一步相转移-沉淀法制备轻质碳酸钙的沉淀工艺条件研究

Study of deposition technological conditions of one-step route for the preparation of light calcium carbonates from phosphogypsum

文章以磷石膏为原料,开展一步法制备轻质碳酸钙的沉淀反应工艺条件研究。以碳酸钙样品的产率为主要考察指标,通过单因素条件实验和正交实验,分别考察了沉淀反应温度、反应时间、钙离子与碳酸氢根离子的摩尔比、沉淀反应体系pH值等因素的变化对轻质碳酸钙产率的影响。在常压下,确定较适宜的沉淀反应条件为:沉淀反应温度70℃,反应时间75min,钙离子和碳酸氢根离子的摩尔比1∶1.15,沉淀反应体系pH=10。该条件下的重复实验表明,轻质碳酸钙的平均产率为95.25%。

Using phosphogypsum as raw materials, the deposition technological conditions of the onestep route for the preparation of light calcium carbonates were studied. Taking the yield of the prepared sample as the main index of the test, the influence of the deposition technological conditions, such as reaction temperature, reaction time, tool ratio of Ca2＋ to HCO3-, and the pH value of reaction system, on the yield of the sample was respectively investigated by the single-factor and orthogo- nal experiments. Under the normal pressure, the conditions were optimized as follows： the reaction temperature was 70℃, the reaction time was 75 rain, the tool ratio of Ca2＋ to HCO3 was 1 ： 1.15, and the pH value of reaction system was 10. Repeated experiments under the above optimized conditions showed that the average yield of light calcium carbonate was 95.25%.