Aminotrimethylene Phosphonic Acid and Sodium Ethyl Xanthate for Purification of Stripped Phosphoric Acid Produced from Commercial Acid by Solvent Extraction

PHOSPHORIC acid is the second most produced acid after. H2SO4. It was used as a raw material for the production of detergents, food products, and alimentary supplies for cattle, toothpastes and fertilizers. High grade phosphoric acid was obtained using liquid-liquid extraction with aliphatic alcohols to separate metal and fluoride ion impurities in the aqueous phase. The influence of alcohol concentration, organic/aqueous phase ratio, temperature, shaking time and phosphoric acid concentration on P2O5 extraction was studied. N-Nonanol proved to be the most efficient and selective alcohol and the temperature had a slight positive effect and the extraction was enhanced by increasing P2O5 and with the increase of organic/aqueous phase ratio. The optimum organic/ aqueous phase ratio was determined to be 2.0. Stripping was also investigated, the purification of stripped phosphoric acid was achieved using sodium ethyl xanthate where 95.1% of iron was removed, also aminotrimethylene phosphonic acid can be successfully used for decreasing iron content to 190.9 ppm and to produce highly pure grade phosphoric acid.