Method for controlling the morphology size of anhydrous magnesium carbonate

Abstract

The application discloses a morphology size control method of anhydrous magnesium carbonate, and uses urea and magnesium chloride hexahydrate as a carbon source and a magnesium source, uses succinic acid as a crystal morphology modifier, and changes reaction conditions to prepare anhydrous magnesium carbonate with different morphologies, and through adding different molar amounts of succinic acid, under different pH, reaction temperature and reaction time, anhydrous magnesium carbonate powder with different particle sizes and morphologies is prepared. With the increase of the addition amount of succinic acid, the morphology of the anhydrous magnesium carbonate gradually unifies. The anhydrous magnesium carbonate particles prepared under the condition of pH=9 are easy to agglomerate, the particle size of the anhydrous magnesium carbonate prepared under the condition of pH=10 and pH=11 gradually decreases, and the morphology is changed from diamond-like to cubic-like. The preparation method is simple, the condition is mild, and various anhydrous magnesium carbonates with different morphologies can be prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inorganic material preparation, and particularly relates to a morphology size control method of anhydrous magnesium carbonate. BACKGROUND

[0002] Anhydrous magnesium carbonate powder has good thermal stability, non-toxicity and stable chemical properties. Its thermal decomposition not only absorbs a large amount of heat, but also reduces the oxygen concentration on the surface of combustible materials, and MgO can prevent the combustible materials from continuing to burn, so it has very high potential application value in the field of flame retardants. Because Mg 2+ Highly hydrated in aqueous solution, anhydrous magnesium carbonate powder needs to be prepared at high temperature and high pressure. At present, hydrothermal synthesis is a relatively mild method. Urea, ascorbic acid, other carbonates or bicarbonates are used as precursors of carbonates to synthesize anhydrous magnesium carbonate. By adding different additives during the hydrothermal synthesis process, anhydrous magnesium carbonate crystals with controllable morphology can be obtained. Cubic crystal morphology of anhydrous magnesium carbonate is prepared by using CH4N2O and MgCl2 as raw materials, adding sodium dodecyl benzene sulfonate at 180℃ for about 3h. Corn kernel, cubic and spherical structure anhydrous magnesium carbonate is synthesized by using CH4N2O and MgSO4 as raw materials, adding sodium citrate, tartaric acid and anionic polyacrylamide, and reacting at 180℃ for 3h. Under different pH conditions, different concentrations of ascorbic acid can adjust the formation of dumbbell-shaped, ball-shaped and cubic-shaped anhydrous magnesium carbonate.

[0003] However, controlling the morphology of anhydrous magnesium carbonate is a great challenge. Uniform morphology of anhydrous magnesium carbonate is of great significance for application in the fields of inorganic fillers, formation of porous MgO, adsorbent materials, catalysis and antibacterial, etc. SUMMARY

[0004] Based on different application fields of anhydrous magnesium carbonate with different morphologies, the application provides a preparation method of morphology-controllable anhydrous magnesium carbonate. The application uses succinic acid as a morphology regulator, urea and magnesium chloride hexahydrate as carbon source and magnesium source respectively, and prepares anhydrous magnesium carbonate with different morphologies by changing the addition amount of succinic acid, reaction pH, reaction temperature and reaction time. The preparation method is simple, the conditions are mild, and various morphologies of anhydrous magnesium carbonate can be prepared.

[0005] The preparation method of morphology-controllable anhydrous magnesium carbonate comprises the following steps:

[0006] 0.1 mol urea was added into deionized water, then 0.003-0.005 mol succinic acid was added, and then sodium hydroxide solution was slowly added dropwise until the succinic acid was dissolved; 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water and then added into the system, the pH value of the system was adjusted to pH=9-11, and then the system was transferred into a hydrothermal reactor, and reacted at 160-200 ℃ for 3-9 h, and then naturally cooled.

[0007] The present application uses urea and magnesium chloride hexahydrate as carbon source and magnesium source, and uses succinic acid as crystal morphology modifier to prepare anhydrous magnesium carbonate with different morphologies by changing the reaction conditions. With the increase of the amount of succinic acid, the morphology of the anhydrous magnesium carbonate gradually unifies. The anhydrous magnesium carbonate particles prepared under the condition of pH=9 are easy to agglomerate, the particle size of the anhydrous magnesium carbonate prepared under the conditions of pH=10 and pH=11 gradually decreases, and the morphology changes from diamond-like to cubic-like. The particle size of the anhydrous magnesium carbonate prepared at 160 ℃ is quite different, the particle size of the anhydrous magnesium carbonate gradually decreases with the increase of the temperature. With the change of the reaction time, the particle size of the anhydrous magnesium carbonate gradually increases, and the magnesium carbonate particles finally become cubic-like. Under the conditions of pH value, temperature and time, the molecular motion and crystal growth promoting the interaction between succinic acid and magnesium ions form controllable multi-morphology particles.

[0008] The present application uses urea and magnesium chloride hexahydrate as carbon source and magnesium source, and uses succinic acid as crystal morphology modifier to prepare anhydrous magnesium carbonate with different morphologies by changing the reaction conditions. With the increase of the amount of succinic acid, the morphology of the anhydrous magnesium carbonate gradually unifies. The anhydrous magnesium carbonate particles prepared under the condition of pH=9 are easy to agglomerate, the particle size of the anhydrous magnesium carbonate prepared under the conditions of pH=10 and pH=11 gradually decreases, and the morphology changes from diamond-like to cubic-like. The particle size of the anhydrous magnesium carbonate prepared at 160 ℃ is quite different, the particle size of the anhydrous magnesium carbonate gradually decreases with the increase of the temperature. With the change of the reaction time, the particle size of the anhydrous magnesium carbonate gradually increases, and the magnesium carbonate particles finally become cubic-like. Under the conditions of pH value, temperature and time, the molecular motion and crystal growth promoting the interaction between succinic acid and magnesium ions form controllable multi-morphology particles.

[0009] Compared with the prior art, the beneficial effects of the present application are embodied in that:

[0010] The present application first uses succinic acid as a morphology modifier of anhydrous magnesium carbonate. The particle size of the anhydrous magnesium carbonate can be controlled in a wide range. Under controllable conditions, anhydrous magnesium carbonate with various morphologies can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 SEM image of anhydrous magnesium carbonate (S1) prepared in Example 1.

[0012] Figure 2 SEM of anhydrous magnesium carbonate (S2) prepared for Example 2, with high magnification SEM on the right.

[0013] Figure 3 SEM of anhydrous magnesium carbonate (S3) prepared for Example 3, with high magnification SEM on the right.

[0014] Figure 4 SEM of anhydrous magnesium carbonate (S4) prepared for Example 4, with high magnification SEM on the right.

[0015] Figure 5 SEM of anhydrous magnesium carbonate (S5) prepared for Example 5, with high magnification SEM on the right.

[0016] Figure 6 SEM of anhydrous magnesium carbonate (S6) prepared for Example 6, with high magnification SEM on the right.

[0017] Figure 7 SEM of anhydrous magnesium carbonate (S7) prepared for Example 7, with high magnification SEM on the right.

[0018] Figure 8 SEM of anhydrous magnesium carbonate (S8) prepared for Example 8, with high magnification SEM on the right.

[0019] Figure 9 SEM of anhydrous magnesium carbonate (S9) prepared for Example 9, with high magnification SEM on the right.

[0020] Figure 10 SEM of anhydrous magnesium carbonate (S10) prepared for Example 10, with high magnification SEM on the right.

[0021] Figure 11 FTIR of anhydrous magnesium carbonate prepared for Examples 1-10 (a figure for S1-S5, b figure for S6-S10).

[0022] Figure 12 XRD of anhydrous magnesium carbonate prepared for Examples 1-10 (a figure for S1-S5, b figure for S6-S10). DETAILED DESCRIPTION

[0023] Example 1:

[0024] 0.1 mol urea was added to deionized water, then 0.02 mol magnesium chloride hexahydrate was added, and after the solution pH was adjusted to 10 with 5 mol / L sodium hydroxide solution, the solution was moved to a hydrothermal reactor, which was placed in an oven at 180°C, and reacted for 3 hours. After the reaction was completed, the reactor was naturally cooled to room temperature, and the solution was removed, centrifuged, and washed 5 times with deionized water, and dried in an oven at 100°C for 12 hours.

[0025] By Figure 11 (a) S1, 744 cm -1 and 877 cm -1 correspond to CO3 2- out-of-plane bending vibration characteristic peaks, 1090 cm -1 and 1450 cm -1 correspond to C-O symmetric and asymmetric stretching vibration characteristic peaks. The peaks at 744, 877, 1090 and 1450 cm -1 are characteristic peaks of anhydrous magnesium carbonate crystal.

[0026] By Figure 12 (a) S1, the XRD characteristic peaks of S1 are consistent with the standard anhydrous magnesium carbonate XRD characteristic peaks, and no other impurity peaks appear, indicating that pure anhydrous magnesium carbonate is prepared.

[0027] By Figure 1 , the anhydrous magnesium carbonate particles have no fixed shape, and the particle size is about 15.5 μm.

[0028] Example 2:

[0029] 0.1 mol urea was added to deionized water, then 0.003 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added until the succinic acid was completely dissolved. Then 0.02 mol magnesium chloride hexahydrate was added to deionized water and dissolved. After the two solutions were uniformly mixed, the solution pH was adjusted to 10 with 5 mol / L sodium hydroxide solution. The solution was then moved to a hydrothermal reactor, which was placed in an oven at 180°C and reacted for 3 hours. After the reaction was completed, the reactor was naturally cooled to room temperature, and the solution was removed and centrifuged and washed 5 times with deionized water. The solution was then dried in an oven at 100°C for 12 hours.

[0030] By Figure 11 (a) and Figure 12 (a) can be obtained, and pure anhydrous magnesium carbonate is prepared in Example 2.

[0031] By Figure 2 , the anhydrous magnesium carbonate particles are diamond-like, and the particle size is about 5.2 μm.

[0032] Example 3:

[0033] 0.1 mol urea was added to deionized water, then 0.004 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then, 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water, and the two solutions were uniformly mixed. Then, 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 10, and then the solution was moved to a hydrothermal reactor, which was placed in an oven at 180°C for 3 hours. After the reaction was completed, the reactor was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0034] From Figure 11 (a) and Figure 12 (a) can be obtained, and pure anhydrous magnesium carbonate was prepared in Example 3.

[0035] From Figure 3 , the anhydrous magnesium carbonate particles were diamond-like, and the particle size was about 3.3 μm.

[0036] Example 4:

[0037] 0.1 mol urea was added to deionized water, then 0.005 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then, 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water, and the two solutions were uniformly mixed. Then, 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 10, and then the solution was moved to a hydrothermal reactor, which was placed in an oven at 180°C for 3 hours. After the reaction was completed, the reactor was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0038] From Figure 11 (a) and Figure 12 (a) can be obtained, and pure anhydrous magnesium carbonate was prepared in Example 4.

[0039] From Figure 4 , the anhydrous magnesium carbonate particles were diamond-like, and the particle size was about 7.5 μm.

[0040] Example 5:

[0041] 0.1 mol urea was added to deionized water, then 0.005 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then, 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water, and the two solutions were uniformly mixed. Then, 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 9, and then the solution was moved to a hydrothermal reaction kettle. The reaction was carried out in an oven at 180°C for 3 hours. After the reaction was completed, the reaction kettle was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0042] According to the above method, the pure anhydrous magnesium carbonate can be prepared. Figure 11 (a) and Figure 12 According to the above method, the pure anhydrous magnesium carbonate can be prepared.

[0043] According to the above method, the pure anhydrous magnesium carbonate can be prepared. Figure 5 The anhydrous magnesium carbonate particles are in a cubic shape, and the particle size is about 5.2 μm.

[0044] Example 6:

[0045] 0.1 mol urea was added to deionized water, then 0.005 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then, 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water, and the two solutions were uniformly mixed. Then, 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 11, and then the solution was moved to a hydrothermal reaction kettle. The reaction was carried out in an oven at 180°C for 3 hours. After the reaction was completed, the reaction kettle was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0046] According to the above method, the pure anhydrous magnesium carbonate can be prepared. Figure 11 (b) and Figure 12 According to the above method, the pure anhydrous magnesium carbonate can be prepared.

[0047] According to the above method, the pure anhydrous magnesium carbonate can be prepared. Figure 6 The anhydrous magnesium carbonate particles are in a cubic shape, and the particle size is about 5.2 μm.

[0048] Example 7:

[0049] 0.1 mol urea was added to deionized water, then 0.005 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then, 0.02 mol magnesium chloride hexahydrate was dissolved in deionized water, and the two solutions were uniformly mixed. Then, 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 10, and then the solution was moved to a hydrothermal reaction kettle. The reaction was carried out in an oven at 160°C for 3 hours. After the reaction was completed, the reaction kettle was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0050] By Figure 11 (b) and Figure 12 (b) can be obtained, the implementation case 7 to prepare pure anhydrous magnesium carbonate.

[0051] By Figure 7 , anhydrous magnesium carbonate particles are diamond-like, particle size of about 5.8 μm.

[0052] Example 8:

[0053] 0.1 mol urea into deionized water, then add 0.005 mol succinic acid, slowly drop 5 mol / L sodium hydroxide solution until the succinic acid is completely dissolved, then 0.02 mol magnesium chloride hexahydrate into deionized water dissolved, after the two solutions are mixed evenly, then use 5 mol / L sodium hydroxide solution to adjust the solution pH = 10, the solution is moved to the hydrothermal reactor, in the 200 ℃ oven, reaction 3 hours. After the reaction is finished, the reactor is cooled to room temperature, the solution is removed, centrifuged, washed 5 times with deionized water, dried in the 100 ℃ oven for 12 hours.

[0054] By Figure 11 (b) and Figure 12 (b) can be obtained, the implementation case 8 to prepare pure anhydrous magnesium carbonate.

[0055] By Figure 8 , anhydrous magnesium carbonate particles are cubic-like, particle size of about 4.1 μm.

[0056] Example 9:

[0057] 0.1 mol urea into deionized water, then add 0.005 mol succinic acid, slowly drop 5 mol / L sodium hydroxide solution until the succinic acid is completely dissolved, then 0.02 mol magnesium chloride hexahydrate into deionized water dissolved, after the two solutions are mixed evenly, then use 5 mol / L sodium hydroxide solution to adjust the solution pH = 10, the solution is moved to the hydrothermal reactor, in the 180 ℃ oven, reaction 6 hours. After the reaction is finished, the reactor is cooled to room temperature, the solution is removed, centrifuged, washed 5 times with deionized water, dried in the 100 ℃ oven for 12 hours.

[0058] By Figure 11 (b) and Figure 12 (b) can be obtained, the implementation case 9 to prepare pure anhydrous magnesium carbonate.

[0059] By Figure 9 , anhydrous magnesium carbonate particles are cubic-like, particle size of about 7.9 μm.

[0060] Example 10:

[0061] 0.1 mol urea was added to deionized water, then 0.005 mol succinic acid was added, and then 5 mol / L sodium hydroxide solution was slowly added dropwise until the succinic acid was completely dissolved. Then 0.02 mol magnesium chloride hexahydrate was added to deionized water and dissolved, and then the two solutions were uniformly mixed. Then 5 mol / L sodium hydroxide solution was used to adjust the pH of the solution to 10, and then the solution was moved to a hydrothermal reactor. The reactor was placed in an oven at 180°C and reacted for 9 hours. After the reaction was completed, the reactor was naturally cooled to room temperature, and the solution was removed. The solution was centrifuged and washed 5 times with deionized water, and then dried in an oven at 100°C for 12 hours.

[0062] (b) and Figure 11 (b) can be obtained, and Example 10 was prepared to obtain pure anhydrous magnesium carbonate. Figure 12

[0063] (b) and Figure 10 obtained, the anhydrous magnesium carbonate particles were diamond-like, and the particle size was about 9.5 μm.​

Claims

1. A morphology size control method of anhydrous magnesium carbonate, characterized in that: 0.1 mol of urea is added to deionized water, then 0.005 mol of succinic acid is added, and then 5 mol / L of sodium hydroxide solution is added dropwise until the succinic acid is completely dissolved; 0.02 mol of magnesium chloride hexahydrate is then added to deionized water and dissolved; the two solutions are uniformly mixed; 5 mol / L of sodium hydroxide solution is used to adjust the pH of the solution to 11; the solution is then moved to a hydrothermal reaction kettle; the kettle is placed in an oven at 180°C and reacted for 3 hours; after the reaction is completed, the kettle is naturally cooled to room temperature, the solution is taken out, centrifuged and washed 5 times with deionized water, and dried in an oven at 100°C for 12 hours to obtain anhydrous magnesium carbonate particles; the anhydrous magnesium carbonate particles are cubic in shape, and the particle size is 5.2 μm.

2. A morphology size control method of anhydrous magnesium carbonate, characterized in that: 0.1 mol of urea is added to deionized water, then 0.005 mol of succinic acid is added, and then 5 mol / L of sodium hydroxide solution is added dropwise until the succinic acid is completely dissolved; 0.02 mol of magnesium chloride hexahydrate is then added to deionized water and dissolved; the two solutions are uniformly mixed; 5 mol / L of sodium hydroxide solution is used to adjust the pH of the solution to 10; the solution is then moved to a hydrothermal reaction kettle; the kettle is placed in an oven at 180°C and reacted for 6 hours; after the reaction is completed, the kettle is naturally cooled to room temperature, the solution is taken out, centrifuged and washed 5 times with deionized water, and dried in an oven at 100°C for 12 hours to obtain anhydrous magnesium carbonate particles; the anhydrous magnesium carbonate particles are cubic in shape, and the particle size is 7.9 μm. ​ ​

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