用天然石膏制备硫酸铵和氯化钙的工艺研究

以天然石膏和碳酸氢铵为原料进行复分解反应制备硫酸铵,副产碳酸钙粗品。考察了反应温度、反应时间、配料比、液固比等因素对硫酸钙转化率的影响,通过正交实验确定了复分解反应的最佳工艺条件。探讨副产物碳酸钙的回收利用方法,用盐酸处理碳酸钙粗品制备氯化钙,研究确定了工艺条件。整个生产过程无废渣排放,工艺简单清洁。通过本方法,可将天然石膏转化为具有更高价值的硫酸铵和氯化钙,研制的产品质量达到有关标准,应用前景广阔。

Production process of ammonium sulphate and calcium chloride from natural gypsum

Ammonium sulphate and by-product crude calcium carbonate were prepared by double decomposition reaction with natural gypsum and ammonium bicarbonate as raw materials.Influences of the factors,such as reaction temperature,reaction time,mix ratio,and liquid-solid ratio,on conversion rate of calcium sulphate were discussed,and the optimum technological conditions of double decomposition reaction were determined by orthogonal experiment.Recycling method of by-product calcium carbonate was discussed.Calcium chloride can be obtained by the reaction of hydrochloric acid and crude calcium carbonate,meanwhile the technological conditions of this reaction were also determined.Total production process had no waste residue discharge and the process was simple and clean.Through this method,natural gypsum can be converted to ammonium sulfate and calcium chloride with higher value,the quality of the obtained products reach the corresponding chemical standards and the application prospect of the products is much wide.