Microwave preparation method of alpha-calcium sulfate hemihydrate

[0028] Example 1

[0029] Add 5.0g calcium sulfate dihydrate and 100mL mixed salt solution (calcium chloride 100g/L, sodium chloride 50g/L) to the reaction vessel, put it into the CW-2000 ultrasonic/microwave collaborative extraction/reactor, and set the procedure: Under the combined action of ultrasonic waves and microwaves, the reaction system was heated to 105°C at a heating rate of 4°C/min, and then maintained at a constant temperature for 2 h; immediately after the reaction, the reaction mixture was filtered and washed, and the solid product was placed in a 60°C oven to dry 19h, obtained α-calcium sulfate hemihydrate.

[0030] figure 2 is the scanning electron microscope image of the prepared α-calcium sulfate hemihydrate, obtained from figure 2 It can be seen that the obtained α-calcium sulfate hemihydrate has a uniform fibrous structure with an average length of 112.9 μm and an average diameter of 7.37 μm.

[0031] Example 2

[0032] Add 5.0g calcium sulfate dihydrate and 100mL mixed salt solution (calcium chloride 100g/L, sodium chloride 50g/L) to the reaction vessel, put it into the CW-2000 ultrasonic/microwave collaborative extraction/reactor, and set the procedure: Under the combined action of ultrasonic waves and microwaves, the reaction system was heated to 105°C at a heating rate of 8°C/min, and then maintained at a constant temperature for 3 hours; immediately after the reaction, the reaction mixture was filtered and washed, and the solid product was placed in a 60°C oven Dry for 12h to obtain α-calcium sulfate hemihydrate.

[0033] image 3 is the scanning electron microscope image of the prepared α-calcium sulfate hemihydrate, by image 3 It can be seen that the obtained α-calcium sulfate hemihydrate has a uniform fibrous structure with an average length of 113.78 μm and an average diameter of 8.31 μm.

[0034] Figure 4 is the XRD pattern of the obtained α-calcium sulfate hemihydrate, obtained by Figure 4 It can be seen that the prepared α-calcium sulfate hemihydrate has a very sharp XRD diffraction peak, and the phase search analysis shows that the sample is relatively pure and has a high degree of crystallinity.

[0035] The obtained α-calcium sulfate hemihydrate crystal XRD pattern of each peak index and crystallinity data are shown in Table 1.

[0036] Each peak index and crystallinity data of XRD pattern of α-calcium sulfate hemihydrate crystal prepared in Table 1

[0037]

[0038] It is known from Table 1 that the crystallinity of the obtained α-calcium sulfate hemihydrate crystals is 96.88%.

[0039] Example 3

[0040] Add 8.0g calcium sulfate dihydrate and 100mL mixed salt solution (calcium chloride 80g/L, sodium chloride 50g/L) to the reaction vessel, put it into the CW-2000 ultrasonic/microwave collaborative extraction/reactor, and set the procedure: Under the combined action of ultrasonic waves and microwaves, the reaction system was heated to 105°C at a heating rate of 2°C/min, and then maintained at a constant temperature for 3 hours; immediately after the reaction, the reaction mixture was filtered and washed, and the solid product was placed in a 60°C oven. Dry for 18h to obtain α-calcium sulfate hemihydrate. The obtained α-calcium sulfate hemihydrate crystal has a uniform fibrous structure, with an average crystal length of 110.78 μm and an average diameter of 7.31 μm.