Artificial bone preparation method and artificial bone material

Abstract

The present invention proposes a method for preparing an artificial bone, and the preparation method comprises the following steps: S1, synthesizing β-tricalcium phosphate powder; S2, preparing an organic template, wherein the organic template is obtained by molding organic template particles in an organic template mold; S3, preparing artificial bone slurry, wherein the raw materials of the artificial bone slurry include: β-tricalcium phosphate powder, water, a dispersant, and an adhesive; S4, grouting, pouring the artificial bone slurry into an artificial bone mold containing an organic template; S5, drying; S6, sintering. The present invention can obtain β-tricalcium phosphate powder with fine grains, good crystallization state, and good dispersibility by synthesizing β-tricalcium phosphate powder, thereby improving the quality of the formed artificial bone. Artificial bone is obtained by the preparation method of the present invention, and artificial bone can be prepared in batches. Compared with existing preparation technologies, the production efficiency of the preparation method provided by the present invention is significantly better.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial bone preparation, in particular to an artificial bone preparation method and an artificial bone material. Background Art

[0002] Artificial bone is a biomaterial designed to mimic the function of human bone. It can be used to repair, replace, or reinforce damaged bones. There are many different types of artificial bone, including metal bone, bioceramic bone, and polymer bone. Bioceramic bone has been widely studied and applied due to its excellent biocompatibility and osteoconductivity.

[0003] Bioceramic bone materials include hydroxyapatite and tricalcium phosphate, which have chemical compositions similar to those of human bones and have good biocompatibility and osteoinductivity.

[0004] Existing methods for preparing bioceramic bones have low preparation efficiency, making it difficult to produce bioceramic bones in large quantities. Summary of the Invention

[0005] The purpose of the present invention is to provide an artificial bone preparation method and artificial bone material to solve the problem of low preparation efficiency and difficulty in mass production of bioceramic bone.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a method for preparing artificial bone, the preparation method comprising the following steps: S1, synthesizing β-tricalcium phosphate powder; S2, preparing an organic template, wherein the organic template is obtained by molding organic template particles in an organic template mold; S3, preparing artificial bone slurry, wherein the raw materials of the artificial bone slurry include: β-tricalcium phosphate powder, water, a dispersant and a binder; S4, grouting, pouring the artificial bone slurry into the artificial bone mold containing the organic template; S5, drying; S6, sintering.

[0007] Compared with existing technologies, the present preparation method has the following advantages: by synthesizing β-tricalcium phosphate powder, the present invention can obtain β-tricalcium phosphate powder with fine grains, good crystallinity, and good dispersibility, thereby improving the quality of the formed artificial bone. The preparation method of the present invention can produce artificial bone in batches, and compared with existing preparation technologies, the production efficiency provided by the preparation method of the present invention is significantly superior.

[0008] Preferably, the above S1 specifically includes the following steps: weighing 3MOL of calcium chloride and 2MOL of diammonium hydrogen phosphate at a calcium-phosphorus ratio of 1.5; dissolving the calcium chloride in 4L of ultrapure water, stirring to dissolve, and transferring to a reactor; dissolving the diammonium hydrogen phosphate in 4L of ultrapure water, stirring to dissolve, and transferring to the upper dropping tank; slowly adding the uniformly mixed diammonium hydrogen phosphate solution dropwise to the calcium chloride solution; stirring the reactor at a speed of 150 rpm; adjusting the pH to 6.5-7.2 with aqueous ammonia; and continuing the reaction until the diammonium hydrogen phosphate solution is completely added dropwise; after the addition is complete, continuing the reaction for 21 hours, and controlling the pH to 6.5-7.2;

[0009] After aging for 20 hours, the β-tricalcium phosphate powder was discarded after settling, and then washed with ultrapure water. The powder was allowed to settle and then washed with water three times. The washed powder was centrifuged, washed with water three times and then with ethanol three times, and then thoroughly centrifuged until no liquid flowed out.

[0010] The centrifuged and cleaned β-tricalcium phosphate powder was transferred to a drying oven for drying at 80°C for 24 hours. After drying, the β-tricalcium phosphate powder was transferred to a muffle furnace for sintering to obtain β-TCP powder, which was then ground and sieved (300 mesh).

[0011] Preferably, the sintering method is to raise the temperature to 800° C. in 240 minutes and keep the temperature for 2 hours.

[0012] Preferably, the above S2 specifically includes the following steps: adding organic template particles into an organic template mold, placing a gasket on the bottom surface of the organic template mold, adding 75% concentration acetone solvent, soaking for 3-4 minutes, turning on the air pump to drain the acetone solvent in the organic template mold, adding purified water to clean the acetone, using a push rod to push the organic template out of the organic template mold, soaking the organic template in purified water for 5 minutes, taking out the organic template and putting it into an oven for drying, the drying temperature is 60 degrees and lasts for 2 hours.

[0013] Preferably, the organic template particles are PMMA particles, and the particle size of the organic template particles is 500 μm.

[0014] Preferably, the above S3 specifically includes the following steps: adding water accounting for 29%wt of the total mass of the artificial bone slurry, a dispersant accounting for 1%wt of the total mass of the artificial bone slurry, and β-tricalcium phosphate powder accounting for 65%wt of the total mass of the artificial bone slurry in sequence, then adding a mill, covering it and tightening the nut to fix it; placing it in the mill and grinding it for 2 hours; stopping the machine and opening the cover to check that the tank has become a slurry, adding a binder accounting for 5%wt of the total mass of the artificial bone slurry according to the process parameters; placing it in a blender and stirring for 10 minutes.

[0015] Preferably, the above S4 specifically includes the following steps:

[0016] Place the prepared organic template neatly in the artificial bone mold, pour the slurry on the surface of the organic template, and always keep the slurry submerged in the organic template; wait for the slurry to penetrate into the organic template and fill the organic template, ensuring that the dried slurry solid phase finally fills the organic template, the grouting is completed, and the slurry is naturally completely dry.

[0017] Preferably, in the above S5, the drying temperature is 50 degrees and the drying time is 24 hours.

[0018] Preferably, the above S6 specifically includes the following steps:

[0019] S61, the temperature is increased at a rate of 1°C / min;

[0020] S62, temperature rises to 220℃, keep warm for 12 hours

[0021] S63, the temperature is increased at a rate of 1°C / min;

[0022] S64, the temperature is raised to 260 ° C and kept at this temperature for 6 hours;

[0023] S65, the temperature is increased at a rate of 1°C / min;

[0024] S66, raise the temperature to 290°C and keep warm for 3 hours;

[0025] S67, the temperature is increased at a rate of 3°C / min;

[0026] S68, raise the temperature to 1100°C and keep it for 3 hours;

[0027] S69, cooling (cooling with the furnace).

[0028] Based on another purpose of the present invention, the present invention provides the following technical solution: an artificial bone material, the artificial bone material is the β-tricalcium phosphate powder in the above-mentioned artificial bone preparation method, and the β-tricalcium phosphate powder includes the following raw materials: diammonium hydrogen phosphate, calcium chloride, ammonia water, purified water, and ethanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 A technical roadmap for an artificial bone preparation method;

[0031] Figure 2 is the X-ray diffraction pattern of β-tricalcium phosphate;

[0032] Figure 3 Schematic diagram of the three-dimensional structure of the organic template mold;

[0033] Figure 4 is a cross-sectional view of an organic template mold;

[0034] Figure 5 for Figure 4 A partial enlarged view of point A in the middle.

[0035] In the figure: base 1, sealing strip 2, air hole 3, organic template 4, uniform cross-section mold cavity 5, ejector rod 6, handle 7, guide hole 8, guide plate 9, mold main board 11, gasket 12, air hole bottom plate 13, installation space 14, positioning part 15. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0037] In this article, terms such as "upper, lower, inside, outside" are established based on the positional relationships shown in the drawings. Depending on the different drawings, the corresponding positional relationships may also change accordingly. Therefore, they cannot be understood as absolute limitations on the scope of protection; moreover, relational terms such as "first" and "second" are only used to distinguish one component from another with the same name, and do not necessarily require or imply any actual relationship or order between these components.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a method for preparing an artificial bone, which includes the following steps: S1, synthesizing β-tricalcium phosphate powder; S2, preparing an organic template, which is obtained by molding organic template particles in an organic template mold; S3, preparing artificial bone slurry, the raw materials of the artificial bone slurry include: β-tricalcium phosphate powder, water, a dispersant and a binder; S4, grouting, pouring the artificial bone slurry into an artificial bone mold containing the organic template; S5, drying; S6, sintering.

[0040] Specifically, this embodiment synthesizes β-tricalcium phosphate powder to obtain β-tricalcium phosphate powder with fine grains, good crystallinity, and good dispersibility, thereby improving the quality of the formed artificial bone. The preparation method of this embodiment can produce artificial bone in batches, and compared to existing preparation technologies, the preparation method provided by this embodiment has significantly better production efficiency.

[0041] Furthermore, the above S1 specifically includes the following steps: weighing 3MOL of calcium chloride and 2MOL of diammonium hydrogen phosphate at a calcium-phosphorus ratio of 1.5; dissolving the calcium chloride in 4L of ultrapure water, stirring to dissolve, and transferring to a reactor; dissolving the diammonium hydrogen phosphate in 4L of ultrapure water, stirring to dissolve, and transferring to the upper addition tank; slowly adding the uniformly mixed diammonium hydrogen phosphate solution dropwise to the calcium chloride solution; stirring the reactor at a speed of 150 rpm; adjusting the pH to 6.5-7.2 with aqueous ammonia; and continuing the reaction for 21 hours after the addition is complete, and controlling the pH to 6.5-7.2;

[0042] Aging treatment for 20 hours. Aging treatment is to prevent the β-tricalcium phosphate powder from settling in a sealed container for 20 hours. After the β-tricalcium phosphate powder settles, the liquid above is poured out and then washed with ultrapure water. Settling - washing with water 3 times. The washed powder is centrifuged, washed with water 3 times and then with ethanol 3 times, and thoroughly centrifuged until no liquid flows out.

[0043] The centrifuged and cleaned β-TCP powder was transferred to a drying oven for drying at 80°C for 24 hours. After drying, the β-TCP powder was transferred to a muffle furnace for sintering. The sintering method was to increase the temperature to 800°C over 240 minutes and hold the temperature for 2 hours. The resulting β-TCP powder was then ground and sieved (300 mesh).

[0044] Furthermore, the above S2 specifically includes the following steps: adding organic template particles to an organic template mold, placing a gasket on the bottom surface of the organic template mold, adding a 75% concentration of acetone solvent, soaking for 3 to 4 minutes, turning on the air pump to drain the acetone solvent in the organic template mold, adding purified water to clean the acetone, using a push rod to push the organic template out of the organic template mold, soaking the organic template in purified water for 5 minutes, removing the organic template and placing it in an oven for drying, the drying temperature is 60 degrees and lasts for 2 hours. Furthermore, the organic template particles are PMMA particles, and the particle size of the organic template particles is 500μm.

[0045] Specifically, such as Figure 3-5As shown, this embodiment provides an organic template mold, including: a base 1, in which an installation space 14 is provided; a pore 3 bottom plate, which is installed on the base 1 and is provided with a plurality of pores 3; a gasket 12, which is placed on the pore 3 bottom plate and covers the plurality of pores 3; a molding main board 11, in which a plurality of uniform cross-section mold cavities 5 are provided, and the upper and lower ends of the uniform cross-section mold cavities 5 are both open. During the preparation of the organic template 4, the pore 3 bottom plate is directly installed into the base 1. The gasket 12 is laid flat on top of the pores 3. When laying the gasket 12 flat, it should be noted that the gasket 12 must completely cover the pores 3. After laying the gasket 12, the molding main board 11 is pressed into the base 1. During installation, the molding main board 11 and the gasket 12 should be tightly attached to each other without leaking. The organic template 4 particles are added into the uniform cross-section mold cavities 5 of the molding main board 11 without overflowing. Acetone solvent is added. Once the organic template 4 is formed within the uniform cross-sectional mold cavity 5, the mold base 11 is removed and the gasket 12 is removed. The mold base 11 is then reinstalled into the base 1. Negative pressure is applied to the bottom plate of the air holes 3 to drain the acetone. Purified water is then added to clean the organic template 4. After cleaning, the organic template 4 can be removed from the uniform cross-sectional mold cavity 5. This step allows for convenient batch production of organic templates 4.

[0046] Preferably, the device also includes a sealing strip 2, which is provided between the bottom plate of the air hole 3 and the base 1. The sealing strip 2 is first installed on the bottom plate of the air hole 3, and then the bottom plate of the air hole 3 with the sealing strip 2 is directly installed into the base 1. This ensures a tight seal and improves the suction effect when the bottom plate of the air hole 3 is opened to generate negative pressure.

[0047] Preferably, the assembly further includes: a guide plate 9 having guide holes 8 adapted to accommodate a plurality of uniform-section mold cavities 5; and a push rod 6 adapted to accommodate the guide holes 8. The guide holes 8 are also through-holes extending through the guide plate 9 along its height. After the organic template 4 is cleaned, the mold base 11 is removed, and the guide plate 9 is installed directly above the mold base 11, aligning the guide holes 8 with the uniform-section mold cavities 5 of the mold base 11. The push rod 6 is then used to eject the organic template 4 from the uniform-section mold cavities 5. The arrangement of the guide plate 9 and push rod 6 facilitates the removal of the organic template 4.

[0048] Preferably, the mold base 11 further includes positioning portions 15, which are provided at both ends of the mold base 11, and the guide plates 9 are placed on the positioning portions 15. The positioning portions 15 are stepped square grooves, and the shape and size of the positioning portions 15 exactly match the guide plates 9, that is, the guide plates 9 can fit neatly into the positioning portions 15. When the guide plates 9 are placed on the positioning portions 15, the guide holes 8 of the guide plates 9 are aligned with the uniform cross-sectional mold cavities 5 of the mold base 11. The provision of the positioning portions 15 makes it easier to align the uniform cross-sectional mold cavities 5 with the guide holes 8.

[0049] Preferably, the apparatus further comprises a handheld portion 7 connected to the ejector rod 6, and having anti-slip grooves. In order to facilitate ejection of the organic template 4 by the ejector rod 6, the handheld portion 7 is provided to facilitate the relevant staff to hold it. Of course, the handheld portion 7 can also be connected to a power source to realize automatic ejection of the organic template 4.

[0050] Preferably, the cross-section of the uniform cross-section mold cavity 5 is rectangular; or, the cross-section of the uniform cross-section mold cavity 5 is arc-shaped; or, the cross-section of the uniform cross-section mold cavity 5 is elliptical; or, the cross-section of the uniform cross-section mold cavity 5 is trapezoidal. The specific cross-section of the uniform cross-section mold cavity 5 is not limited here and can be selected according to actual circumstances. Preferably, the cross-section of the uniform cross-section mold cavity 5 is rectangular.

[0051] Preferably, the base 1 is overfitted with the mold main board 11. The mold main board 11 needs to be pressed into the base 1 by an external force, and after being pressed in, the position of the mold main board 11 will not change easily.

[0052] Preferably, the bottom plate of the air hole 3 is connected to an air pump to provide suction force.

[0053] Furthermore, the above-mentioned S3 specifically includes the following steps: adding water accounting for 29%wt of the total mass of the artificial bone slurry, a dispersant accounting for 1%wt of the total mass of the artificial bone slurry, and β-tricalcium phosphate powder accounting for 65%wt of the total mass of the artificial bone slurry in sequence, and then adding a mill, covering it and tightening the nut to fix it; putting it into the mill and grinding it for 2 hours; stopping the machine and opening the cover to check that the tank has become a slurry, and adding an adhesive accounting for 5%wt of the total mass of the artificial bone slurry according to the process parameters; putting it into the mixer and stirring for 10 minutes.

[0054] Furthermore, the above S4 specifically includes the following steps:

[0055] Place the prepared organic template neatly in the artificial bone mold, pour the slurry on the surface of the organic template, and always keep the slurry submerged in the organic template; wait for the slurry to penetrate into the organic template and fill the organic template, ensuring that the dried slurry solid phase finally fills the organic template, the grouting is completed, and the slurry is naturally completely dry.

[0056] Furthermore, in the above S5, the drying temperature is 50 degrees and the drying time is 24 hours.

[0057] Furthermore, the above S6 specifically includes the following steps:

[0058] S61, the temperature is increased at a rate of 1°C / min;

[0059] S62, temperature rises to 220℃, keep warm for 12 hours

[0060] S63, the temperature is increased at a rate of 1°C / min;

[0061] S64, the temperature is raised to 260 ° C and kept at this temperature for 6 hours;

[0062] S65, the temperature is increased at a rate of 1°C / min;

[0063] S66, raise the temperature to 290°C and keep warm for 3 hours;

[0064] S67, the temperature is increased at a rate of 3°C / min;

[0065] S68, raise the temperature to 1100°C and keep it for 3 hours;

[0066] S69, cooling (cooling with the furnace).

[0067] Example 2

[0068] The same parts in this embodiment as those in the first embodiment are given the same reference numerals, and the same text descriptions are omitted.

[0069] This embodiment discloses an artificial bone material, which is the β-tricalcium phosphate powder described in the artificial bone preparation method of Example 1. The β-tricalcium phosphate powder comprises the following raw materials: diammonium phosphate, calcium chloride, ammonia water, purified water, and ethanol. The specific preparation steps for the β-tricalcium phosphate powder are as follows: 3 MOL of calcium chloride and 2 MOL of diammonium phosphate are weighed at a calcium-to-phosphorus ratio of 1.5; the calcium chloride is dissolved in 4 L of ultrapure water, stirred to dissolve, and then transferred to a reaction vessel; the diammonium phosphate is dissolved in 4 L of ultrapure water, stirred to dissolve, and then transferred to an upper addition tank; the uniformly mixed diammonium phosphate solution is slowly added dropwise to the calcium chloride solution; the reactor is stirred at 150 rpm; the pH is adjusted to 6.5-7.2 with ammonia water until the diammonium phosphate solution is completely added dropwise; after completion of the addition, the reaction is continued for 21 hours, maintaining the pH at 6.5-7. 2. Aging treatment for 20 hours. To prevent aging, place the β-tricalcium phosphate powder in a sealed container for 20 hours. After the β-tricalcium phosphate powder settles, pour out the liquid on top and wash it with ultrapure water. Settle and wash it with water three times. Centrifuge the washed powder, wash it three times with water and then three times with ethanol. Centrifuge thoroughly until no liquid flows out. Transfer the centrifuged and washed β-tricalcium phosphate powder to a drying oven for drying at 80°C for 24 hours. After drying, transfer the β-tricalcium phosphate powder to a muffle furnace for sintering. The sintering method is to heat it to 800°C in 240 minutes and keep it warm for 2 hours. After sintering, the β-TCP powder is obtained and then ground and sieved (300 mesh). Figure 2 As shown, the diffraction peaks of the β-tricalcium phosphate powder prepared in this example are narrow, sharp, and highly intense, indicating good crystallinity. The three main peaks are consistent with the standard spectrum, with no miscellaneous peaks present. This indicates that the β-tricalcium phosphate powder prepared by the sufficient reaction of calcium chloride and diammonium hydrogen phosphate is highly pure.

[0070] Preferably, the β-tricalcium phosphate content in the β-tricalcium phosphate powder is no less than 95%. The trace element content in the β-tricalcium phosphate powder should meet the following requirements: a maximum arsenic (As) content of 3 μg / g, a maximum cadmium (Cd) content of 5 μg / g, a maximum mercury (Hg) content of 5 μg / g, a maximum lead (Pb) content of 30 μg / g, and a total heavy metal content (calculated as Pb) of 50 μg / g.

[0071] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for preparing artificial bone, characterized in that: The preparation method comprises the following steps: S1, synthetic β-tricalcium phosphate powder; S2. preparing an organic template, wherein the organic template is obtained by molding organic template particles in an organic template mold; S3, preparing artificial bone paste, wherein the raw materials of the artificial bone paste include: β-tricalcium phosphate powder, water, a dispersant and a binder; S4, grouting, pouring the artificial bone slurry into the artificial bone mold containing the organic template; S5, drying; S6, sintering; The above S1 specifically includes the following steps: weighing 3MOL of calcium chloride and 2MOL of diammonium hydrogen phosphate at a calcium-phosphorus ratio of 1.5; dissolving the calcium chloride in 4L of ultrapure water, stirring to dissolve, and transferring to a reactor; dissolving the diammonium hydrogen phosphate in 4L of ultrapure water, stirring to dissolve, and transferring to the upper addition tank; slowly adding the uniformly mixed diammonium hydrogen phosphate solution dropwise to the calcium chloride solution; stirring the reactor at a speed of 150 rpm; adjusting the pH to 6.5-7.2 with aqueous ammonia; and continuing the reaction for 21 hours after the addition is complete, and controlling the pH to 6.5-7.2; After aging for 20 hours, the β-tricalcium phosphate powder was discarded after settling, and then washed with ultrapure water. The powder was allowed to settle and then washed with water three times. The washed powder was centrifuged, washed with water three times and then with ethanol three times, and then thoroughly centrifuged until no liquid flowed out. The centrifuged and cleaned β-tricalcium phosphate powder was transferred to a drying oven for drying at 80°C for 24 hours. After drying, the β-tricalcium phosphate powder was transferred to a muffle furnace for sintering to obtain β-TCP powder, which was then ground and sieved. The above-mentioned S3 specifically includes the following steps: adding water accounting for 29%wt of the total mass of artificial bone slurry, dispersant accounting for 1%wt of the total mass of artificial bone slurry and β-tricalcium phosphate powder accounting for 65%wt of the total mass of artificial bone slurry in sequence, then adding a mill, covering and tightening the nut to fix it; placing it in the mill and grinding it for 2 hours; stopping the machine and opening the cover to check the tank to confirm that it has become a slurry, adding a binder accounting for 5%wt of the total mass of artificial bone slurry according to the process parameters; placing it in a blender and stirring for 10 minutes.

2. The method for preparing an artificial bone according to claim 1, wherein: The sintering method is to heat up to 800°C in 240 minutes and keep the temperature for 2 hours.

3. The method for preparing an artificial bone according to claim 1, wherein: The above-mentioned S2 specifically includes the following steps: adding organic template particles into the organic template mold, placing a gasket on the bottom surface of the organic template mold, then adding 75% concentration acetone solvent, soaking for 3 to 4 minutes, turning on the air pump to drain the acetone solvent in the organic template mold, adding purified water to clean the acetone, using a push rod to push the organic template out of the organic template mold, soaking the organic template in purified water for 5 minutes, taking out the organic template and putting it into an oven for drying, the drying temperature is 60 degrees and lasts for 2 hours.

4. The method for preparing an artificial bone according to claim 3, wherein: The organic template particles are PMMA particles, and the particle size of the organic template particles is 500 μm.

5. The method for preparing an artificial bone according to claim 1, characterized in that: The above S4 specifically includes the following steps: Place the prepared organic template neatly in the artificial bone mold, pour the slurry on the surface of the organic template, and always keep the slurry submerged in the organic template; wait for the slurry to penetrate into the organic template and fill the organic template, ensuring that the dried slurry solid phase finally fills the organic template, the grouting is completed, and the slurry is naturally completely dry.

6. The method for preparing an artificial bone according to claim 1, characterized in that: In the above S5, the drying temperature is 50 degrees and the drying time is 24 hours.

7. The method for preparing an artificial bone according to claim 1, characterized in that: The above S6 specifically includes the following steps: S61, the temperature is increased at a rate of 1°C / min; S62, temperature rises to 220℃, keep warm for 12 hours S63, the temperature is increased at a rate of 1°C / min; S64, the temperature is raised to 260 ° C and kept at this temperature for 6 hours; S65, the temperature is increased at a rate of 1°C / min; S66, raise the temperature to 290°C and keep warm for 3 hours; S67, the temperature is increased at a rate of 3°C / min; S68, raise the temperature to 1100°C and keep it for 3 hours; S69, cool down.

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