JP3371539B2 - Method for mass production of quaternary calcium phosphate by wet method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to a large-scale wet production method of quaternary calcium phosphate that can be used as a component of a biocement or the like. 2. Description of the Related Art Calcium phosphate cements for living organisms which have good biocompatibility and harden in a practical time only by mixing with water have been developed (for example, FC PEPORT, vol.
6 (1988), pp. 475-480, "Hydraulic apatite as bioceramics"). The main hardening component of such a calcium phosphate cement is α-type tricalcium phosphate or quaternary calcium phosphate.
It is calcium phosphate. Among these, the methods for producing the quaternary calcium phosphate include dry methods (for example, gypsum and lime, No. 202, p151 to 155, (1986) "Synthesis of tetracalcium phosphate") and mechanochemical pulverization methods (for example, Proposal of a synthesis method based on the 9th Inorganic Phosphorous Chemistry Symposium Proceedings, p19-20 (1992) "Synthesis of tetracalcium phosphate"). However, since the quaternary calcium phosphate obtained by the dry method has too good pulverizability, only a powder having a relatively narrow range of particle size distribution can be obtained. 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, it is necessary to perform high-temperature sintering exceeding 1500 ° C., so that it is not suitable for mass synthesis. [0004] It is an object of the present invention to provide a bio-based cement or the like having a suitable crushing property as a constituent component of a bio-calcium phosphate cement or the like, and to increase the strength of the resulting bio-cement or the like. It is an object of the present invention to provide a large-scale wet production method of quaternary calcium phosphate which can be performed. [0005] Another object of the present invention is to provide a method for mass production of quaternary calcium phosphate, which can be mass-synthesized. [0006] According to the present invention, the water temperature 3
In an aqueous solution at 0 ° C. or lower, a raw material slurry is obtained by wet synthesis so that the Ca / P molar ratio of the calcium supply material and the phosphorus supply material is more than 2.00 and less than 2.10. After dehydration and drying, 400 ~ 1
A large-scale wet production method of quaternary calcium phosphate is provided, wherein the method is calcined at 200 ° C and further calcined at 1300 to 1500 ° C. Hereinafter, the present invention will be described in more detail. In the production method of the present invention, first, a raw material slurry is prepared by performing wet synthesis in an aqueous solution at a specific temperature or lower so that the Ca / P molar ratio of the calcium supply material and the phosphorus supply material is in a specific range. The calcium supply material and the phosphorus supply material are not particularly limited as long as they can constitute quaternary calcium phosphate. Examples of the calcium supply material include CaCl ₂ , Ca (N
O ₃ ) ₂ , Ca (OH) _2, etc., and the phosphorus supply materials include H ₃ PO ₃ , KH ₂ PO ₄ , and (NH ₄ ) ₂ H
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 feed and the phosphorus feed is determined by the dehydration and
In order to prevent discharge of unreacted calcium components in the aqueous solution during drying and to synthesize quaternary calcium phosphate having a small amount of impurities, the Ca / P molar ratio of the calcium supply material and the phosphorus supply material is adjusted to the theoretical Ca of hydroxyapatite.
/ P molar ratio must be higher than 1.67, specifically 2.00, and preferably 2.02 to synthesize reproducible and less contaminated quaternary calcium phosphate.
It is. The upper limit is 2.10 in order to prevent free lime from being mixed in after the main firing, and preferably 2.08 in order to synthesize quaternary calcium phosphate with less reproducibility and less impurities. In order to prepare a raw material slurry by wet-synthesizing the calcium supply material and the phosphorus supply material, for example, a method in which the aqueous solution containing the phosphorus supply material is gradually added dropwise to the aqueous solution containing the calcium supply material while stirring. Can be obtained by In the raw material slurry obtained at this time,
Hydroxyapatite, which is the most stable in calcium phosphate, is also generated and its crystallinity is increased in an aqueous solution, so that the hydroxyapatite may remain as an impurity after the main firing described below. In order to prevent this, it is effective to promote the reaction by suppressing the heat of 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 a constant temperature condition. . Therefore, the water temperature of the aqueous solution for synthesizing the raw material slurry is 30 ° C. or lower, preferably 20 ° C. or lower, particularly preferably 10 ° C. or lower. The lower limit temperature is sufficient if the aqueous solution does not freeze. Next, in the production method of the present invention, the raw material slurry is dehydrated and dried. When the synthesis amount of the raw material slurry is small (for example, 15 liters or less), the whole slurry can be dried as it is with a usual dryer, but as in the production method of the present invention, the synthesis amount is large ( (For example, 50 liters or more), it is necessary to dehydrate before drying, for example, by using a centrifuge, discarding the supernatant, or spray-drying using a spray drier. The theoretical Ca / P molar ratio when synthesizing quaternary calcium phosphate by a wet method is determined by its structural formula (Ca
₄ (PO ₄ ) ₂ · O), which is 2.00 as is clear. However, when the quaternary calcium phosphate is actually prepared by wet synthesis, in addition to the desired quaternary calcium phosphate, hydroxyapatite having a more stable and low Ca / P molar ratio,
A mixture with unreacted calcium components is also obtained. When the dehydration step is an essential requirement to increase the amount of synthesis as in the production method of the present invention, the composition is shifted by the amount of the calcium component remaining in the waste liquid, and when calcined, the quaternary calcium phosphate And a mixture of hydroxyapatite 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 the theoretical value of 2.00 to compensate for the calcium component lost during dehydration,
By reacting with metastable hydroxyapatite at the time of firing, mass synthesis of quaternary calcium phosphate was made possible. As the dehydration, in particular, it is efficient to forcibly dehydrate with a centrifugal separator, and then dry it with a normal dryer, and the compound whose density has been increased by centrifugal force by such a centrifuge. Is suitably collected as a raw material for high-strength cement because it is appropriately collected by drying to increase the density of a fired product after the main firing described below. Further, when such a high-density fired product is pulverized, a 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 cemented,
The liquid ratio can be increased, and as a result, the strength of the cement can be increased. [0012] In the production method of the present invention, after the dehydration and drying, pre-firing and main firing are performed at a specific temperature.
The desired quaternary calcium phosphate can be obtained. [0013] The calcining is an essential step for preventing unreacted calcium feedstock in the dried raw material from remaining as free lime after the next main firing. The lower limit of the calcination temperature is 400 ° C., preferably 700 ° C. in order to obtain quaternary calcium phosphate with less impurities, and the upper limit is 1200 ° C., preferably in order to prevent free lime from remaining. 1000 to obtain quaternary calcium phosphate with less
It must be performed in the temperature range of ° C. Further, the main firing is
Preferably, the calcined product obtained by calcining is desirably pulverized by a crusher or the like to obtain a uniform powder. The lower limit of the calcining temperature is to obtain quaternary calcium phosphate with less impurities. 1300 ° C., preferably 1350 ° C. in order to obtain quaternary calcium phosphate with less impurities, and the upper limit is 1500 ° C. in consideration of the durability of an electric furnace such as an electric furnace and mass production at low cost. It is necessary to do within a range. The calcination has a holding time at the highest temperature of 1
５5 hours and the holding time at the maximum temperature of the main firing are 3 to 1
It is preferable to set the range to 0 hours. When the quaternary calcium phosphate obtained by the production method of the present invention is used as a raw material for calcium phosphate, for example, after the main baking, the quaternary calcium phosphate is preferably ground and used as a powder. The average particle size of the powder is preferably about 3 to 10 μm, but in order to enhance the fluidity of the paste when kneading the cement with water and to increase the strength of the cement, a powder having a relatively wide particle size distribution is used. It is preferred to use To obtain such a powder,
For example, it can be obtained by dry pulverization for about 30 minutes to 3 hours using a crusher. According to the method for producing a fourth calcium phosphate of the present invention, a calcium supply material and a phosphorus supply material are slurried by wet synthesis under specific conditions, dried, and then calcined and calcined at a specific temperature. As a result, the resulting quaternary calcium phosphate has more excellent properties as a raw material of a biological calcium phosphate than the quaternary calcium phosphate produced by a conventional dry method or mechanochemical pulverization method. Further, in the method for producing a quaternary calcium phosphate of the present invention, the calcium feed and the phosphorus feed Ca
By setting the / P molar ratio to a specific range, unnecessary water contained in the slurry after the wet synthesis can be dehydrated in large amounts, and mass production of high-purity quaternary calcium phosphate is possible. The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Examples 1 to 4 Into four 50 liter stainless steel tanks, 40 liters of water were respectively charged, and 40 mols of calcium feed materials shown in Table 1 were charged into each stainless steel tank, and sufficiently stirred. did. Then, each of the phosphorus feedstocks shown in Table 1 was separately reacted with the calcium feedstock in an amount such that the molar ratio of Ca / P became 2.05.
After dissolution in 1 liter, the obtained aqueous solution was gradually dropped into the corresponding stainless steel tank over 2 hours while stirring. During the reaction, the entire capacity of each stainless steel tank was changed to “TRL107A Spiral Handy Cooler” (manufactured by Thomas Kagaku) and “TC”
The temperature was maintained at 10 ° C. in combination with a “-107E type temperature controller” (manufactured by Thomas Science Co., Ltd.). Leave it for one day after the completion of the reaction, and trade name "H600S type continuous high-speed centrifuge" (manufactured by Domestic Centrifuge)
, And dried at 110 ° C for 24 hours with a dryer. Next, the obtained dried product was calcined at 900 ° C. for 3 hours. The obtained calcined product is crushed (made by Ishikawa Plant,
The product was subdivided into 1 kg pieces under the trade name “Vertical stirrer No. 20” and pulverized for 30 minutes each, and finally mixed to obtain a uniform powder, which was finally baked at 1400 ° C. for 3 hours. Done. Finally, the obtained fired product was subdivided into 1 kg by using the same crusher as 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 Corporation), it was confirmed that each powder was a single phase of quaternary calcium phosphate. [Table 1] Test Example 1 Calcium phosphate cement was prepared by mixing the quaternary calcium phosphate synthesized in Example 3 and the second calcium phosphate (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) at a molar ratio of 1: 1. The weight ratio of the obtained cement and water is 1
Knead at 00:35 to make a cement paste, 7m in diameter
m, and poured into a mold having a height of 14 mm. At this time, the fluidity of the cement paste was good and the operability was excellent.
37 ° C, 100% humidity
And cured. After curing, dipped in physiological saline for 7 days,
The compressive strength of the cured product taken out was measured with the wet condition being 47.7 ± 4.9 MPa. The measurement was performed using a universal testing machine “1125 type” manufactured by Instron. Comparative Example 1 344 g of dicalcium phosphate dihydrate (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) was calcined at 550 ° C. for 3 hours to obtain 254 g of calcium pyrophosphate. Next, the obtained calcium pyrophosphate and calcium carbonate (special grade, manufactured by Kanto Chemical Co., Ltd.) were mixed at a Ca / P molar ratio of 2.00.
And mixed so that Thereafter, baking at 1400 ° C. for 3 hours was repeated twice to obtain a single-phase quaternary calcium phosphate by a dry method. This was crushed for 30 minutes by the same grinder as in Examples 1 to 4, and the average particle size was already 4.5 μm.
The spread of the particle size distribution was clearly narrow as compared with any of Examples 1 to 4. Next, the obtained quaternary calcium phosphate and the second
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 lower than that in Test Example 1, the weight ratio of cement to water had to be 100: 40. As a result, the compressive strength is 36.3 ± 7.
The value was 1 MPa, which was clearly lower than that of Test Example 1. Example 5 and Comparative Example 2 Table 2 shows the temperatures of calcination and main calcination.
Except having been changed as shown in Table 2, a fired product was obtained in the same manner as in Example 3, and identification was performed using an X-ray diffractometer. Table 2 shows the results.
Shown in [Table 2] 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 using an X-ray diffractometer. Table 3 shows the results. Note that the same handy cooler and temperature controller as in Example 3 were used for temperature control. Comparative Example 3 The temperature of the stainless steel tank during the reaction was not controlled,
A baked product was obtained in the same manner as in Example 3 except that the temperature of the slurry during the reaction was set at 40 ° C. by the heat of reaction, and identification was performed using an X-ray diffractometer. Table 3 shows the results. [Table 3] 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 ratio of the calcium feed and the phosphorus feed was changed as shown in Table 4. Identification was performed using a diffractometer. Table 4 shows the results. [Table 4]

Claims (1)

(57) [Claim 1] In an aqueous solution at a water temperature of 30 ° C. or lower, the Ca / P molar ratio of a calcium feedstock and a phosphorus feedstock is more than 2.00 and less than 2.10. The raw material slurry is obtained by wet synthesis so that the raw material slurry is dehydrated and
After drying, it is calcined at 400 to 1200 ° C.
A large-scale wet production method for quaternary calcium phosphate, which is calcined at 0 to 1500 ° C.