Method for preparing calcium carbonate with controllable topography by using calcium sulfate

[0023] Disperse the freshly prepared calcium sulfate precursor in 50 mL of N,N-dimethylformamide with magnetic stirring at 35 °C; 50 mL of 0.06 mol / L NaHCO 3 Quickly pour the solution into the suspension, stir and react at 35°C for 4 hours; centrifuge the precipitate and transfer it to a beaker, add 200ml of distilled water, and stir magnetically at room temperature for 3 hours; centrifuge, wash and dry the separated product, That is, calcium carbonate powder is obtained. figure 1 It is X-ray powder diffraction result, shows that it is single-phase calcium carbonate. From figure 2 It can be seen from the scanning electron microscope photo that it is a mixture of fusiform and flower-shaped.

[0025] Disperse the freshly prepared calcium sulfate precursor in 50 mL of N,N-dimethylformamide with magnetic stirring at 35 °C; 50 mL of 0.18 mol / L NaHCO 3 Quickly pour the solution into the suspension, stir and react at 35°C for 4 hours; centrifuge the precipitate and transfer it to a beaker, add 200ml of distilled water, and stir magnetically at room temperature for 3 hours; centrifuge, wash and dry the separated product, That is, calcium carbonate powder is obtained. image 3 It can be clearly seen from the scanning electron microscope photo that it is mainly fusiform calcium carbonate.

[0027] Disperse the freshly prepared calcium sulfate precursor in 50 mL of N,N-dimethylformamide with magnetic stirring at 35 °C; 50 mL of 0.06 mol / L NaHCO 3 Quickly pour the solution into the suspension, stir and react at 60°C for 4 hours; centrifuge the precipitate and transfer it to a beaker, add 200ml of distilled water, and stir magnetically at room temperature for 3 hours; centrifuge, wash and dry the separated product, That is, calcium carbonate powder is obtained. Figure 4 It can be clearly seen that it is mainly spherical calcium carbonate from its scanning electron microscope photo.