Alkaline earth metal phosphate compounds and methods for producing the same
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- JGC CATALYSTS & CHEMICALS LTD
- Filing Date
- 2022-09-15
- Publication Date
- 2026-07-16
Smart Images
Figure 0007891398000002 
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Abstract
Description
Technical Field
[0001] The present invention relates to alkaline earth metal phosphate compounds.
Background Art
[0002] Alkaline earth metal phosphate compounds represented by magnesium phosphate and calcium phosphate are widely used as fertilizers, refractory binders, flame retardants, additives for food and drink, and catalyst materials. For example, Patent Document 1 discloses magnesium phosphate used in food and drink. Further, Patent Document 2 discloses a catalyst containing magnesium phosphate.
[0003] Methods for producing alkaline earth metal phosphate compounds are also widely known. For example, Patent Document 3 discloses a method for producing magnesium phosphate compounds ceramics, characterized in that magnesium phosphate tribasic, magnesium hydrogen phosphate, and magnesium oxide or magnesium carbonate are weighed, an appropriate amount of water is added, and the mixture is stirred at room temperature in a pot mill. The obtained slurry is dried to obtain a magnesium phosphate tribasic powder of a hydrate. Further, anhydrous magnesium phosphate tribasic is obtained by calcining.
[0004] Thus, alkaline earth metal phosphate compounds and methods for producing them are widely known. Further, alkaline earth metal phosphate compounds are used in a wide range of applications, and their forms are various, such as powders and molded bodies.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Patent Document 3
Summary of the Invention
[0006] Alkaline earth metal phosphate compounds obtained by conventional manufacturing methods had the problem of poor moldability when molded into molded articles.
[0007] Therefore, the present invention aims to provide a method for producing alkaline earth metal phosphate compounds with good moldability. [Means for solving the problem]
[0008] The present inventors have found that the above problems can be solved by using a method for producing alkaline earth metal phosphate compounds, which includes an alkaline earth metal-containing suspension preparation step of preparing an alkaline earth metal-containing suspension in which a salt containing an alkaline earth metal is dispersed in water; a phosphorus aqueous solution preparation step of preparing an aqueous solution in which a phosphorus-containing compound is dissolved; a temperature adjustment step of adjusting the temperature of the alkaline earth metal-containing suspension to 50°C or higher and 95°C or lower; and a reaction step of mixing the alkaline earth metal-containing suspension obtained in the temperature adjustment step with the phosphorus aqueous solution, and have completed the present invention. [Effects of the Invention]
[0009] According to the present invention, a method for producing alkaline earth metal phosphate compounds with good moldability can be provided. [Brief explanation of the drawing]
[0010] [Figure 1] This is a spectrum showing the X-ray diffraction pattern of Example 1. [Modes for carrying out the invention]
[0011] This invention includes an invention relating to a method for producing alkaline earth metal phosphate compounds (hereinafter also referred to as "the manufacturing method of the present invention"). The manufacturing method of the present invention will be described in detail below.
[0012] [Manufacturing method of the present invention] The manufacturing method of the present invention includes: an alkaline earth metal-containing suspension preparation step of preparing a suspension in which a salt containing an alkaline earth metal is dispersed in water; a phosphorus aqueous solution preparation step of preparing an aqueous solution in which a compound containing phosphorus is dissolved; a temperature adjustment step of adjusting the temperature of the alkaline earth metal-containing suspension to 50°C or higher and 95°C or lower; and a reaction step of mixing the alkaline earth metal-containing suspension obtained in the temperature adjustment step with the phosphorus aqueous solution.
[0013] [Preparation process for alkaline earth metal-containing suspension] In this step, an alkaline earth metal-containing suspension is prepared, in which a salt containing an alkaline earth metal is dispersed. In this invention, "suspension" refers to a liquid dispersed as a solid in water. Therefore, in this step, it is preferable to use a salt containing an alkaline earth metal with low solubility in water. Specifically, it is preferable to use any of alkaline earth metal carbonates, alkaline earth metal hydroxides, or mixtures thereof (basic alkaline earth metal carbonate salts), and it is particularly preferable to use alkaline earth metal hydroxides with low solubility in water. Furthermore, the alkaline earth metal contained in this salt is at least one selected from Be, Mg, Ca, Sr, Ba, and Ra, preferably at least one selected from Mg, Ca, and Ba, and more preferably Mg.
[0014] In this process, an alkaline earth metal-containing suspension can be prepared by adding the aforementioned alkaline earth metal-containing salt to water and stirring. Furthermore, the method for preparing the alkaline earth metal-containing suspension is not limited to stirring; for example, after adding the alkaline earth metal-containing salt to water, the salt can be dispersed in the water by ultrasonic dispersion or shaking. The alkaline earth metal-containing salt content in the alkaline earth metal-containing suspension obtained in this process is preferably in the range of 1% to 25% by mass, more preferably in the range of 3% to 20% by mass, and particularly preferably in the range of 5% to 15% by mass, based on the formula weight of the salt (excluding crystal water). Using an alkaline earth metal-containing suspension with an alkaline earth metal-containing salt content within the above range allows for the acquisition of alkaline earth metal phosphate compounds with better moldability.
[0015] [Phosphorus aqueous solution preparation process] In this step, a phosphorus aqueous solution containing phosphorus is prepared. In this invention, "aqueous solution" refers to a liquid that does not contain solids and in which all components other than water are dissolved in water. Therefore, in this step, a phosphorus aqueous solution can be prepared by dissolving a phosphorus-containing compound with high solubility in water in water. For example, it can be prepared by dissolving a phosphate compound or phosphorus pentoxide in water. Alternatively, phosphoric acid may be used as is or mixed with water. The phosphorus content of the phosphorus aqueous solution obtained in this step is preferably in the range of 20% by mass or more and less than 85% by mass, more preferably in the range of 25% by mass or more and 80% by mass or less, and particularly preferably in the range of 30% by mass or more and 75% by mass or less, in terms of H3PO4. Using a phosphorus aqueous solution with a phosphorus content within the above range allows for the acquisition of alkaline earth metal phosphate compounds with better moldability.
[0016] [Temperature adjustment process] In this step, the temperature of the alkaline earth metal-containing suspension obtained in the previous step is adjusted to a range of 50°C to 95°C. For example, the temperature of the alkaline earth metal-containing suspension obtained in the previous step can be adjusted by heating it with a heater. In this step, it is preferable to adjust the temperature of the alkaline earth metal-containing suspension to a range of 75°C to 95°C, and more preferably to a range of 75°C to 85°C. When the temperature of the alkaline earth metal-containing suspension is within the above range, an alkaline earth metal phosphate compound with better moldability can be obtained.
[0017] [Reaction Process] In this step, the alkaline earth metal-containing suspension obtained in the aforementioned temperature adjustment step is mixed with the aforementioned phosphorus aqueous solution. At this time, the alkaline earth metal phosphate precipitates as a solid component in the resulting mixture. In this step, various alkaline earth metal phosphate compounds can be synthesized by adjusting the molar ratio of alkaline earth metal to phosphorus (alkaline earth metal / phosphorus). For example, when synthesizing a magnesium phosphate compound, adjusting the ratio to around 1 / 2 will synthesize monomagnesium phosphate (Mg(H2PO4)2·4H2O), adjusting it to around 1 / 1 will synthesize dimamagnesium phosphate (MgHPO4·3H2O), and adjusting it to around 3 / 2 will synthesize trimagnesium phosphate (Mg3(PO4)2·8H2O). At this time, it is preferable to adjust the molar ratio of alkaline earth metal to phosphorus to within ±20% of the target molar ratio, and more preferably to within ±10% of the target molar ratio. For example, when synthesizing dismagnesium phosphate, it is preferable to adjust the aforementioned molar ratio to a range of 0.8 to 1.2, and more preferably to a range of 0.9 to 1.1.
[0018] In this step, methods such as adding an aqueous phosphorus solution to the alkaline earth metal-containing suspension, adding the alkaline earth metal-containing suspension to the aqueous phosphorus solution, and simultaneously adding the alkaline earth metal-containing suspension and the aqueous phosphorus solution can be used. In this step, it is preferable to use the method of adding the aqueous phosphorus solution to the alkaline earth metal-containing suspension. By using this method, an alkaline earth metal phosphate compound with better formability can be obtained. At this time, it is preferable to add the total amount of the aqueous phosphorus solution to the alkaline earth metal-containing suspension within 5 minutes or more and 120 minutes or less, and it is more preferable to add the total amount of the aqueous phosphorus solution to the alkaline earth metal-containing suspension within 15 minutes or more and 90 minutes or less. For example, the addition rate may be adjusted using a pump or the like so that the total amount of the above-mentioned aqueous solution can be added within the above-mentioned time range. When the above-mentioned aqueous solution is added at such an addition rate, an alkaline earth metal phosphate compound with even better formability can be obtained. If this time is shortened, the particle size of the alkaline earth phosphate compound tends to be larger, and the bulk density also tends to be higher.
[0019] In this step, due to the heat of reaction when the alkaline earth metal-containing suspension and the aqueous phosphorus solution are mixed, the temperature of the mixed solution rises. It is preferable to suppress the increase in this temperature to 15°C or less, and more preferable to suppress it to 10°C or less. For example, when the temperature rises rapidly, the heat of reaction can be suppressed by waiting for the temperature of the mixed solution to decrease by suppressing the above-mentioned addition rate, or by adjusting the temperature of the heater. When the increase in temperature is suppressed to the above-mentioned range by such a method, an alkaline earth metal phosphate compound with better formability can be obtained.
[0020] In this step, it is preferable that the concentration of the solid content (mainly the alkaline earth metal phosphate compound) contained in the above-mentioned mixed solution is in the range of 5% by mass or more and 30% by mass or less. The concentration of the solid content can be adjusted by adjusting the concentration of the alkaline earth metal contained in the above-mentioned alkaline earth metal-containing suspension and the concentration of phosphorus contained in the above-mentioned aqueous phosphorus solution.
[0021] In this step, it is preferable to age the aforementioned mixture at a temperature of 50°C to 95°C for 15 minutes or more. At this time, it is preferable to adjust the temperature of the mixture to a range of 75°C to 95°C, and more preferably to a range of 75°C to 85°C. Furthermore, the holding time is preferably in the range of 30 minutes to 180 minutes, and more preferably in the range of 45 minutes to 90 minutes. The alkaline earth metal phosphate compound obtained by aging under these conditions has particularly good moldability.
[0022] The mixture obtained in this process contains alkaline earth metal phosphate compounds, and the solvent can be removed from the mixture as needed to separate the alkaline earth metal phosphate compounds. For example, water can be removed and the alkaline earth metal phosphate compounds separated using conventionally known methods such as filtration, centrifugation, decantation, spray drying, or evaporation to dryness. The separated alkaline earth metal phosphates may also be washed with water or warm water. Furthermore, if water is to be removed by drying, it is preferable to dry at a temperature between 80°C and 150°C. The drying time in this case can be, for example, in the range of 1 hour to 24 hours. Separation can also be performed by methods that do not involve heat, for example, by using vacuum drying.
[0023] [Alkaline earth metal phosphate compounds of the present invention] This invention includes inventions relating to alkaline earth metal phosphate compounds (hereinafter also referred to as "the compounds of the present invention"). The compounds of the present invention will be described in detail below.
[0024] The compound of the present invention is an alkaline earth metal phosphate compound. An alkaline earth metal phosphate compound is a salt containing an alkaline earth metal ion and a phosphate ion. The alkaline earth metal is at least one selected from Be, Mg, Ca, Sr, Ba, and Ra, preferably at least one selected from Mg, Ca, and Ba, and more preferably Mg. Magnesium phosphates include monomagnesium phosphate (Mg(H2PO4)2·4H2O), dimamagnesium phosphate (MgHPO4·3H2O), and trimagnesium phosphate (Mg3(PO4)2·8H2O). The compound of the present invention is preferably dimamagnesium phosphate. These compounds can be identified by X-ray diffraction measurement. Specifically, by comparing the X-ray diffraction pattern of the compound of the present invention with the X-ray diffraction pattern of these compounds, if the peak positions of the three peaks with strong peak intensity in the X-ray diffraction pattern of the present invention are all included within 2θ±0.5° of the peak positions in the X-ray diffraction pattern of these compounds, they can be identified as the same compound.
[0025] The compounds of the present invention have a median diameter in the range of 20 μm to 200 μm, preferably in the range of 20 μm to 100 μm, and more preferably in the range of 20 μm to 50 μm. Compounds of the present invention having a median diameter within the aforementioned range have good moldability.
[0026] The compound of the present invention has a bulk density in the range of 0.5 g / mL to 1.3 g / mL, preferably in the range of 0.5 g / mL to 1 g / mL, and more preferably in the range of 0.5 g / mL to 0.8 g / mL. The compound of the present invention having a bulk density in the aforementioned range has good moldability.
[0027] The compounds of the present invention preferably have a TAP density in the range of 0.7 g / mL to 1.9 g / mL, more preferably in the range of 0.7 g / mL to 1.4 g / mL, and particularly preferably in the range of 0.7 g / mL to 1.1 g / mL. Compounds of the present invention having a TAP density within the aforementioned range have good moldability. The compounds of the present invention preferably have a ratio of TAP density to bulk density (TAP density / bulk density × 100%) in the range of 100% to 150%, more preferably in the range of 100% to 145%, and particularly preferably in the range of 100% to 140%. Compounds of the present invention having a TAP density ratio to bulk density within the above range exhibit particularly good moldability.
[0028] The compounds of the present invention can be used in a variety of applications, and are preferably used as molding powders. For example, they are more preferably used as powders for compression molding or extrusion molding. They are particularly preferably used as powders for compression molding. Furthermore, the molded compounds of the present invention can be suitably used as fertilizers, binders for refractories, flame retardants, additives for food and beverages, and catalysts, and are particularly suitably used as catalysts.
[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. [Measurement method or evaluation method] Various measurements and evaluations were performed as follows:
[0030] [1] X-ray diffraction measurement Powder X-ray diffraction measurements were performed on the powders obtained in each example under the following conditions. X-ray diffractometer: MiniFlex600 (manufactured by Rigaku Corporation) Radiation source: Cu-Kα radiation Acceleration voltage, current: 40kV, 15mA Light-receiving slit: 13mm Scan speed: 5.0° / min Step width: 0.01° Measurement range (2θ): 10~80°
[0031] [2] Particle size distribution measurement (median diameter) The median diameter of the powder obtained in each example was determined using a laser diffraction / scattering particle size distribution analyzer (Horiba, Ltd.: LA-950v2). Specifically, in room temperature air, an aqueous sodium hexametaphosphate solution was added to the slurry, dispersed by ultrasonic dispersion and stirring, and adjusted to a transmittance of 30% to 60%. Then, the cumulative particle size distribution (volume-based) was measured using the above-mentioned apparatus under conditions of a refractive index of 1.76.
[0032] [3] Bulk density measurement The powders obtained in each example were dropped into a 100 mL glass graduated cylinder from a height of 10 cm above the top of the cylinder by gravity, and the filling volume was determined. The bulk density was calculated by dividing the weight of the filled powder by the filling volume.
[0033] [4] TAP density measurement The powder obtained in each example was placed in a 100 mL graduated cylinder until it reached the 100 mL mark, and then the cylinder was raised and lowered 10 times from a height of approximately 1 cm. The weight placed in the graduated cylinder was T (g), and the mark after 10 raising and lowering movements was P (cm). 3 ) and TAP density [g / cm³ 3 ] was calculated using T / P.
[0034] [5] Evaluation of moldability The powders obtained in each example were molded into 5mm x 5mm cylindrical shapes using a tablet press (Hata Iron Works Co., Ltd., HT-AP15SS-II). The minimum compression pressure (in kgf) required to form the molded body was determined by varying the compression pressure within an arbitrary range. Tablets with lower compression pressures were judged to have better moldability.
[0035] [Example 1] 300.0 g of pure water was placed in a 1000 mL glass beaker. 30.41 g of magnesium hydroxide (product name: UD-650, manufactured by Ube Materials Co., Ltd.) was added to this beaker and stirred to obtain a magnesium hydroxide suspension. 122.5 g of a 40% by mass phosphoric acid aqueous solution was also prepared. The magnesium hydroxide suspension was heated to 80°C using a heater. Then, the phosphoric acid aqueous solution was added to the magnesium hydroxide suspension. The addition rate was adjusted so that the entire volume of the phosphoric acid aqueous solution was added over 60 minutes. The mixture obtained after adding the entire volume of the phosphoric acid aqueous solution was held at 80°C for 1 hour while stirring. The solid components in the mixture were then filtered and separated. The obtained solid components were dried at 100°C for 12 hours to obtain a powder. The measurements and evaluations described in [1] to [5] above were performed on this powder. The results are shown in Table 1. The X-ray diffraction pattern obtained from measurement [1] is shown in Figure 1.
[0036] [Comparative Example 1] The powder was obtained in the same manner as in Example 1, except that the temperature of the magnesium hydroxide suspension was adjusted to 20°C and the mixture was held at 20°C for 2 hours while stirring. The measurements and evaluations described in [1] to [5] above were performed on this powder. The results are shown in Table 1.
[0037] [Table 1]
Claims
1. Alkaline earth metal-containing suspension preparation step: Prepare a suspension in which a salt containing an alkaline earth metal is dispersed in water. A phosphorus aqueous solution preparation step, in which an aqueous solution containing a phosphorus-containing compound is prepared. A temperature adjustment step to adjust the temperature of the alkaline earth metal-containing suspension to 50°C or higher and 95°C or lower. The reaction step comprises mixing the alkaline earth metal-containing suspension obtained in the temperature adjustment step with the phosphorus aqueous solution, A method for producing an alkaline earth metal phosphate compound, wherein the phosphorus concentration in the phosphorus aqueous solution is in the range of 30% by mass or more and 75% by mass or less, in terms of H₃PO₄.
2. The manufacturing method according to claim 1, wherein the salt containing the alkaline earth metal is an alkaline earth metal hydroxide.
3. The manufacturing method according to claim 2, wherein in the temperature adjustment step, the temperature of the alkaline earth metal-containing suspension is adjusted to 75°C or higher and 95°C or lower.
4. The salt containing the alkaline earth metal is at least one of an alkaline earth metal carbonate and an alkaline earth metal hydroxide, The method for producing phosphorus according to claim 1, wherein the phosphorus-containing compound is phosphoric acid.
5. The manufacturing method according to any one of claims 1 to 4, wherein in the reaction step, the alkaline earth metal-containing suspension and the phosphorus aqueous solution are mixed so that the molar ratio of alkaline earth metal to phosphorus (alkaline earth metal / phosphorus) is in the range of 0.8 or more and 1.2 or less.
6. The median diameter is in the range of 20 μm to 200 μm. An alkaline earth metal phosphate compound having a bulk density in the range of 0.5 g / mL to 1.3 g / mL, The alkaline earth metal phosphate compound is a magnesium phosphate compound.
7. The median diameter is in the range of 20 μm to 200 μm. An alkaline earth metal phosphate compound having a bulk density in the range of 0.5 g / mL to 1.3 g / mL, The alkaline earth metal phosphate compound wherein the alkaline earth metal phosphate compound is dismagnesium phosphate.