中文摘要：

采用SEM研究了乙二胺四乙酸（EDTA）对α半水脱硫石膏晶体形貌的影响、EDTA在α半水石膏表面的吸附作用，分析了EDTA的调晶机理。结果表明，EDTA能显著改变α半水石膏晶体形貌，使其从长棒状转变为短柱状，且晶体尺寸增大；EDTA调晶效果对pH值比较敏感，在中性范围内EDTA有最佳调晶效果；Al3＋会影响ED—TA的调晶效果，为了得到最佳的调晶效果，要控制溶液中的杂质金属离子含量；EDTA通过与Ca2＋的络合反应吸附于“半水石膏晶体（111）晶面上，抑制晶体在c轴方向的生长，从而改变各个晶面的相对生长速率，使α半水石膏晶体形貌发生变化。

英文摘要：

Influences of EDTA on crystal morphology and adsorption on surface of α-hemihydrate desulfurization gypsum were studied by SEM. Moreover, the crystal modification mechanism was analysed. The results show that EDTA changes the crystal morphology of α-hemihydrate gypsum greatly,which transforms the morphology from long clavate to short columnar and makes the size bigger. PH value is very important to the effect of EDTA,and the best extend is neutral. AP＋ weakens the effect of EDTA, so other metal ions must be in a low level in the action solution for better effect of crystal modification. The complex reaction between EDTA and Ca2＋ makes EDTA adsorb on （111） crystal plane of α-hemihydrate gypsum, which restrains the growth of crystal on C axis and changes the relative growth rate of different crystal planes so that the crystal morphology of α-chemihydrate gypsum is changed.