JPS63170205A - Production of hydroxyapatite - Google Patents

Abstract

PURPOSE:To obtain the title stoichiometrical hydroxyapatite in high yield, by introducing a calcium salt soln., a phosphate soln., and an alkaline soln. into a mixer, and discharging the reaction product from an outlet. CONSTITUTION:The calcium salt soln., phosphate soln., and alkaline soln. as the raw materials for hydroxyapatite are simultaneously introduced into the soln. mixer 1 respectively from one inlet 2c of a double pipe, the other inlet 2b of the double pipe, and an inlet 2a. The alkaline soln. is allowed to simultaneously react with the solns. of the calcium salt and phosphate. The obtained reaction product is discharged from an outlet 3, and hydroxyapatite is obtained. Besides, other metallic salts (the salts of Pb, Ba, Sr, Cd, Zn, Ni, Mg, Na, K, and Al) are partly mixed into the calcium salt, and the reaction products having various properties can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing hydroxyapatite, and more specifically, a calcium salt solution, a phosphate solution, and an alkaline solution, which are raw materials for hydroxyapatite, are introduced into the solution from respective inlets. The present invention relates to a continuous manufacturing method in which hydroxyapatite is introduced into a mixer, mixed and reacted, and then the resulting reaction product is discharged from an outlet to obtain hydroxyapatite in a stoichiometric ratio at a high yield.

[Prior art] Methods for synthesizing hydroxyapatite include ■Dry method, ■
It can be roughly divided into wet methods, ■hydrothermal methods, and ■solid-aqueous methods.

In the dry method (■), Ca 3 (PO4) 2, Ca
It is obtained by subjecting HPO4, Ca 2 P207, etc. to a solid phase reaction in water vapor at a high temperature of 800° C. or higher.

In the hydrothermal method (2), large crystals are obtained by reacting Ca HPO4 in an autoclave at 300° C. or higher and under several hundred atmospheric pressures for a long period of time.

In the solid-water method (2), hydroxyapatite with low solubility is precipitated from Ca HPO4 and CaCO3.

However, in the cases of (1) and (2), a reaction vessel that can withstand high temperature and high pressure is required, and in (2), a high temperature and a long time are required to complete the reaction and increase the yield. On the other hand, the wet method (■) conventionally employs a unilateral addition method, and therefore
It is difficult to obtain crystals with a stoichiometric ratio of P=1.67, and in order to overcome this, the range of E)H is limited.

In addition, the methods of the prior art (1) to (2) all involve batch production, which requires reaction vessels depending on the scale of production, and has the disadvantage that the properties of the products from each batch tend to differ.

Furthermore, in the conventional wet method, in order to adjust the Ca/P ratio, the charging ratio of an alkali source such as aqueous ammonia is used, but the precipitation rate of Ca (OH)2 or the Ca3 (PO4)2 The precipitation rate increases, and the Ca/P ratio of the precipitate differs between the start and end of the reaction. As a result, a mixture of hydroxyapatites with different Ca/P ratios is obtained, and in order to achieve uniformity, aging, boiling, etc. are performed.

[Problems to be Solved by the Invention] In view of the problems of the prior art, the present invention provides a method for continuously producing homogeneous and high-quality hydroxyapatite on an industrial scale.

In other words, the stoichiometric ratio Ca/P=1.67.
' The objective is to continuously and stably produce hydroxyapatite represented by Ca + o (PO4)6 (OH)2.

[Means and effects for solving the problem] As a result of intensive studies to achieve the above object, the present inventors have developed a solution that uses a calcium salt solution, a phosphate solution, and an alkaline solution as raw materials for human oxyapatite. The present invention was based on the knowledge that the above objective can be achieved by introducing the solutions into a solution mixer from each inlet, mixing and reacting each solution, and then drawing out the resulting reaction product from the outlet. The invention has been achieved.

Examples of calcium salts that are raw materials for hydroxyapatite used in the present invention include salts such as calcium nitrate, calcium chloride, calcium formate, and calcium acetate. Examples of phosphates include ammonium monophosphate, ammonium diphosphate, Examples include tertiary ammonium phosphate.

In addition, the alkaline solution is appropriately selected depending on the type of calcium salt or phosphate, but ammonia water, aqueous ammonia,
An ammonium bicarbonate solution, a sodium carbonate solution, a mixed solution thereof, etc. are used as appropriate. Note that some of the calcium salts contain other metal salts (Pb, Ba, Sr,
Cd, Zn1Ni.

By mixing Mg, N81, and AU salt), reaction products with various properties can be obtained.

Hereinafter, the present invention will be specifically explained based on the drawings.

FIG. 1 and FIG. 2 are schematic diagrams showing an example of the method for producing hydroxyapatite of the present invention, respectively.
is a solution mixer, 28 to 2C are inlets, and 3 is an outlet.

In FIG. 1, the alkaline solution is introduced from the inlet 2a of the solution mixer 1, and the phosphate and calcium salt solutions are simultaneously introduced from the inlets 2b and 2C, which are double pipes. and phosphate solutions are arranged to react simultaneously.

Moreover, FIG. 2 shows a solution mixer that can be used when an alkaline solution is mixed in advance with a solution of calcium salt and/or phosphate.

As described above, the solution mixer 1 used in the present invention has a plurality of inlets 2 and one outlet 3, but the shape thereof may be arbitrary as shown in FIGS. 1 and 2. An arbitrary shape may be adopted in consideration of the order of addition of the alkaline solution and the calcium salt or phosphate solution, dilution rate, flow rate, etc.

In the present invention, a solution mixer 1 having an arbitrary shape as shown in FIGS. 1 and 2 is used, and the dilution rate, concentration, flow rate, etc. of the alkaline solution, calcium salt or phosphate solution are adjusted. However, by maintaining the set conditions, the desired reaction product (produced precipitate) can be obtained regardless of the scale of production. For example, Ca /P-
A solution of a calcium salt and a solution of a phosphate, adjusted to give a concentration of Direct it to the filter as it is and filter it, Ca /P=
1.67 of the product can be obtained continuously. In general, not only the composition of Ca / P-1,67, but also the concentration of alkaline solution or flow rate after changing the concentration of calcium salt or its liquid feeding rate or the concentration of phosphate or its liquid feeding rate. By adjusting, Ca
/P ratio can be easily changed.

In addition, if a baffle plate, glass filter, slit, etc. is provided in the place where the alkaline solution, calcium salt, or phosphate solution is mixed in the solution mixer 1 to create turbulence, it is possible to create a turbulent flow. The phosphate solution can be mixed efficiently, and the shape of the solution mixer 1 can be made compact.

In this way, the alkaline solution and the calcium salt or phosphate solution are mixed in the solution mixer 1, and a reaction product (produced precipitate) is obtained. This reaction product is led out from the outlet 3 and is introduced onto a filter for filtration.

Next, hydroxyapatite is obtained by washing and drying by a conventional method.

The hydroxyapatite thus obtained is homogeneous and of high quality. Therefore, the hydroxyapatite obtained according to the present invention is suitable for applications requiring homogeneous properties such as materials for bioceramics.

[Examples] Hereinafter, the present invention will be explained in more detail based on Examples.

Hydroxyapatite was produced using a solution mixer 1 shown in FIG.

A containing 1.25 mol of ammonia as alkaline solution
A solution 1500yj, a solution B 1500yf containing 0.9 mole of ammonium phosphate, and a solution C 1500if containing 1.5 mole calcium nitrate were prepared, respectively.

These solutions A, B, and C were introduced continuously for 15 minutes at room temperature (approximately 20°C) from the inlets 2a, 2b, and 2c of the solution mixer 1 shown in FIG. product) was obtained. In parallel with the reaction, this reaction product was passed onto a filter and filtered, and after repeated washing and filtration, it was dried with hot air and then pulverized in a grinding bowl.

As a result of measuring the Ca/P ratio of the obtained reaction product, it was found to be 1
．． 67, and there was no leakage of calcium or phosphorus from the filtrate.

Example 2 Hydroxyapatite was produced in exactly the same manner as in Example 1 using the solution mixer 1 shown in FIG.

1.1 mol of ammonia, 1 mol of ammonium phosphate
．． Mixing was carried out under exactly the same conditions as in Example 1, except that Ca(NO3)2 was 0 mol and Ca(NO3)2 was 1.5 mol.

As a result of measuring the Ca/P ratio of the obtained reaction product, 1.
5, and there was no leakage of either calcium or phosphorus from the filtrate.

Example 3 1.1 mol of ammonia was mixed in advance into a solution containing 1.5 mol of ammonium phosphate as solution B, and 1,500 mol of ammonia was mixed in advance.
The procedure was carried out in exactly the same manner as in Example 1 except that xf was used, and the solution 1500if containing 6.3 moles of ammonia was used as the A solution, and the solution 150011 containing 2,925 moles calcium nitrate was used as the C solution.

As a result of measuring the Ca/P ratio of the obtained reaction product, it was found to be 1
．． 95, and there was no leakage of calcium or phosphorus from the filtrate.

Table 1 summarizes the results of Examples 1 to 3.

Table 1 [Effects of the Invention] As explained above, the method for producing hydroxyapatite of the present invention using a solution mixer has the following effects.

■Stoichiometric ratio Ca /P-1, which was previously considered difficult.
67 can be easily obtained.

(2) It can be obtained continuously and stably regardless of the amount, and the composition is reproducible.

■General-purpose reaction equipment other than the solution mixer will suffice, and no special equipment is required.

■Synthesis can be performed by setting the Ca/P ratio arbitrarily depending on the purpose.

Therefore, according to the present invention, uniform and high quality hydroxyapatite can be continuously produced on an industrial scale.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the method for producing hydroxyapatite of the present invention, and FIG. 2 is a schematic diagram of another embodiment of the present invention. 1: Solution mixer, 2a to 2C: Inlet, 3: Outlet.

Claims (1)

[Claims] 1. A calcium salt solution, a phosphate solution, and an alkaline solution, which are raw materials for hydroxyapatite, are introduced into a solution mixer through their respective inlets and mixed, and the resulting reaction product is flowed. A method for producing hydroxyapatite, characterized in that it is derived from an outlet. 2. The method for producing hydroxyapatite according to claim 1, wherein an alkaline solution is added to the calcium salt solution and/or phosphate solution in advance, and then each solution is introduced from each inlet.