Mg^(2+) 对半水硫酸钙晶须结晶习性的影响  

Effect of Mg ^(2+)on Crystallization Habit of Calcium Sulfate Hemihydrate Whiskers

作　　者：王青 刁华利[2,3] 刘冬梅 张典 徐港[1,2] WANG Qing;DIAO Huali;LIU Dongmei;ZHANG Dian;XU Gang(Hubei Key Laboratory of Disaster Prevention and Mitigation,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,China;Three Gorges Tourism Polytechnic College,Yichang 443000,China)

机构地区：[1]防灾减灾湖北省重点实验室,宜昌443002 [2]三峡大学土木与建筑学院,宜昌443002 [3]三峡旅游职业技术学院,宜昌443000

出　　处：《人工晶体学报》2023年第10期1897-1906,共10页Journal of Synthetic Crystals

基　　金：土木工程防灾减灾湖北省引智创新示范基地(2021EJD026);国家级地方高校能源和环境材料化学学科创新引智基地(D20015)。

摘　　要：本文以磷石膏为原料蒸压制备半水硫酸钙晶须,采用数字显微镜、X射线衍射(XRD)和X射线光电子能谱(XPS)等微观测试方法对Mg^(2+)作用下的半水硫酸钙晶须微观形貌、组成及晶面发育情况等进行试验研究,运用分子动力学技术模拟计算Mg^(2+)在半水硫酸钙晶体晶面的相互作用能和径向分布函数,两者结合探讨Mg^(2+)对半水硫酸钙晶体不同晶面结晶习性的影响。结果表明,Mg^(2+)和半水硫酸钙晶体不同晶面的相互作用能从小到大顺序为:ΔE_((200))<ΔE_((002))<ΔE_((400))<ΔE_((020))<ΔE_((204))即Mg^(2+)主要吸附在半水硫酸钙晶体的(200)、(002)、(400)晶面上。Mg^(2+)与SO^(2-)_(4)间的作用距离小于Ca^(2+)与SO^(2-)_(4)间的作用距离,Mg与S之间产生了明显的电子效应,且电子效应随硫酸镁掺量的增加而增强,XRD衍射峰位置随硫酸镁掺量的增多向右偏移变得更加明显,说明有少量的Mg^(2+)嵌入半水硫酸钙晶格。在硫酸镁掺量0.15%(质量分数,下同)时,优先促进晶体c轴方向的生长,使半水硫酸钙晶须呈细长针状,平均长度为47.29μm,平均长径比为36.07;在硫酸镁掺量为0.30%时,抑制晶体沿c轴和径向的生长,使半水硫酸钙晶须呈细短针状,平均长度为39.72μm,平均长径比为28.91。In this paper,calcium sulfate hemihydrate whiskers were prepared by autoclaving using phosphogypsum as raw material.Digital microscope,X-ray diffraction(XRD)and X-ray photoelectron spectrometer(XPS)were used to investigate the microscopic morphology,composition and crystal surface development of calcium sulfate hemihydrate whiskers under the effect of Mg^(2+).Using molecular dynamics technology to simulate the interaction energy and radial distribution function of Mg^(2+)in the crystal surface of the calcium sulfate crystal.The effect of Mg^(2+)on the crystallization habits of calcium sulfate crystals was explored by combining the two techniques.The results show that the interaction energies of Mg^(2+)and different crystal faces of calcium sulfate hemihydrate crystals from smallest to largest are listed below:ΔE_((200))<ΔE_((002))<ΔE_((400))<ΔE_((020))<ΔE_((204)),which illustrates that Mg^(2+)is mainly adsorbed on the(200),(400)and(002)crystal faces of calcium sulfate hemihydrate crystals.The interaction distance between Mg^(2+)and SO^(2-)_(4) is smaller than that between Ca^(2+)and SO^(2-)_(4).There is an obvious electronic effect between Mg and S,and the electronic effect is enhanced with the increase of magnesium sulfate content.The position of XRD diffraction peak is more obvious to the right with the increase of magnesium sulfate.All indicate that a small amount of Mg^(2+)is embedded in the crystal lattice of calcium sulfate hemihydrate.At 0.15%(mass fraction,the same as below)of magnesium sulfate content,the growth of c-axis direction was preferentially promoted,resulting in slender needle-like calcium sulfate hemihydrate whiskers with an average length of 47.29μm and an average L/D ratio of 36.07.At 0.30%of magnesium sulfate content,the growth of c-axis and radial direction was inhibited,resulting in slender needle-like calcium sulfate hemihydrate whiskers with an average length of 39.72μm and an average L/D ratio of 28.91.

关 键 词：半水硫酸钙晶须 磷石膏 Mg^(2+) 结晶习性 分子动力学模拟 

分 类 号：TQ132.3[化学工程—无机化工]