湿法磷酸脱色脱氟实验研究

Experimental Study of Decoloration and Defluorination of Wet-Process Phosphoric Acid

采用贵州宏福有限公司提供的浓缩湿法磷酸进行脱色、脱氟净化研究,为后续的溶剂萃取进行预净化,从而制取高纯度磷酸。通过实验,选取了较好的脱色、脱氟剂,探讨了脱色及脱氟剂加入量、温度、时间等因素对磷酸净化效果的影响及变化规律,确定了适宜的脱色、脱氟条件分别为:在磷酸中添加0．5％E型粉状活性炭,于60℃脱色1 h;在搅拌转速300 r／min及50℃下,加入1．2倍计算理论量的Na2CO3脱氟2 h,磷酸的脱氟率达95％以上。

A study is made of the decoloration, defluorination, and purification of the concentrated wet-process phosphoric acid provided by Hongfu Co. , Ltd. in Guizhou, as a step of pre-purification for the follow-up solvent extraction, so as to manufacture high-purity phosphoric acid. By this experiment good decoloring and defluorinating agents have been selected. An inquiry is made into the effect of the addition of decoloring and defluorinating agents, temperature and time on the results of purification of the acid and the pattern of change. The proper conditions are ascertained for decoloration and defluorination as follows ： the addition of 0.5% Type E powdery activated carbon into the acid and decoloration at 60 ℃ for I h ; with agitation at 300 r/min and at 50 ℃, the addition of 1.2 times the stoichiometric quantity of Na2CO3 and defluorination for 2 h, the defluorination of the acid being over 95%.