Comparison of thermal property and dissolution behavior of synthetic compound and natural hemimorphite

A comparison of the thermodynamic properties, crystal structure, thermal characterization and dissolution behavior of the synthetic compound and the natural hemimorphite was made. It was found that the synthetic compound shows the same crystal structure but is poorly crystallized compared with the natural hemimorphite. Both the synthetic compound and natural hemimorphite display the similar characteristics of phase formation during calcination, except that the poor crystallization of synthetic compound leads to the structural reorganization with an intense exothermic peak at 700 °C to form a stable phase after losing structural water at 633 °C. The natural hemimorphite exhibits an endothermic peak at 700 °C for the removal of structural water during TGA/DTA analysis. Although, synthetic compound shows a more rapid dissolution rate than the natural hemimorphite in ammoniacal solution, the final states exhibit the same when they are completely dissolved.