稀土石膏制备硫酸钙晶须及晶须形成机理

Preparation of Calcium Sulfate Whiskers from Rare Earth Gypsum and Formation Mechanism of Whiskers

为解决稀土冶金过程中产生的废渣回收利用问题,以稀土石膏为原料制备硫酸钙晶须(CSW)。通过扫描电镜(SEM)、X射线衍射(XRD)和热重-差示扫描量热(TG-DSC)等对样品进表征,研究晶须生长时间和钙离子浓度对CSW形貌的影响。结果表明,CSW的生长基本经历成核-轴向生长-溶解-纵向生长。其生长机理主要是轴向螺旋位错和层-层自组装生长方式。陈化时间为1.5 h,晶须生长完全。钙离子浓度越高越有助于晶核形成,从而对CSW的形成过程起到强化作用,促进其快速生长。

For the purpose of solving the problem of waste residue recycling in rare earth metallurgy process,calcium sulfate whisker(CSW)was prepared with rare earth gypsum as raw material.The effects of whisker growth time and calcium ion concentration on the morphology of CSW were studied by means of SEM,XRD and TG-DSC.The results show that the growth of CSW basically undergoes nucleation-axial growth-dissolution-longitudinal growth.The growth mechanism is mainly axial spiral dislocation and layer-layer self-assembly.When the aging time is 1.5 h,the whiskers grow completely.The higher the concentration of calcium ions,the more conducive to the formation of crystal nucleus,thus strengthens the formation process of CSW and promotes its rapid growth.