工业级氢氟酸合成牙膏级氟化钠工艺研究

发布时间：2018-05-17 03:30

  本文选题：工业级氢氟酸 + 工业级硫酸钠　； 参考：《昆明理工大学》2015年硕士论文

【摘要】：目前,磷肥行业副产的氟硅酸多用于生产氟硅酸钠,氟资源利用不合理问题突出。氟化钠作为重要的氟化盐,由于其防龋齿效果较好用作了牙膏添加剂。牙膏级氟化钠市场供需不平衡,供不应求问题突出。针对存在的问题,本课题提出制备牙膏级氟化钠的构思,结合云天化股份有限公司生产的特点,希望探索出一条绿色、环保、节能的牙膏级氟化钠的生产路线。实验以原料纯化处理→产品合成→产品洗涤为路线进行工艺探索,通过对工艺条件的优化,找出较为适宜的工艺条件。1.原料的纯化处理主要包括氢氟酸脱硅处理和硫酸钠脱除铁、镁、钙离子两部分。(1)原料氢氟酸中含有0.5%氟硅酸对产品氟化钠的质量有影响,需对氢氟酸进行脱硅实验。实验以脱硅率为指标,确定了较优的脱硅工艺条件为：碳酸钠作为脱硅剂,在室温(25±5℃),用量为理论量过量5%,反应时间为30min。(2)硫酸钠中的铁、镁、钙离子等离子对产品质量有一定影响。实验在60℃的硫酸钠溶液中加入氢氧化钠,并控制反应后pH在11.5-12.0以上,反应时间为30min,搅拌强度为100r/min。纯化所得硫酸钠溶液中的钙镁铁含量分别降低到0.032%、0.021%、0.0042%。2.对于产品合成过程主要采用热力学分析结合实验的方法对实验过程进行探讨。(1)通过对主反应的热力学分析探讨了实验的可行性。通过计算确定了△rHm'0, △rSm'0、△rGm0,反应的推动力为溶解度差,因此反应温度对实验结果的影响较大。(2)通过分析确定了单因素实验的考察指标为产品的产率和氟化钠的纯度。通过单因素实验与正交实验,优化了工艺参数：氢氟酸浓度为18mol/L,反应温度选择为40℃,反应时间在60min,陈化温度为15℃,陈化时间为15min。在此优化的工艺条件下,得到的粗产品的平均收率为98.338%,平均纯度为96.578%。同时通过对粗产品的洗涤研究,开展了洗涤单因素实验,确定了较优的工艺条件为：蒸馏水用量为2 L/kg产品,洗涤水温度为35～40℃。洗涤后产品的氟化钠含量≥98.5%,硫酸根含量≤0.05%。通过上述工艺合成的牙膏级氟化钠,反应的最终收率在95%以上,产品就能较好的达到企业标准Q/XWJ114-2007的要求。
[Abstract]:At present, fluorosilicic acid in phosphate fertilizer industry is mostly used to produce sodium fluorosilicate. As an important fluoride salt, sodium fluoride has been used as toothpaste additive because of its good anti-dental caries effect. Toothpaste-grade sodium fluoride market supply and demand imbalance, demand is outstanding. In view of the existing problems, this paper puts forward the idea of preparing toothpaste grade sodium fluoride, combined with the characteristics of Yuntian Chemical Co., Ltd., hoping to explore a green, environmental protection, energy saving toothpaste grade sodium fluoride production route. In this experiment, the purification of raw materials and the washing of synthetic products were used as the route to explore the process. Through the optimization of the process conditions, the more suitable technological conditions were found out. The purification of raw materials mainly includes desilication of hydrofluoric acid and removal of iron from sodium sulfate. Magnesium and calcium ions in the raw material contain 0.5% fluorosilicic acid, which has an effect on the quality of sodium fluoride. The desilication experiment of hydrofluoric acid is needed. With the desilication rate as the index, the optimum desilication process conditions were determined as follows: sodium carbonate as desilication agent, iron and magnesium in sodium sulfate at room temperature of 25 卤5 鈩，

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