萃取磷酸生产中磷氟化合物的性质分析(续完)

Property Analysis of Fluorophosphate Compounds in Production of Extracted Phosphoric Acid(finished)

氟硅酸是由以SiF4为核心的过氟氟硅酸nH2F2.SiF4、氟硅酸H2F2.SiF4和氧氟硅酸H2O.SiF4组成,萃取磷酸不是正磷酸H3PO4,而是以氟磷酸——mH2O.nH2F2.(P2O5.kSiF4)形式存在的,HF、SiF4还可与硫酸结合成氟硫酸。分析了在萃取磷酸浓缩过程中,当磷酸能量浓度CE(H3PO4)>73.13%条件下,SiF4与P2O5的能量系数α(SiF4)与α(P2O5)相接近,因此要从氟磷酸中脱氟非常困难,尤其是从含有Fe2O3、Al2O3、MgO等杂质的萃取磷酸中脱氟更为困难。

Fluorosilicic acid consists of perfluorosilicic acid nH2F2·SiF4,fluorosilicic acid H2F2·SiF4 and oxygen fluorosilicic acid H2O·SiF4 which is mainly SiF4.Extracted phosphoric acid is not orthophosphoric acid H3PO4,instead,it exists in the forms of fluorophosphoric acid mH2O·nH2F2·(P2O5·kSiF4),and HF and SiF4 can be combined with sulfuric acid to form fluorosulfonic acid.The fact is analyzed that during concentration of extracted phosphoric acid,when the energy concentration of phosphoric acid CE(H3PO4)>73.13%,the energy coefficient of SiF4 and P2O5 is close to α(SiF4) and α(P2O5),hence defluorination from fluorophosphoric acid is very difficult,and particularly,it is even more difficult for defluorination from extracted phosphoric acid containing impurities like Fe2O3,Al2O3 and MgO.