自贡地下黄卤制备高纯柠檬酸钙的工艺研究

Study on preparation process of high purity calcium citrate from Zigong underground yellow brine

利用卤水制盐过程中产生的碳酸钙制备高纯柠檬酸钙可实现卤水净化废物的再利用,为企业带来更大的经济效益。通过单因素实验探讨碳酸钠浓度和用量对碳酸钙产率和纯度的影响,通过正交实验探讨柠檬酸浓度、用量和反应温度对柠檬酸钙产率和纯度的影响。制备柠檬酸钙的最佳工艺条件为:碳酸钠溶液的浓度为0.2 mol/L,碳酸钠用量为卤水中钙物质的量的100%,柠檬酸浓度为2 mol/L,柠檬酸用量以碳酸钙物质的量计过量5%,反应温度为65℃。红外光谱、X射线衍射谱图和扫描电镜分析确定了最佳工艺下制得的柠檬酸钙的形貌和结构特点,产品产率为92.68%±1.09%,纯度可达97.73%,铅、砷含量及干燥质量损失符合GB 1903.14—2016《食品安全国家标准食品营养强化剂柠檬酸钙》要求。

The preparation of high⁃purity calcium citrate from calcium carbonate in the process of brine salt production can realize the reuse of brine purification waste and bring greater economic benefits to enterprises.The effects of sodium carbon⁃ate concentration and dosage on the yield and purity of calcium carbonate were discussed by single factor test,and the ef⁃fects of citric acid concentration,dosage and temperature on the yield and purity of calcium citrate were discussed by or⁃thogonal test.The optimum process for preparing calcium citrate were as follows:the concentration of sodium carbonate solu⁃tion was 0.2 mol/L,the dosage of sodium carbonate was 100%of the amount of calcium in the brine,the concentration of cit⁃ric acid was 2 mol/L,the dosage of citric acid was 5%excessive based on the amount of calcium carbonate,and the reaction temperature was 65℃.The morphology and structure characteristics of calcium citrate prepared under the optimum process were determined by IR,XRD and SEM.The product yield was 92.68%±1.09%,and the purity could reach 97.73%.The con⁃tent of lead,arsenic and loss on drying met the requirements of GB 1903.14—2016“National food safety standard Food nu⁃trition fortifier calcium citrate”.