TWI750137B - Method for manufacturing zirconium tungstate phosphate - Google Patents

Abstract

The present invention provides a method for obtaining a single-phase zirconium phosphate tungstate useful as a negative thermal expansion material by an industrially advantageous method. The method for producing zirconium phosphate tungstate of the present invention is characterized in that a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium is used as a reaction precursor, and the reaction precursor is calcined; and the reaction precursor is preferably It has an infrared absorption peak at least at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak in this range is located at 1030 (±20) cm ^-1 .

Description

Manufacturing method of zirconium tungstate phosphate

The present invention relates to a method for producing a zirconium phosphate tungstate useful as a negative thermal expansion material.

If the temperature rises, most substances will increase in length or volume with thermal expansion. On the other hand, when heated, a material (hereinafter sometimes also referred to as a "negative thermal expansion material") that exhibits negative thermal expansion is also known in which the volume becomes smaller on the contrary. It is known that materials exhibiting negative thermal expansion can be used with other materials to suppress changes in thermal expansion of the material caused by temperature changes.

Materials exhibiting negative thermal expansion are known, for example: β-eucryptite, zirconium tungstate (ZrW ₂ O ₈ ), zirconium tungstate phosphate (Zr ₂ WO ₄ (PO ₄ ) ₂ ), Zn _x Cd _1-x ( CN) ₂ , manganese nitride (manganese nitride), bismuth. nickel. Iron oxides, etc.

The linear expansion coefficient of zirconium tungstate phosphate is -3.4ppm/°C~-3.0ppm/°C in the temperature range of 0°C to 400°C, and the negative thermal expansion is large. It can be used in combination with materials showing positive thermal expansion. Manufacture of materials with low thermal expansion.

As a method for producing zirconium phosphate tungstate, for example, in the following Patent Document 1, a method is proposed in which a reaction accelerator such as crystalline zirconium phosphate, tungsten oxide, and MgO is mixed in a wet ball mill, and the obtained mixture is prepared in a wet ball mill. The calcination is carried out at 1200 ° C; the following patent document 2 proposes the following method: after wet mixing a phosphorus source such as ammonium phosphate, a tungsten source such as ammonium tungstate, and a zirconium source such as zirconium chloride, calcination is performed; the following Non-patent document 1 proposes a method of calcining a mixture containing zirconium oxide, tungsten oxide, and ammonium dihydrogen phosphate at 1200° C., and the like.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-35840, Item 3, Paragraph 0035 of the scope of the application.

[Patent Document 2] Japanese Patent Laid-Open No. 2015-10006, paragraphs 0023 to 0025.

[Non-patent literature]

[Non-Patent Document 1] "Materials Research Bulletin", 44 (2009), pp. 2045-2049.

As a negative thermal expansion material, zirconium tungstate phosphate is considered to be promising as a member for ultra-precision machining, and development of a method for obtaining zirconium tungstate phosphate by an industrially advantageous method is also expected.

Therefore, an object of the present invention is to provide a method for obtaining a single-phase zirconium tungstate phosphate for X-ray diffraction useful as a negative thermal expansion material by an industrially advantageous method.

In view of the above-mentioned facts, the inventors of the present invention have repeatedly conducted intensive studies, and as a result, have found that phosphorus removal in the presence of a tungsten compound that is insoluble or sparingly soluble in water A tungsten compound obtained by the reaction of an acid with a specific zirconium compound, and a mixture of an amorphous compound containing phosphorus and zirconium are reactive precursors with excellent reactivity, and are easily obtained in X-ray diffraction by using the reactive precursors It is a single-phase zirconium phosphate tungstate, thereby completing the present invention.

That is, the method for producing zirconium phosphate tungstate provided by the present invention is characterized in that a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium is used as a reaction precursor, and the reaction precursor is calcined.

According to the present invention, a single-phase zirconium tungstate phosphate for X-ray diffraction useful as a negative thermal expansion material can be obtained by an industrially advantageous method.

FIG. 1 is an X-ray diffraction diagram of the reaction precursor obtained in Example 1. FIG.

Figures 2(a), (b), (c) and (d) are Fourier Transform-Infrared (FT-IR) spectra. FIG. 2( a ) is the FT-IR spectrum of the reaction precursor obtained in Example 1. FIG. Figure 2(b) is the FT-IR spectrum of zirconium hydroxide. Figure 2(c) is the FT-IR spectrum of phosphoric acid. Figure 2(d) is the FT-IR spectrum of tungsten trioxide.

3 is an X-ray diffraction diagram of the zirconium phosphate tungstate obtained in Example 1. FIG.

FIG. 4 is an X-ray diffraction diagram of the reaction precursor obtained in Comparative Example 1. FIG.

5 is an X-ray diffraction diagram of the zirconium phosphate tungstate obtained in Comparative Example 1. FIG.

Fig. 6 is the scanning electron microscope of the zirconium tungstate phosphate obtained in Example 2 (Scanning Electron Microscope, SEM) photograph.

FIG. 7 is an X-ray diffraction diagram of the reaction precursor obtained in Example 3. FIG.

FIG. 8 is an FT-IR spectrum of the reaction precursor obtained in Example 3. FIG.

9 is an X-ray diffraction diagram of the zirconium phosphate tungstate obtained in Example 3. FIG.

FIG. 10 is an SEM photograph of the zirconium phosphate tungstate obtained in Example 3. FIG.

(Top): 30000 times, (bottom): 400 times

Hereinafter, the present invention will be described based on preferred embodiments of the present invention.

The method for producing zirconium phosphate tungstate of the present invention is characterized in that a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium is used as a reaction precursor, and the reaction precursor is calcined.

The present inventors discovered that the amorphous compound containing phosphorus and zirconium obtained by the reaction of phosphoric acid and a zirconium compound is a fine primary particle containing phosphorus atoms and zirconium atoms in a desired molar ratio. In addition, in the slurry in which the tungsten compound is uniformly dispersed, by performing the reaction, a slurry in which the tungsten compound and the amorphous compound containing phosphorus and zirconium are uniformly dispersed is obtained. Furthermore, when this is subjected to a drying treatment, each raw material is uniformly dispersed, and a reaction precursor containing Zr, W, and P in a desired molar ratio is excellent in reactivity.

For example, in the case of using zirconium hydroxide as the zirconium compound, X-ray diffraction analysis of the obtained reaction precursor revealed only the diffraction peak of the tungsten compound (see FIG. 1 ), and no hydroxide was observed. Diffraction peaks of zirconium. In addition, when the reaction precursor was analyzed by FT-IR, zirconium hydroxide and phosphoric acid showed different red From the patterns of the external absorption peaks (see FIGS. 2( a ), ( b ), ( c ) and ( d ) ), it was confirmed that the zirconium hydroxide added to the slurry reacted with phosphoric acid.

In addition, the present inventors presume that the amorphous compound containing phosphorus and zirconium obtained by the reaction of phosphoric acid and a zirconium compound is an amorphous zirconium phosphate.

In this manufacturing method, the reaction precursor preferably ^{has an infrared absorption peak at least at 950 cm −1} to 1150 cm ⁻¹ , and the maximum value of the infrared absorption peak in this range is located at 1030 (±20) cm ⁻¹ .

In addition, the molar ratio of Zr, W and P in the reaction precursor is Zr/W=1.7-2.3, preferably 1.9-2.1, and P/W=1.7-2.3, preferably 1.9-2.1.

In the present invention, the reaction precursor is preferably obtained by the following two methods.

(1) A method (hereinafter referred to as "first method") comprising the following steps: a first step, preparation of a slurry containing a tungsten compound; a second step, followed by adding phosphoric acid and a compound selected from zirconium hydroxide to the slurry and the zirconium compound in the zirconium carbonate; and the third step, followed by the total drying of the obtained slurry.

(2) A method comprising the following steps (hereinafter referred to as "second method"): Step A, heat-treating a slurry containing a tungsten compound, a phosphorus source and a zirconium source; Step B, then using a media mill to The slurry is subjected to wet pulverization treatment; and the C-th step, followed by drying the total amount of the obtained slurry.

<First method>

Hereinafter, a method for producing the reaction precursor by the first method will be described.

The first step of the first method is a step of preparing a slurry obtained by uniformly dispersing a tungsten compound in an aqueous medium serving as a dispersion medium.

The tungsten compound in the first step is preferably a compound that is insoluble or poorly soluble in water, and examples thereof include tungsten compounds such as tungsten trioxide, ammonium tungstate, and tungsten chloride. Among these compounds, tungsten trioxide is preferred from the viewpoint of being industrially easy to obtain and having high purity and also being easy to handle.

From the viewpoint of obtaining a reactive precursor with excellent reactivity, the preferred physical properties of the tungsten compound that can be used are: using laser diffraction. The average particle diameter determined by the scattering method is 100 μm or less, preferably 0.1 μm to 50 μm.

The solvent for dispersing the tungsten compound in the first step is not limited to water, and may be a mixed solvent of water and a hydrophilic solvent.

From the viewpoint of making the slurry with a viscosity that is easy to handle and handle, the slurry concentration in the first step is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 30% by mass.

From the viewpoint of obtaining a reactive precursor with excellent reactivity, the first step is preferably the preparation using laser diffraction. The average particle diameter of the solid content determined by the scattering method is 5 μm or less, preferably 2 μm or less.

In the first step, the method of uniformly dispersing the tungsten compound in the water solvent can be used without particular limitation if the method can uniformly disperse the tungsten compound in the water solvent, but the particles of the tungsten compound are particularly strong due to their cohesiveness. Therefore, a method of adding a dispersant to the slurry is also possible, and from the viewpoint of obtaining a reaction precursor with more excellent reactivity, it is particularly preferred that the average particle size of the solid content falls within the above-mentioned range. It is carried out by wet pulverization treatment using a media mill capable of pulverizing and dispersing at the same time.

The dispersant to be used may be appropriately selected according to the type of dispersion medium. When the dispersion medium is, for example, water, various surfactants, polycarboxylate ammonium salts, and the like can be used as the dispersing agent. From the viewpoint of improving the dispersion effect, the concentration of the dispersant in the slurry is preferably 0.01% by weight to 10% by weight, and particularly preferably 0.1% by weight to 5% by weight.

As the media mill, a bead mill, a ball mill, a paint shaker, an attritor, a sand mill, and the like can be used. It is especially preferred to use a bead mill. In this case, the operating conditions and the type and size of beads may be appropriately selected according to the size of the apparatus and the throughput.

From the viewpoint of more efficient processing using a media mill, a dispersant may be added to the slurry. The dispersant to be used may be appropriately selected according to the type of dispersion medium. When the dispersion medium is, for example, water, various surfactants, polycarboxylate ammonium salts, and the like can be used as the dispersing agent. From the viewpoint of improving the dispersion effect, the concentration of the dispersant in the slurry is preferably 0.01% by weight to 10% by weight, and particularly preferably 0.1% by weight to 5% by weight.

From the viewpoint of obtaining a reaction precursor with more excellent reactivity, the pulverization treatment using a media mill is preferably carried out to using laser diffraction. The average particle diameter of the solid content determined by the scattering method is 1 μm or less, preferably 0.1 μm to 1 μm.

In this way, a slurry in which the tungsten compound is uniformly dispersed in an aqueous solvent can be prepared.

Then, in the second step, phosphorus is added to the slurry obtained in the first step An acid and a zirconium compound selected from zirconium hydroxide and zirconium carbonate (hereinafter, abbreviated as "zirconium compound" in some cases) are used to prepare a reaction precursor.

In the second step, a slurry containing a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium is obtained by reacting phosphoric acid and a zirconium compound in the presence of a tungsten compound.

The phosphoric acid in the second step can be used without particular limitation as long as it is industrially available, and the phosphoric acid can be added to the slurry obtained in the first step as an aqueous phosphoric acid solution.

The zirconium compound in the second step is zirconium hydroxide and/or zirconium carbonate.

Zirconium carbonate can be a basic salt or a double salt of ammonia or sodium and potassium.

The zirconium compound can be used without particular limitation as long as it is industrially available, and the zirconium compound may be an anhydrous salt or a hydrous salt.

The zirconium compound may be directly added as a powder to the slurry obtained in the first step, or may be added as a suspension dispersed in an aqueous solvent or as a solution dissolved in an aqueous solvent.

From the viewpoint of obtaining the larger negative thermal expansion, the amount of phosphoric acid added to the slurry is preferably set to the molar ratio of the P element in the phosphoric acid in the slurry to the W element in the tungsten compound (P/ W) is calculated as 1.7 to 2.3, preferably 1.9 to 2.1.

From the viewpoint of obtaining the larger negative thermal expansion, the addition amount of the zirconium compound in the slurry is preferably set to the molar ratio of the Zr element in the zirconium compound in the slurry to the W element in the tungsten compound ( Zr/W) is calculated as 1.7 to 2.3, preferably 1.9 to 2.1.

In addition, from the viewpoint of obtaining a larger negative thermal expansion, the mixing ratio of the tungsten compound and phosphoric acid added to the slurry is preferably a molar ratio of the element P in the phosphoric acid to the element W in the tungsten compound (P/W) is calculated as 1.7 to 2.3, preferably 1.9 to 2.1.

The reaction conditions of the phosphoric acid and the zirconium compound in the slurry are preferably 5°C to 100°C, preferably 10°C to 50°C, from the viewpoint of obtaining a slurry with a viscosity that is easy to handle and handle. .

The reaction time in the second step is not critical in the present production method, and the reaction may be performed for a sufficient time until an amorphous compound containing phosphorus and zirconium is formed. In many cases, it is possible to produce a slurry in which the tungsten compound having satisfactory physical properties and the amorphous compound containing phosphorus and zirconium are uniformly dispersed in 0.5 hours or more, preferably 1 hour to 4 hours.

After the reaction, the slurry after the second step is not subjected to solid-liquid separation, but the total amount of the slurry is dried in the third step, whereby the first method can be used to obtain the reaction precursor used in the present invention. thing. The method of drying the total amount of the slurry is not particularly limited. If the drying process is performed by spray drying, a granulated material in a state in which the raw material particles are densely aggregated is obtained, and therefore, it is easier to obtain a granulated product which is in the state of X-ray diffraction. It is preferable from the viewpoint of single-phase zirconium phosphate tungstate.

In the spray drying method, a reaction precursor is obtained by atomizing a slurry by a predetermined method, and drying the fine droplets generated thereby. The atomization of the slurry includes, for example, a method using a rotating disk and a method using a pressure nozzle. Either method can be used in the third step.

In the spray drying method, the size of the atomized droplets is not particularly limited, but is preferably 1 μm to 40 μm, and particularly preferably 5 μm to 30 μm. The supply amount of the slurry in the spray drying apparatus is preferably determined in consideration of this viewpoint.

In addition, the temperature of the hot air in the spray drying apparatus is preferably adjusted to 100°C to 270°C, preferably 150°C to 230°C, from the viewpoint of preventing moisture absorption of the powder and facilitating recovery of the powder.

<Second method>

Hereinafter, a method for producing the reaction precursor by the second method will be described.

The A-step of the second method is a step of heat-treating a slurry containing a zirconium compound selected from zirconium hydroxide and zirconium carbonate, phosphoric acid, and a tungsten compound.

If the phosphoric acid and the zirconium compound are not added after preparing the slurry in which the tungsten compound is uniformly dispersed in advance, the viscosity of the slurry increases due to the tungsten compound, and it tends to be difficult to uniformly mix the raw materials. The inventors found that by heat-processing a slurry containing a tungsten compound, phosphoric acid, and a zirconium compound, the viscosity is reduced, and a slurry that can be wet-pulverized by a media mill is obtained. Therefore, in the second method, by carrying out the step A, a slurry in which the tungsten compound and the amorphous compound containing phosphorus and zirconium are uniformly dispersed can be obtained at once while the reaction of phosphoric acid and the zirconium compound proceeds.

As the tungsten compound, phosphoric acid, and zirconium compound in the A-step, the same compounds as those used in the first and second steps of the first method can be used.

From the viewpoint of obtaining the larger negative thermal expansion, the zirconium compound in the slurry The addition amount is preferably 1.7 to 2.3, preferably 1.9 to 2.1, in terms of the molar ratio (Zr/W) of the Zr element in the zirconium compound in the slurry to the W element in the tungsten compound.

From the viewpoint of obtaining the larger negative thermal expansion, the amount of phosphoric acid added to the slurry is preferably set to the molar ratio of the P element in the phosphoric acid in the slurry to the W element in the tungsten compound (P/ W) is calculated as 1.7 to 2.3, preferably 1.9 to 2.1.

The solvent for dispersing the tungsten compound, phosphoric acid, and zirconium compound in the step A is not limited to water, and may be a mixed solvent of water and a hydrophilic solvent.

From the viewpoint of the handleability and easy handling of the slurry, the slurry concentration in the A-step is preferably 5 to 50 mass %, more preferably 10 to 30 mass %.

In addition, in the step A, the order of adding each raw material is not particularly limited, but it is preferably performed in consideration of a reaction apparatus and the like, and is preferably used for preparing a slurry containing a tungsten compound from the viewpoint of easier handling. Then, phosphoric acid and a zirconium compound are added to this slurry.

The temperature of the slurry heat treatment in the A-step is preferably 40°C to 110°C, from the viewpoint of obtaining a slurry with a viscosity that is easy to handle and handle while the reaction between phosphoric acid and the zirconium compound proceeds, preferably 60℃~90℃.

The heat treatment time in the A-step is not critical in the present production method, and the reaction may be performed for a sufficient time until an amorphous compound containing phosphorus and zirconium is formed and the slurry viscosity is moderately reduced. In most cases, it can take more than 0.5 hours, preferably 1 hour to 4 hours, to generate satisfactory substances A low-viscosity slurry in which a tungsten compound with high properties and an amorphous compound containing phosphorus and zirconium are uniformly dispersed.

Next, in the B-th step, the slurry obtained in the A-step process is subjected to wet pulverization with a media mill.

The B-step is a step of subjecting the slurry after the A-step to wet pulverization with a media mill to obtain a slurry in which each raw material is finely and uniformly dispersed.

As the media mill, a bead mill, a ball mill, a paint shaker, an attritor, a sand mill, and the like can be used. It is especially preferred to use a bead mill. In this case, the operating conditions and the type and size of beads may be appropriately selected according to the size of the apparatus and the throughput.

From the viewpoint of more efficient processing using a media mill, a dispersant may be added to the slurry. The dispersant to be used may be appropriately selected according to the type of dispersion medium. When the dispersion medium is, for example, water, various surfactants, polycarboxylate ammonium salts, and the like can be used as the dispersing agent. From the viewpoint of improving the dispersion effect, the concentration of the dispersant in the slurry is preferably 0.01% by weight to 10% by weight, and particularly preferably 0.1% by weight to 5% by weight.

If the pulverization process using the media mill is carried out to the use of laser diffraction. The average particle diameter of the solid content determined by the scattering method is preferably 2 μm or less, preferably 1 μm or less, and particularly preferably 0.1 μm to 0.5 μm, from the viewpoint of obtaining a reaction precursor with more excellent reactivity.

In this way, a slurry with low viscosity in which the fine tungsten compound and the amorphous compound containing phosphorus and zirconium are uniformly dispersed can be prepared.

After the reaction, the slurry after the B step is not subjected to solid-liquid separation, but The total amount of the slurry is dried in the C-th step, whereby the reaction precursor used in the present invention can be obtained by the second method. The method of drying the total amount of the slurry is not particularly limited. If the drying process is performed by spray drying, a granulated material in a state in which the raw material particles are densely aggregated is obtained, and therefore, it is easier to obtain a granulated product which is in the state of X-ray diffraction. It is preferable from the viewpoint of single-phase zirconium phosphate tungstate.

In the spray drying method, a reaction precursor is obtained by atomizing a slurry by a predetermined method, and drying the fine droplets generated thereby. The atomization of the slurry includes, for example, a method using a rotating disk and a method using a pressure nozzle. Either method can be used in step C.

In the spray drying method, the size of the atomized droplets is not particularly limited, but is preferably 1 μm to 40 μm, and particularly preferably 5 μm to 30 μm. The supply amount of the slurry in the spray drying apparatus is preferably determined in consideration of this viewpoint.

In addition, the temperature of the hot air in the spray drying apparatus is preferably adjusted to 100°C to 270°C, preferably 150°C to 230°C, from the viewpoint of preventing moisture absorption of the powder and facilitating recovery of the powder.

In the present production method, the reaction precursor obtained by the first method and the second method may contain a sintering aid component.

Examples of sintering aid components include: Mg, Zn, Cu, Fe, Cr, Mn, Ni, V, Li, Al, B, Na, K, F, Cl, Br, I, Ca, Sr, Ba, Ti, Hf, Nb, Ta, Y, Yb, Si, S, Mo, Co, Bi, Te, Pb, Ag, Cd, In, Sn, Sb, Te, Ga, Ge, La, Ce, Nd, Sm, Elements such as Eu, Tb, Dy, Ho, and the like may be used alone or in two or more. these elements Among them, elements selected from Mg and/or V are preferred.

The sintering aid component is preferably added to the slurry before the second step to the third step in the first method as a compound containing the sintering aid component.

In addition, in the second method, preferably in the slurry before the A-th step to the B-th step, specifically, before the A-th step is performed, in the middle of the A-th step, and after the A-th step is completed, the The compound containing this sintering aid component is added in at least one situation before the B-step and in the middle of the B-step.

Examples of the compound containing the sintering aid component include oxides, hydroxides, carbonates, organic acid salts, ammonium salts, nitrates, phosphates, sulfates, chlorides, bromides, Among these compounds, iodides and the like, are preferably used as oxides and hydroxides containing a sintering aid component from the viewpoint that the purity of the product can be easily controlled and a high-purity product can be easily obtained.

In addition, in the first method and the second method, in order to dissolve or precipitate the added compound containing the sintering aid component in the slurry, the pH may be adjusted with an alkali or an acid as necessary.

The addition amount of the compound containing the sintering aid component in the slurry is preferably 0.05% by mass to 5.0% by mass, preferably 0.1% by mass to 3.0% by mass, based on the sintering aid component. in the reaction precursor.

The sintering aid component can be directly contained in the reaction precursor as the added compound containing the sintering aid component, and the added compound containing the sintering aid component can also be reacted in the slurry to be converted into other sintering aid components. The compound of the auxiliary component is contained in the reaction precursor.

For example, when a hydroxide is used as the compound containing the sintering aid component, it may react with phosphoric acid in the slurry, convert it into a phosphate containing the sintering aid component, and contain it in the reaction precursor. .

In addition, the compound containing the sintering aid component contained in the reaction precursor may be crystalline or amorphous.

In the present invention, the target zirconium tungstate phosphate can be obtained by providing a calcination step for calcining the reaction precursor.

In the calcination step, the calcination temperature for calcining the reaction precursor is 900°C to 1300°C. The reason for this is that when the calcination temperature is lower than 900°C, unreacted oxides and the like remain, making it difficult to obtain single-phase zirconium tungstate phosphate by X-ray diffraction. On the other hand, if the calcination temperature is higher than At 1300°C, the particles become lumps in a state where particles are consolidated, and it tends to be difficult to obtain powder.

In addition, in this production method, since the single-phase zirconium phosphate tungstate in X-ray diffraction can be obtained at low temperature, in order to effectively utilize this advantage, it is preferable to carry out the calcination temperature at 900°C to 1100°C. .

The calcination time is not critical in the present production method, and the reaction is carried out for a sufficient time until the single-phase zirconium phosphate tungstate is produced by X-ray diffraction. In many cases, zirconium phosphate tungstate with satisfactory physical properties can be produced in 1 hour or more, preferably 2 hours to 20 hours. In addition, the firing environment is not particularly limited, and may be any of an inert gas environment, a vacuum environment, an oxidizing gas environment, and the atmosphere.

Calcination may be performed as many times as necessary. Or, to make the powder properties uniform For the purpose, the one calcined can also be pulverized and then calcined again.

After calcination, appropriate cooling is performed, and if necessary, pulverization, crushing, classification, etc. are performed to obtain a single-phase zirconium phosphate tungstate in X-ray diffraction.

The zirconium phosphate tungstate obtained by the present production method is represented by Zr ₂ (WO ₄ )(PO ₄ ) ₂ and is a single-phase zirconium tungstate phosphate in X-ray diffraction. When zirconium tungstate is used as a filler in resin, glass, etc., it is preferable that the average primary particle size determined by scanning electron microscope observation is 5 μm or less from the viewpoint of easy handling. It is 0.1μm~4μm, the average secondary particle size is 1μm~40μm, preferably 4μm~30μm, and the Brunauer-Emmett-Teller (BET) specific surface area is 0.1m ² /g~20m ² /g, relatively Preferably, it is 0.1 m ² /g to 10 m ² /g.

The zirconium phosphotungstate obtained by the present production method is particularly useful as a negative thermal expansion material exhibiting negative thermal expansion, and the linear expansion coefficient of the zirconium phosphotungstate obtained by the present production method in the temperature range of 0°C to 400°C is - 3.4ppm/°C to -2.6ppm/°C, preferably -3.4ppm/°C to -2.8ppm/°C.

The zirconium phosphate tungstate obtained by this production method can be used as a powder or a paste. When used as a paste, it can be used in the state of a paste with a low viscosity liquid resin. Alternatively, it may be used in the state of a paste containing a solvent and, if necessary, a binder, a flux, a dispersant, and the like.

The zirconium phosphate tungstate obtained by this production method can be used as a composite material in combination with various organic compounds or inorganic compounds. The organic compound or inorganic compound is not particularly limited, and examples of the organic compound include rubber, polyolefin, polycyclic Olefin, polystyrene, acrylonitrile butadiene styrene (ABS), polyacrylate, polyphenylene sulfide, phenol resin, polyamide resin, polyimide resin, epoxy resin, silicone resin, polycarbonate resin, polyethylene resin, polypropylene resin, polyethylene terephthalate resin (PET resin), polyvinyl chloride resin, etc. In addition, the inorganic compound includes silica, graphite, sapphire, various glass materials, concrete materials, various ceramic materials, and the like.

Since the composite material contains zirconium tungstate phosphate, which is the negative thermal expansion material of the present invention, negative thermal expansion coefficient, zero thermal expansion coefficient, or low thermal expansion coefficient can be realized according to the mixing ratio with other compounds.

[Example]

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

<Evaluation Device>

1. X-ray diffraction analysis: X-ray diffraction analysis of zirconium tungstate phosphate and reaction precursors was performed using Ultima IV from Rigaku. Cu-Kα was used as radiation source. The measurement conditions were made into a tube voltage of 40 kV, a tube current of 40 mA, and a scanning speed of 0.1°/sec.

2. Infrared absorption spectrometry (FT-IR) analysis: The infrared absorption spectroscopic analysis of the reaction precursors was performed using a NICOLET 6700 manufactured by Thermo Fisher Scientific, with a decomposition capacity of 4 cm ^-1 , Cumulative number: 256 times, Measurement wave number area: 400cm ^-1 ~ 4000cm ^-1 conditions to measure. Measurement was performed by an attenuated total reflection (ATR) method, and ATR correction and spectral smoothing processing were performed.

3. Average particle size: The average particle size of the solid content in each raw material and slurry is determined by laser diffraction. The scattering method was measured using a Microtrac MT3300EXII particle size analyzer (manufactured by MicrotracBEL).

{Example 1}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter of 1.2 μm) was added to the beaker, 84 parts by weight of pure water was further added, and 1 part by weight of ammonium polycarboxylate was added as a dispersant.

It stirred at room temperature (25 degreeC) for 120 minutes using a Three-One Motor mixer, and prepared the 15 mass % slurry containing tungsten trioxide. The average particle diameter of the solid content in the slurry was 1.2 μm.

Next, to this slurry, zirconium hydroxide and an 85 mass % phosphoric acid aqueous solution were added at room temperature (25° C.) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. , and reacted for 2 hours while stirring.

After the completion of the reaction, the total amount of the slurry was dried at 200° C. under the atmosphere for 24 hours to obtain a reaction precursor. When X-ray diffraction was performed on the obtained reaction precursor, only the diffraction peak of tungsten trioxide was observed (see FIG. 1 ). In addition, as a result of analysis by FT-IR, there was ^{an infrared absorption peak at 950 cm -1} to 1150 cm ^-1 , and the maximum value of the infrared absorption peak appeared at 1027 cm ^-1 (see FIGS. 2( a ), ( b ), (c) and (d)).

Next, the obtained reaction precursor was subjected to 2 The calcination reaction was carried out for hours to obtain a white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, it was found that the calcined product was single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ (see FIG. 3 ).

{Example 2}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle size of 25 μm) was weighed and put into the tank. 84 parts by weight of pure water and 1 part by weight of ammonium polycarboxylate as a dispersant were put into the tank.

Next, stirring the slurry, it was supplied to a medium stirring type bead mill into which zirconia beads having a diameter of 0.5 mm were put, and mixed for 15 minutes to perform wet pulverization. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, to this slurry, zirconium hydroxide and an 85 mass % phosphoric acid aqueous solution were added at room temperature (25° C.) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. , and reacted for 2 hours while stirring.

After the completion of the reaction, the slurry was supplied at a supply rate of 2.4 L/h in a jet dryer set at 220° C. to obtain a reaction precursor. As a result of X-ray diffraction of the obtained reaction precursor, only the diffraction peak of tungsten trioxide was observed. Further, the results are analyzed in FT-IR of at 950cm ^-1 ~ 1150cm ^-1 has an infrared absorption peak, the maximum value here is the infrared absorption peak appears at 1030cm ^-1.

Next, the obtained reaction precursor was subjected to a calcination reaction at 950° C. in the air for 2 hours to obtain a white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, the calcined product was a single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ .

{Comparative Example 1}

7 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle size: 25 μm) and commercially available zirconia (ZrO ₂ ; average particle size: 6.5 μm) were weighed so that the molar ratio of W:Zr was 2.00:1.00. way into the slot. 84 parts by weight of pure water and 1 part by weight of ammonium polycarboxylate as a dispersant were added to the tank to prepare a slurry having a solid content concentration of 15%.

Next, stirring the slurry, it was supplied to a medium stirring type bead mill into which zirconia beads having a diameter of 0.5 mm were put, and mixed for 15 minutes to perform wet pulverization. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, 85 mass % phosphoric acid aqueous solution was added to this slurry so that the molar ratio of Zr:W:P in the slurry might be 2.00:1.00:2.00, and it stirred at room temperature (25 degreeC) for 2 hours.

After the completion of the reaction, the total amount of the slurry was dried at 200° C. under the atmosphere for 24 hours to obtain a reaction precursor. As a result of X-ray diffraction of the obtained reaction precursor, diffraction peaks of tungsten trioxide and zirconia were observed (see FIG. 4 ).

Next, the obtained reaction precursor was subjected to a calcination reaction at 950° C. in the air for 2 hours, to obtain a green-white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, it was found that the calcined product contained a large amount of different phases, and Zr ₂ (WO ₄ )(PO ₄ ) _{2 was} slightly generated (see FIG. 5 ).

<Evaluation of physical properties>

For the zirconium tungstate phosphates obtained in Examples 1 to 2 and Comparative Example 1, the average primary particle size, the average secondary particle size, the BET specific surface area, and the thermal expansion coefficient were measured. The results are shown in Table 1. In addition, the SEM photograph of the zirconium phosphate tungstate obtained in Example 2 is shown in FIG. 6 .

(Evaluation of Average Primary Particle Size)

The average primary particle size of the zirconium tungstate phosphate was determined based on the average value of 50 or more particles arbitrarily extracted at a magnification of 5,000 times in scanning electron microscope observation.

(Evaluation of Average Secondary Particle Size)

The average secondary particle size of the zirconium tungstate phosphate was determined based on the average value of 50 or more particles arbitrarily extracted at a magnification of 400 times in scanning electron microscope observation.

(Evaluation of Linear Expansion Coefficient)

Using an X-Ray Diffractometer (XRD) apparatus (Rigaku, Ultima IV) with a heating function, the target temperature was reached at a heating rate of 20°C/min for 10 minutes, and then the measurement was performed. The lattice constants of the sample with respect to the a-axis, b-axis, and c-axis were calculated by linear conversion of the lattice volume change (cuboids) (refer to "Journal of Materials Science, J. Mat. .Sci.)”, 35 (2000) pp. 2451-2454).

{Example 3}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter of 1.2 μm) was added to the beaker, and 84 parts by weight of pure water was further added.

It stirred at room temperature (25 degreeC) for 120 minutes, and prepared the 15 mass % slurry containing tungsten trioxide. The average particle diameter of the solid content in the slurry was 1.2 μm.

Next, to this slurry, zirconium hydroxide and 85 mass of zirconium hydroxide were added at room temperature (25° C.) so that the molar ratio of Zr:W:P:Mg in the slurry was 2.00:1.00:2.00:0.1. After % phosphoric acid aqueous solution and magnesium hydroxide, the temperature was raised to 80°C, and the mixture was reacted for 4 hours while stirring.

After the completion of the reaction, 1 part by weight of polycarboxylate ammonium salt as a dispersant was put in, and the slurry was supplied to a medium stirring type bead mill into which zirconia beads with a diameter of 0.5 mm were put in while stirring, and mixed for 15 minutes. for wet grinding. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, the slurry was supplied at a supply rate of 2.4 L/h in a jet dryer set at 220° C. to obtain a reaction precursor. As a result of X-ray diffraction of the obtained reaction precursor, only a diffraction peak of tungsten trioxide was observed (see FIG. 7 ). In addition, as a result of analysis by FT-IR, it ^{has an infrared absorption peak at 950 cm -1} to 1150 cm ^-1 , and the maximum value of the infrared absorption peak in this period appears at 1042 cm ^-1 (see FIG. 8 ).

In addition, it is presumed that Mg of the sintering aid component is present in the reaction precursor as amorphous magnesium phosphate by the reaction of phosphoric acid and magnesium hydroxide in the slurry.

Next, the obtained reaction precursor was subjected to a calcination reaction at 1050° C. in the air for 2 hours to obtain a white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, it was found that the calcined product was single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ (see FIG. 9 ).

{Example 4}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter of 1.2 μm) was added to the beaker, 84 parts by weight of pure water was further added, and 1 part by weight of ammonium polycarboxylate was added as a dispersant.

It stirred at room temperature (25 degreeC) for 120 minutes, and prepared the 15 mass % slurry containing tungsten trioxide. The average particle diameter of the solid content in the slurry was 1.2 μm.

Next, to this slurry, hydroxide was added at room temperature (25° C.) so that the molar ratio of Zr:W:P:Mg:V in the slurry was 2.00:1.00:2.00:0.1:0.05. After zirconium, 85 mass % phosphoric acid aqueous solution, magnesium hydroxide, and vanadium pentoxide, the temperature was raised to 80° C., and the mixture was reacted for 4 hours while stirring.

After the completion of the reaction, the slurry was supplied to a medium stirring type bead mill into which zirconia beads having a diameter of 0.5 mm were charged, and the slurry was mixed for 15 minutes to perform wet pulverization. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, the slurry was supplied at a supply rate of 2.4 L/h in a jet dryer set at 220° C. to obtain a reaction precursor. As a result of X-ray diffraction of the obtained reaction precursor, only the diffraction peak of tungsten trioxide was observed. Further, the results are analyzed in FT-IR of at 950cm ^-1 ~ 1150cm ^-1 has an infrared absorption peak, the maximum value here is the infrared absorption peak appears at 1030cm ^-1.

In addition, it is presumed that Mg of the sintering aid component is present in the reaction precursor as amorphous magnesium phosphate by the reaction of phosphoric acid and magnesium hydroxide in the slurry. On the other hand, it is presumed that V of the sintering aid component exists in the reaction precursor as vanadium pentoxide, although a diffraction peak is not detected because it is below the detection limit in X-ray diffraction. thing.

Next, the obtained reaction precursor was subjected to a calcination reaction at 1050° C. in the air for 2 hours to obtain a white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, the calcined product was a single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ .

{Example 5}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter of 1.2 μm) was added to the beaker, and 84 parts by weight of pure water was further added.

It stirred at room temperature (25 degreeC) for 120 minutes, and prepared the 15 mass % slurry containing tungsten trioxide. The average particle diameter of the solid content in the slurry was 1.2 μm.

Next, to this slurry, zirconium hydroxide and 85 mass of zirconium hydroxide were added at room temperature (25° C.) so that the molar ratio of Zr:W:P:Mg in the slurry was 2.00:1.00:2.00:0.1. After % phosphoric acid aqueous solution and magnesium hydroxide, the temperature was raised to 80°C, and the mixture was reacted for 4 hours while stirring.

After the completion of the reaction, 1 part by weight of polycarboxylate ammonium salt as a dispersant was put in, and the slurry was supplied to a medium stirring type bead mill into which zirconia beads with a diameter of 0.5 mm were put in while stirring, and mixed for 15 minutes. for wet grinding. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, the slurry was supplied at a supply rate of 2.4 L/h in a jet dryer set at 220° C. to obtain a reaction precursor. As a result of X-ray diffraction of the obtained reaction precursor, only the diffraction peak of tungsten trioxide was observed. Further, the results are analyzed in FT-IR of at 950cm ^-1 ~ 1150cm ^-1 has an infrared absorption peak, the maximum value here is the infrared absorption peak appears at 1030cm ^-1.

In addition, it is presumed that Mg of the sintering aid component is present in the reaction precursor as amorphous magnesium phosphate by the reaction of phosphoric acid and magnesium hydroxide in the slurry.

Next, the obtained reaction precursor was subjected to a calcination reaction at 960° C. in the air for 2 hours to obtain a white calcined product. This was pulverized with a jet mill to obtain a pulverized product.

As a result of X-ray diffraction analysis of the obtained calcined product, the calcined product was a single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ .

{Example 6}

15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter of 1.2 μm) was added to the beaker, and 84 parts by mass of pure water was further added.

It stirred at room temperature (25 degreeC) for 120 minutes, and prepared the 15 mass % slurry containing tungsten trioxide. The average particle diameter of the solid content in the slurry was 1.2 μm.

Next, to this slurry, zirconium hydroxide and an 85 mass % phosphoric acid aqueous solution were added at room temperature (25° C.) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. Then, it heated up to 80 degreeC, and it reacted for 4 hours, stirring.

After the completion of the reaction, 1 part by mass of polycarboxylate ammonium salt as a dispersant was charged, and the slurry was supplied to a medium stirring type bead mill into which zirconia beads with a diameter of 0.5 mm were charged while stirring, and mixed for 15 minutes. for wet grinding. The average particle diameter of the solid content in the slurry after wet grinding was 0.3 μm.

Next, the slurry was supplied at a supply rate of 2.4 L/h in a jet dryer set at 220° C. to obtain a reaction precursor. X-ray diffraction was performed on the obtained reaction precursor, and only the diffraction peak of tungsten trioxide was observed. Further, the results are analyzed in FT-IR of at 950cm ^-1 ~ 1150cm ^-1 has an infrared absorption peak, the maximum value here is the infrared absorption peak appears at 1042cm ^-1.

Next, the obtained reaction precursor was subjected to a calcination reaction in the air at 1220° C. for 8 hours to obtain a white calcined product.

As a result of X-ray diffraction analysis of the obtained calcined product, the calcined product was a single-phase Zr ₂ (WO ₄ )(PO ₄ ) ₂ .

<Evaluation of physical properties>

For the zirconium tungstate phosphates obtained in Examples 3 to 6, in the same manner as in Examples 1 to 2 and Comparative Example 1, the average primary particle size, average secondary particle size, BET specific surface area, and linearity were measured. Thermal expansion coefficient. The results are shown in Table 2. In addition, the SEM photograph of the zirconium phosphate tungstate obtained in Example 3 is shown in FIG. 10 (upper: 30000 times, lower: 400 times).

Claims (16)

A method for producing zirconium phosphate tungstate, characterized in that a mixture of a tungsten compound and an amorphous compound containing phosphorus and zirconium is used as a reaction precursor, and the reaction precursor is calcined. The scope of the patent application of the method for manufacturing a first zirconium phosphate tungstate, wherein the reactive precursors at least within the range of 950cm ^-1 ~ 1150cm ^-1 of an infrared absorption peak, and the infrared absorption peak in the range The maximum value is located at 1030(±20) cm ^-1 . The method for producing zirconium tungstate phosphate according to item 1 of the claimed scope, wherein the reaction precursor is obtained by implementing the following steps: the first step is to prepare a slurry containing a tungsten compound; the second step is to perform the following steps: adding phosphoric acid and a zirconium compound selected from zirconium hydroxide and zirconium carbonate to the slurry; and a third step, followed by drying the total amount of the slurry after the second step. The method for producing zirconium tungstate phosphate according to claim 3, wherein the first step includes a step of wet pulverizing the slurry containing the tungsten compound using a media mill. The method for producing zirconium tungstate phosphate according to claim 3, wherein the first step prepares a slurry having an average particle diameter of solid content of 5 μm or less. The method for producing zirconium tungstate phosphate according to claim 3, wherein the first step prepares a slurry having an average particle diameter of solid content of 1 μm or less. The method for producing zirconium phosphate tungstate according to item 1 of the scope of the application, wherein the reaction precursor is obtained by implementing the following steps: Step A, comprising a zirconium compound selected from the group consisting of zirconium hydroxide and zirconium carbonate, The slurry of phosphoric acid and tungsten compound is subjected to heat treatment; step B, then, using a media mill to wet pulverize the slurry after step A; and step C, then, to the slurry after step B Carry out total drying. The method for producing zirconium tungstate phosphate according to claim 7, wherein the step B prepares a slurry having an average particle diameter of solid content of 2 μm or less. The method for producing zirconium tungstate phosphate according to any one of items 3 to 8 of the claimed scope, wherein the total amount drying is performed by spray drying. The method for producing zirconium phosphate tungstate according to any one of items 1 to 8 of the patent application scope, wherein the calcination temperature is 900°C to 1300°C. The method for producing zirconium tungstate phosphate according to any one of items 1 to 8 of the patent application scope, wherein the tungsten compound is tungsten trioxide. The method for producing zirconium tungstate phosphate according to any one of items 1 to 8 of the scope of the application, wherein the reaction precursor further contains a sintering aid component. The method for producing zirconium tungstate phosphate according to item 12 of the claimed scope, wherein the sintering aid component is selected from the group consisting of Mg, Zn, Cu, Fe, Cr, Mn, Ni, V, Li, Al, B, Na, K, F, Cl, Br, I, Ca, Sr, Ba, Ti, Hf, Nb, Ta, Y, Yb, Si, S, Mo, Co, Bi, Te, Pb, Ag, Cd, In, Sn, Sb, Te, Ga, Ge, La, Ce, Nd, Sm, Eu, Tb and Dy, One or two or more elements of Ho. The method for producing zirconium tungstate phosphate according to claim 3, wherein a compound containing a sintering aid component is added to the slurry before the second step to the third step. The method for producing zirconium tungstate phosphate according to claim 7, wherein a compound containing a sintering aid component is added to the slurry before the A-step to the B-step. The method for producing zirconium tungstate phosphate according to claim 14 or claim 15, wherein the added compound containing a sintering aid component is selected from oxides and hydroxides containing a sintering aid component middle.

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