Method for preparing vaterite type nanoscale calcium carbonate by taking ardealite as raw material and application of vaterite type nanoscale calcium carbonate

Abstract

The invention provides a method for preparing vaterite type nanoscale calcium carbonate with ardealite as a raw material and application of the method, and relates to the technical field of inorganic nano-material preparation.The method comprises the following steps that firstly, efficient dissociation of calcium ions in the ardealite is achieved through a phase transfer method, then digestion treatment is conducted on a leaching solution, and the leaching solution is obtained; a crystal morphology regulating agent is further introduced to construct a mineralized microenvironment, and then through a carbon dioxide carbonization reaction, vaterite type nano-scale calcium carbonate with a specific average particle size (200-400 nm) is prepared. According to the preparation method, natural high polymer materials such as collagen are introduced in the preparation process to serve as green crystal form guiding agents, so that the coordination effect of the natural high polymer materials and calcium ions can be utilized, the crystal morphology can be effectively regulated and controlled, and the biocompatibility of the nano material is improved; and the application possibility of calcium carbonate in the biomedical fields of drug carriers, bone repair materials and the like is expanded.

Description

Technical Field

[0001] This invention relates to the field of inorganic nanomaterial preparation technology, and in particular to a method for preparing aragonite-type nanoscale calcium carbonate using phosphogypsum as a raw material and its application. Background Technology

[0002] Phosphogypsum is a byproduct of the wet-process phosphoric acid production. Achieving high-quality utilization of phosphogypsum is of paramount strategic importance for promoting resource recycling and reducing environmental pollution. Currently, the main methods for producing nano-sized calcium carbonate from aragonite using phosphogypsum are the "ammonia-carbonation method" and the "phase transfer-precipitation method."

[0003] In the prior art, application number 201410161345.5, published on July 16, 2014, entitled "Method for preparing high-purity metastable aragonite calcium carbonate using gypsum," describes a method that uses phosphogypsum as a raw material and prepares aragonite calcium carbonate by adding ammonium carbonate solution and anionic surfactant. This method produces aragonite calcium carbonate with high crystal purity, a simple preparation process, and the high concentration of ammonium carbonate increases the yield, significantly reducing production costs. However, the surface of the aragonite calcium carbonate crystals obtained by this method is not hydrophobic, and it cannot avoid particle agglomeration, resulting in uneven particle size in the calcium carbonate product.

[0004] Secondly, application number 201510113545.8, published on June 10, 2015, entitled "A Simple Method for Preparing Spheroidal Aragonite-Type Calcium Carbonate Microspheres," describes a method that uses a natural sericin solution as a template to control the morphology of calcium carbonate microspheres. It employs a metathesis method to prepare spheroidal aragonite-type calcium carbonate microspheres with a particle size of 1-1.5 μm. With the addition of calcium ions, due to charge attraction, some sericin nanoparticles bind to calcium ions, forming nucleation sites and promoting the formation of initial nanosphere crystals. To reduce surface energy, the nanoparticles may continue to grow or aggregate. The remaining sericin nanoparticles are responsible for further regulating the behavior of these spheroidal aragonite nanocrystals. Ultimately, due to the spatial blocking effect of sericin, the growth of calcium carbonate microspheres is inhibited, resulting in the final calcium carbonate microspheres. However, the calcium carbonate microspheres prepared by this method are large in size, limiting their application areas.

[0005] In view of this, it is necessary to design an improved method for preparing aragonite-type nano-sized calcium carbonate from phosphogypsum and its application to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material and its application.

[0007] To achieve the above-mentioned objective, in a first aspect, the present invention provides a method for preparing aragonite-type nano-sized calcium carbonate from phosphogypsum as a raw material, comprising the following steps:

[0008] S1. Add phosphogypsum to a phase transfer solution and filter to obtain leachate A; digest leachate A to obtain leachate B.

[0009] S2. Add a crystal form control agent to the leachate B and introduce carbon dioxide gas to react and obtain aragonite-type nano-sized calcium carbonate.

[0010] Preferably, in step S2, the crystal form control agent is a solution formed from one or more of soluble starch, collagen, and silk fibroin, and the amount of solute added to the crystal form control agent is 2-8% of the theoretical mass of nano-calcium carbonate.

[0011] Preferably, in step S1, the concentration of the phase transfer solution is 2.23-2.24 mol / L, and it is a potassium acetate solution or a sodium acetate solution.

[0012] Preferably, in step S1, the volume ratio of the phase transfer solution to the mass ratio of the phosphogypsum is 70 (mL): 1 (g), and the reaction time is 40 min.

[0013] Preferably, in step S2, the flow rate of carbon dioxide gas is 250 mL / min, and the introduction time is 30 min.

[0014] Preferably, in step S1, the digestion treatment involves adding potassium hydroxide solution to the leachate A, and the pH of the leachate B is 13.

[0015] Preferably, in step S2, the reaction temperature is 20-25°C.

[0016] Secondly, the present invention provides a spheroidal aragonite-type nano-sized calcium carbonate with an average particle size of 200-400 nm.

[0017] Thirdly, the present invention provides an application of aragonite-type nano-sized calcium carbonate in the preparation of drug carriers or bone repair materials.

[0018] The beneficial effects of this invention are:

[0019] 1. The present invention provides a method for preparing nano-sized aragonite-type calcium carbonate, which involves first dissociating calcium ions in phosphogypsum using a phase transfer method, then digesting the leachate with an alkaline solution, further introducing a crystal morphology regulator to construct a mineralization microenvironment, and finally controlling the carbon dioxide carbonization reaction and crystallization process to successfully prepare nano-sized aragonite-type calcium carbonate with a specific crystal structure (aragonite type) and an average particle size of 200-400 nm.

[0020] 2. The method for preparing aragonite-type nano-sized calcium carbonate provided by the present invention introduces natural polymer materials such as collagen as green crystal form guiding agents during the preparation process. This not only utilizes their coordination with calcium ions to achieve effective control of crystal morphology, but also significantly improves the biocompatibility of nanomaterials, expanding the application possibilities of calcium carbonate in biomedical fields such as drug carriers and bone repair materials.

[0021] 3. The method for preparing aragonite-type nano-sized calcium carbonate provided by the present invention achieves high-quality utilization of phosphogypsum by using phosphogypsum as raw material, thereby promoting solid waste disposal; secondly, the method has mild process conditions and simple operation, making it suitable for large-scale production. Attached Figure Description

[0022] Figure 1 This is a SEM image of the aragonite-type nano-sized calcium carbonate prepared in Example 1 of this invention;

[0023] Figure 2 This is a SEM image of the aragonite-type nano-sized calcium carbonate prepared in Example 1 of the present invention at another magnification.

[0024] Figure 3 This is a SEM image of the aragonite-type nano-sized calcium carbonate obtained in Example 2 of this invention;

[0025] Figure 4 This is a SEM image of the aragonite-type nano-sized calcium carbonate obtained in Example 3 of the present invention;

[0026] Figure 5 This is a SEM image of the aragonite-type nano-sized calcium carbonate obtained in Example 4 of this invention;

[0027] Figure 6 This is a SEM image of the aragonite-type nano-sized calcium carbonate obtained in Example 7 of this invention;

[0028] Figure 7 This is a SEM image of the nano-sized calcium carbonate prepared in Comparative Example 1 of this invention.

[0029] Figure 8 This is the drug release curve of nano-sized aragonite-type calcium carbonate in Application Example 1 of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0032] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] On one hand, the present invention provides a method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material, comprising the following steps:

[0034] S1. Add phosphogypsum to the phase transfer solution and filter to obtain leachate A; digest leachate A to obtain leachate B.

[0035] S2. Add a crystal form control agent to leachate B and introduce carbon dioxide gas to react and obtain nano-sized calcium carbonate of the aragonite type.

[0036] In the above technical solution, by treating phosphogypsum with a phase transfer solution, the calcium sulfate encapsulation structure in the phosphogypsum can be broken while dissolving it, facilitating the release of impurity ions. Secondly, the pH and ionic environment can be adjusted to create favorable conditions for the formation of nano-sized calcium carbonate. Through digestion treatment, a crystal morphology regulator is further introduced to construct a mineralization microenvironment. Utilizing the coordination effect between the crystal form control agent and calcium ions, a directional crystallization template is constructed to achieve the controllable synthesis of uniformly sized aragonite-type nano-sized calcium carbonate. By first treating the phosphogypsum with a phase transfer solution and then performing digestion treatment, calcium ions in the phosphogypsum can be gradually released, ensuring sufficient release of calcium ions and improving the utilization rate of the phosphogypsum raw material.

[0037] Specifically, the formation mechanism of the above-mentioned aragonite-type nano-sized calcium carbonate is as follows: By adding a crystal form control agent, its polar -OH groups can be used to promote the nucleation reaction, reduce the surface energy of calcium carbonate crystal nuclei, and enable smaller crystal nuclei to exist stably, inhibiting the aggregation and growth of calcium carbonate crystal nuclei, and generating smaller nano-sized calcium carbonate particles; with the introduction of carbon dioxide, the supersaturation of carbonate ions in the liquid phase increases, and a large number of small crystal nuclei are generated instantaneously in the reaction system, obtaining nano-sized calcium carbonate microcrystals. This process greatly shortens the formation time of nano-sized calcium carbonate and improves the preparation efficiency; at the same time, the crystal form control agent (polymer materials such as collagen) can provide nucleation sites for calcium ions, allowing calcium carbonate to grow on a predetermined template until aragonite-type nano-sized calcium carbonate is formed. Secondly, the addition of the crystal form control agent can also form a colloidal environment in the solution, which is conducive to the adsorption and removal of impurity ions in the solution and improves the purity of calcium carbonate.

[0038] In some embodiments, in step S1, the concentration of the phase transfer solution is 2.23-2.24 mol / L, which is a potassium acetate solution or a sodium acetate solution, preferably a potassium acetate solution.

[0039] In some embodiments, in step S1, the ratio of the volume (mL) of the phase transfer solution to the mass (g) of phosphogypsum is 70:1, and the reaction time is 40 min.

[0040] In some embodiments, in step S1, the digestion treatment of leachate A can be carried out using potassium hydroxide solution, the pH of leachate B is 13, and the amount of potassium hydroxide solution added can be adjusted according to the concentration of leachate A, as long as the digestion treatment requirements are met; this is not a limitation. It should be noted that in other embodiments, other substances can also be used, as long as the purpose of digestion treatment can be achieved.

[0041] In some embodiments, in step S2, the crystal form control agent is one or more solutions of soluble starch, collagen, and silk fibroin, and the amount of solute added to the solution is 2-8% of the theoretical mass of nano-calcium carbonate. By selecting the above-mentioned natural polymer materials as crystal form control agents, the use of traditional organic templates can be avoided, the high-temperature removal process and the risk of organic residues can be avoided, and the biocompatibility of the product can be improved. In this case, calcium carbonate is prepared using a biological template to simulate biomineralization, resulting in a higher proportion of aragonite morphology and higher stability in the obtained calcium carbonate. Secondly, during the synthesis of nano-scale calcium carbonate, because the crystal form control agent has a polar -OH group in its structure, and the O in the molecule has a lone pair of electrons and has high electronegativity, it can react with Ca. 2+ Coordination disperses Ca in the solution 2+ , so that Ca in a unit space 2+The reduced concentration inhibited the growth of nano-calcium carbonate crystals, promoting the formation of nano-calcium carbonate particles with even smaller particle sizes.

[0042] In some embodiments, in step S2, the flow rate of carbon dioxide gas is 250 mL / min, the introduction time is 30 min, and the reaction temperature is 20-25 °C.

[0043] On the other hand, the present invention provides a spheroidal aragonite-type nano-sized calcium carbonate with an average particle size of 200-400 nm. Nano-sized calcium carbonate with this characteristic can be applied in biomedical fields such as drug carriers and bone repair materials.

[0044] The following specific embodiments further illustrate the method for preparing aragonite-type nano-sized calcium carbonate from phosphogypsum and its applications provided by the present invention:

[0045] Example 1

[0046] This embodiment provides a method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material, comprising the following steps:

[0047] S1. After passing dried phosphogypsum (from Hubei Huangmailing Phosphate Chemical Co., Ltd.) through a 60-mesh sieve, weigh 5g of phosphogypsum and dissolve it in 0.35L of 2.24mol / L potassium acetate solution at 25℃. Stir the reaction for 40min. After the reaction is complete, filter and discard the filter residue to obtain leachate A. Under stirring conditions at 25℃, add 70mL of 1mol / L potassium hydroxide solution dropwise to leachate A for digestion treatment to obtain leachate B with a pH of 13.

[0048] S2. At 25℃, a soluble starch solution was added to leachate B, and carbon dioxide gas was bubbled into the solution at a rate of 250 mL / min for 30 min. The solid product was collected, washed three times with anhydrous ethanol, and dried at 25℃ for 12 h to obtain aragonite-type nano-sized calcium carbonate. The CaO in the solution after the reaction was detected by ICP. 2+ According to the formula In the formula: c 滤液 Ca in the filtrate after carbonization reaction 2+ Concentration, in mol / L, V 滤液 This refers to the volume of the filtrate after the carbonization reaction, in L and c. 浸出 Ca in the leachate 2+ Concentration, in mol / L, V 浸出 The volume of the leachate is given in liters (L). The Ca2+ was calculated. 2+The conversion rate was 99.28%, and the purity of the aragonite-type nano-sized calcium carbonate was 99%. The soluble starch solution was obtained by dissolving soluble starch in 5 mL of water, and the amount of soluble starch added was 4% of the theoretical mass of the nano-calcium carbonate. It should be noted that, unless otherwise specified, all reagents and raw materials used in the embodiments of this invention can be obtained commercially.

[0049] The SEM images of the spherulite-type nanoscale calcium carbonate prepared in this embodiment at different magnifications are as follows: Figure 1 and Figure 2 As shown in the figure, the product appears as spherical aggregates with an average particle size of 244 nm, which is consistent with the common crystallization characteristics of aragonite, indicating that aragonite-type nanoscale calcium carbonate has been successfully prepared.

[0050] Example 2

[0051] This embodiment provides a method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material, comprising the following steps:

[0052] S1. After passing the dried phosphogypsum through a 60-mesh sieve, weigh 5g of phosphogypsum and dissolve it in 0.35L of 2.24mol / L potassium acetate solution at 25℃. Stir the reaction for 40min. After the reaction is complete, filter the solution and discard the filter residue to obtain leachate A. Under stirring conditions at 25℃, add 70mL of 1mol / L potassium hydroxide solution dropwise to leachate A for digestion treatment to obtain leachate B with a pH of 13.

[0053] S2. At 25°C, after adding the collagen solution to the leachate B, carbon dioxide gas was introduced into the solution at a rate of 250 mL / min, and the reaction was allowed to proceed for 30 min. The solid product was collected, washed three times with anhydrous ethanol, and then dried at 25°C for 12 h to obtain aragonite-type nano-sized calcium carbonate. The collagen solution was obtained by dissolving collagen (brand: Anaiji, purity 90%) in 5 mL of water, and the amount of collagen added was 4% of the mass of calcium ions in leachate B. The SEM image of the aragonite-type nano-sized calcium carbonate obtained in this example is shown below. Figure 3 As shown in the figure, the product is a spherical aggregate with an average particle size of 325 nm.

[0054] Example 3

[0055] This embodiment provides a method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material, comprising the following steps:

[0056] S1. After passing the dried phosphogypsum through a 60-mesh sieve, weigh 5g of phosphogypsum and dissolve it in 0.35L of 2.24mol / L potassium acetate solution at 25℃. Stir the reaction for 40min. After the reaction is complete, filter the solution and discard the filter residue to obtain leachate A. Under stirring conditions at 25℃, add 70mL of 1mol / L potassium hydroxide solution dropwise to leachate A for digestion treatment to obtain leachate B with a pH of 13.

[0057] S2. At 25℃, after adding the silk fibroin solution to the leachate B, carbon dioxide gas was introduced into the solution at a rate of 250 mL / min, and the reaction was allowed to proceed for 30 min. The solid product was collected, washed three times with anhydrous ethanol, and then dried at 25℃ for 12 h to obtain aragonite-type nano-sized calcium carbonate. The silk fibroin solution was obtained by dissolving silk fibroin in 5 mL of a 1 mol / L potassium hydroxide solution, and the amount of silk fibroin added was 4% of the theoretical mass of the nano-sized calcium carbonate. The SEM image of the aragonite-type nano-sized calcium carbonate obtained in this example is shown below. Figure 4 As shown in the figure, the product is a spherical aggregate with an average particle size of 390 nm.

[0058] It should be noted that the silk fibroin used in the above preparation process is obtained by treating silkworm silk, and its specific preparation method is as follows:

[0059] Boil 1L of Na2CO3 (2.12g / L) aqueous solution, add 10g of raw silkworm silk, stir to degumme for 20min, remove the silk and wash it with deionized water, then boil it in 60℃ water for 20min, and wash it with deionized water 4-5 times to remove residual sericin; loosen the degummed silk fibroin and spread it evenly on clean tin foil and dry it at 60℃ for 12h. Take 5g of dried silk fibroin fiber and dissolve it in 20mL of 9.3M LiBr solution, seal it and place it in a 60℃ environment for 4h to dissolve, stirring and shaking it from time to time to promote uniform dissolution. Then take it out and put it into a treated dialysis bag, and dialyze it in deionized water for three days at a volume ratio of not less than 1:100; after dialysis, dry the white gelatinous substance at 25℃ to obtain silk fibroin.

[0060] Examples 4 to 7

[0061] The only difference between Examples 4 to 7 and Example 1 is that the amount of crystal form control agent added in step S2 is different from that in Example 1. All other experimental parameters are the same as in Example 1 and will not be repeated here. The amounts of crystal form control agent added in Examples 1 and Examples 4 to 7 are shown in Table 1. The amount of crystal form control agent added is based on the theoretical mass of nano-calcium carbonate; for example, the amount of crystal form control agent added in Example 1 is 4% of the theoretical mass of nano-calcium carbonate.

[0062] Table 1. Amounts of crystal form control agent added in Examples 1 and 4 to 7

[0063] project Amount of crystal form control agent added (%) purity(%) Example 1 4 99 Example 4 0.1 99 Example 5 2 99 Example 6 8 95 Example 7 10 95

[0064] SEM image of the spheroidal aragonite-type nano-sized calcium carbonate prepared in Example 4 is shown below. Figure 5 As shown, the results indicate that the calcium carbonate spheres prepared under these conditions are more fragmented compared to Example 1. This is because the calcium carbonate crystals are mixed with calcite-type and aragonite-type calcium carbonate. The SEM image of the aragonite-type nanoscale calcium carbonate prepared in Example 7 is shown below. Figure 6 As shown, the results indicate that calcium carbonate has poor uniformity and a large particle size, with an average particle size of 1.3 μm.

[0065] Comparative Example 1

[0066] The only difference between this comparative example and Example 1 is that no crystal form control agent is added in step S2. The specific preparation method includes the following steps:

[0067] S1. After passing the dried phosphogypsum through a 60-mesh sieve, weigh 5g of phosphogypsum and dissolve it in 0.35L of 2.24mol / L potassium acetate solution at 25℃. Stir the reaction for 40min. After the reaction is complete, filter the solution and discard the filter residue to obtain leachate A. Under stirring conditions at 25℃, add 70mL of 1mol / L potassium hydroxide solution dropwise to leachate A to obtain leachate B with a pH of 13.

[0068] S2. At 25℃, 5 mL of water was added to leachate B, and carbon dioxide gas was bubbled into the solution at a rate of 250 mL / min. The reaction was allowed to proceed for 30 min. The solid product was collected, washed three times with anhydrous ethanol, and dried at 25℃ for 12 h to obtain nano-sized calcium carbonate. The SEM image of the nano-sized calcium carbonate prepared in this comparative example is shown below. Figure 7 As shown, the results indicate that its crystal morphology is cubic nano-calcium carbonate with an average particle size of 455 nm. When compared with... Figures 1 to 4 Comparative studies show that crystal form control agents can regulate the morphology of nano-calcium carbonate, enabling the efficient synthesis of spheroidal aragonite-type nano-scale calcium carbonate.

[0069] Application Example 1

[0070] This application example provides the use of spheroidal aragonite-type nanoscale calcium carbonate as a drug carrier, including the following steps:

[0071] S1. The three types of aragonite-type nano-sized calcium carbonate obtained in Examples 1 to 3 were stirred and reacted in a metformin hydrochloride solution with a concentration of 0.1 mg / mL for 9 hours to allow the drug to be adsorbed onto the surface of the nanospheres. The nanosphere carriers that had completed drug adsorption were filtered, washed and dried to obtain drug-loaded hybrid nanospheres.

[0072] S2. The drug-loaded nanospheres were dispersed in 25 mL of buffer solution and then placed in dialysis bags. The dialysis bags were placed in beakers containing 500 mL of buffer solutions with pH values ​​of 7.4 and 5.0, respectively. All samples underwent simultaneous drug release at a constant temperature of 37°C. At predetermined intervals, 3 mL of the dialysis fluid was collected every 6 hours for absorbance analysis in the first 60 hours, and then every 15 hours thereafter. An equal volume of fresh buffer solution with the corresponding pH value was added. Drug concentration was determined using UV-Vis, and the drug release rate (DR) was measured. Three parallel measurements were performed for each sample, and the average value was taken.

[0073] The formula for calculating DR is as follows: DR=(M1-M2) / M0×100%, where M1 is the mass of drug in the buffer solution at the nth hour; M2 is the mass of drug in the buffer solution at the 0th hour; and M0 is the mass of drug in the buffer solution when the drug-loaded microparticles are completely dissolved after acidification with hydrochloric acid.

[0074] In vitro sustained-release experiments showed that the drug release from this sustained-release carrier was significantly higher in a simulated weakly acidic environment of tumor cells (pH=5.0) than in a normal cell environment (pH=7.4). Furthermore, the drug release was almost uniform under the same pH conditions, exhibiting pH responsiveness and achieving controlled release of the loaded drug. The drug release rate curves for different drug carriers are shown below. Figure 8 As shown.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing aragonite-type nano-sized calcium carbonate using phosphogypsum as a raw material, characterized in that, Includes the following steps: S1. Add phosphogypsum to a phase transfer solution and filter to obtain leachate A; digest leachate A to obtain leachate B. S2. Add a crystal form control agent to the leachate B and introduce carbon dioxide gas to react and obtain aragonite-type nano-sized calcium carbonate.

2. The method according to claim 1, characterized in that, In step S2, the crystal form control agent is a solution formed from one or more of soluble starch, collagen, and silk fibroin, and the amount of solute added to the crystal form control agent solution is 2-8% of the theoretical mass of nano-calcium carbonate.

3. The method according to claim 1, characterized in that, In step S1, the concentration of the phase transfer solution is 2.23-2.24 mol / L.

4. The method according to claim 1, characterized in that, In step S1, the volume ratio of the phase transfer solution to the mass of the phosphogypsum is 70 (mL): 1 (g), and the reaction time is 40 min.

5. The method according to claim 1, characterized in that, In step S2, the flow rate of carbon dioxide gas is 250 mL / min, and the introduction time is 30 min.

6. The method according to claim 3, characterized in that, In step S1, the phase transfer solution is a potassium acetate solution or a sodium acetate solution.

7. The method according to claim 1, characterized in that, In step S1, the digestion process involves adding potassium hydroxide solution to the leachate A, and the pH of the leachate B is 13.

8. The method according to claim 1, characterized in that, In step S2, the reaction temperature is 20-25℃.

9. A nano-sized aragonite-type calcium carbonate prepared by the method of any one of claims 1-8, characterized in that, The average particle size of the aragonite-type nano-sized calcium carbonate is 200-400 nm.

10. The application of the aragonite-type nano-sized calcium carbonate prepared by any one of claims 1-8 or the aragonite-type nano-sized calcium carbonate of claim 9 in the preparation of drug carriers and bone repair materials.

Images