稀土石膏常压酸化法制备硫酸钙晶须的研究

以含稀土的石膏为原料运用常压酸化法合成硫酸钙晶须,探讨了不同工艺条件对生成的硫酸钙晶须形貌的影响,同时还考察了晶型助长剂的种类和晶型助长剂的含量对硫酸钙晶须生长的影响,利用SEM和XRD分别对硫酸钙晶须的表面形貌、物相特征做了表征分析。实验得到制备硫酸钙晶须的最佳的反应条件：稀土石膏质量浓度为0.22 g/mL、反应时间为25 min、盐酸浓度为2.8 mol/L、反应温度为70 ℃、陈化时间为4 h,在此条件下合成的硫酸钙晶须平均长度为61 μm,平均长径比为30.5;通过对比实验选出了CuCl₂作为促进硫酸钙晶须生长的助长剂,在添加5%（质量分数）的CuCl₂的情况下可使硫酸钙晶须长径比从30.5增至41,长度从61 μm增至81 μm。

Study on preparation of calcium sulfate whisker by atmospheric pressure acidification using rare earth gypsum

Calcium sulfate whiskers were synthesized by atmospheric pressure acidification using rare earth-containing gypsum as raw material.The effects of different process conditions on the morphology of the formed calcium sulfate whiskers were investigated.At the same time,the effects of the type of crystal growth promoter and the content of crystal growth promoter on the growth of calcium sulfate whiskers were also investigated.The surface morphology and phase characteristics of calcium sulfate whiskers were characterized by SEM and XRD,respectively.The experimental results showed that the optimal reaction conditions for preparing calcium sulfate whiskers were rare earth gypsum mass concentration of 0.22 g/mL,reaction time of 25 min,hydrochloric acid concentration of 2.8 mol/L,reaction temperature of 70 ℃ and aging time of 4 h.The average length of the calcium sulfate whiskers synthesized under these conditions was 61 μm,and the average aspect ratio was 30.5. CuCl₂ was selected as a growth promoter for promoting the growth of calcium sulfate whiskers by contrast experiments.With the addition of 5%（mass fraction） CuCl₂,the aspect ratio of calcium sulfate whisker was increased from 30.5 to 41,and the length was increased from 61 μm to 81 μm.