Method for preparing hollow whisker-shaped anhydrous magnesium carbonate by template method
The hollow whisker-like anhydrous magnesium carbonate is prepared by the template method, which solves the problems of uncontrollable morphology and poor dispersibility in the existing technology, realizes the efficient utilization of anhydrous magnesium carbonate, and broadens its application field.
Patent Information
- Application Number
- CN202510869139.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-26
- Publication Date
- 2025-09-19
AI Technical Summary
Existing technologies make it difficult to prepare whisker-like anhydrous magnesium carbonate, resulting in uncontrollable morphology and poor dispersibility, which limits its performance in high-end application scenarios.
Hollow whisker-like anhydrous magnesium carbonate was prepared by a template method, using crystalline magnesium sulfate as a magnesium source, ammonium carbonate as a carbon source, and tartaric acid as an additive. Anhydrous magnesium carbonate crystals were prepared by a hydrothermal method, using magnesium carbonate trihydrate as a precursor and introducing tartaric acid to form a three-dimensional complex structure, thereby controlling the crystal morphology and particle size.
The anhydrous magnesium carbonate has achieved uniform particle size distribution, good dispersibility and controllable morphology, expanding its application space in high-end fields.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to a synthesis method in the field of chemistry, and in particular to a method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a template method. Background Art
[0002] Anhydrous magnesium carbonate (MgCO3) is a single crystal of magnesium carbonate salt, naturally occurring as magnesite. Due to its unique physical and chemical properties, such as thermal stability and adsorption properties, it is an important inorganic chemical material with broad application prospects in various fields, including chemicals, pharmaceuticals, food, and building materials.
[0003] In recent years, anhydrous magnesium carbonate crystals have attracted the attention of many researchers as a new inorganic flame retardant with high added value and the greatest industrial potential. However, the so-called anhydrous magnesium carbonate products on the market are mostly natural dolomite powder that has been mechanically ground. They have shortcomings such as uneven particle size, irregular morphology, and uncontrollable shape. This leads to poor performance in high-end application scenarios and severely limits the efficient use of the material. Studies have found that the shape of the crystal has a direct impact on its performance. Whisker-like inorganic materials have unique advantages in flame retardancy, composite materials, and other fields due to their high aspect ratio, excellent mechanical properties, and directional reinforcement characteristics. However, in existing technologies, there are no reports on the successful preparation of whisker-like anhydrous magnesium carbonate. Current research on anhydrous magnesium carbonate mainly focuses on the relationship between crystal synthesis temperature and additives. Key technical bottlenecks still exist in the regulation of crystal phase and precise control of microstructure, especially the formation of whisker structures with specific orientation. How to optimize the reaction conditions to achieve the transformation of anhydrous magnesium carbonate from irregular particles to whisker-like crystals and break through the morphological limitations of existing products has become a technical problem that needs to be solved urgently in this field. Summary of the Invention
[0004] In view of the shortcomings of the current existing technology, the present invention provides a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method. The method uses crystalline magnesium sulfate as a magnesium source, ammonium carbonate as a carbon source, tartaric acid as an additive, prepares magnesium carbonate trihydrate as a precursor as a template, and adopts a hydrothermal method to prepare anhydrous magnesium carbonate crystals. It has the advantages of simple process flow and low energy consumption, and the prepared anhydrous magnesium carbonate has a uniform particle size distribution, good dispersibility and regular morphology. It realizes the directional growth of the crystal morphology into a whisker structure, solves the problems of uncontrollable morphology and poor dispersibility of existing products, and expands the application space of anhydrous magnesium carbonate in high-end fields.
[0005] To achieve the above object, the technical solution adopted by the present invention is:
[0006] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method, the specific steps are as follows:
[0007] (1) preparing crystalline magnesium sulfate and ammonium carbonate solution respectively with deionized water, and magnetically stirring to obtain a mixed solution;
[0008] (2) placing the mixed solution in a water bath and heating it, stirring it for a period of time to react, and after the reaction is completed, filtering, washing, and drying it to obtain precursor magnesium carbonate trihydrate crystals;
[0009] (3) After the precursor magnesium carbonate trihydrate crystals are mixed with deionized water and magnetically stirred, a certain amount of tartaric acid is added and the mixture is placed in a reactor and heated to react. After the reaction is completed, the mixture is naturally cooled to room temperature, and anhydrous magnesium carbonate crystals are obtained after filtration, washing, and drying.
[0010] Furthermore, the molar ratio of the crystalline magnesium sulfate to the ammonium carbonate solution in step (1) is 1:1 to 1:5 of the molar ratio of the magnesium source to the carbon source in the solution.
[0011] Furthermore, the magnetic stirring rate in step (1) is 80 r / min to 200 r / min, and the stirring time is 10 min to 30 min.
[0012] Furthermore, the reaction temperature in step (2) is 20° C. to 60° C., the reaction time is 30 min to 120 min, and the reaction stirring rate is 150 r / min to 250 r / min.
[0013] Furthermore, in step (3), the solid-liquid ratio of the precursor magnesium carbonate trihydrate to deionized water is 1:5, the magnetic stirring rate is 100 r / min to 200 r / min, and the stirring time is 10 min to 30 min.
[0014] Furthermore, the reaction temperature in step (3) is 110° C. to 160° C., and the reaction time is 2 h to 8 h.
[0015] Furthermore, the amount of tartaric acid added in step (3) is 3 wt.% to 25 wt.%.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] 1. The present invention uses magnesium carbonate trihydrate as a precursor and as a template, and uses a hydrothermal method to Figure 3 The visible size of magnesium carbonate trihydrate whiskers is 2 to 5 μm in width and has an aspect ratio of >28. This provides a good template for the subsequent hydrothermal preparation of hollow whisker-like anhydrous magnesium carbonate.
[0018] 2. The present invention can be combined with the magnesium ion in the solution by introducing an appropriate amount of tartaric acid as an additive to form a three-dimensional cyclic complex structure overlapping each other, so that the solid phase conversion of magnesium carbonate trihydrate precursor is hollow whisker-shaped anhydrous magnesium carbonate crystals. The morphology and granularity of anhydrous magnesium carbonate are effectively improved and controlled by the complexing action of tartaric acid. The process of the present invention is simple, has great industrialization potential, and the gained hollow whisker-shaped anhydrous magnesium carbonate particle size is uniform, good dispersibility, and controllable morphology. It can be used as high-quality powder filler for inorganic chemical industry, and has widened the application field of anhydrous magnesium carbonate. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The XRD pattern of the precursor magnesium carbonate trihydrate prepared in Example 1-8;
[0020] Figure 2 The XRD pattern of the anhydrous magnesium carbonate prepared in Example 1-8;
[0021] Figure 3 This is a particle size distribution diagram of anhydrous magnesium carbonate prepared in Examples 1-8;
[0022] Figure 4 This is an SEM image of the magnesium carbonate trihydrate precursor prepared in Example 1, and the upper right corner is a high-magnification SEM image;
[0023] Figure 5 The SEM image of the anhydrous magnesium carbonate prepared in Example 1; the upper right corner is a high-magnification SEM image;
[0024] Figure 6 This is an SEM image of the anhydrous magnesium carbonate prepared in Example 2; the upper right corner is a high-magnification SEM image. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail with reference to the following examples.
[0026] The following provides a specific embodiment of a method for preparing hollow whisker-like anhydrous magnesium carbonate by a template method of the present invention, comprising the following steps:
[0027] Example 1
[0028] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0029] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2.5, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0030] (2) The mixed solution was placed in a magnetic constant temperature water bath with a magnetic stirring rate of 200 r / min, a reaction temperature of 45°C, and a reaction time of 100 min. After the reaction, the solution was filtered and washed to obtain precursor magnesium carbonate trihydrate crystals.
[0031] (3) Add 8% tartaric acid to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and stir magnetically for 30 minutes at a speed of 100 r / min. Add the raw materials to the reactor device, the reaction temperature is 160°C, the reaction time is 7 hours, and after the reactor is naturally cooled to room temperature, the mixture is centrifuged and filtered to obtain a filter cake, which is dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals. Figure 1 、 2 , 3, 4 and Figure 5 It can be seen that the obtained product is a hollow whisker-like pure phase anhydrous magnesium carbonate crystal with a length of 30 μm to 60 μm, a width of 1 μm to 4 μm and an average particle size of 10 μm.
[0032] Example 2
[0033] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0034] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2.5, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0035] (2) The mixed solution was placed in a magnetic constant temperature water bath, the magnetic stirring rate was 200 r / min, the reaction temperature was 50 ° C, and the reaction time was 80 min. After the reaction, the solution was filtered and washed to obtain the precursor magnesium carbonate trihydrate crystals.
[0036] (3) Add 10% tartaric acid to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and stir magnetically for 30 minutes at a speed of 100 r / min. Add the raw materials to the reactor device, the reaction temperature is 150°C, the reaction time is 8 hours, and after the reactor is naturally cooled to room temperature, the mixture is centrifuged and filtered to obtain a filter cake, which is dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals. Figure 1 、 2 , 3 and Figure 6 It can be seen that the obtained product is a hollow whisker-like pure phase anhydrous magnesium carbonate crystal with a length of 30 μm to 60 μm, a width of 1 μm to 4 μm and an average particle size of 10 μm.
[0037] Example 3
[0038] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0039] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0040] (2) The mixed solution was placed in a magnetic constant temperature water bath, the magnetic stirring rate was 200 r / min, the reaction temperature was 50 ° C, and the reaction time was 70 min. After the reaction, the solution was filtered and washed to obtain the precursor magnesium carbonate trihydrate crystals.
[0041] (3) Add 15% tartaric acid to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and stir magnetically for 30 minutes at a speed of 100 r / min. Add the raw materials to the reactor device, the reaction temperature is 160°C, and the reaction time is 8 hours. After the reactor is naturally cooled to room temperature, the mixture is centrifuged and filtered to obtain a filter cake, which is dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0042] Example 4
[0043] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0044] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0045] (2) The mixed solution was placed in a magnetic constant temperature water bath, the magnetic stirring rate was 200 r / min, the reaction temperature was 50 ° C, and the reaction time was 60 min. After the reaction, the solution was filtered and washed to obtain the precursor magnesium carbonate trihydrate crystals.
[0046] (3) Add 15% tartaric acid to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and stir magnetically for 30 minutes at a speed of 100 r / min. Add the raw materials to the reactor device, the reaction temperature is 160°C, and the reaction time is 8 hours. After the reactor is naturally cooled to room temperature, the mixture is centrifuged and filtered to obtain a filter cake, which is dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0047] Example 5
[0048] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0049] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2.5, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0050] (2) The mixed solution was placed in a magnetic constant temperature water bath, the magnetic stirring rate was 200 r / min, the reaction temperature was 40 ° C, and the reaction time was 90 min. After the reaction, the solution was filtered and washed to obtain the precursor magnesium carbonate trihydrate crystals.
[0051] (3) 17% tartaric acid was added to a mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and magnetic stirring was performed for 30 minutes at a magnetic stirring speed of 100 r / min. The raw materials were added to the reactor device, the reaction temperature was 170°C, and the reaction time was 9 hours. After the reactor was naturally cooled to room temperature, the mixture was centrifuged and filtered to obtain a filter cake, which was dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0052] Example 6
[0053] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0054] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0055] (2) The mixed solution was placed in a magnetic constant temperature water bath with a magnetic stirring rate of 200 r / min, a reaction temperature of 55°C, and a reaction time of 70 min. After the reaction, the solution was filtered and washed to obtain precursor magnesium carbonate trihydrate crystals.
[0056] (3) 13% tartaric acid was added to a mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and magnetic stirring was performed for 30 minutes at a magnetic stirring speed of 100 r / min. The raw materials were added to the reactor device, the reaction temperature was 170°C, and the reaction time was 8 hours. After the reactor was naturally cooled to room temperature, the mixture was centrifuged and filtered to obtain a filter cake, which was dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0057] Example 7
[0058] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0059] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0060] (2) The mixed solution was placed in a magnetic constant temperature water bath, the magnetic stirring rate was 200 r / min, the reaction temperature was 45 ° C, and the reaction time was 80 min. After the reaction, the solution was filtered and washed to obtain the precursor magnesium carbonate trihydrate crystals.
[0061] (3) 15% tartaric acid was added to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and the mixture was magnetically stirred for 30 minutes at a speed of 100 r / min. The raw materials were added to the reactor device, the reaction temperature was 180°C, and the reaction time was 9 hours. After the reactor was naturally cooled to room temperature, the mixture was centrifuged and filtered to obtain a filter cake, which was dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0062] Example 8
[0063] A method for preparing hollow whisker-shaped anhydrous magnesium carbonate using a structure-directing agent template method, comprising the following steps:
[0064] (1) Crystalline magnesium sulfate and ammonium carbonate solution were prepared separately with deionized water so that the molar ratio of magnesium source to carbon source was 1:2, and the mixed solution was magnetically stirred for 10 min at a magnetic stirring rate of 100 r / min;
[0065] (2) The mixed solution was placed in a magnetic constant temperature water bath with a magnetic stirring rate of 200 r / min, a reaction temperature of 55°C, and a reaction time of 90 min. After the reaction, the solution was filtered and washed to obtain precursor magnesium carbonate trihydrate crystals.
[0066] (3) 15% tartaric acid was added to the mixed solution of the precursor and deionized water with a solid-liquid ratio of 1:5, and the mixture was magnetically stirred for 30 minutes at a speed of 100 r / min. The raw materials were added to the reactor device, the reaction temperature was 150°C, and the reaction time was 9 hours. After the reactor was naturally cooled to room temperature, the mixture was centrifuged and filtered to obtain a filter cake, which was dried in an oven at 60°C for 12 hours to obtain pure anhydrous magnesium carbonate crystals.
[0067] As can be seen from the above examples, in the process of preparing anhydrous magnesium carbonate crystals, the present invention can convert magnesium carbonate trihydrate into pure anhydrous magnesium carbonate crystals through a template method; adding an appropriate amount of tartaric acid as an additive can regulate the morphology and size of the anhydrous magnesium carbonate. The process of the present invention is simple, has great industrial potential, and the obtained anhydrous magnesium carbonate particles are uniform in size, good in dispersibility, and have controllable morphology. It can be used as a high-quality powder filler in the field of inorganic chemicals.
[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made within the scope of this application are intended to fall within the scope of the present invention. In the following specific embodiments, all raw materials used were purchased from the market and used directly without further processing.
Claims
1. A method for preparing hollow whisker-shaped anhydrous magnesium carbonate by template method, characterized in that, The specific steps are as follows: (1) preparing crystalline magnesium sulfate and ammonium carbonate solution respectively with deionized water, and magnetically stirring to obtain a mixed solution; (2) placing the mixed solution in a water bath and heating it, stirring it for a period of time to react, and after the reaction is completed, filtering, washing, and drying it to obtain precursor magnesium carbonate trihydrate crystals; (3) After the precursor magnesium carbonate trihydrate crystals are mixed with deionized water and magnetically stirred, a certain amount of tartaric acid is added and the mixture is placed in a reactor and heated to react. After the reaction is completed, the mixture is naturally cooled to room temperature, and anhydrous magnesium carbonate crystals are obtained after filtration, washing, and drying.
2. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by template method according to claim 1, is characterized in that, The molar ratio of the crystalline magnesium sulfate to the ammonium carbonate solution in step (1) is 1:1 to 1:5, which is the molar ratio of the magnesium source to the carbon source in the solution.
3. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method according to claim 1, is characterized in that, The magnetic stirring rate in step (1) is 80 r / min to 200 r / min, and the stirring time is 10 min to 30 min.
4. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by template method according to claim 1, is characterized in that, The reaction temperature in step (2) is 20° C. to 60° C., the reaction time is 30 min to 120 min, and the reaction stirring rate is 150 r / min to 250 r / min.
5. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method according to claim 1, is characterized in that, In step (3), the solid-liquid ratio of the precursor magnesium carbonate trihydrate to deionized water is 1:5, the magnetic stirring rate is 100 r / min to 200 r / min, and the stirring time is 10 min to 30 min.
6. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method according to claim 1, is characterized in that, The reaction temperature in step (3) is 110° C. to 160° C., and the reaction time is 2 h to 8 h.
7. a method for preparing hollow whisker-shaped anhydrous magnesium carbonate by a template method according to claim 1, is characterized in that, The amount of tartaric acid added in step (3) is 3wt.% to 25wt.%.