WO2022113669A1 - Procédé de production de sel de métal alcalin d'acide tungstique, procédé de production de tungstène, et composition contenant un sel de métal alcalin d'acide tungstique - Google Patents

Procédé de production de sel de métal alcalin d'acide tungstique, procédé de production de tungstène, et composition contenant un sel de métal alcalin d'acide tungstique Download PDF

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WO2022113669A1
WO2022113669A1 PCT/JP2021/040440 JP2021040440W WO2022113669A1 WO 2022113669 A1 WO2022113669 A1 WO 2022113669A1 JP 2021040440 W JP2021040440 W JP 2021040440W WO 2022113669 A1 WO2022113669 A1 WO 2022113669A1
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alkali metal
tungsten
tungstic acid
metal salt
producing
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PCT/JP2021/040440
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English (en)
Japanese (ja)
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幸司 安田
滉平 鈴木
理加 萩原
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国立大学法人京都大学
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Publication of WO2022113669A1 publication Critical patent/WO2022113669A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/70—Chemical treatment, e.g. pH adjustment or oxidation
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G41/00—Compounds of tungsten
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • 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
    • C22B34/36—Obtaining tungsten
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/12—Dry methods smelting of sulfides or formation of mattes by gases
    • C22B5/14—Dry methods smelting of sulfides or formation of mattes by gases fluidised material

Definitions

  • the present invention relates to a method for producing an alkali metal salt of tungstic acid, a method for producing tungsten, and a composition containing an alkali metal salt of tungstic acid.
  • Tungsten is a metal with features such as high hardness, high heat resistance, high wear resistance, and high melting point, and is used in a wide range of industrial fields.
  • Cemented carbide tools which account for 80% of the domestic demand for tungsten, are typically made of a composite material in which 90 wt% tungsten carbide (WC) particles are bound with 8 wt% metallic cobalt. The remaining 2 wt% is an additive such as tantalum.
  • the molten nitrate method is known as one of the prior arts for recycling tungsten carbide.
  • scrap of a super hard tool is oxidatively dissolved by the oxidizing power of nitrate to obtain Na 2 WO 4 .
  • Further treatment of Na 2 WO 4 is obtained to obtain metallic tungsten (Patent Document 1).
  • the oxide is dissolved in the molten salt, so that the growth of the oxide on the surface of the WC does not stop and the treatment can be continuously proceeded.
  • the molten nitrate method has an advantage that hard scrap can be processed because the oxidative dissolution reaction proceeds at a high speed. On the other hand, it is difficult to treat powdered soft scrap having a large surface area by the molten nitrate method because of the possibility of explosion due to a huge exothermic reaction. In addition, since the reaction vessel is severely corroded, it is necessary to use an expensive material having corrosion resistance for the reaction vessel. Further, the molten nitrate method has a problem that toxic nitrogen oxides (NO x ) are generated as exhaust gas.
  • NO x toxic nitrogen oxides
  • Non-Patent Document 1 a method of using a molten carbonate instead of the molten nitrate has been proposed.
  • the molten carbonate method has advantages such as being able to process both hard scrap and soft scrap, no NO x being generated, and no possibility of explosion.
  • the aqueous solution becomes weakly alkaline in the dissolution treatment of the product in water, it is also an advantage that the separability between tungsten and other components is good.
  • the conventional molten carbonate method has a problem that the reaction rate of the oxidative dissolution reaction is not sufficient and the efficiency is poor. Possible causes are insufficient oxidizing power of the molten carbonate and low solubility of oxygen ion species (peroxide ion and superoxide ion) in the molten carbonate.
  • An object of the present invention is to provide a technique for recovering tungsten safely and efficiently.
  • the present invention Includes contacting a tungsten-containing material with a molten carbonate containing a metal ion that acts as an oxidant to the alkali metal carbonate and tungsten.
  • a method for producing an alkali metal salt of tungstic acid is provided.
  • the invention is: The method for producing an alkali metal salt of tungstic acid of the present invention is included. Provided is a method for producing tungsten.
  • the invention is: The method for producing an alkali metal salt of tungstic acid of the present invention is included. A method for producing ammonium paratungstate is provided.
  • the invention is: Alkali metal carbonate and Alkali metal salt of tungstic acid and Reduction products of metal ions that act as an oxidant for tungsten, Provided is a composition comprising an alkali metal salt of tungstic acid.
  • the invention is: Contains tungsten and cobalt, The ratio of the cobalt concentration to the tungsten concentration is 0.5% or less.
  • alkali metal salts of tungstic acid are provided.
  • the invention is: Contains tungsten and cobalt, The ratio of the cobalt concentration to the tungsten concentration is 0.5% or less. Provide ammonium paratungstate.
  • tungsten can be recovered safely and efficiently.
  • FIG. 1 is a process diagram of a method for recovering tungsten according to an embodiment of the present invention.
  • FIG. 2A is a schematic diagram of the process of step S1 of FIG.
  • FIG. 2B is a diagram showing a reaction in which an oxygen ion species oxidizes tungsten.
  • FIG. 2C is a diagram showing a reaction in which carbonate ions oxidize tungsten.
  • FIG. 3 is a schematic cross-sectional view of the reactor used in the examples.
  • FIG. 4 is an optical photograph of the cemented carbide chip of Example 1 after the reaction.
  • FIG. 5 shows the XRD pattern of the cemented carbide chip of Example 1 after the reaction.
  • FIG. 6A is an optical photograph of the cemented carbide chip of Example 3 after the reaction.
  • FIG. 6B is an optical photograph of the cemented carbide chip of Example 4 after the reaction.
  • FIG. 7A shows the XRD pattern of the carbide chip of Example 3 after the reaction.
  • FIG. 7B shows the XRD pattern of the carbide chip of Example 4 after the reaction.
  • FIG. 8 is an optical photograph of the crucibles of Examples 9, 10, 11 and 12 after the reaction.
  • FIG. 1 is a process diagram of a method for recovering tungsten according to an embodiment of the present invention.
  • the step of step S1 is a step of oxidizing and dissolving the tungsten-containing material in the molten carbonate.
  • the step of step S1 is a step of bringing the molten carbonate into contact with the tungsten-containing material.
  • the carbonate is an alkali metal carbonate.
  • FIG. 2A is a schematic diagram of the process of step S1 of FIG.
  • the necessary materials are put into the container 28.
  • the required materials are alkali metal carbonate, metal ion source and tungsten-containing material 24.
  • heating the container 28 with the heater 18 produces molten carbonate 22.
  • the molten carbonate 22 contains a metal ion derived from a metal ion source and an alkali metal carbonate.
  • the tungsten-containing material 24 is contained in the container 28 so that the tungsten-containing material 24 is in contact with the molten carbonate 22.
  • a metal ion source may be added to the container 28.
  • the tungsten-containing material 24 may be added to the container 28.
  • the tungsten contained in the tungsten-containing material 24 can be efficiently oxidized. Can be done.
  • the oxidized tungsten dissolves in the molten carbonate 22 in the form of tungstic acid ions.
  • the oxidative dissolution reaction proceeds rapidly, but is not explosive. Therefore, powdered tungsten-containing materials can also be processed. Since no toxic exhaust gas is generated, the equipment cost is low and the environment is not polluted. High corrosion resistance is not required for the container 28, and various materials can be used as the material for the container 28.
  • the alkali metal carbonate comprises at least one selected from the group consisting of Na 2 CO 3 , Li 2 CO 3 and K 2 CO 3 .
  • Na 2 CO 3 and K 2 CO 3 are recommended due to their low cost.
  • the melting point of Na 2 CO 3 is 851 ° C.
  • the eutectic point of the Na 2 CO 3 ⁇ Li 2 CO 3 system is 497 ° C.
  • the eutectic point of the Na 2 CO 3 -K 2 CO 3 system is 702 ° C.
  • the eutectic point of the K 2 CO 3 ⁇ Li 2 CO 3 system is 488 ° C.
  • the eutectic point of the Na 2 CO 3 -Li 2 CO 3 -K 2 CO 3 system is 390 ° C.
  • the melting point of the alkali metal carbonate is lowered, and tungsten can be recovered at a lower temperature, which is advantageous in terms of energy consumption.
  • Alkali metal carbonate may be used properly according to the type of the metal ion source.
  • the metal ion source supplies metal ions that act as an oxidizing agent to tungsten by dissolving in a melt of an alkali metal carbonate. Specifically, the metal ion source acts as an oxidant for the tungsten component contained in the tungsten-containing material 24.
  • the metal ion derived from the metal ion source includes not only the metal ion (cation) represented by M n + but also the metal oxo anion represented by MO a b- (a, b, n are positive integers). ).
  • the metals contained in the metal ion source are metals other than alkali metals, alkaline earth metals, lanthanides and actinides.
  • a metalloid such as Sb is also included in "metal".
  • the metal ion source can be a metal compound that does not generate NO x and can supply metal ions that act as an oxidizing agent for tungsten.
  • metal compounds include metal oxides, metal carbonates, metal sulfates and the like.
  • the metal compound preferably comprises at least one selected from the group consisting of metal oxides and metal carbonates.
  • the metal oxide is dissolved in the melt of the alkali metal carbonate according to the acidic dissolution of the following formula (1a) or the basic dissolution of (1b).
  • the metal ion derived from the metal oxide oxidizes the tungsten contained in the tungsten-containing material 24 according to the following formula (2a) or (2b).
  • the metal ion is reduced and changed to a reduction product 26 such as a simple substance metal.
  • the metal oxide dissolves in a melt of an alkali metal carbonate to generate metal ions and oxide ions. Both metal ions and oxide ions act as oxidants, and unnecessary ions are not generated in the molten carbonate.
  • Unwanted ions may reduce the solubility of oxides and alkali metal salts of tungstic acid in the molten carbonate 22.
  • a metal oxide may be produced by oxidizing the reduction product 26 (step S8 described later). The obtained metal oxide can be reused as an oxidizing agent.
  • the metal oxide may be a composite oxide. In the following equation, a, b, p, q, r and x each represent a positive integer.
  • Metallic carbonates such as CuCO 3 and FeCO 3 exist as compounds at room temperature. However, when it is dissolved in a high-temperature alkali metal carbonate melt, it is thermally decomposed according to the following formulas (3a) and (3b), for example.
  • the metal oxide is dissolved in the melt of the alkali metal carbonate according to the above formula (1a). CO 2 diffuses into the surrounding atmosphere as a gas. That is, when a metal carbonate is used, the same result as when a metal oxide is used can be obtained.
  • the metal ion M n + is completely reduced to zero valence.
  • the metal ion M n + may be reduced to M m + (n> m) having a smaller valence.
  • the metal ion derived from the metal oxide oxidizes the tungsten contained in the tungsten-containing material 24 according to the following formula (2c) or (2d).
  • a, b, c, d, p, q, m and n each represent a positive integer.
  • FIG. 2A shows the oxidation-dissolution reaction of tungsten. Even when a tungsten compound such as tungsten carbide is used, tungsten is oxidized by a reaction according to the above formulas (2a) to (2d) and dissolved in the molten carbonate 22.
  • the metal ion to be supplied from the metal ion source contains at least one selected from the group consisting of Cu ion, Fe ion, Ni ion, Sn ion, Mn ion, V ion, Pb ion, Sb ion, and Co ion. You may be. These metal ions can oxidize tungsten.
  • the metal ions to be supplied from the metal ion source are Cu (+1), Cu (+2), Fe (+2), Fe (+3), Ni (+2), Sn (+2), Sn (+4), Mn (+2). ), Mn (+4), V (+2), V (+3), V (+4), V (+5), Pb (+2), Pb (+4), Sb (+3), Sb (+4), Sb (+5) ), Co (+2), and Co (+3) may contain at least one selected from the group. These metal ions can oxidize tungsten.
  • the metal ion is used in this embodiment. It is possible. According to this embodiment, since the redox potential of the molten carbonate 22 can be controlled by the type of metal ion, it is easy to treat a powdered tungsten-containing material having a large surface area.
  • the redox potential of the molten nitrate is defined by NO x generated in the reaction, so that it is practically impossible to control the redox potential of the molten nitrate.
  • the metal oxides that can supply the above-mentioned metal ions are CuO, Cu 2 O, FeO, Fe 2 O 3 , NiO, SnO, SnO 2 , MnO, MnO 2 , VO, V 2 O 3 , VO 2 , respectively.
  • the metal oxide may contain at least one selected from the group consisting of CuO, Cu2O , VO, V2O3 , VO2 , and V2O5 .
  • the solubility of copper oxide in the molten carbonate 22 is high. Therefore, when copper oxide is used as the metal oxide, copper ions and oxide ions can be reliably generated. Further, when the metal contained in the metal oxide does not form an alloy with the metal contained in the tungsten-containing material 24, the separation of each metal is easy in the downstream process. For example, scrap of cemented carbide tools contains a large amount of Co. Since Cu and Co do not form an alloy, Cu and Co can be sorted by a known method such as magnetic force sorting. Therefore, it is recommended to use CuO and / or Cu 2O as the metal oxide when processing the scrap of the cemented carbide tool by the method of this embodiment. Vanadium oxide is also recommended because it has a strong ability to oxidize tungsten.
  • the amount of alkali metal carbonate used to prepare the molten carbonate 22 is, for example, 0.3 mol or more and 20 mol or less with respect to 1 mol of tungsten contained in the tungsten-containing material to be treated. This makes it possible to sufficiently oxidize and dissolve tungsten. For example, a maximum of 3.3 mol of Na 2 WO 4 is dissolved in 1 mol of Na 2 CO 3 . From this point of view, the lower limit of the amount of alkali metal carbonate is determined. The upper limit of the amount of alkali metal carbonate is determined from the viewpoint of economy.
  • the amount of the metal ion source added to the molten carbonate 22 is not particularly limited.
  • the amount of alkali metal carbonate used is used as a reference (100 mol%), the amount of the metal ion source added is, for example, 0.5 mol% or more and 50 mol% or less.
  • the oxidizing power derived from the alkali metal carbonate is exerted by peroxide ions (O 2 2- ), superoxide ions (O 2- ) and carbonate ions (CO 3 2- ).
  • FIG. 2B is a diagram showing a reaction in which oxygen ion species (O 2 2- , O 2- ) oxidize tungsten.
  • FIG. 2C is a diagram showing a reaction in which carbonate ions (CO 3 2- ) oxidize tungsten.
  • O 2 in the atmosphere is chemically dissolved in the molten carbonate as O 2 2- ion or O 2 - ion, diffused in the molten carbonate, and then tungsten is formed. Oxidize.
  • CO 3 2- present in the molten carbonate directly oxidizes tungsten.
  • the target temperature of the molten carbonate 22 is determined according to the melting point of the alkali metal carbonate.
  • the target temperature of the molten carbonate 22 is, for example, 500 ° C. or higher and 1000 ° C. or lower.
  • the target temperature may be 700 ° C. or higher and 950 ° C. or lower.
  • the target temperature of the molten carbonate 22 may be set in consideration of the solubility of the metal ion source in the molten carbonate 22. This is because when the metal ion source is sufficiently dissolved in the molten carbonate 22, the metal ions acting as an oxidizing agent are sufficiently supplied from the metal ion source.
  • the predetermined time for maintaining the molten carbonate 22 at the target temperature is not particularly limited, and is, for example, 0 hours or more and 50 hours or less, preferably 25 hours or less, more preferably 5 hours or less, still more preferably 2.5 hours. It's less than an hour. According to this embodiment, the reaction can be sufficiently advanced in a short time. “0 hours” means that the temperature of the molten carbonate 22 is raised at a predetermined rate, and after the molten carbonate 22 reaches the target temperature, the temperature lowering process is immediately started. As will be clear from the examples described later, the reaction can proceed even in this case. After maintaining the molten carbonate 22 at the target temperature for a predetermined time, the temperature of the molten carbonate 22 may be lowered to room temperature at a predetermined rate.
  • scrap of a cemented carbide tool containing tungsten carbide as a main component can be mentioned.
  • the scrap of the cemented carbide tool may be a large hard scrap that retains the shape of the cemented carbide tool, may be a powdery soft scrap, or may contain both of them. According to the method of the present embodiment, both hard scrap and soft scrap can be safely processed.
  • "Main component" means the component contained most in the mass ratio.
  • the material of the container 28 is not particularly limited, and may be, for example, a ceramic such as alumina, or a metal material such as iron or nickel.
  • the molten nitrate method described in Patent Document 1 requires an expensive container having corrosion resistance. However, according to the present embodiment, there is no such restriction, and various materials can be used as the material of the container 28.
  • the surrounding atmosphere in which the container 28 is placed is not particularly limited.
  • the ambient atmosphere may be an inert atmosphere or an oxidizing atmosphere.
  • An inert gas such as a noble gas or N 2 gas is used for the inert atmosphere.
  • the oxidizing atmosphere include an atmosphere containing an oxidizing agent gas such as O 2 gas.
  • a mixed gas of the inert gas and the oxidant gas may be used as the atmospheric gas. The partial pressure of each component in the mixed gas is adjusted appropriately.
  • the pressure of the ambient atmosphere is not particularly limited and may be substantially equal to the atmospheric pressure.
  • the atmospheric gas with which the molten carbonate 22 is in contact may contain CO 2 gas.
  • a mixed gas of a noble gas and a CO 2 gas can be used as the atmospheric gas.
  • the partial pressure of each gas is not particularly limited.
  • the partial pressure of the CO 2 gas is, for example, 1 ⁇ 10 -7 atm or more and 1 atm or less, preferably 1 ⁇ 10 -4 atm or more and 0.8 atm or less.
  • the lower limit of the partial pressure of CO 2 gas is determined based on the value assumed when the atmosphere is diluted with another gas.
  • the lower limit of the partial pressure of CO 2 gas is determined based on the value assumed when another gas such as O 2 gas is added to pure CO 2 gas.
  • the partial pressure of the CO 2 gas By adjusting the partial pressure of the CO 2 gas, it is possible to control the basicity of the molten carbonate 22. Thereby, the reaction rate of the oxidative dissolution reaction can be controlled.
  • the partial pressure of the CO 2 gas By adjusting the partial pressure of the CO 2 gas, it is also possible to adjust the solubility of the metal ion source in the molten carbonate 22 and the solubility of the alkali metal salt of tungsten acid in the molten carbonate 22.
  • the partial pressure of the CO 2 gas may be adjusted according to the type of metal ion.
  • the basicity of the molten nitrate is defined by NO x generated in the reaction, so that it is practically impossible to control the basicity of the molten nitrate.
  • the molten carbonate 22 may be stirred in the step S1.
  • Metals derived from metal ion sources are deposited on the surface of the carbide tool tip. By stirring, the metal deposited from the surface of the chip can be removed. As a result, the oxidation-dissolution reaction of tungsten can proceed more smoothly.
  • O 2 gas may be bubbled to the molten carbonate 22.
  • oxygen ion species O 2 2- , O 2-
  • metal ions as an oxidizing agent can be regenerated by the O 2 gas reoxidizing the metal after oxidizing tungsten.
  • the composition comprises an alkali metal salt of tungsten acid, an unreacted alkali metal carbonate, and a reduction product 26 of the metal ion derived from the metal ion source.
  • the reduction product 26 typically contains a simple metal, may contain a salt such as NaVO 2 , or may contain both.
  • the composition may further contain an unreacted tungsten-containing material 24 and by-products. By-products include metal residues, alkali metal oxides and the like. The metal residue contains other metals contained in the tungsten-containing material and the like.
  • other metals include Co and Ta.
  • the composition containing the alkali metal salt of tungstic acid is, for example, in the form of powder.
  • the presence of the alkali metal carbonate and the alkali metal salt of tungsten acid can be confirmed.
  • the presence of elemental metals derived from metal ion sources can be confirmed by inductively coupled plasma emission spectroscopy.
  • an aqueous solution of the alkali metal salt of tungsten acid can be easily obtained only by adding water to the composition containing the alkali metal salt of tungsten acid.
  • the composition containing the alkali metal salt of tungstic acid is excellent in storage and transportability. Therefore, the composition may be transported to another location to carry out the downstream process.
  • step S2 of FIG. 1 water is added to the container 28, and the composition containing the alkali metal salt of tungstic acid is dissolved in water.
  • Substances that are insoluble in water precipitate as solids.
  • the pH of the aqueous solution may be appropriately adjusted.
  • Alkali metal salts of tungstic acid are neutral or alkaline and are well soluble in water.
  • the aqueous solution containing the alkali metal salt of tungstic acid is weakly acidic.
  • a weakly alkaline aqueous solution can be obtained. Therefore, it is possible to obtain a tungsten aqueous solution having a low solubility of components other than tungsten and a lower impurity concentration.
  • the ratio (M2 / M1) of the cobalt concentration M2 (unit: mass ppm) to the tungsten concentration M1 (unit: mass ppm) is a percentage. In representative, it is preferably 0.5% or less, and more preferably 0.25% or less.
  • the lower limit of the ratio (M2 / M1) is not particularly limited, and is, for example, 0.0001%, which may be equal to or lower than the lower limit of detection.
  • step S3 of FIG. 1 solid-liquid separation of an aqueous solution containing an alkali metal salt of tungstic acid is performed.
  • a water-insoluble precipitate eg, Cu, Co, Ta, etc.
  • the method of solid-liquid separation is not particularly limited, and known methods such as filtration, centrifugation, and precipitation can be adopted.
  • step S8 the metal used in step S1 is recovered from the precipitate recovered in step S3.
  • the recovered metal is oxidized to obtain a metal oxide.
  • the obtained metal oxide can be reused in the step S1 and is economical.
  • an aqueous solution containing an alkali metal salt of tungsten acid is treated by ion exchange using an ion exchange resin.
  • the alkali metal ion is replaced with ammonium ion, and an aqueous solution of ammonium tungstate ((NH 4 ) 2 WO 4 ) is obtained.
  • the ammonium paratungate aqueous solution is concentrated to crystallize ammonium paratungate (APT: Ammonium paratungstate).
  • APT Ammonium paratungstate
  • the ratio (m2 / m1) of the cobalt concentration m2 (unit: mass ppm) to the tungsten concentration m1 (unit: mass ppm) is preferably 0.5% or less in terms of percentage, and more. It is preferably 0.25% or less.
  • the lower limit of the ratio (m2 / m1) is not particularly limited, and is, for example, 0.0001%, which may be equal to or lower than the detection lower limit.
  • step S6 of FIG. 1 ammonium paratungstate is dried and roasted. This gives tungsten oxide (WO 3 ).
  • step S7 of FIG. 1 the tungsten oxide is reduced.
  • metallic tungsten (W) is obtained.
  • the reduction of tungsten oxide is carried out by a known method such as hydrogen reduction.
  • the following experiment was conducted to confirm whether the metal oxide functions as an oxidizing agent in the process of recovering tungsten as an alkali metal salt of tungsten acid from the super hard chip by the molten carbonate method.
  • FIG. 3 is a schematic cross-sectional view of the reactor used in the examples.
  • the reaction apparatus 10 includes a reaction tube 11 made of alumina, a stainless steel lid 12, and an electric furnace 17.
  • the reaction tube 11 is closed by the stainless steel lid 12.
  • the reaction tube 11 is housed in an electric furnace 17.
  • the stainless steel lid 12 is provided with an inlet port 13 and an outlet port 14.
  • a supply pipe 15 is attached to the inlet port 13.
  • An exhaust pipe 16 is attached to the outlet port 14.
  • the atmosphere inside the reaction tube 11 can be adjusted through the supply pipe 15 and the exhaust pipe 16.
  • a crucible 20 is arranged inside the reaction tube 11.
  • the molten carbonate 22 and the tungsten-containing material 24 are arranged in the crucible 20. By heating the reaction tube 11, molten carbonate 22 is generated from the raw material, and the reaction proceeds.
  • Example 1 As raw materials for molten carbonate, Na 2 CO 3 powder (manufactured by Fujifilm Wako Junyaku Co., Ltd.) crushed by a mortar and pestle and a metal oxide used as an oxidant are used in an alumina crucible (manufactured by Nikkato Corporation, SSA). -S, outer diameter 37 mm x height 25 mm) was filled. The amount of Na 2 CO 3 was 3.1 g, and the depth of the molten salt at the time of dissolution was adjusted to 6 mm. Cu 2 O (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the metal oxide. Based on the amount of Na 2 CO 3 used (100 mol%), the amount of Cu 2 O added was 6.4 mol%. The crucible filled with Na 2 CO 3 powder and metal oxide was dried overnight in a vacuum oven at 180 ° C. to remove residual water.
  • a cemented carbide chip (TPG070202FN, 450 mg, manufactured by Daishowa Seiki Co., Ltd.) was embedded in Na 2 CO 3 powder in a crucible and allowed to stand. Then, as described with reference to FIG. 3, a crucible was placed in an airtight container having a reaction tube (outer diameter 80 mm ⁇ inner diameter 70 mm ⁇ length 500 mm) and a stainless steel lid and allowed to stand. A supply pipe and an exhaust pipe were fixed to each port of the stainless steel lid by an O-ring. The stainless steel lid was air-cooled with a cooling fan to prevent deterioration of the O-ring.
  • reaction tube After inserting the reaction tube into a horizontal electric furnace (KTF040N1 manufactured by Koyo Thermo System Co., Ltd.), the temperature was raised from room temperature at 5 ° C./min, and after reaching 900 ° C., the reaction was allowed to proceed for 25 hours.
  • Alumina protection pipes manufactured by Nikkato Corporation, SSA-S, outer diameter 6.0 mm x inner diameter 4.0 mm) were used as the supply pipe and the exhaust pipe.
  • the obtained salt was dissolved in nitrate containing tartrate acid, which is a chelating agent for tungsten ions, and then the tungsten concentration was analyzed by inductively coupled plasma emission spectroscopy (ICP-AES, AMETEK, SPECTROBLUE). From this, it was confirmed that the weight loss rate was the oxidative elution of tungsten carbide in the cemented carbide chip.
  • An X-ray diffractometer (XRD, manufactured by Rigaku, SmartLab, Cu-K ⁇ ray, 40 kV, 30 mA) was used to identify the phase of the obtained salt and the residual cemented carbide chip.
  • Example 1 to which Cu 2 O was added showed a larger weight loss rate than Comparative Example 1.
  • the reason for this is that Cu 2 O functions as an oxidant and the oxidative elution reaction of tungsten proceeds rapidly.
  • FIG. 4 is an optical photograph of the cemented carbide chip of Example 1 after the reaction. As shown in the left figure of FIG. 4, orange-red precipitates were deposited on the surface of the cemented carbide chip. As shown in the right figure of FIG. 4, when the surface precipitate was peeled off, a black unreacted chip remained inside.
  • FIG. 5 shows the XRD pattern of the cemented carbide chip of Example 1 after the reaction.
  • the XRD pattern of Cu powder and the XRD pattern of Co powder are also shown. From the comparison with the XRD pattern of Cu powder and the XRD pattern of Co powder, it was confirmed that the precipitate was metallic Cu.
  • the small peak of the metal Co is a peak derived from the metal Co adhering to Cu.
  • Example 2 The cemented carbide chip was oxidatively dissolved by the molten carbonate method in the same manner as in Example 1 except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 3.
  • Example 2 Even if the partial pressure of CO 2 was lowered, Example 2 showed a large weight loss rate due to the addition of Cu 2 O. However, Example 1 having a high CO 2 partial pressure showed a larger weight loss rate than Example 2 having a low CO 2 partial pressure.
  • Example 3 The cemented carbide chip was oxidatively dissolved by the molten carbonate method in the same manner as in Example 1 except that 6.4 mol% FeO (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the metal oxide. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 4.
  • Example 4 Except for the fact that 2.1 mol% Fe 2 O 3 (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the metal oxide, the oxidative dissolution treatment of the superhard chip by the molten carbonate method was carried out in the same manner as in Example 1. did. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 4.
  • Example 3 to which FeO was added and Example 4 to which Fe 2O 3 was added showed a larger weight loss rate than that of Comparative Example 1.
  • the reason for this is that FeO and Fe 2 O 3 function as oxidizing agents, and the oxidative elution reaction proceeds rapidly.
  • Example 3 when the oxidative elution reaction is represented by the following formula (A2), 6.4 mol% of FeO corresponds to 20.1% in terms of the weight loss rate of tungsten carbide.
  • Example 4 when the oxidation elution reaction is represented by the following formula (A3), 2.1 mol% of Fe 2 O 3 corresponds to 20.1% in terms of the weight loss rate of tungsten carbide.
  • FIG. 6A is an optical photograph of the cemented carbide chip of Example 3 after the reaction.
  • FIG. 6B is an optical photograph of the cemented carbide chip of Example 4 after the reaction. Silver-colored precipitates having a metallic luster were deposited on the surfaces of the cemented carbide chips of Examples 3 and 4, respectively.
  • FIG. 7A shows the XRD pattern of the cemented carbide chip of Example 3 after the reaction.
  • FIG. 7B shows the XRD pattern of the carbide chip of Example 4 after the reaction.
  • Each XRD pattern showed a peak of Fe. From this, it was confirmed that the surface precipitates in Examples 3 and 4 were metallic Fe.
  • Example 5 The cemented carbide chip was oxidatively dissolved by the molten carbonate method in the same manner as in Example 3 except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm. Then, the weight loss rate was calculated by the same method as in Example 3. The results are shown in Table 5.
  • Example 6 The cemented carbide chip was oxidatively dissolved by the molten carbonate method in the same manner as in Example 4 except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm. Then, the weight loss rate was calculated by the same method as in Example 4. The results are shown in Table 5.
  • Examples 5 and 6 showed a slightly larger weight loss rate than Comparative Example 2. On the other hand, Examples 5 and 6 showed a smaller weight loss rate than Examples 3 and 4. The reason for this is that FeO and Fe 2 O 3 have low solubility in carbonate at low CO 2 partial pressure. Therefore, when FeO and Fe 2 O 3 are used, the control of the partial pressure of CO 2 is more important for promoting the oxidative dissolution reaction.
  • Example 7 Except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm and the reaction time was changed to 2.5 hours, the super hard chip by the molten carbonate method was used in the same manner as in Example 1. An oxidative dissolution treatment was carried out. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 6.
  • Example 8 Examples except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm, the amount of Cu 2 O added was changed to 12.8 mol%, and the reaction time was changed to 0 hour.
  • the oxidative dissolution treatment of the super hard chip by the molten carbonate method was carried out by the same method as in 1. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 6.
  • the reaction time of 0 hours means that the temperature of the molten carbonate is raised to 900 ° C. and then immediately lowered.
  • Example 9 Except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm, the amount of Cu 2 O added was changed to 12.8 mol%, and the reaction time was changed to 2.5 hours.
  • the oxidative dissolution treatment of the super hard chip by the molten carbon dioxide method was carried out by the same method as in Example 1. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 6.
  • the measured values of inductively coupled plasma emission spectroscopy for the salt obtained in Example 9 were 40.7 mass ppm for tungsten and 0.01 mass ppm or less, which is the detection limit for cobalt. Therefore, the ratio of the cobalt concentration to the tungsten concentration in the alkali metal salt was 0.5% or less (0.25% or less). Further, since the tungsten concentration does not change at least in ion exchange, it can be easily inferred that the ratio of the cobalt concentration to the tungsten concentration in ammonium paratungstate is 0.5% or less (0.25% or less). Cobalt is derived from the binder contained in the carbide chip and is an impurity contained in the alkali metal salt of tungstic acid and ammonium paratungstate.
  • Example 3 Melting by the same method as in Example 1 except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm, Cu 2 O was not added, and the reaction time was changed to 0 hours. The oxidative dissolution treatment of the super hard chip by the carbonate method was carried out. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 6.
  • Example 4 The same method as in Example 1 except that the partial pressure of CO 2 was changed to 6.0 ⁇ 10 -4 atm, Cu 2 O was not added, and the reaction time was changed to 2.5 hours. The oxidative dissolution treatment of the super hard chip was carried out by the molten carbon dioxide method. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 6.
  • Example 7 The weight loss rate in Example 7 was almost equal to the weight loss rate in Example 2 (Table 3). This indicates that the oxidative dissolution reaction was almost completed in 2.5 hours.
  • Example 8 with a reaction time of 0 hours also showed a weight loss rate of 8.3%. This indicates that the oxidative dissolution reaction proceeded even in the process of raising and lowering the temperature.
  • Example 10 The CO 2 partial pressure was changed to 6.0 ⁇ 10 -4 atm, and tungsten carbide powder (manufactured by High Purity Chemical Co., Ltd., average particle size 150 ⁇ m, 100 mg) was used instead of the super hard chip. Tungsten carbide powder was oxidatively dissolved by the molten carbonate method in the same manner as in Example 1 except that the addition amount was changed to 12.8 mol% and the reaction time was changed to 2.5 hours. .. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 7.
  • Example 10 is much larger than the weight loss rate in Comparative Example 4 (Table 6), and the weight loss rate in Example 9 (Table 6) under the same conditions except that the tungsten carbide is a powder is the same. Was bigger than.
  • Example 11 K 2 CO 3 powder was used as a carbonate instead of Na 2 CO 3 powder, the CO 2 partial pressure was changed to 6.0 ⁇ 10 -4 atm, and the amount of Cu 2 O added was 12.8 mol%.
  • the oxidative dissolution treatment of the super hard chip by the molten carbonate method was carried out by the same method as in Example 1 except that the reaction time was changed to 2.5 hours. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 8.
  • Example 11 12.8 mol% of Cu 2 O corresponds to 40.2% in terms of the weight loss rate of tungsten carbide.
  • the weight loss rate in Example 11 was about the same as the weight loss rate in Example 9 (Table 6). As can be understood from the results of Example 11, the oxidative dissolution reaction proceeded sufficiently even when K 2 CO 3 was used as the carbonate.
  • Example 12 A mixture of Na 2 CO 3 powder and K 2 CO 3 powder was used as a carbonate, the CO 2 partial pressure was changed to 6.0 ⁇ 10 -4 atm, and the amount of Cu 2 O added was 12.8 mol.
  • 12.8 mol% of Cu 2 O corresponds to 40.2% in terms of the weight loss rate of tungsten carbide.
  • the weight loss rate in Example 12 was lower than that of Example 9 (Table 6) using molten Na 2 CO 3 at 900 ° C., and from Example 11 (Table 8) using molten K 2 CO 3 at 900 ° C. Was also low. This is considered to be related to the eutectic temperature of the Na 2 O-Cu 2 O system being 806 ° C. That is, it is expected that the weight loss rate in Example 12 was low because the solubility of Cu 2 O in the molten salt was high at 900 ° C., but the solubility of Cu 2 O in the molten salt was low at 780 ° C. From this result, when Cu 2 O or Cu O is used, it is desirable to set the target temperature of the molten salt in the range of 800 ° C. or higher and 1000 ° C. or lower.
  • FIG. 8 is an optical photograph of the crucibles of Examples 9, 10, 11 and 12 after the reaction.
  • FIGS. 8 (a) and 8 (b) show the results in Examples 9 and 10, respectively, which contain only Na 2 CO 3 as a carbonate.
  • FIG. 8 (c) shows the results in Example 11 containing only K 2 CO 3 as a carbonate.
  • FIG. 8 (d) shows the results in Example 12 containing both Na 2 CO 3 and K 2 CO 3 as carbonates.
  • Example 9 in Example 9 using only Na 2 CO 3 , metal Cu (dark colored portion) is intensively adhered to the surface of the cemented carbide chip.
  • metal Cu (dark colored portion) was deposited on the bottom of the crucible.
  • FIGS. 8 (c) and 8 (d) in Examples 11 and 12 using K 2 CO 3 , the product (mainly the alkali metal salt of tungstic acid) was entirely covered with metallic Cu (dense). The colored part) was dispersed. The cause is expected to be the difference in wettability and surface tension of metallic Cu. Cu adhering to the surface of the cemented carbide chip may inhibit the diffusion of ions and delay the oxidative dissolution reaction. The use of K 2 CO 3 as the carbonate may avoid such disadvantages.
  • Example 13 to 16 Oxidation-dissolution treatment of cemented carbide chips by the molten carbonate method in the same manner as in Example 9 except that 12.8 mol% MnO 2 , SnO 2 , Sb 2 O 3 or V 2 O 5 was used as the metal oxide. Was carried out. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 10.
  • 12.8 mol% of MnO 2 , SnO 2 , Sb 2 O 3 , and V 2 O 5 are 80.4%, 80.4%, and 120.6%, respectively, when converted to the weight loss rate of tungsten carbide. And 201%.
  • Example 16 The weight loss rate of Examples 13 to 16 was larger than the weight loss rate (2.0%) of Comparative Example 4 (Table 6) under the same experimental conditions except that no metal oxide was added. In Example 16 using V 2 O 5 , the weight could not be measured because the carbide chips were completely changed to powder. In Example 16, when the tungsten concentration in the recovered salt was measured by ICP-AES, 62.2% of the tungsten in the cemented carbide chip was dissolved. In other words, vanadium oxide exerted a very high effect.
  • Example 17 Except for the fact that Co 3 O 4 or Ni O was used as the metal oxide, the cemented carbide chip was oxidatively dissolved by the molten carbonate method in the same manner as in Example 7. Then, the weight loss rate was calculated by the same method as in Example 1. The results are shown in Table 11.
  • the present invention is useful for recovering tungsten from a tungsten-containing material.

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Abstract

Un procédé de production d'un sel de métal alcalin d'acide tungstique selon la présente invention comprend un processus selon lequel un carbonate fondu, qui contient des ions métalliques qui servent d'oxydant par rapport à un carbonate de métal alcalin et au tungstène, et un matériau contenant du tungstène, sont mis en contact l'un avec l'autre. Les ions métalliques sont fournis, par exemple, à partir d'au moins une substance qui est choisie dans le groupe constitué d'oxydes métalliques et de carbonates métalliques. Les ions métalliques peuvent comprendre au moins un type d'ions qui sont choisis dans le groupe constitué par des ions Cu, des ions Fe, des ions Ni, des ions Sn, des ions Mn, des ions V, des ions Pb, des ions Sb et des ions Co.
PCT/JP2021/040440 2020-11-24 2021-11-02 Procédé de production de sel de métal alcalin d'acide tungstique, procédé de production de tungstène, et composition contenant un sel de métal alcalin d'acide tungstique WO2022113669A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11505801A (ja) * 1995-06-12 1999-05-25 エイチ・シー・スタルク・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング・ウント・コンパニー・コマンジツトゲゼルシヤフト タングステン酸ナトリウムの製造法
JP2010512456A (ja) * 2006-12-08 2010-04-22 タンドラ パーティクル テクノロジーズ，リミティド ライアビリティ カンパニー アルカリ金属メタレートを使用した融解方法
WO2010104009A1 (fr) * 2009-03-11 2010-09-16 株式会社アライドマテリアル Procédé de fabrication de tungstate de sodium, méthode de recueillement de tungstène, appareil pour la fabrication de tungstate de sodium et procédé de fabrication d'une solution aqueuse de tungstate de sodium
WO2014142003A1 (fr) * 2013-03-15 2014-09-18 株式会社アライドマテリアル Procédé de production de tungstate de sodium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11505801A (ja) * 1995-06-12 1999-05-25 エイチ・シー・スタルク・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング・ウント・コンパニー・コマンジツトゲゼルシヤフト タングステン酸ナトリウムの製造法
JP2010512456A (ja) * 2006-12-08 2010-04-22 タンドラ パーティクル テクノロジーズ，リミティド ライアビリティ カンパニー アルカリ金属メタレートを使用した融解方法
WO2010104009A1 (fr) * 2009-03-11 2010-09-16 株式会社アライドマテリアル Procédé de fabrication de tungstate de sodium, méthode de recueillement de tungstène, appareil pour la fabrication de tungstate de sodium et procédé de fabrication d'une solution aqueuse de tungstate de sodium
WO2014142003A1 (fr) * 2013-03-15 2014-09-18 株式会社アライドマテリアル Procédé de production de tungstate de sodium

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