氧化-沉淀法净化湿法磷酸的研究

Study on purification of wet-process phosphoric acid by oxidation and precipitation methods

为对湿法磷酸进行脱色和除铁、铝离子,采用氧化-沉淀法对湿法磷酸进行净化。首先向湿法磷酸中加入一定量的过氧化氢进行脱色,然后加入一定量的沉淀剂草酸钾和助沉淀剂碳酸钠去除磷酸中的铁、铝离子。通过单因素实验,得到湿法磷酸净化的最佳工艺条件:过氧化氢用量为1%(体积分数),草酸钾用量为0.5%(质量分数),碳酸钠用量为0.3%(质量分数),反应温度为45℃,反应时间为12 h。在最佳条件下,湿法磷酸脱色率达到95%以上,铁和铝的净化率分别达到47.51%和9.30%。

In order to make decoloration and to remove iron and aluminum ions for wet-process phosphoric acid,the method of oxidation and deposition was used to purify wet-process phosphoric acid.Firstly,a certain amount of hydrogen peroxide was added for decoloration of wet-process phosphoric acid,and then a certain amount of precipitator potassium oxalate and precipitation assistant sodium carbonate were added for removing iron and aluminum ions.With single factor experiments,the best technological conditions of purifying wet-process phosphoric acid were obtained as follows：decolored rate could reach above 95%,and the purification rates of iron and aluminum could reach 47.51% and 9.30% respectively when the temperature was 45 ℃,amount of hydrogen peroxide was 1%（volume fraction）,dosage of potassium oxalate was 0.5%（mass fraction）,dosage of sodium carbonate was 0.3%（mass fraction）,and the time was 12 h.