Investigation on Characteristics of Gypsum Crystallization With Metallic Ions at Different Temperatures in Wet Limestone-gypsum Desulfurization

A dynamic batch crystallization reactor was used to study the characteristics of gypsum crystallization in wet flue gas desulfurization.Through this study,the results can be concluded that the induction time of gypsum crystallization is decreased as the temperature increases and in the same concentration of metallic ions,the sequence of inhibit crystallization are followed as Al3+ Fe3+ Mg2+,the influence of Mg2+ for induction time of gypsum crystallization nearly can be ignored.The morphology of gypsum crystallization was studied by scanning electron microscope(SEM).And the SEM analysis shows that the quality of crystal morphology in higher temperature is better than that in lower temperature conditions.Moreover,the influence of metallic ions on crystal form was investigated also.When adding different impurities such as metallic ions Fe3+,Mg2+,the crystal trapezoid body gradually turns to needle shaped gypsum which reduces the dehydration of gypsum.The orthogonal experiments show that the most significant impact on gypsum crystal induction time is the concentration of calcium,and generally impact factors followed as Al3+,Fe3+,Mn2+,while the influence of Cu2+,Ni2+ is no significant.