TECHNOLOGICAL STUDIES ON THE SCRUBBING STAGE DURING PHOSPHORIC ACID PURIFICATION PROCESS FOR PRODUCTION OF PARTIALLY PURIFIED AND HIGHLY PURE GRADE PHOSPHORIC ACID

The production of highly pure grade phosphoric acid is very important due to its high economic value in
the different industrial applications. One of the most important purification techniques is solvent extraction
method which includes three main stages; extraction of P2O5 followed by scrubbing process of the loaded
organic solvent and finally stripping process of the P2O5 using distilled water (DW). Scrubbing stage is
considered as the most important stage of this technique that controls the purity degree of the phosphoric
acid and also controls the economic cost of the purification process. In this paper, the effect of different
added scrubber solutions on the scrubbing process of the tri-butyl phosphate (TBP) loaded organic solvent
were studied. In this context, pure phosphoric acid, oxalic acid, sodium hydroxide and DW were studied,
and the effects of the different factors on the P2O5 amount loss from the loaded organic solvent such as the
concentration of the added scrubber solution, stirring time and added scrubber solution to loaded organic
solvent phase ratio were investigated. From the obtained data, DW was considered as the most preferable
scrubber and iron was decreased from 40560 ppm to reach 10 ppm only, while Cu, Cd, Mn, Zn, U were not
detected and F- was decreased to reach 8 ppm in the highly pure grade phosphoric acid.