采用扫描电镜、显微红外分析仪和X光电子能谱研究了丁二酸对α半水脱硫石膏晶体生长习性与形貌的影响,从晶体生长角度分析了丁二酸的晶形调节作用机理.结果表明:丁二酸显著改变了α半水脱硫石膏晶体的生长习性,使其由长棒状转变为短柱状或片状,且晶体发育更完整,晶体尺度变大;控制丁二酸的掺量,可制备长径比为1∶1的短柱状α半水脱硫石膏晶体;通过羟基与Ca2+络合作用,丁二酸选择吸附在α半水脱硫石膏的(111)面,抑制其在c轴方向生长,使晶体沿c轴生长的比较优势被削弱或逆转,从而改变了晶面在不同轴向的相对生长速率,使α半水脱硫石膏晶体生长习性和形貌发生改变;丁二酸降低α半水石膏晶体生长速率,晶体生长发育的时间更充分,导致晶体尺度增大.
Effect of succinic acid on the crystalline growth habit and crystal morphology of α-hemihydrate desulfogypsum was investigated.Furthermore,by use of SEM(scanning electron microscope),micro-FTIR(microscopic Fourier transform infrared spectrum analyzer) and XPS(X-ray photoelectron spectroscopy analysis)technique,its crystal modifying mechanism was also analyzed from the viewpoint of crystal growth.The results show that succinic acid evidently changes the crystalline growth habit of dihydrate,leading to large crystal size and transformation of crystal shape from long clavate-like to short prismatic or lamellar-shaped.Short columnar-shaped α-hemihydrate desulfurization gypsum crystals with a length-diameter ratio of 1∶1 could be prepared by controlling the dosage of succinic acid.Succinic acid is selectively chemisorbed on the(111) face of gypsum crystal by complies reaction between hydroxyl and Ca2+,which inhibits the growth along c axis and alters the relative growth rate of crystal faces in different axis directions,consequently leading to the transformation of crystalline growth habit and crystal morphology of dihydrate gypsum.The addition of succinic acid decreases the growth rate of α-hemihydrate desulfogypsum crystal,so the crystals have plenty time to grow,and as a result,the dihydrate crystals are coarsened.