硫酸-无机盐中脱硫石膏水热合成硫酸钙晶须

以脱硫石膏为原料,利用水热法在硫酸-无机盐-水体系中成功制备出硫酸钙晶须。借助SEM、图像粒度分析等方法,考察反应温度、时间、硫酸浓度、晶型控制剂等条件对晶须形貌及长径比的影响,并初步讨论硫酸-无机盐-水体系对晶须成核和生长过程的影响。结果表明:在硫酸-无机盐-水体系中,反应温度、反应时间、硫酸浓度和晶型控制剂的类型,都会改变硫酸钙晶须的平均长径比。制备硫酸钙晶须的最优工艺条件为:脱硫石膏质量分数5%,反应温度135℃,反应时间150 min,硫酸浓度10-3 mol/L,使用的晶型控制剂为氯化铜(质量分数为0.17%)。在此条件下制备的半水硫酸钙晶须平均长径比可达到74.38。

Preparation of Calcium Sulfate Whiskers from FGD Gypsum via Hydrothermal Crystallization in the Sulfuric Acid-inorganic Salt

Using flue-gas desulfurization (FGD) gypsum as raw materials, calcium sulfate whisker in sulfuric acid-inorganic salt-water system by hydrothermal crystallization was prepared. With the help of SEM, image granularity analysis method, investigate the effects of reaction temperature, time, concentration of sulfuric acid, crystal control agent and other conditions on the whisker morphology and the effect of the length to diameter ratio, and discussed the effect of sulfuric acid-inorganic salt water system on the whisker nucleation and growth process. The results showed that: in sulfuric acid-inorganic salt water system, reaction temperature and reaction time, the concentration of sulfuric acid and chemical additives, will change the average length diameter ratio of calcium sulfate whisker.The optimal experimental conditions of hemihydrate calcium sulfate whiskers preparation:FGD gypsum mass fraction of 5%, reaction temperature for 135 ℃, reaction time for 150 min, the concentration of sulfuric acid is 10-3 mol/L, the chemical additives was CuCl2 (the quality score is 0.17%). Hemihydrate calcium sulfate whiskers prepared under these conditions the average length diameter ratio reached 74.38.