JPH07315814A - Wet mass-production of calcium tetraphosphate - Google Patents

Abstract

PURPOSE:To produce calcium tetraphosphate, especially useful as a raw material for calcium phosphate for organisms in high purity and large amount, compared with a conventional drying method or a mechanochemical powdering method. CONSTITUTION:This wet mass-producing method of calcium tetraphosphate is to carry out wet synthesis from a calcium feed raw material and a phosphorus feed raw material so that a molar ratio Ca/P of the calcium feed raw material to the phosphorus feed raw material become >2.00 and <=2.10 in an aqueous solution kept to <=30 deg.C, providing raw material slurry, dehydrate and dry the resultant slurry and calcine the dried material at 400-1200 deg.C and further bake the calcined material at 1300-1500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has an appropriate grindability,
The present invention relates to a method for mass production of quaternary calcium phosphate that can be used as a component of biomedical cement or the like.

[0002]

2. Description of the Related Art Calcium phosphate cement for living organisms has been developed which has good biocompatibility and hardens within a practical time simply by mixing with water (for example, FC PEPORT, vol.
6 (1988), p.475-480, "Hydraulic apatite as bioceramics"). The main hardening components of such calcium phosphate cement are α-type tricalcium phosphate and quaternary calcium phosphate.
It is calcium phosphate. Among these, as a method for producing quaternary calcium phosphate, a dry method (for example, gypsum and lime, No. 202, p151-155, (1986) “Synthesis of tetracalcium phosphate”) and a mechanochemical grinding method (for example, Proposal of 9th Inorganic Phosphorus Chemistry Conference Proceedings, p19-20 (1992) "Synthesis of Tetracalcium Phosphate") has been proposed.

However, since the quaternary calcium phosphate obtained by the dry method has too good pulverizability, only powders having a particle size distribution in a relatively narrow range can be obtained, and the paste when kneaded with water is used. Has a problem that the cement using quaternary calcium phosphate cannot obtain high strength. On the other hand, in the case of the mechanochemical pulverization method, since it is necessary to perform high-temperature calcination exceeding 1500 ° C., it is not suitable for mass synthesis in the actual situation.

[0004]

The object of the present invention is to have an appropriate pulverizability as a constituent component of a calcium phosphate cement for living body and the like, and to make the resulting cement for living body high in strength. It is to provide a method for mass production of quaternary calcium phosphate.

Another object of the present invention is to provide a method for mass production of quaternary calcium phosphate which can be mass-produced.

[0006]

According to the present invention, a water temperature of 3
A raw material slurry is obtained by wet synthesis in an aqueous solution at 0 ° C. or lower so that the Ca / P molar ratio of the calcium feed material and the phosphorus feed material is more than 2.00 and less than 2.10. After dehydration and drying, 400-1
Provided is a method for mass-producing a large amount of quaternary calcium phosphate, which comprises calcination at 200 ° C. and main calcination at 1300 to 1500 ° C.

The present invention will be described in more detail below. In the production method of the present invention, first, in an aqueous solution at a specific temperature or lower, wet synthesis is performed so that the Ca / P molar ratio of the calcium feedstock and the phosphorus feedstock falls within a specific range to prepare a raw material slurry.

The calcium feed material and the phosphorus feed material are not particularly limited as long as they are capable of forming a quaternary calcium phosphate, and examples of the calcium feed material include CaCl ₂ and Ca (N
_{O 3) 2, Ca (OH} ) 2 or the like can be mentioned, as the phosphorus _{feed, H 3 PO 3, KH 2} PO 4, (NH 4) 2 H
Examples include PO ₄ , NH ₄ H ₂ PO _{4, and the} like.

The lower limit of the mixing ratio in the wet synthesis of the calcium feedstock and the phosphorus feedstock is the dehydration
In order to prevent the unreacted calcium component from being discharged from the aqueous solution during the drying and synthesize the quaternary calcium phosphate having less impurities, the Ca / P molar ratios of the calcium feedstock and the phosphorus feedstock are calculated based on the theoretical Ca of hydroxyapatite.
/ P molar ratio needs to be higher than 1.67, specifically 2.00, and preferably 2.02 in order to synthesize reproducibly quaternary calcium phosphate with less impurities.
Is. Further, the upper limit is 2.10 in order to prevent the inclusion of free lime after the main calcination, and is preferably 2.08 in order to synthesize reproducibly quaternary calcium phosphate containing less impurities.

In order to prepare a raw material slurry by wet-synthesizing the calcium feedstock and the phosphorus feedstock, for example, a method of gradually dropping the aqueous solution containing the phosphorus feedstock under stirring into the aqueous solution containing the calcium feedstock, etc. Can be obtained by In the raw material slurry obtained at this time,
The most stable hydroxyapatite is also produced in calcium phosphate, and its crystallinity is increased in an aqueous solution, so the hydroxyapatite may remain as an impurity after the main calcination described later. To prevent this, it is effective to suppress the heat of reaction to promote the reaction, and in order to always synthesize under the same conditions, it is necessary to control the temperature of the reaction system and synthesize under constant temperature conditions. . Therefore, the water temperature of the aqueous solution for synthesizing the raw material slurry is 30 ° C. or lower, preferably 20 ° C. or lower, and particularly preferably 10 ° C. or lower. Further, the lower limit temperature is sufficient if it is a temperature at which the respective aqueous solutions do not freeze.

Next, in the manufacturing method of the present invention, the raw material slurry is dehydrated and dried. When the raw material slurry has a small amount of synthesis (for example, 15 liters or less), the entire amount of the slurry can be dried as it is with an ordinary dryer, but as in the production method of the present invention, the amount of synthesis is large ( In the case of, for example, 50 liters or more), it is necessary to dehydrate before drying by, for example, a method using a centrifuge, discarding the supernatant, spray drying using a spray dryer, or the like. The theoretical Ca / P molar ratio when synthesizing quaternary calcium phosphate by the wet method is
_As is clear from ₄ (PO ₄ ) ₂ · O), it is 2.00. However, when the quaternary calcium phosphate is actually prepared by wet synthesis, in addition to the objective quaternary calcium phosphate, more stable hydroxyapatite having a low Ca / P molar ratio,
A mixture with unreacted calcium components is also obtained. When the dehydration step is an essential requirement for increasing the amount of synthesis as in the production method of the present invention, the composition shifts by the amount of the calcium component remaining in the waste liquid, and when calcined, the tetracalcium phosphate And a hydroxyapatite mixture is formed. Therefore, in the production method of the present invention, the Ca / P molar ratio is set to the above-mentioned numerical range and set to an amount exceeding 2.00 which is the theoretical value to compensate for the calcium component lost during dehydration,
By reacting with metastable hydroxyapatite during firing, it was possible to synthesize a large amount of quaternary calcium phosphate. As the dehydration, it is particularly effective to forcibly dehydrate with a centrifuge and then to dry it with an ordinary dryer, and a compound whose density is increased by the centrifugal force of such a centrifuge. Is suitable for use as a raw material for high-strength cement, since it quasi-assembles properly by drying and increases the density of the fired product after the main firing described later. Further, when such a high-density fired product is pulverized, powder having a wide range of particle size distribution is generally obtained. This is to improve the fluidity of the cement paste when it is made into cement.
The liquid ratio can be increased, and as a result, the strength of cement can be increased.

In the manufacturing method of the present invention, after the dehydration / drying, by performing calcination and main calcination at a specific temperature,
The desired quaternary calcium phosphate can be obtained.

Calcination is an essential step for preventing the unreacted calcium feedstock in the dried raw material from remaining as free lime after the next main calcination. In order to prevent the calcination temperature, the lower limit of the calcination temperature is 400 ° C., preferably 700 ° C. for obtaining less quaternary calcium phosphate, and the upper limit is 1200 ° C. for preventing the residual free lime, preferably impurities. 1000 to get low quaternary calcium phosphate
It is necessary to perform in the temperature range of ° C. Furthermore, the main firing is
Preferably, the calcined product obtained by calcination is pulverized with a crusher or the like to obtain a uniform powder, and the lower limit of the calcination temperature is to obtain quaternary calcium phosphate containing few impurities. 1300 ° C., preferably 1350 ° C. to obtain quaternary calcium phosphate with less impurities, and the upper limit is a temperature of 1500 ° C. in consideration of durability of an electric furnace such as an electric furnace and mass production at low cost. Must be done in range. The calcination has a maximum holding time of 1
~ 5 hours and holding time at the maximum temperature of main firing is 3-1
It is preferably within the range of 0 hours.

When the quaternary calcium phosphate obtained by the production method of the present invention is used as a calcium phosphate raw material, it is preferable to grind the quaternary calcium phosphate after the main calcination and use it as a powder. The average particle size of the powder is preferably about 3 to 10 μm, but the powder has a relatively wide particle size distribution in order to improve the fluidity of the paste when the cement is kneaded with water and to increase the strength of the cement. Is preferably used. To obtain such powder,
For example, it can be obtained by dry pulverization using a crusher for about 30 minutes to 3 hours.

[0015]

According to the fourth method for producing calcium phosphate of the present invention, the calcium feedstock and the phosphorus feedstock are slurried by wet synthesis under specific conditions, dried, and then calcined and fired at a specific temperature. The obtained quaternary calcium phosphate has more excellent properties as a raw material of calcium phosphate for living body than the quaternary calcium phosphate produced by the conventional dry method or mechanochemical pulverization method.

In the fourth method for producing calcium phosphate according to the present invention, the calcium feedstock and the phosphorus feedstock Ca
By setting the / P molar ratio within a specific range, a large amount of unnecessary water contained in the slurry after wet synthesis can be dehydrated, and mass production of highly pure quaternary calcium phosphate can be achieved.

[0017]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0018]

Examples 1 to 4 40 liters of water were put into four 50 liter stainless steel tanks, and 40 mol of the calcium feedstock shown in Table 1 was put into each stainless steel tank and sufficiently stirred. Then, each of the phosphorus feedstocks shown in Table 1 is treated separately with water in an amount such that the Ca / P molar ratio becomes 2.05 when reacted with the calcium feedstock.
After being dissolved in liters, the obtained aqueous solutions were gradually dropped into the corresponding stainless steel tanks for 2 hours while stirring. During the reaction, the total volume of each stainless steel tank was changed to the trade name "TRL107A type spiral handy cooler" (manufactured by Thomas Kagaku) and the trade name "TC".
-107E type temperature controller "(manufactured by Thomas Kagaku Co.) was used in combination and maintained at 10 ° C. Leave it for 1 day after the reaction, and trade name "H600S continuous high-speed centrifuge" (made by domestic centrifuge company)
After being dehydrated using, the product was dried in a dryer at 110 ° C. for 24 hours. Next, the obtained dried product was calcined at 900 ° C. for 3 hours. The obtained calcined product was crushed (made by Ishikawa Factory,
Product name "Stirring and crushing machine Tate no. 20") is divided into 1kg aliquots, crushed for 30 minutes each, and finally mixed to form a uniform powder, and then main-baked at 1400 ° C for 3 hours. I did. The finally obtained calcined product was divided into 1 kg each by using the same crushing machine as described above, and pulverized for 3 hours each to obtain about 3.7 kg of powder having an average particle size of 5 to 8 μm. When the obtained powder was identified by a trade name “RINT2000 type X-ray diffractometer” (manufactured by Rigaku Denki Co., Ltd.), it was confirmed that it was a single phase of quaternary calcium phosphate.

[0019]

[Table 1]

[0020]

TEST EXAMPLE 1 Calcium phosphate cement was prepared by mixing the fourth calcium phosphate synthesized in Example 3 and the second calcium phosphate (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) in a molar ratio of 1: 1. The weight ratio of the obtained cement to water is 1
Kneading at 00:35 to make cement paste, diameter 7m
It was poured into a mold having a height of m and a height of 14 mm. At this time, the fluidity of the cement paste was good and the operability was excellent.
Cement paste poured, 37 ℃, 100% humidity
Cured. After curing, soak in physiological saline for 7 days,
When the compression strength of the cured product taken out was measured while it was wet, it was 47.7 ± 4.9 MPa. For the measurement, a universal testing machine "1125 type" manufactured by Instron was used.

[0021]

Comparative Example 1 344 g of dicalcium phosphate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was calcined at 550 ° C. for 3 hours to obtain 254 g of calcium pyrophosphate. Then, the obtained calcium pyrophosphate and calcium carbonate (manufactured by Kanto Chemical Co., Inc., special grade) have a Ca / P molar ratio of 2.00.
Mixed so that Thereafter, firing at 1400 ° C. for 3 hours was repeated twice to obtain a single-phase quaternary calcium phosphate by a dry method. When this was crushed for 30 minutes with the same crusher as in Examples 1 to 4, the average particle size was already 4.5 μm.
The spread of the particle size distribution was obviously narrower than that of any of Examples 1 to 4.

Next, the obtained fourth calcium phosphate and second calcium
Calcium phosphate was mixed at a molar ratio of 1: 1 to prepare a cured product according to Test Example 1, and the compressive strength was measured. At this time, since the fluidity of the cement paste was worse than in Test Example 1, the weight ratio of cement and water was forced to be 100: 40. As a result, the compressive strength was 36.3 ± 7.
The value was 1 MPa, which was clearly lower than that in Test Example 1.

[0023]

[Example 5 and Comparative Example 2] Table 2 shows the temperatures of calcination and main calcination.
A calcined product was obtained in the same manner as in Example 3 except that the substitution was performed as shown in FIG. The results are shown in Table 2.
Shown in.

[0024]

[Table 2]

[0025]

Example 6 A fired product was obtained in the same manner as in Example 3 except that the temperature of the stainless steel tank during the reaction was changed as shown in Table 3.
Identification was performed by an X-ray diffractometer. The results are shown in Table 3. The temperature control was performed using the same handy cooler and temperature controller as in Example 3.

[0026]

[Comparative Example 3] Without controlling the temperature of the stainless steel tank during the reaction,
A calcined product was obtained in the same manner as in Example 3 except that the temperature of the slurry during the reaction was set to 40 ° C. by the heat of reaction, and the identification was performed by the X-ray diffractometer. The results are shown in Table 3.

[0027]

[Table 3]

[0028]

[Example 7 and Comparative Example 4] A calcined product was obtained in the same manner as in Example 3 except that the Ca / P molar ratios of the calcium feedstock and the phosphorus feedstock were changed as shown in Table 4, and the obtained product was analyzed by an X-ray diffractometer. Identification was performed. The results are shown in Table 4.

[0029]

[Table 4]

Claims (1)

[Claims] 1. A raw material slurry which is wet-synthesized in an aqueous solution having a water temperature of 30 ° C. or less so that the Ca / P molar ratio of a calcium feed material and a phosphorus feed material is more than 2.00 and less than 2.10. To dehydrate the raw material slurry
After drying, it is calcined at 400-1200 ° C, then 130
A method for mass production of quaternary calcium phosphate in a large amount, which comprises performing a main calcination at 0 to 1500 ° C.