WO2023145520A1 - Tungsten oxide powder - Google Patents

Tungsten oxide powder Download PDF

Info

Publication number
WO2023145520A1
WO2023145520A1 PCT/JP2023/001031 JP2023001031W WO2023145520A1 WO 2023145520 A1 WO2023145520 A1 WO 2023145520A1 JP 2023001031 W JP2023001031 W JP 2023001031W WO 2023145520 A1 WO2023145520 A1 WO 2023145520A1
Authority
WO
WIPO (PCT)
Prior art keywords
tungsten oxide
tungsten
sodium
oxide powder
potassium
Prior art date
Application number
PCT/JP2023/001031
Other languages
French (fr)
Japanese (ja)
Inventor
直樹 岩井
貴彦 牧野
志賢 青木
Original Assignee
京セラ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京セラ株式会社 filed Critical 京セラ株式会社
Publication of WO2023145520A1 publication Critical patent/WO2023145520A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
    • B22F9/26—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions using gaseous reductors
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • C01B32/949—Tungsten or molybdenum carbides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G41/00—Compounds of tungsten
    • C01G41/02—Oxides; Hydroxides

Definitions

  • the disclosed embodiments relate to tungsten oxide powder.
  • tungsten is a component that constitutes cemented carbide and cemented carbide such as cermet, and is used together with cobalt, niobium, etc., and is widely used in cutting tools and the like.
  • tungsten since tungsten has a high melting point, it is used in various applications such as heating elements, structural members, catalysts for the petrochemical industry, environmental equipment, wiring for ceramic wiring boards, and heat dissipation members. In order to effectively utilize these resources, a method of recycling tungsten from waste materials (scrap) has been devised (see Patent Document 1).
  • a tungsten oxide powder according to one aspect of the embodiment contains a powder containing tungsten oxide crystal grains as a main component.
  • the tungsten oxide grains contain sodium and potassium. Further, the tungsten oxide crystal grains have a structure in which the sodium concentration is higher than the potassium concentration over the entire depth direction.
  • FIG. 1 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide according to an embodiment.
  • FIG. 2 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide in a reference example.
  • FIG. 3 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder according to the embodiment.
  • FIG. 4 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder in Reference Example.
  • the tungsten oxide powder according to the embodiment contains powder containing tungsten oxide crystal grains as a main component.
  • the tungsten oxide powder according to the embodiment contains powder composed of tungsten oxide crystal grains and unavoidable impurities.
  • the tungsten oxide crystal grains according to the embodiment contain sodium and potassium instead of being composed of only tungsten oxide.
  • the tungsten oxide crystal grains contained in the tungsten oxide powder have a structure in which the sodium concentration is higher than the potassium concentration throughout the depth direction.
  • the reaction promoting effect can be enhanced in the hydrogen reduction treatment for producing metallic tungsten, which is an intermediate in producing tungsten carbide from tungsten oxide powder. The reason will be explained below.
  • the melting point of sodium is 98 (°C) and the boiling point is 883 (°C)
  • the melting point of potassium is 64 (°C) and the boiling point is 759 (°C).
  • the treatment temperature for reducing tungsten oxide powder to metal tungsten with hydrogen gas is generally 800 (° C.) to 950 (° C.).
  • the temperature for the hydrogen reduction treatment of the tungsten oxide powder as described above is 800 (° C.) to 950 (° C.), which is close to the boiling point of sodium.
  • the temperature for the hydrogen reduction treatment of the tungsten oxide powder as described above is 800 (° C.) to 950 (° C.), which is close to the boiling point of sodium.
  • potassium since potassium reaches the boiling point, it evaporates during the treatment and disappears. Therefore, due to the effect of heat of vaporization when potassium volatilizes, the volatilization of sodium is suppressed even though the temperature is close to the boiling point of sodium. For these reasons, sodium tends to exist in a molten state when the tungsten oxide powder is subjected to hydrogen reduction treatment.
  • the reduction treatment can proceed while adjoining particles are adhered to each other.
  • grain growth of metallic tungsten can be achieved with lower energy (that is, at a lower temperature and in a shorter time) than in the case of containing only sodium without containing potassium.
  • the sodium concentration in the powder is higher than the potassium concentration. Since the sodium concentration is relatively high, the effect of adhering adjacent particles due to the molten state of sodium is high. In addition, since the potassium concentration is relatively small but not 0, the effect of suppressing the volatilization of sodium can be simultaneously obtained while ensuring a high effect of adhering adjacent particles due to the molten state of sodium.
  • the tungsten oxide crystal grains are configured such that the sodium concentration is higher than the potassium concentration throughout the depth direction.
  • formation of metallic tungsten tends to proceed not only on the surface of the powder but also on the entire powder toward the center. Therefore, the production efficiency of metallic tungsten is improved. Therefore, tungsten carbide can be efficiently produced from tungsten oxide powder.
  • a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain may be formed on the surface of the tungsten oxide crystal grain.
  • tungsten carbide can be more efficiently produced from tungsten oxide powder.
  • the high sodium concentration region formed on the surface of the tungsten oxide crystal grain may exist at a depth of up to 100 (nm) from the surface of the tungsten oxide crystal grain.
  • tungsten carbide can be more efficiently produced from tungsten oxide powder.
  • the tungsten oxide crystal grains may have a sodium concentration of 5 (ppm) to 100 (ppm), and may have a sodium concentration of 20 (ppm) to 100 (ppm). preferable.
  • tungsten carbide can be more efficiently produced from tungsten oxide powder.
  • the sodium contained in the tungsten oxide crystal grains decomposes and disappears when exposed to a high temperature of 1200 (°C) or higher in the carbonization process that produces tungsten carbide from metallic tungsten. Therefore, even if tungsten oxide crystal grains themselves contain sodium, there is no particular problem with the quality of tungsten carbide.
  • a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain is formed on the surface of the tungsten oxide crystal grain, thereby facilitating the decomposition and disappearance of sodium in the carbonization process. . Therefore, according to embodiments, high quality tungsten carbide can be produced.
  • FIG. 1 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide according to an embodiment. As shown in FIG. 1, in the step of producing tungsten oxide powder and tungsten carbide according to the embodiment, first, cemented carbide scrap was prepared.
  • Cemented carbide which is a kind of cemented carbide, is mainly composed of composite carbides such as metal tungsten and tungsten carbide, and has iron, nickel, cobalt, etc. as a binding phase, and if necessary, as additive components TiC, TaC, NbC, VC, Cr 3 C 2 and the like. Moreover, the scrap in the examples further contains sodium and potassium in addition to these additive components.
  • Materials to be treated containing cemented carbide are, for example, cutting tools (cutting inserts, drills, end mills, etc.), molds (forming rolls, molds, etc.), civil engineering and mining tools (oil drilling tools, rock crushing tools, etc.).
  • the prepared cemented carbide scrap was then oxidatively roasted to obtain a mixture of tungsten oxide (WO 3 ) and cobalt tungstate (CoWO 4 ). If the amount of sodium and potassium contained in the cemented carbide scrap is small, sodium and potassium may be added when obtaining the mixture. Then, the resulting mixture was refluxed with an aqueous sodium hydroxide (NaOH) solution and then extracted to obtain a tungsten compound solution containing sodium tungstate (Na 2 WO 4 ).
  • NaOH aqueous sodium hydroxide
  • the adsorbent in the present disclosure is not limited to containing lysine, Alanine, Cystine, Methionine, Tyrosine, Valine, Glutamic acid, Histidine ( Histidine, Proline, Threonine, Asparagine, Glycine, Isoleucine, Ornithine, Arginine, Serine, Citrulline and Cystathionine ( Cystathionine).
  • the total addition amount of the salt of the first amino acid in the adsorbent is 0.2 (mol) to 1.1 (mol) with respect to 1 (mol) of the metal component of the tungsten compound. Add in proportion. As a result, a large amount of tungsten compound can be adsorbed with a small amount of adsorbent.
  • the total added amount of the salt of the first amino acid is, for example, 10 (g/l) to 300 (g/l) with respect to the tungsten compound solution.
  • the viscosity of the solution does not increase, and the recovery efficiency of the metal compound is less likely to decrease.
  • the adsorbent consists of an amino acid salt, the viscosity of the solution is less likely to increase, resulting in good workability.
  • the temperature may be adjusted according to the activity of free amino acids, and usually room temperature is fine.
  • the tungsten compound solution to which the adsorbent has been added may be adjusted using hydrochloric acid or the like so that the zeta potential of free amino acids is positive. This allows the adsorbent to adsorb tungsten compound ions, which are anions.
  • the pH of the solution may be less than 7 (acidic).
  • the free amino acid is glutamic acid, the preferred pH is 1.5 or less.
  • Potassium has a higher tendency to ionize than sodium. Therefore, when the solution is acidic, potassium is easier to ionize than sodium. That is, sodium is relatively difficult to ionize and is difficult to be removed in the step of washing the adsorbent, which will be described later.
  • the sodium concentration in the powder can be higher than the potassium concentration for the reasons described above.
  • the recovery rate of the tungsten compound can be increased by the above steps. Either the step of adjusting the pH of the solution or the step of adding the adsorbent to the solution containing the metal compound may be performed first.
  • the sodium concentration in the powder can be made higher than the potassium concentration. is possible.
  • the recovery efficiency of the adsorbent is higher if the adsorption reaction is within 1 hour. That is, when the adsorption reaction exceeds 1 hour, part of the adsorbed metal compound may be desorbed from the free amino acid.
  • the adsorbent with the tungsten compound ions adsorbed was dehydrated by centrifugation or other means. Then, if necessary, the adsorbent is washed in the order of acid washing and pure water washing. Instead of acid cleaning, hot water of 40 (° C.) or more may be used for cleaning. Impurities were removed by washing with pure water until the electric conductivity of the washing filtrate became 500 ( ⁇ S/m) or less. As a result, the tungsten compound can be highly graded and recovered.
  • the adsorbent with the tungsten compound ions adsorbed thereon was incinerated, for example, at a temperature of 300 (° C.) or higher in the atmosphere to oxidize the tungsten compound and remove organic components including the adsorbent.
  • a tungsten oxide powder (WO 3 ) according to the embodiment was obtained.
  • the obtained tungsten oxide powder is heat-treated at a temperature of 800 (° C.) to 950 (° C.) in a reducing atmosphere (eg, hydrogen gas atmosphere) to reduce the tungsten oxide compound.
  • a reducing atmosphere eg, hydrogen gas atmosphere
  • metallic tungsten (W) can be obtained.
  • tungsten carbide (WC) By carbonizing the obtained metal tungsten, it is possible to obtain tungsten carbide (WC) as a raw material of cemented carbide.
  • FIG. 2 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide in a reference example.
  • a procedure for producing tungsten oxide powder and tungsten carbide in a reference example in the step of producing tungsten oxide powder and tungsten carbide in the reference example, first, cemented carbide scrap was prepared. Moreover, the scrap in the reference example also contains sodium and potassium, like the scrap in the example.
  • the prepared cemented carbide scrap was then oxidatively roasted to obtain a mixture of tungsten oxide (WO 3 ) and cobalt tungstate (CoWO 4 ).
  • a tungsten compound solution containing sodium tungstate (Na 2 WO 4 ) was obtained by extracting the resulting mixture with an aqueous sodium hydroxide (NaOH) solution. Since each process up to this point is the same as the above-described embodiment, detailed description thereof is omitted.
  • the resulting tungsten compound solution was ion-exchanged with an ion exchange resin or the like to produce an aqueous solution of ammonium tungstate ((NH 4 ) 2 WO 4 ). Then, the resulting aqueous solution was heated and concentrated to crystallize the tungsten compound as ammonium paratungstate (APT). At this time, since the aqueous solution of ammonium tungstate used in the comparative example is not an acidic solution, a large amount of sodium is removed in the step of crystallizing APT, and the content ratio of potassium to sodium tends to increase.
  • metal tungsten (W) can be obtained by heat-treating the obtained tungsten oxide powder in a reducing atmosphere to reduce the tungsten oxide compound.
  • tungsten carbide (WC) By carbonizing the obtained metal tungsten, it is possible to obtain tungsten carbide (WC) as a raw material of cemented carbide.
  • the obtained tungsten oxide powders of the embodiment and reference example were analyzed by ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry). Specifically, the depth distribution of sodium and potassium in the tungsten oxide powders of the embodiment and reference example was measured by ToF-SIMS.
  • the measurement conditions for ToF-SIMS are as follows.
  • the tungsten oxide powders of the embodiment and reference example were fixed, and the powder surface was measured at 100 ( ⁇ m) square.
  • the measuring device is TOF.
  • SIMS5 was used, Bi (bismuth) was selected as the primary ion source, and elemental analysis in the depth direction was measured.
  • FIG. 3 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder according to the embodiment.
  • FIG. 4 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder in the reference example.
  • the sodium concentration is higher than the potassium concentration throughout the depth direction.
  • the tungsten oxide crystal grains contained in the tungsten oxide powder according to the embodiment had a particle size of about several tens to several hundred (nm). Therefore, by measuring the depth distribution up to 500 (nm) as shown in FIG. 3, it can be estimated that the sodium concentration is higher than the potassium concentration throughout the depth direction.
  • tungsten carbide can be efficiently produced from the tungsten oxide powder as described above. Specifically, the processing temperature can be lowered by about 5% to 10%, thereby reducing the energy required during manufacturing by about 5% to 20%.
  • a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain is formed on the surface of the tungsten oxide crystal grain to a depth of about 100 (nm) from the surface.
  • tungsten carbide can be more efficiently produced from tungsten oxide powder.
  • the sodium content of the obtained tungsten oxide powder according to the embodiment was evaluated by an ICP (Inductively Coupled Plasma) emission spectrometer. As a result, it was found that the tungsten oxide crystal grains contained in the tungsten oxide powder according to the embodiment had 5 (ppm) to 100 (ppm) of sodium.
  • ICP Inductively Coupled Plasma
  • tungsten carbide can be more efficiently produced from tungsten oxide powder.
  • the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present invention.
  • the above embodiment shows the case of producing (recycling) tungsten oxide powder and tungsten carbide from cemented carbide scrap, but the present disclosure is not limited to such examples, and tungsten oxide powder and tungsten carbide are produced from ore. It can also be applied when generating

Abstract

This tungsten oxide powder includes a powder body having a tungsten oxide crystal grain as a main component. The tungsten oxide crystal grain contains sodium and potassium. In addition, the tungsten oxide crystal grain has a composition in which the sodium concentration is higher than the potassium concentration throughout the depth direction.

Description

酸化タングステン粉末tungsten oxide powder
　開示の実施形態は、酸化タングステン粉末に関する。 The disclosed embodiments relate to tungsten oxide powder.
　近年、金属または金属化合物のリサイクル技術の開発が進められている。たとえば、タングステンは、超硬合金やサーメットなどの超硬質合金を構成する成分であり、コバルト、ニオブなどとともに用いられ、切削工具などに多く使用されている。 In recent years, the development of recycling technology for metals or metal compounds has progressed. For example, tungsten is a component that constitutes cemented carbide and cemented carbide such as cermet, and is used together with cobalt, niobium, etc., and is widely used in cutting tools and the like.
　また、タングステンは、高融点であることから、発熱体、構造部材、石油化学工業用の触媒、環境機器、セラミック配線基板の配線、放熱部材などの種々の用途に用いられている。これらの資源を有効活用するため、廃材（スクラップ）からタングステンをリサイクルする方法が考案されている（特許文献１を参照）。 In addition, since tungsten has a high melting point, it is used in various applications such as heating elements, structural members, catalysts for the petrochemical industry, environmental equipment, wiring for ceramic wiring boards, and heat dissipation members. In order to effectively utilize these resources, a method of recycling tungsten from waste materials (scrap) has been devised (see Patent Document 1).
特開２００４－００２９２７号公報JP 2004-002927 A
　実施形態の一態様に係る酸化タングステン粉末は、酸化タングステン結晶粒を主成分とする粉体を含む。前記酸化タングステン結晶粒は、ナトリウム及びカリウムを含有する。また、前記酸化タングステン結晶粒は、深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高い構成である。 A tungsten oxide powder according to one aspect of the embodiment contains a powder containing tungsten oxide crystal grains as a main component. The tungsten oxide grains contain sodium and potassium. Further, the tungsten oxide crystal grains have a structure in which the sodium concentration is higher than the potassium concentration over the entire depth direction.
図１は、実施形態に係る酸化タングステン粉末および炭化タングステンの生成工程の手順の一例を示すフローチャートである。FIG. 1 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide according to an embodiment. 図２は、参考例における酸化タングステン粉末および炭化タングステンの生成工程の手順の一例を示すフローチャートである。FIG. 2 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide in a reference example. 図３は、実施形態に係る酸化タングステン粉末におけるナトリウムおよびカリウムの深さ方向分布を示す図である。FIG. 3 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder according to the embodiment. 図４は、参考例における酸化タングステン粉末におけるナトリウムおよびカリウムの深さ方向分布を示す図である。FIG. 4 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder in Reference Example.
　従来技術では、タングステンのリサイクル工程において、中間体である酸化タングステン粉末から、超硬合金の原料となる炭化タングステンを効率よく生成するという点でさらなる改善の余地があった。 With the conventional technology, there is room for further improvement in terms of efficiently producing tungsten carbide, which is a raw material for cemented carbide, from the intermediate tungsten oxide powder in the tungsten recycling process.
　そこで、上記の課題を解決し、炭化タングステンを効率よく生成することができる酸化タングステン粉末を提供することができる技術の実現が期待されている。 Therefore, it is expected to realize a technology that can solve the above problems and provide tungsten oxide powder that can efficiently produce tungsten carbide.
　以下、添付図面を参照して、本願の開示する酸化タングステン粉末の実施形態について説明する。なお、以下に示す実施形態によりこの発明が限定されるものではない。 Hereinafter, embodiments of the tungsten oxide powder disclosed in the present application will be described with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.
　実施形態に係る酸化タングステン粉末は、酸化タングステン結晶粒を主成分とする粉体を含む。たとえば、実施形態に係る酸化タングステン粉末は、酸化タングステン結晶粒および不可避不純物からなる粉体を含む。また、実施形態に係る酸化タングステン結晶粒は、酸化タングステンのみからなる構成ではなく、ナトリウム及びカリウムを含有している。 The tungsten oxide powder according to the embodiment contains powder containing tungsten oxide crystal grains as a main component. For example, the tungsten oxide powder according to the embodiment contains powder composed of tungsten oxide crystal grains and unavoidable impurities. Further, the tungsten oxide crystal grains according to the embodiment contain sodium and potassium instead of being composed of only tungsten oxide.
　そして、実施形態では、酸化タングステン粉末に含まれる酸化タングステン結晶粒が、深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高い構成である。 In the embodiment, the tungsten oxide crystal grains contained in the tungsten oxide powder have a structure in which the sodium concentration is higher than the potassium concentration throughout the depth direction.
　これにより、カリウム濃度がナトリウム濃度よりも高い場合と比べて、酸化タングステン粉末から炭化タングステンを生成する際の中間体である金属タングステンを生成する水素還元処理において、反応促進効果を高めることができる。その理由について以下に説明する。 As a result, compared to the case where the potassium concentration is higher than the sodium concentration, the reaction promoting effect can be enhanced in the hydrogen reduction treatment for producing metallic tungsten, which is an intermediate in producing tungsten carbide from tungsten oxide powder. The reason will be explained below.
　ナトリウムの融点は９８（℃）、沸点は８８３（℃）であり、カリウムの融点は６４（℃）、沸点は７５９（℃）である。また、酸化タングステン粉末を水素ガスで金属タングステンに還元する際の処理温度は、８００（℃）～９５０（℃）が一般的である。 The melting point of sodium is 98 (°C) and the boiling point is 883 (°C), and the melting point of potassium is 64 (°C) and the boiling point is 759 (°C). The treatment temperature for reducing tungsten oxide powder to metal tungsten with hydrogen gas is generally 800 (° C.) to 950 (° C.).
　上記のように酸化タングステン粉末を水素還元処理する際の温度は、８００（℃）～９５０（℃）であってナトリウムの沸点に近い温度である。一方、酸化タングステン粉末を水素還元処理する際、カリウムは沸点に達しているため、処理中に揮発が生じて消失が進行する。そのため、カリウムが揮発する際の気化熱の影響もあり、ナトリウムの沸点に近い温度でありながらもナトリウムの揮発が抑えられる。このような理由から、酸化タングステン粉末を水素還元処理する際、ナトリウムが溶融した状態で存在しやすい。 The temperature for the hydrogen reduction treatment of the tungsten oxide powder as described above is 800 (° C.) to 950 (° C.), which is close to the boiling point of sodium. On the other hand, when the tungsten oxide powder is subjected to the hydrogen reduction treatment, since potassium reaches the boiling point, it evaporates during the treatment and disappears. Therefore, due to the effect of heat of vaporization when potassium volatilizes, the volatilization of sodium is suppressed even though the temperature is close to the boiling point of sodium. For these reasons, sodium tends to exist in a molten state when the tungsten oxide powder is subjected to hydrogen reduction treatment.
　このナトリウムの溶融状態によって、実施形態では、隣接する粒子同士を接着させた状態で還元処理を進行させることができる。その結果、カリウムを含有せず、ナトリウムのみを含有する場合と比較して、より低いエネルギー（すなわち、低温・短時間）で金属タングステンの粒成長を達成することができる。 Due to this molten state of sodium, in the embodiment, the reduction treatment can proceed while adjoining particles are adhered to each other. As a result, grain growth of metallic tungsten can be achieved with lower energy (that is, at a lower temperature and in a shorter time) than in the case of containing only sodium without containing potassium.
　さらに、実施形態によれば、粉体におけるナトリウム濃度がカリウム濃度よりも高い。ナトリウム濃度が相対的に高いため、ナトリウムの溶融状態による、隣接する粒子同士を接着させる効果が高い。また、カリウム濃度が相対的に小さいものの０ではないことから、ナトリウムの溶融状態による、隣接する粒子同士を接着させる効果を高く確保しつつ、ナトリウムの揮発を抑える効果も同時に得られる。 Furthermore, according to the embodiment, the sodium concentration in the powder is higher than the potassium concentration. Since the sodium concentration is relatively high, the effect of adhering adjacent particles due to the molten state of sodium is high. In addition, since the potassium concentration is relatively small but not 0, the effect of suppressing the volatilization of sodium can be simultaneously obtained while ensuring a high effect of adhering adjacent particles due to the molten state of sodium.
　さらに、実施形態によれば、酸化タングステン結晶粒が深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高い構成である。このような場合、粉体の表面だけでなく中心にかけての粉体の全体において金属タングステンの生成が進みやすい。そのため、金属タングステンの生成効率が向上する。したがって、酸化タングステン粉末から炭化タングステンを効率よく生成することができる。 Furthermore, according to the embodiment, the tungsten oxide crystal grains are configured such that the sodium concentration is higher than the potassium concentration throughout the depth direction. In such a case, formation of metallic tungsten tends to proceed not only on the surface of the powder but also on the entire powder toward the center. Therefore, the production efficiency of metallic tungsten is improved. Therefore, tungsten carbide can be efficiently produced from tungsten oxide powder.
　また、実施形態では、酸化タングステン結晶粒の表面に、かかる酸化タングステン結晶粒の内部よりもナトリウム濃度の高い領域が形成されてもよい。これにより、上述した隣接する粒子同士を接着させた状態での還元処理をさらに促進できることから、さらに低いエネルギーで金属タングステンの粒成長を達成することができる。 Further, in the embodiment, a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain may be formed on the surface of the tungsten oxide crystal grain. As a result, the reduction treatment can be further accelerated while the adjacent particles are bonded to each other, and grain growth of metallic tungsten can be achieved with even lower energy.
　したがって、実施形態によれば、酸化タングステン粉末から炭化タングステンをさらに効率よく生成することができる。 Therefore, according to the embodiment, tungsten carbide can be more efficiently produced from tungsten oxide powder.
　また、実施形態では、酸化タングステン結晶粒の表面に形成されるナトリウム濃度の高い領域が、酸化タングステン結晶粒の表面から１００（ｎｍ）までの深さに存在してもよい。これにより、上述した隣接する粒子同士を接着させた状態での還元処理をさらに促進できることから、さらに低いエネルギーで金属タングステンの粒成長を達成することができる。 In addition, in the embodiment, the high sodium concentration region formed on the surface of the tungsten oxide crystal grain may exist at a depth of up to 100 (nm) from the surface of the tungsten oxide crystal grain. As a result, the reduction treatment can be further accelerated while the adjacent particles are bonded to each other, and grain growth of metallic tungsten can be achieved with even lower energy.
　したがって、実施形態によれば、酸化タングステン粉末から炭化タングステンをさらに効率よく生成することができる。 Therefore, according to the embodiment, tungsten carbide can be more efficiently produced from tungsten oxide powder.
　また、実施形態では、酸化タングステン結晶粒は、５（ｐｐｍ）～１００（ｐｐｍ）のナトリウム濃度を有していてもよく、２０（ｐｐｍ）～１００（ｐｐｍ）のナトリウム濃度を有していると好ましい。 Further, in the embodiment, the tungsten oxide crystal grains may have a sodium concentration of 5 (ppm) to 100 (ppm), and may have a sodium concentration of 20 (ppm) to 100 (ppm). preferable.
　これにより、上述した隣接する粒子同士を接着させた状態での還元処理をさらに促進できることから、さらに低いエネルギーで金属タングステンの粒成長を達成することができる。したがって、実施形態によれば、酸化タングステン粉末から炭化タングステンをさらに効率よく生成することができる。 As a result, the above-described reduction treatment can be further promoted while the adjacent particles are bonded to each other, so that grain growth of metallic tungsten can be achieved with even lower energy. Therefore, according to the embodiment, tungsten carbide can be more efficiently produced from tungsten oxide powder.
　なお、酸化タングステン結晶粒に含まれるナトリウムは、金属タングステンから炭化タングステンを生成する炭化処理において、１２００（℃）以上の高温に曝されることで分解して消失する。そのため、酸化タングステン結晶粒自体にナトリウムが含まれていても、炭化タングステンの品質に特に問題は無い。 It should be noted that the sodium contained in the tungsten oxide crystal grains decomposes and disappears when exposed to a high temperature of 1200 (°C) or higher in the carbonization process that produces tungsten carbide from metallic tungsten. Therefore, even if tungsten oxide crystal grains themselves contain sodium, there is no particular problem with the quality of tungsten carbide.
　さらに、実施形態では、酸化タングステン結晶粒の表面に、かかる酸化タングステン結晶粒の内部よりもナトリウム濃度の高い領域が形成されることで、炭化処理におけるナトリウムの分解・消失を容易にすることができる。したがって、実施形態によれば、高品質の炭化タングステンを生成することができる。 Furthermore, in the embodiment, a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain is formed on the surface of the tungsten oxide crystal grain, thereby facilitating the decomposition and disappearance of sodium in the carbonization process. . Therefore, according to embodiments, high quality tungsten carbide can be produced.
　以下、本開示の実施例を具体的に説明する。図１は、実施形態に係る酸化タングステン粉末および炭化タングステンの生成工程の手順の一例を示すフローチャートである。図１に示すように、実施形態に係る酸化タングステン粉末および炭化タングステンの生成工程では、まず、超硬合金のスクラップを準備した。 Examples of the present disclosure will be specifically described below. FIG. 1 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide according to an embodiment. As shown in FIG. 1, in the step of producing tungsten oxide powder and tungsten carbide according to the embodiment, first, cemented carbide scrap was prepared.
　超硬質合金の一種である超硬合金は、金属タングステンや炭化タングステンなどの複合炭化物を主体とし、鉄、ニッケル、コバルトなどを結合相とし、必要に応じて添加物成分としてＴｉＣ、ＴａＣ、ＮｂＣ、ＶＣ、Ｃｒ３Ｃ２などを含む。また、実施例におけるスクラップは、これらの添加物成分に加えて、さらにナトリウム及びカリウムを含有している。 Cemented carbide, which is a kind of cemented carbide, is mainly composed of composite carbides such as metal tungsten and tungsten carbide, and has iron, nickel, cobalt, etc. as a binding phase, and if necessary, as additive components TiC, TaC, NbC, VC, Cr 3 C 2 and the like. Moreover, the scrap in the examples further contains sodium and potassium in addition to these additive components.
　対象となる超硬合金を含んだ被処理材は、たとえば、切削工具（切削インサート、ドリル、エンドミル等）、金型（成形ロール、成形型等）、土木鉱山用工具（石油掘削用工具、岩石粉砕用工具等）などである。 Materials to be treated containing cemented carbide are, for example, cutting tools (cutting inserts, drills, end mills, etc.), molds (forming rolls, molds, etc.), civil engineering and mining tools (oil drilling tools, rock crushing tools, etc.).
　次に、準備された超硬合金スクラップを酸化焙焼し、酸化タングステン（ＷＯ３）およびタングステン酸コバルト（ＣｏＷＯ４）の混合体を得た。なお、超硬合金スクラップが含有するナトリウム及びカリウムの量が少ない場合、混合体を得る際に、ナトリウム及びカリウムを追加してもよい。そして、得られた混合体に対して水酸化ナトリウム（ＮａＯＨ）水溶液で還流後、抽出することで、タングステン酸ナトリウム（Ｎａ２ＷＯ４）を含有するタングステン化合物溶液を得た。 The prepared cemented carbide scrap was then oxidatively roasted to obtain a mixture of tungsten oxide (WO 3 ) and cobalt tungstate (CoWO 4 ). If the amount of sodium and potassium contained in the cemented carbide scrap is small, sodium and potassium may be added when obtaining the mixture. Then, the resulting mixture was refluxed with an aqueous sodium hydroxide (NaOH) solution and then extracted to obtain a tungsten compound solution containing sodium tungstate (Na 2 WO 4 ).
　次に、得られたタングステン化合物溶液にリジン（Lysine）を含む吸着剤を添加して、タングステン化合物イオンをリジンに吸着させた（図ではリジン－ＷＯ４と記載）。 Next, an adsorbent containing lysine was added to the obtained tungsten compound solution to adsorb tungsten compound ions to lysine (denoted as lysine-WO 4 in the figure).
　なお、本開示における吸着剤は、リジンを含む場合に限られず、アラニン（Alanine）、シスチン（Cystine）、メチオニン（Methionine）、チロシン（Tyrosine）、バリン（Valine）、グルタミン酸（Glutamic　acid）、ヒスチジン（Histidine）、プロリン（Proline）、トレオニン（Threonine）、アスパラギン（Asparagine）、グリシン（Glycine）、イソロイシン（Isoleucine）、オルニチン（Ornithine）、アルギニン（Arginine）、セリン（Serine）、シトルリン（Citrulline）およびシスタチオニン（Cystathionine）のうちの少なくとも一種の第１アミノ酸を含んでいてもよい。 Note that the adsorbent in the present disclosure is not limited to containing lysine, Alanine, Cystine, Methionine, Tyrosine, Valine, Glutamic acid, Histidine ( Histidine, Proline, Threonine, Asparagine, Glycine, Isoleucine, Ornithine, Arginine, Serine, Citrulline and Cystathionine ( Cystathionine).
　かかる吸着処理では、たとえば、吸着剤中の第１アミノ酸の塩の合計添加量が、タングステン化合物の金属成分１（ｍｏｌ）に対して、０．２（ｍｏｌ）～１．１（ｍｏｌ）の含有比率で添加する。これによって、少量の吸着剤で多量のタングステン化合物を吸着させることができる。 In such adsorption treatment, for example, the total addition amount of the salt of the first amino acid in the adsorbent is 0.2 (mol) to 1.1 (mol) with respect to 1 (mol) of the metal component of the tungsten compound. Add in proportion. As a result, a large amount of tungsten compound can be adsorbed with a small amount of adsorbent.
　また、第１アミノ酸の塩の合計添加量は、たとえば、タングステン化合物溶液に対して、１０（ｇ／ｌ）～３００（ｇ／ｌ）である。これによって、溶液の粘性が高くならず、金属化合物の回収効率が低下しにくくなる。特に、吸着剤がアミノ酸の塩からなる場合、溶液の粘性が上がりにくく、作業性がよい。 Also, the total added amount of the salt of the first amino acid is, for example, 10 (g/l) to 300 (g/l) with respect to the tungsten compound solution. As a result, the viscosity of the solution does not increase, and the recovery efficiency of the metal compound is less likely to decrease. In particular, when the adsorbent consists of an amino acid salt, the viscosity of the solution is less likely to increase, resulting in good workability.
　温度は遊離アミノ酸の活性に応じて調整すればよく、通常は室温で構わない。吸着剤を添加したタングステン化合物溶液を、塩酸などを用いて遊離アミノ酸のゼータ電位が正となるように調整してもよい。これによって、吸着剤にアニオンであるタングステン化合物イオンを吸着させることができる。 The temperature may be adjusted according to the activity of free amino acids, and usually room temperature is fine. The tungsten compound solution to which the adsorbent has been added may be adjusted using hydrochloric acid or the like so that the zeta potential of free amino acids is positive. This allows the adsorbent to adsorb tungsten compound ions, which are anions.
　また、溶液のｐＨは７未満（酸性）であってもよい。遊離アミノ酸がリジンおよびアルギニンの場合、好適なｐＨは４以下、好ましくは０．５～３、望ましくはｐＨ＝０．８～２．３である。遊離アミノ酸がグルタミン酸の場合、好適なｐＨは１．５以下である。 Also, the pH of the solution may be less than 7 (acidic). When the free amino acids are lysine and arginine, a suitable pH is 4 or less, preferably 0.5-3, desirably pH=0.8-2.3. When the free amino acid is glutamic acid, the preferred pH is 1.5 or less.
　カリウムはナトリウムよりもイオン化傾向が高い。そのため、溶液が酸性である場合には、ナトリウムよりもカリウムがイオン化しやすい。すなわち、ナトリウムが相対的にイオン化しにくく、後述する吸着剤の洗浄工程において除去されにくい。限定されない一例であるが、上記の理由によって、粉体におけるナトリウム濃度をカリウム濃度よりも高めることが可能である。 Potassium has a higher tendency to ionize than sodium. Therefore, when the solution is acidic, potassium is easier to ionize than sodium. That is, sodium is relatively difficult to ionize and is difficult to be removed in the step of washing the adsorbent, which will be described later. As a non-limiting example, the sodium concentration in the powder can be higher than the potassium concentration for the reasons described above.
　上記した工程によって、タングステン化合物の回収率を高めることができる。なお、溶液のｐＨを調整する工程と、金属化合物が含有される溶液中に吸着剤を添加する工程とは、どちらが先でもよい。 The recovery rate of the tungsten compound can be increased by the above steps. Either the step of adjusting the pH of the solution or the step of adding the adsorbent to the solution containing the metal compound may be performed first.
　なお、上記のような酸性の溶液を用いる工程の他にも、例えば、混合体を得る際に追加するナトリウム及びカリウムの量を調整することによって、粉体におけるナトリウム濃度をカリウム濃度よりも高めることが可能である。 In addition to the step of using an acidic solution as described above, for example, by adjusting the amounts of sodium and potassium added when obtaining the mixture, the sodium concentration in the powder can be made higher than the potassium concentration. is possible.
　吸着剤が第１アミノ酸の塩である場合、吸着反応は１時間以内であるほうが、吸着剤の回収効率が高い。すなわち、吸着反応が１時間を越えると、吸着していた金属化合物の一部が遊離アミノ酸から脱離することがある。 When the adsorbent is a salt of the first amino acid, the recovery efficiency of the adsorbent is higher if the adsorption reaction is within 1 hour. That is, when the adsorption reaction exceeds 1 hour, part of the adsorbed metal compound may be desorbed from the free amino acid.
　リジンへの吸着工程につづいて、タングステン化合物イオンが吸着した吸着剤を、遠心分離等の手段により脱水した。そして、必要に応じて、酸洗浄と純水洗浄の順に吸着剤を洗浄する。酸洗浄の代わりに４０（℃）以上の温水で洗浄してもよい。そして洗浄ろ液の電気伝導度が５００（μＳ／ｍ）以下になるまで純水洗浄をするなどして不純物を除去した。これによって、タングステン化合物を高品位化し、回収することができる。 Following the adsorption step to lysine, the adsorbent with the tungsten compound ions adsorbed was dehydrated by centrifugation or other means. Then, if necessary, the adsorbent is washed in the order of acid washing and pure water washing. Instead of acid cleaning, hot water of 40 (° C.) or more may be used for cleaning. Impurities were removed by washing with pure water until the electric conductivity of the washing filtrate became 500 (μS/m) or less. As a result, the tungsten compound can be highly graded and recovered.
　次に、タングステン化合物イオンが吸着した吸着剤を、たとえば大気中で３００（℃）以上の温度で焼却してタングステン化合物を酸化するとともに、吸着剤を含む有機物成分を除去した。これにより、実施形態に係る酸化タングステン粉末（ＷＯ３）が得られた。 Next, the adsorbent with the tungsten compound ions adsorbed thereon was incinerated, for example, at a temperature of 300 (° C.) or higher in the atmosphere to oxidize the tungsten compound and remove organic components including the adsorbent. As a result, a tungsten oxide powder (WO 3 ) according to the embodiment was obtained.
　なお、図１に示すように、得られた酸化タングステン粉末を、還元雰囲気（たとえば、水素ガス雰囲気）にて８００（℃）～９５０（℃）の温度で熱処理し、酸化タングステン化合物を還元する。これにより、金属タングステン（Ｗ）を得ることができる。そして、得られた金属タングステンを炭化することで、超硬合金の原料となる炭化タングステン（ＷＣ）を得ることができる。 Note that, as shown in FIG. 1, the obtained tungsten oxide powder is heat-treated at a temperature of 800 (° C.) to 950 (° C.) in a reducing atmosphere (eg, hydrogen gas atmosphere) to reduce the tungsten oxide compound. Thereby, metallic tungsten (W) can be obtained. By carbonizing the obtained metal tungsten, it is possible to obtain tungsten carbide (WC) as a raw material of cemented carbide.
　図２は、参考例における酸化タングステン粉末および炭化タングステンの生成工程の手順の一例を示すフローチャートである。図２に示すように、参考例における酸化タングステン粉末および炭化タングステンの生成工程では、まず、超硬合金のスクラップを準備した。また、参考例におけるスクラップも、実施例におけるスクラップと同様に、ナトリウム及びカリウムを含有している。 FIG. 2 is a flow chart showing an example of a procedure for producing tungsten oxide powder and tungsten carbide in a reference example. As shown in FIG. 2, in the step of producing tungsten oxide powder and tungsten carbide in the reference example, first, cemented carbide scrap was prepared. Moreover, the scrap in the reference example also contains sodium and potassium, like the scrap in the example.
　次に、準備された超硬合金スクラップを酸化焙焼し、酸化タングステン（ＷＯ３）およびタングステン酸コバルト（ＣｏＷＯ４）の混合体を得た。そして、得られた混合体に対して水酸化ナトリウム（ＮａＯＨ）水溶液で抽出することで、タングステン酸ナトリウム（Ｎａ２ＷＯ４）を含有するタングステン化合物溶液を得た。ここまでの各工程は上述の実施形態と同様であるため、詳細な説明は省略する。 The prepared cemented carbide scrap was then oxidatively roasted to obtain a mixture of tungsten oxide (WO 3 ) and cobalt tungstate (CoWO 4 ). A tungsten compound solution containing sodium tungstate (Na 2 WO 4 ) was obtained by extracting the resulting mixture with an aqueous sodium hydroxide (NaOH) solution. Since each process up to this point is the same as the above-described embodiment, detailed description thereof is omitted.
　次に、得られたタングステン化合物溶液をイオン交換樹脂などでイオン交換し、タングステン酸アンモニウム（（ＮＨ４）２ＷＯ４）の水溶液を生成した。そして、得られた水溶液を加熱濃縮することで、タングステン化合物をパラタングステン酸アンモニウム（ＡＰＴ）として晶析させた。このとき、比較例で用いられたタングステン酸アンモニウムの水溶液が酸性溶液ではないことから、ＡＰＴを晶析する工程において、多くのナトリウムが除去され、ナトリウムに対するカリウムの含有比率が高まりやすい。 Next, the resulting tungsten compound solution was ion-exchanged with an ion exchange resin or the like to produce an aqueous solution of ammonium tungstate ((NH 4 ) 2 WO 4 ). Then, the resulting aqueous solution was heated and concentrated to crystallize the tungsten compound as ammonium paratungstate (APT). At this time, since the aqueous solution of ammonium tungstate used in the comparative example is not an acidic solution, a large amount of sodium is removed in the step of crystallizing APT, and the content ratio of potassium to sodium tends to increase.
　次に、得られたＡＰＴを熱分解することでＡＰＴを酸化し、参考例の酸化タングステン粉末（ＷＯ３）が得られた。 Next, the obtained APT was thermally decomposed to oxidize the APT, and a tungsten oxide powder (WO 3 ) of Reference Example was obtained.
　なお、図２に示すように、得られた酸化タングステン粉末を還元雰囲気で熱処理し、酸化タングステン化合物を還元することで、金属タングステン（Ｗ）を得ることができる。そして、得られた金属タングステンを炭化することで、超硬合金の原料となる炭化タングステン（ＷＣ）を得ることができる。 As shown in FIG. 2, metal tungsten (W) can be obtained by heat-treating the obtained tungsten oxide powder in a reducing atmosphere to reduce the tungsten oxide compound. By carbonizing the obtained metal tungsten, it is possible to obtain tungsten carbide (WC) as a raw material of cemented carbide.
　次に、得られた実施形態および参考例の酸化タングステン粉末に対して、ＴｏＦ－ＳＩＭＳ（Time-of-Flight　Secondary　Ion　Mass　Spectrometry：飛行時間型二次イオン質量分析法）による分析を行った。具体的には、ＴｏＦ－ＳＩＭＳによって、実施形態および参考例の酸化タングステン粉末におけるナトリウムおよびカリウムの深さ方向分布を測定した。 Next, the obtained tungsten oxide powders of the embodiment and reference example were analyzed by ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry). Specifically, the depth distribution of sodium and potassium in the tungsten oxide powders of the embodiment and reference example was measured by ToF-SIMS.
　ＴｏＦ－ＳＩＭＳの測定条件は以下の通りである。実施形態および参考例の酸化タングステン粉末を固定し、粉末表面を１００（μｍ）角にて測定した。なお測定装置はＩＯＮ－ＴＯＦ社のＴＯＦ．ＳＩＭＳ５を用い、１次イオン源にＢｉ（ビスマス）を選定し、深さ方向の元素分析について測定した。 The measurement conditions for ToF-SIMS are as follows. The tungsten oxide powders of the embodiment and reference example were fixed, and the powder surface was measured at 100 (μm) square. The measuring device is TOF. SIMS5 was used, Bi (bismuth) was selected as the primary ion source, and elemental analysis in the depth direction was measured.
　図３は、実施形態に係る酸化タングステン粉末におけるナトリウムおよびカリウムの深さ方向分布を示す図である。また、図４は、参考例における酸化タングステン粉末におけるナトリウムおよびカリウムの深さ方向分布を示す図である。 FIG. 3 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder according to the embodiment. Moreover, FIG. 4 is a diagram showing the depth direction distribution of sodium and potassium in the tungsten oxide powder in the reference example.
　図３に示すように、実施形態に係る酸化タングステン粉末に含まれる酸化タングステン結晶粒では、深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高いことがわかる。 As shown in FIG. 3, in the tungsten oxide crystal grains contained in the tungsten oxide powder according to the embodiment, it can be seen that the sodium concentration is higher than the potassium concentration throughout the depth direction.
　なお、実施形態に係る酸化タングステン粉末に含まれる酸化タングステン結晶粒は、粒径が数十～数百（ｎｍ）程度の構成であった。そのため、図３に示すように深さ方向分布を５００（ｎｍ）まで測定することで、深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高いと推定することができる。 It should be noted that the tungsten oxide crystal grains contained in the tungsten oxide powder according to the embodiment had a particle size of about several tens to several hundred (nm). Therefore, by measuring the depth distribution up to 500 (nm) as shown in FIG. 3, it can be estimated that the sodium concentration is higher than the potassium concentration throughout the depth direction.
　一方で、図４に示すように、参考例の酸化タングステン粉末に含まれる酸化タングステン結晶粒では、深さ方向の全体にわたりカリウム濃度がナトリウム濃度よりも高いことがわかる。 On the other hand, as shown in FIG. 4, in the tungsten oxide crystal grains contained in the tungsten oxide powder of the reference example, it can be seen that the potassium concentration is higher than the sodium concentration throughout the depth direction.
　このように、実施形態では、参考例と異なり、深さ方向の全体にわたりナトリウム濃度をカリウム濃度よりも高くすることで、上述したように、酸化タングステン粉末から炭化タングステンを効率よく生成することができる。具体的には、処理温度を５％～１０％程度低下させることができ、これによって、５％～２０％程度、製造時に必要なエネルギーを抑制できる。 Thus, unlike the reference example, in the embodiment, by making the sodium concentration higher than the potassium concentration throughout the depth direction, tungsten carbide can be efficiently produced from the tungsten oxide powder as described above. . Specifically, the processing temperature can be lowered by about 5% to 10%, thereby reducing the energy required during manufacturing by about 5% to 20%.
　また、図３に示すように、実施形態では、酸化タングステン結晶粒の表面に、酸化タングステン結晶粒の内部よりもナトリウム濃度の高い領域が、表面から１００（ｎｍ）程度までの深さに形成されていることがわかる。 Further, as shown in FIG. 3, in the embodiment, a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain is formed on the surface of the tungsten oxide crystal grain to a depth of about 100 (nm) from the surface. It can be seen that
　これにより、実施形態では、酸化タングステン粉末から炭化タングステンをさらに効率よく生成することができる。 Thereby, in the embodiment, tungsten carbide can be more efficiently produced from tungsten oxide powder.
　また、得られた実施形態に係る酸化タングステン粉末のナトリウム含有量をＩＣＰ（Inductively　Coupled　Plasma）発光分光分析装置によって評価した。その結果、実施形態に係る酸化タングステン粉末に含まれる酸化タングステン結晶粒は、５（ｐｐｍ）～１００（ｐｐｍ）のナトリウムを有することがわかった。 In addition, the sodium content of the obtained tungsten oxide powder according to the embodiment was evaluated by an ICP (Inductively Coupled Plasma) emission spectrometer. As a result, it was found that the tungsten oxide crystal grains contained in the tungsten oxide powder according to the embodiment had 5 (ppm) to 100 (ppm) of sodium.
　これにより、実施形態では、上述したように、酸化タングステン粉末から炭化タングステンをさらに効率よく生成することができる。 Thereby, in the embodiment, as described above, tungsten carbide can be more efficiently produced from tungsten oxide powder.
　以上、本発明の実施形態について説明したが、本発明は上記実施形態に限定されるものではなく、その趣旨を逸脱しない限りにおいて種々の変更が可能である。たとえば、上記の実施形態では、超硬合金のスクラップから酸化タングステン粉末および炭化タングステンを生成（リサイクル）する場合について示しているが、本開示はかかる例に限られず、鉱石から酸化タングステン粉末および炭化タングステンを生成する際などにも適用することができる。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, the above embodiment shows the case of producing (recycling) tungsten oxide powder and tungsten carbide from cemented carbide scrap, but the present disclosure is not limited to such examples, and tungsten oxide powder and tungsten carbide are produced from ore. It can also be applied when generating
　さらなる効果や他の態様は、当業者によって容易に導き出すことができる。このため、本発明のより広範な態様は、以上のように表しかつ記述した特定の詳細および代表的な実施形態に限定されるものではない。したがって、添付の請求の範囲およびその均等物によって定義される総括的な発明の概念の精神または範囲から逸脱することなく、様々な変更が可能である。 Further effects and other aspects can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments so shown and described. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

Claims (4)

  1. 　酸化タングステン結晶粒を主成分とする粉体を含み、
    　前記酸化タングステン結晶粒は、ナトリウム及びカリウムを含有し、
    　前記酸化タングステン結晶粒は、深さ方向の全体にわたりナトリウム濃度がカリウム濃度よりも高い構成である
    　酸化タングステン粉末。     Containing powder mainly composed of tungsten oxide crystal grains,
    The tungsten oxide crystal grains contain sodium and potassium,
    Tungsten oxide powder, wherein the tungsten oxide crystal grains have a sodium concentration higher than a potassium concentration throughout the depth direction.
  2. 　前記酸化タングステン結晶粒の表面には、前記酸化タングステン結晶粒の内部よりもナトリウム濃度の高い領域が形成される
    　請求項１に記載の酸化タングステン粉末。     2. The tungsten oxide powder according to claim 1, wherein a region having a higher sodium concentration than the inside of the tungsten oxide crystal grain is formed on the surface of the tungsten oxide crystal grain.
  3. 　前記ナトリウム濃度の高い領域は、前記酸化タングステン結晶粒の表面から１００（ｎｍ）までの深さに存在する
    　請求項２に記載の酸化タングステン粉末。     The tungsten oxide powder according to claim 2, wherein the high sodium concentration region exists at a depth of up to 100 (nm) from the surface of the tungsten oxide crystal grain.
  4. 　前記酸化タングステン結晶粒は、５（ｐｐｍ）～１００（ｐｐｍ）のナトリウムを有する
    　請求項１～３のいずれか一つに記載の酸化タングステン粉末。     The tungsten oxide powder according to any one of claims 1 to 3, wherein the tungsten oxide crystal grains have sodium of 5 (ppm) to 100 (ppm).
PCT/JP2023/001031 2022-01-28 2023-01-16 Tungsten oxide powder WO2023145520A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022-012445 2022-01-28
JP2022012445 2022-01-28

Publications (1)

Publication Number Publication Date
WO2023145520A1 true WO2023145520A1 (en) 2023-08-03

Family

ID=87471400

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/001031 WO2023145520A1 (en) 2022-01-28 2023-01-16 Tungsten oxide powder

Country Status (1)

Country Link
WO (1) WO2023145520A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402737A (en) * 1982-09-01 1983-09-06 Gte Products Corporation Method of producing tungsten and tungsten carbide powder
JP2004508461A (en) * 2000-09-06 2004-03-18 ハー　ツェー　シュタルク　ゲゼルシャフト　ミット　ベシュレンクテル　ハフツング Ultra-coarse single crystal tungsten carbide, method for producing the same and hard alloy produced therefrom
CN108046326A (en) * 2017-12-07 2018-05-18 崇义章源钨业股份有限公司 The method for preparing ammonium paratungstate
JP2018119197A (en) * 2017-01-27 2018-08-02 京セラ株式会社 Method of recovering tungsten compound
CN108529628A (en) * 2018-05-28 2018-09-14 株洲硬质合金集团有限公司 A kind of preparation method of Coarse Tungsten Carbide Powder
CN111940753A (en) * 2020-08-27 2020-11-17 崇义章源钨业股份有限公司 System and method for preparing ultra-coarse tungsten powder
CN114436263A (en) * 2022-02-14 2022-05-06 崇义章源钨业股份有限公司 Preparation method of ultra-coarse uniform tungsten carbide powder

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4402737A (en) * 1982-09-01 1983-09-06 Gte Products Corporation Method of producing tungsten and tungsten carbide powder
JP2004508461A (en) * 2000-09-06 2004-03-18 ハー　ツェー　シュタルク　ゲゼルシャフト　ミット　ベシュレンクテル　ハフツング Ultra-coarse single crystal tungsten carbide, method for producing the same and hard alloy produced therefrom
JP2018119197A (en) * 2017-01-27 2018-08-02 京セラ株式会社 Method of recovering tungsten compound
CN108046326A (en) * 2017-12-07 2018-05-18 崇义章源钨业股份有限公司 The method for preparing ammonium paratungstate
CN108529628A (en) * 2018-05-28 2018-09-14 株洲硬质合金集团有限公司 A kind of preparation method of Coarse Tungsten Carbide Powder
CN111940753A (en) * 2020-08-27 2020-11-17 崇义章源钨业股份有限公司 System and method for preparing ultra-coarse tungsten powder
CN114436263A (en) * 2022-02-14 2022-05-06 崇义章源钨业股份有限公司 Preparation method of ultra-coarse uniform tungsten carbide powder

Similar Documents

Publication Publication Date Title
CA3097307C (en) A method for the manufacture of graphene oxide and reduced graphene oxide from kish graphite
JP5344154B2 (en) Tungsten recovery process
EP2450312A1 (en) Recovery of tungsten from waste material by ammonium leaching
TWI411581B (en) Method for recovering ruthenium from waste containing ruthenium
JP2009518544A (en) Thermal and electrochemical treatment for metal production
JP2007323868A (en) Method of recovering electrode-constituting metal from lithium battery
JP2007046090A (en) Method for producing ruthenium powder
CN108044126B (en) Method for preparing plate-shaped WC-Co composite powder by using waste hard alloy
CA3099834C (en) A method for the manufacture of graphene oxide from electrode graphite scrap
Jain et al. Characterization of electrodeposited elemental boron
US20150210616A1 (en) Preparation method for edge-fluorinated graphite via mechanic-chemical process
WO2023145520A1 (en) Tungsten oxide powder
KR20160101297A (en) Tungsten Trioxide Fine Particle and Preparation Method Thereof
KR102529356B1 (en) Method for producing reduced graphene oxide from electrode graphite scrap
JP2011063486A (en) Method for producing high-purity metal boride particle, and high-purity metal boride particle obtained by the method
JP5223085B2 (en) Separation and purification of rare metals by chloride volatilization method
KR101779348B1 (en) Recovering method of valuable metal from used denitration catalyst, manufacturing method of aluminum alloy and aluminum alloy manufactured thereby
WO2024005017A1 (en) Tungsten carbide powder
WO2024005036A1 (en) Tungsten carbide powder
WO2024005100A1 (en) Tungsten carbide powder
EP3793942A1 (en) A method for the manufacture of graphene oxide from kish graphite
WO2023145521A1 (en) Tungsten oxide powder
JP5388721B2 (en) How to recycle cemented carbide
Yao et al. Preparation of ZnO Nanoparticles from Zn-containing Rotary Hearth Furnace Dust
KR101938280B1 (en) Recycling method of tungsten scrap having metal coating layer

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23746734

Country of ref document: EP

Kind code of ref document: A1