Synthesis and kinetic analysis of hydromagnesite with different morphologies by nesquehonite method

Abstract

Hydromagnesite with different morphologies has been synthesized using self-made nesquehonite whiskers as raw materials. The synthesized samples have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that porous rod-like hydromagnesite are generated at 328~353K and in the pH value of 9.30+0.2, while irregular flower-like and flat layered ones are synthesized in the pH values of 10.0+0.05 and 11.0+0.05, respectively. The yield of hydromagnesite improved linearly with the increase of the temperatures and solution pH values. Porous rod-like hydromagneiste crystals with good crystalline and uniform morphology are obtained when the pyrolysis time is over 60 min. Furthermore, the apparent activation energy of phase transformation is calculated to be 3.4080 kJ/mol. According to the results, the experimental data can be well described by the kinetic model, suggesting that the phase transfer rate is dependent on the temperature.