Recovery of Uranium from Wet-Process Phosphoric Acid

Abstract

A two-cycle process for recovering uranium by extraction with di(2-ethylhexyl)phosphoric acid plus trioctylphosphine oxide in an aliphatic diluent has been developed and demonstrated successfully in bench-scale mixer-settler tests. The uranium is recovered from the solvent and concentrated by reducing it to the less extractable tetravalent form with ferrous iron contained in reduced process raffinate. This solution is oxidized and processed in a second cycle with the same extractant. In the second cycle the uranium is stripped from the solvent with ammonium carbonate solution and recovered as a high-grade (>97% UsOs) product. Overall recovery of uranium is about 95%. In the bench-scale tests, losses of the relatively expensive solvent to the aqueous raffinate were satisfactorily low (<0.1 ml/l.). Chemical reagent costs for the process are estimated at less than $1.00 per lb of recovered LLOg.

Recovery of Chromium from Electroplating Wastes by Solvent Extraction

“…According to the values of the distribution coefficient of chromium, the number of the theoretical number of extraction stages could be calculated due to the following mathematical formula: Theoretical number of stages was found according to McCabeThiele diagram ( Figure 5) to be equal 5 stages as found previously by the theoretical calculations [14]. The theoretical number of extracting and stripping stages as seen from McCabe-Thiele diagram based on almost quantitative recovery (>99.99%).…”

Uranium(VI) extraction from concentrated Egyptian wet-process phosphoric acid using a synergistic organophosphorous solvent mixture

“…Efforts are being made worldwide to investigate the newer resources of uranium to meet the required demands. Among the secondary resources of uranium, natural phosphates are found to contain several tens to hundreds parts per million of uranium depending upon the origin of phosphate rocks [1]. Phosphoric acid becomes a potential source of uranium since during the acid digestion of phosphate rocks; most of the uranium ([90 %) reports in phosphoric acid [2] hence the acid product may contain up to 300 ppm uranium together with other rare metals such as V, Cd, and Co and radionuclides like Th and Ra [3].…”

Effect of anions in commercial phosphoric acid on the extraction of uranium by DEHPA /TOPO

“…Uranium is extracted from phosphoric acid by the di-(2-ethylhexyl)phosphoric acid / trioctylphosphine oxide (DEHPA / TOPO) process developed by Hurst at Oak Ridge National laboratory [1][2][3]. The extraction efficiency is influenced by many factors.…”