晶面活性对丁二酸调控α-半水硫酸钙晶体形貌的影响

Effect of crystal surface activity on morphology ofα-calcium sulfate hemihydrate regulated by succinic acid

晶体形貌决定了α-半水硫酸钙(α-HH)的物化性质与应用领域。本文采用第一性原理计算和Wulff构型理论揭示了晶面活性差异对丁二酸调控α-HH晶体形貌的影响。结果表明:α-HH的(204)晶面是晶体形貌调控的关键晶面。(204)晶面上Ca2+连续分布且密度高,导致(204)晶面活性高,有利于媒晶剂作用。丁二酸以O—Ca离子键形式环状吸附在α-HH的(204)晶面。α-HH的高活性晶面优先被媒晶剂吸附并抑制,使晶体形貌沿高活性晶面方向缩短,过量的媒晶剂使晶体各晶面生长均被抑制,实现晶体形貌调控。

The crystal morphology determines the physicochemical properties and application fields ofα-calcium sulfate hemihydrate(α-HH).In this paper,first-principles calculations and Wulff construction were used to reveal the effect of difference of crystal surface activity on the control ofα-HH crystal morphology by succinic acid.The results show that,the(204)surface is the key surface forα-HH crystal morphology control.The continuous distribution and high density of Ca2+ions make the(204)surface highly active,which is beneficial to the adsorption of the modifiers.Succinic acid cyclically adsorbs on the(204)surface ofα-HH in the form of O—Ca ionic bond.The highly active crystal surfaces ofα-HH are preferentially adsorbed and inhibited by the modifiers.Therefore,the crystal morphology is shortened along the direction of the highly active crystal surface.When the amount of modifiers is excessive,the growth of each crystal surface is inhibited,and the crystal morphology is controlled.