Precipitation of iron from wet process phosphoric acid using oxalic acid and potassium hexyl xanthate (PHX)

Egyptian wet process phosphoric acid (WPPA) produced from El-Sebaiya phosphate area by Abu Zaabal Company contains about 2.6% iron. The high concentration of iron is the main reason for many problems and inhibits using the acid in various industrial and fertilizers applications. In this study, two types of additives were studied to decrease the iron content from WPPA using oxalic acid and potassium hexyl xanthate (PHX). Different factors were studied, including, the redox potential, amount of used oxalic acid and PHX, phosphoric acid concentration, stirring time and temperature. The obtained data revealed that 80.0 and 59.3% of the iron can be removed successfully without any loss of P2O5 content using oxalic acid and PHX, respectively. The XRF analysis of the used oxalic acid before and after the treatment of WPPA has confirmed the formation of ferrous oxalate after the treatment of WPPA using the oxalic acid.