to 1100 ° C. to, magnesium, calcium, strontium and method for producing one or more metal nitride selected from barium. The method for producing a metal nitride according to claim 1, wherein the molar ratio (A: B) of the metal amide (A) to the metal (B) is 1: 0.25 to 1: 2.   The method for producing a metal nitride according to claim 1 or 2, wherein the heating is performed in an atmosphere of nitrogen gas or inert gas.   The method for producing a metal nitride according to claim 1, wherein the heating is performed in a nitrogen gas atmosphere.   The metal amide (A) used is a particle having a particle diameter of 0.001 to 100 μm, and the metal (B) is a particle or a lump having a particle diameter of 0.1 mm to 200 mm. The manufacturing method of the metal nitride of description.

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