Device and process for synthesizing porous tricalcium phosphate / tetracalcium phosphate

Abstract

The invention discloses a synthesis device and process of porous tricalcium phosphate / tetracalcium phosphate in the technical field of bone repair materials. The synthesis device comprises a synthesis sintering furnace, a placement mechanism and a separation device, the sintering table is used for placing a sintering material, the synthesis sintering furnace is used for synthesizing tricalcium phosphate, tetracalcium phosphate and a porous material, the placing mechanism is used for placing a sintering raw material, and the separating device is used for enabling the sintering table to be separated from the extending part one by one so as to enable material blocks to fall on the cooling plate. The detachable sintering table is arranged on the placing mechanism, and a high-temperature-resistant metal cooling plate is arranged in the sintering table; after sintering is completed, a sintering table is detached to enable material blocks to fall on a cooling plate, a cooling medium is introduced for cooling, the enough cooling rate is directly achieved in a furnace body, the problem that the cooling rate does not reach the standard due to one-by-one discharging is avoided, the disproportionation reaction of tetracalcium phosphate can be effectively reduced, the purity of tetracalcium phosphate is improved, and the service life of the tetracalcium phosphate is prolonged. Finally, the quality of the porous material is improved.

Description

Technical Field

[0001] This invention relates to the field of bone repair materials, specifically to a porous tricalcium / tetracalcium phosphate synthesis apparatus and process. Background Technology

[0002] Tricalcium phosphate and tetracalcium phosphate are bone repair materials. Both can be synthesized by calcining a mixture of calcium carbonate and calcium hydrogen phosphate in different molar ratios. Porous tricalcium phosphate / tetracalcium phosphate refers to a raw material made by mixing tricalcium phosphate, tetracalcium phosphate, pore-forming agent and functional additives, and then calcining it under certain conditions.

[0003] The above-mentioned calcination synthesis is generally achieved using a sintering furnace. Since tetracalcium phosphate is prone to disproportionation reaction when slowly cooled in the range of 800-1250℃, the calcination synthesis steps of tetracalcium phosphate require quenching treatment (cooling rate greater than 100℃ / s) after calcination. Quenching treatment generally includes methods such as heat conduction cooling of metal plates, liquid nitrogen quenching, and direct blowing of low-temperature protective gas. Existing synthesis and calcination devices do not have a built-in quenching structure. The material blocks can only be removed after sintering and then quenched. This quenching method has the following shortcomings: if there are many material blocks in the sintering furnace, they will not be removed in time. Moreover, after the sintering furnace is turned on, the temperature drops. The material blocks that cannot be removed in time continue to cool down, but the cooling rate does not reach the degree of quenching, which easily leads to disproportionation reaction and the formation of other substances, resulting in insufficient purity of tetracalcium phosphate. Summary of the Invention

[0004] The purpose of this invention is to provide a porous tricalcium / tetracalcium phosphate synthesis apparatus and process, which solves the problem that existing tetracalcium phosphate requires removal from the sintering furnace for rapid cooling.

[0005] The present invention achieves the above objectives through the following technical solutions: A porous tricalcium / tetracalcium phosphate synthesis apparatus, comprising Synthesis sintering furnace, used for synthesizing tricalcium phosphate, tetracalcium phosphate, and porous materials, including furnace body, furnace cover and exhaust pipe; The placement mechanism is used to place sintering raw materials, including an extension that penetrates the furnace cover and several sintering platforms disposed on the side of the extension. The extension is provided with a cooling channel inside and a cooling plate connected to the cooling channel is provided on the side of the extension. The side surface of the extension is detachably provided with a sintering platform covering the cooling plate. The detachment device is used to detach the sintering table one by one from the extension so that the material blocks fall onto the cooling plate.

[0006] As a preferred embodiment of the present invention, the upper end of the extension is provided with a flexible hose that connects to the cooling channel, which is used to connect with an external cooling medium circulation mechanism to continuously pump in the cooling medium. The upper end of the extension is also provided with a lifting and rotating platform, which is used to drive the placement mechanism and the furnace cover to move. This solution continuously pumps in the cooling medium through an external device to achieve the purpose of rapid cooling. It should be noted that the external device is a cooling circulation device, which needs to use existing technology to be compatible with the high temperature and high pressure steam generated by the vaporization of the medium. The flow rate of the medium needs to be kept at a high level to prevent large-scale vaporization at high temperature.

[0007] As a preferred embodiment of the present invention, an extension plate is provided above one end of the extension portion that extends into the furnace body. A limiting strip is provided below the extension plate and the sintering platform, which is used to detach the material block from the sintering platform when the lower sintering platform detaches from the extension portion. Since the material block becomes a brittle block after sintering, in order to detach the material block from the sintering platform, this embodiment adopts a step-by-step detachment method from the sintering platform, from bottom to top. The material block on the sintering platform is pushed by the limiting strip of the upper sintering platform. For the uppermost sintering platform, an additional extension plate is provided for installing the limiting strip.

[0008] As a preferred embodiment of the present invention, the synthesis sintering furnace further includes side chambers disposed on both sides of the furnace body for accommodating the sintering table. The side chambers are provided with extended tracks for the sintering table to slide into. The present invention further provides a method for accommodating the movement of the sintering table.

[0009] As a preferred embodiment of the present invention, an air inlet chamber is further provided on the outer side of the side chamber, and a positive pressure fan is provided on the air inlet chamber to supply air into the air inlet chamber. A through hole is opened between the side chamber and the air inlet chamber, and a heat insulation part is slidably provided in the through hole. An extension rod is provided at one end of the heat insulation part that enters the side chamber, and a hook part is provided at the end of the extension rod for pulling the sintering table. An arc-shaped groove is provided at the bottom of the sintering table so that the hook part can engage with the arc-shaped groove when the sintering table rotates. This embodiment, by providing multiple through holes as air inlets, can form a direct airflow to blow directly onto the material block. The through holes are also used to pull out the sintering table one by one. When rapid cooling is required, the sintering table is pulled out through the heat insulation part and the through hole is opened.

[0010] As a preferred embodiment of the present invention, a pull rod is also provided at the end of the heat insulation part away from the extension rod, which is used to drive the heat insulation part away from the through hole by an external device.

[0011] As a preferred embodiment of the present invention, the cooling plate is provided with guide ribs to facilitate uniform flow of the cooling medium.

[0012] This invention also proposes a synthesis process for porous tricalcium / tetracalcium phosphate, which is synthesized by sintering using any of the above-mentioned synthesis apparatus, and includes the following steps: S1: Calcium carbonate and calcium hydrogen phosphate are mixed in a 3:2 molar ratio, ball-milled, calcined at 900–1100℃ for 4–6 hours in the synthesis apparatus, and then acid-washed to remove impurities after dehydroxylation, to obtain tricalcium phosphate. S2: Calcium carbonate and dicalcium phosphate are mixed in a 2:1 molar ratio and sintered at 1300–1500℃ for 4–6 hours in the synthesis device. After rapid cooling, tetracalcium phosphate is obtained. The rapid cooling method is as follows: after sintering, a low-temperature cooling medium is introduced into the cooling plate for pre-cooling. Then, the sintering platform is separated from the extension section, and the material block falls onto the cooling plate. With the help of forced ventilation in the furnace, the temperature is rapidly cooled to below 300℃ at a cooling rate of 250–300℃ / s. S3: Tricalcium phosphate and tetracalcium phosphate are ball-milled, sieved, mixed at a mass ratio of 3-4:1, and 35 vol% ammonium bicarbonate is added to form a green body. After calcination in the synthesis device, the green body is rapidly cooled to obtain a porous material. The calcination temperature is: 500-600℃ in the first stage and 1350-1400℃ in the second stage.

[0013] The beneficial effects of this invention are as follows: by setting a detachable sintering platform on the placement mechanism and building a high-temperature resistant metal cooling plate inside the sintering platform, after sintering, the material blocks are dropped onto the cooling plate by removing the sintering platform and cooling medium is introduced for cooling, achieving a sufficient cooling rate directly in the furnace body. This avoids the problem of insufficient cooling rate caused by feeding materials one by one, effectively reducing the disproportionation reaction of tetracalcium phosphate, improving the purity of tetracalcium phosphate, and ultimately improving the quality of porous materials. Attached Figure Description

[0014] Figure 1 This is a front sectional view of the present invention; Figure 2 For the present invention Figure 1 View from AA direction; Figure 3 For the present invention Figure 1 Enlarged view of the structure of section B; Figure 4 This is a top sectional view of the cooling channel cooling plate of the present invention; Figure 5 For the present invention Figure 1 C-axis view; Figure 6 For the present invention Figure 5 Schematic diagram of the installation process of the central placement mechanism; In the diagram: 1. Synthesis sintering furnace; 11. Furnace body; 12. Side chamber; 13. Air inlet cavity; 14. Exhaust pipe; 15. Extension track; 16. Positive pressure air supply device; 17. Furnace cover; 2. Placement mechanism; 21. Extension section; 22. Cooling channel; 23. Slot; 24. Sintering table; 25. Cooling plate; 26. Extension plate; 27. Guide rib; 28. Limiting strip; 29. ​​Lifting and rotating table; 210. Arc-shaped groove; 3. Detachment device; 31. Heat insulation section; 32. Tie rod; 33. Extension rod; 34. Hook connection section; 4. Material block. Detailed Implementation

[0015] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0016] Example 1 like Figure 1-6 As shown, a porous tricalcium / tetracalcium phosphate synthesis apparatus includes a synthesis sintering furnace 1, a placement mechanism 2, and a release device 3. The synthesis sintering furnace 1 is used to synthesize tricalcium phosphate, tetracalcium phosphate, and porous materials, and includes a furnace body 11, a furnace cover 17, and an exhaust pipe 14. The placement mechanism 2 is used to place sintering raw materials, including an extension 21 penetrating the furnace cover 17 and a plurality of sintering platforms 24 disposed on the side of the extension 21. The extension 21 has a cooling channel 22 inside, and a cooling plate 25 connected to the cooling channel 22 is disposed on the side of the extension 21. The sintering platforms 24 covering the cooling plate 25 are detachably disposed on the side surface of the extension 21. The release device 3 is used to detach the sintering platforms 24 one by one from the extension 21 so that the material block 4 falls onto the cooling plate 25.

[0017] This solution involves setting a detachable sintering platform 24 on the placement mechanism 2, and embedding a high-temperature resistant metal cooling plate 25 inside the sintering platform 24. After sintering, the sintering platform 24 is removed, causing the material block 4 to fall onto the cooling plate 25, and a cooling medium is introduced for cooling. This achieves a sufficient cooling rate directly within the furnace body 11, avoiding the problem of insufficient cooling rate caused by feeding materials one by one. This effectively reduces the disproportionation reaction of tetracalcium phosphate, improves the purity of tetracalcium phosphate, and ultimately improves the quality of porous materials.

[0018] The upper end of the extension 21 is provided with a flexible hose that connects to the cooling channel 22, which is used to connect to the external cooling medium circulation mechanism to continuously pump in the cooling medium. The upper end of the extension 21 is also provided with a lifting and rotating platform 29, which is used to drive the placement mechanism 2 and the furnace cover 17 to move. This solution continuously pumps in the cooling medium through an external device to achieve the purpose of rapid cooling. It should be noted that the external device is a cooling circulation device, which needs to use existing technology to be compatible with the high temperature and high pressure steam generated by the vaporization of the medium. The flow rate of the medium needs to be kept at a high level to prevent large-scale vaporization at high temperature.

[0019] In this embodiment, an extension plate 26 is provided above one end of the extension 21 that extends into the furnace body 11. A limiting strip 28 is provided below the extension plate 26 and the sintering platform 24. The limiting strip 28 is used to detach the material block 4 from the sintering platform 24 when the lower sintering platform 24 detaches from the extension 21. Since the material block becomes a brittle block after sintering, in order to detach the material block 4 from the sintering platform 24, this embodiment adopts a step-by-step detachment method from the sintering platform 24, detaching the material block 4 from the sintering platform 24 layer by layer from bottom to top. The material block 4 on the sintering platform 24 is pushed and retained in its original position by the limiting strip 28 of the upper sintering platform 24. Finally, after the sintering platform 24 is detached, it falls onto the cooling plate 25. For the uppermost sintering platform 24, an additional extension plate 26 is provided to install the limiting strip 28.

[0020] Furthermore, the synthesis sintering furnace 1 also includes side chambers 12 disposed on both sides of the furnace body 11, which are used to accommodate the sintering platform 24. The side chambers 12 are provided with extended tracks 15 for the sintering platform 24 to slide into. This solution further provides a way to accommodate the movement of the sintering platform 24.

[0021] Specifically, an air inlet chamber 13 is provided on the outside of the side chamber 12. A positive pressure air supply device 16 is provided on the air inlet chamber 13 to supply air into the air inlet chamber 13. A through hole is opened between the side chamber 12 and the air inlet chamber 13 to connect them. A heat insulation part 31 is slidably arranged in the through hole. An extension rod 33 is provided at one end of the heat insulation part 31 that enters the side chamber 12. A hook part 34 is provided at the end of the extension rod 33 to pull the sintering table 24. An arc-shaped groove 210 is provided at the bottom of the sintering table 24 so that the hook part 34 can be engaged with the arc-shaped groove 210 when the sintering table 24 rotates. By setting multiple through holes as air inlets, a direct airflow can be formed to blow directly onto the material block. The through holes are also used to pull out the sintering table 24 one by one. When rapid cooling is required, the sintering table 24 is pulled out through the heat insulation part 31 and the through hole is opened.

[0022] A pull rod 32 is also provided at the end of the heat insulation part 31 away from the extension rod 33, which is used to drive the heat insulation part 31 away from the through hole by an external device.

[0023] The cooling plate 25 is provided with guide ribs 27 to facilitate the uniform flow of the cooling medium.

[0024] This invention also proposes a synthesis process for porous tricalcium / tetracalcium phosphate, which is synthesized by sintering using any of the above-mentioned synthesis apparatus, and includes the following steps: S1: Calcium carbonate and calcium hydrogen phosphate were mixed and ball-milled in a 3:2 molar ratio, calcined at 1000℃ for 5 hours in a synthesis device, and then acid-washed to remove impurities after dehydroxylation to obtain tricalcium phosphate. S2: Calcium carbonate and dicalcium phosphate are mixed in a 2:1 molar ratio and sintered at 1400℃ for 5 hours in a synthesis device. After rapid cooling, tetracalcium phosphate is obtained. The rapid cooling method is as follows: after sintering, a low-temperature cooling medium is introduced into the cooling plate 25 for pre-cooling. Then, the sintering platform 24 is separated from the extension 21, and the material block 4 falls onto the cooling plate 25. With the forced ventilation of the furnace body 11, the temperature is rapidly cooled to below 300℃, and the cooling rate is 270℃ / s. As another implementation method, cooling rates of 250°C / s and 300°C / s are used respectively, and the flow rates are controlled by the flow rate of the cooling medium and the flow rate of the gas. S3: Tricalcium phosphate and tetracalcium phosphate are ball-milled, sieved, mixed at a mass ratio of 4:1, and 35 vol% ammonium bicarbonate is added to form a green body. After calcination in a synthesis device, the green body is rapidly cooled to obtain a porous material. The calcination temperatures are: 550℃ in the first stage and 1380℃ in the second stage.

[0025] Detailed implementation: The placement mechanism 2 and the furnace cover 17 are placed into the furnace body 11 via the lifting and rotating platform 29, as follows: Figure 6 The object is placed at the angle shown, and then sintered according to preset conditions. After the sintering processes in steps S2 and S3, the placement mechanism 2 is rotated 90° by the lifting and rotating table 29. Figure 5 In the state shown, the hook part 34 enters the arc-shaped groove 210, and the edge of the sintering table 24 is mounted on the upper part of the extension track 15. By pulling out the pull rods 32 one by one, it can be controlled one by one by the servo device or manually pulled out. The hook part 34 hooks out the sintering table 24 and enters the side chamber 12 along the extension track 15. The limiting strip 28 causes the material block 4 to fall onto the cooling plate 25. The cooling channel 22 is filled with a high-flow-rate cooling medium and enters the cooling plate 25 for cooling. In addition, the positive pressure wind device 16 introduces low-temperature inert gas into the air inlet chamber 13. After the heat insulation part 31 leaves the through hole, multiple air inlets are exposed. The gas blown into the furnace body 11 can directly blow the material block 4 on each cooling plate 25 to rapidly cool the upper surface of the material block 4. The airflow is discharged from the exhaust pipe 14, taking away the heat in the furnace body 11. This part of the heat can be recovered in the exhaust pipe 14. After rapid cooling, the furnace is opened and the placement mechanism 2 is taken out. During reset, the lifting rotary table 29 controls the placement mechanism 2 to descend, aligning the cooling plate 25 with the sintering table 24. Then, the hook part 34 pushes the sintering table 24 to slide along the side chamber 12 and the extension track 15, fitting it onto the cooling plate 25. A chamfer can be provided at the joint. Continue pushing until the sintering table 24 is completely fitted onto the cooling plate 25. The placement mechanism 2 then... Figure 5 Rotation Figure 6 After reaching the desired state, the placement mechanism 2 is raised to facilitate the next sintering.

[0026] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A porous tricalcium / tetracalcium phosphate synthesis apparatus, characterized in that, include Synthesis sintering furnace (1), which is used to synthesize tricalcium phosphate, tetracalcium phosphate and porous materials, includes furnace body (11), furnace cover (17) and exhaust pipe (14). The placement mechanism (2) is used to place sintering raw materials, including an extension (21) that penetrates the furnace cover (17) and a plurality of sintering platforms (24) provided on the side of the extension (21). The extension (21) is provided with a cooling channel (22) inside, and a cooling plate (25) connected to the cooling channel (22) is provided on the side of the extension (21). The side surface of the extension (21) is detachably provided with sintering platforms (24) covering the cooling plate (25). The detachment device (3) is used to detach the sintering table (24) one by one from the extension (21) so that the material block (4) falls onto the cooling plate (25).

2. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 1, characterized in that, The upper end of the extension (21) is provided with a flexible hose that connects to the cooling channel (22), which is used to connect with the external cooling medium circulation mechanism to continuously pump in the cooling medium. The upper end of the extension (21) is also provided with a lifting and rotating platform (29), which is used to drive the placement mechanism (2) and the furnace cover (17) to move.

3. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 1, characterized in that, An extension plate (26) is provided above one end of the extension (21) that extends into the furnace body (11). A limit strip (28) is provided below the extension plate (26) and the sintering table (24), which is used to make the material block (4) detach from the sintering table (24) when the lower sintering table (24) detaches from the extension (21).

4. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 3, characterized in that, The synthesis sintering furnace (1) also includes side chambers (12) on both sides of the furnace body (11), which are used to accommodate the sintering platform (24). The side chambers (12) are provided with an extension track (15) for the sintering platform (24) to slide into.

5. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 4, characterized in that, An air inlet chamber (13) is also provided on the outside of the side chamber (12). A positive pressure wind device (16) is provided on the air inlet chamber (13) to supply air into the air inlet chamber (13). A through hole is opened between the side chamber (12) and the air inlet chamber (13) to communicate with each other. A heat insulation part (31) is slidably provided in the through hole. An extension rod (33) is provided at one end of the heat insulation part (31) that enters the side chamber (12). A hook part (34) is provided at the end of the extension rod (33) to pull the sintering table (24). An arc-shaped groove (210) is provided at the bottom of the sintering table (24) to allow the hook part (34) to engage with the arc-shaped groove (210) when the sintering table (24) rotates.

6. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 5, characterized in that, The end of the heat insulation part (31) away from the extension rod (33) is also provided with a pull rod (32), which is used to drive the heat insulation part (31) away from the through hole by an external device.

7. The porous tricalcium / tetracalcium phosphate synthesis apparatus according to claim 1, characterized in that, The cooling plate (25) is provided with guide ribs (27).

8. A process for synthesizing porous tricalcium / tetracalcium phosphate, comprising sintering using the synthesis apparatus described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Calcium carbonate and calcium hydrogen phosphate are mixed in a 3:2 molar ratio, ball-milled, calcined at 900–1100℃ for 4–6 hours in the synthesis apparatus, and then acid-washed to remove impurities after dehydroxylation, to obtain tricalcium phosphate. S2: Calcium carbonate and dicalcium phosphate are mixed in a 2:1 molar ratio and sintered at 1300–1500℃ for 4–6 hours in the synthesis device. After rapid cooling, tetracalcium phosphate is obtained. The rapid cooling method is as follows: after sintering, the cooling plate (25) is pre-cooled by passing a low-temperature cooling medium through it. Then, the sintering platform (24) is separated from the extension (21), and the material block (4) falls onto the cooling plate (25). With the forced ventilation of the furnace body (11), the material is rapidly cooled to below 300℃ at a cooling rate of 250–300℃ / s. S3: Tricalcium phosphate and tetracalcium phosphate are ball-milled, sieved, mixed at a mass ratio of 3-4:1, and 35-40 vol% ammonium bicarbonate is added to form a green body. After calcination in the synthesis device, the green body is rapidly cooled to obtain a porous material. The calcination temperature is: 500-600℃ in the first stage and 1350-1400℃ in the second stage.

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