磷矿酸解液制备硫酸钙晶须工艺研究

首先以盐酸分解磷矿制备酸解液,再通过向酸解液中加入硫酸制备硫酸钙晶须。实验考察了加料时间、搅拌转速、硫酸浓度、硫酸根与钙离子物质的量比、氧化钙质量分数、反应温度对硫酸钙形貌及晶须长径比的影响。采用扫描电镜观察硫酸钙形貌并用Image-Pro-Plus对硫酸钙SEM图进行分析得到硫酸钙晶须的平均长径比。实验得到硫酸钙晶须的最佳制备工艺条件是：加料时间为20 min、搅拌转速为350 r/min、硫酸质量分数为40%、反应温度为70 ℃、硫酸根与钙离子物质的量比为0.2、氧化钙质量分数为5.5%,在此工艺条件下可以得到长径比达到98.84的硫酸钙晶须,且形貌均匀。

Study on process of preparing calcium sulfate whiskers from phosphate rock acid hydrolysis solution

Acid hydrolysis solution was prepared by decomposing of phosphate rock with hydrochloric acid firstly,and then sulfuric acid was added into the acid hydrolysis solution to prepare calcium sulfate whiskers.The effect of feeding time,stir-ring speed,sulfuric acid concentration,the amount ratio of sulfate to calcium ion,the mass fraction of calcium oxide and reac-tion temperature on the morphology of calcium sulfate and the aspect ratio of whiskers was investigated.The morphology of calcium sulfate was observed by scanning electron microscope and the SEM image of calcium sulfate was analyzed by Image-Pro-Plus to obtain the average aspect ratio of calcium sulfate whiskers.The optimal preparation process conditions for calcium sulfate whiskers obtained in the experiment were：Feeding time of 20 min,stirring speed of 350 r/min,sulfuric acid concentra-tion of 40%,reaction temperature of 70 ℃,sulfate radical to calcium ion molar ratio of 0.2,calcium oxide percentage of 5.5%. Under this process condition,calcium sulfate whiskers with a length-to-diameter ratio of 98.84 could be obtained,and the morphology was uniform.