An Empirical Equation for Estimating Nitric-Acid Extraction by Tri-n-Buytl Phosphate from Nitric Acid and Nitric-Acid/Sodium-Nitrate Solutions

An empirical equation has been developed that predicts nitric-acid extraction from aqueous nitric-acid/sodium-nitrate solutions by tri-n-butyl phosphate (TBP) solutions. The predicted nitric-acid concentrations in the organic phase, for both 20 and 30 vol% TBP, are generally within ±0.02 M units of the experimental values when the total nitrate molarity in the aqueous phase is 1 to 7 M. The equation also predicts the extraction of nitric acid from nitric-acid solutions with reasonable accuracy.