PROGRESS REPORT ON RAW MATERIALS FOR JULY 1957. Chemical Technology Div'

Abstract

Systematic Studies. Three new amine samples, tris (tridecyl)-, N-(1- undecyldodecyl)dodecyl-, and N(1-nonyldecyl)-dodecylamine, showed good uranium extraction performance and low losses to aqueous liquors. Tests with a new batch of trilaurylamine continued to show the potential utility of this reagent. The purity of the new sample was lower tham for previous batches, however, and the phase separations during extraction were slower. Tests with tri(n- octyl)phosphine oxide and 2-phenylvinyl(diociyl)phosphine oxide showed the latter to be the poorer extractant. In further tests of synergistic reagent systems for uranium extraction, diamyl annylphosphonate (DHHP) was shown to be a promising reagent for process use. The compound is potentially availeble in commercial quantities at a price lower tham that of dihexyl hexylphosphonate (DHHP). Uranium extraction performance and losses to aqueous liquors are similar to those for DHHP. Process Development. The coefficients for extraction of uranium with trin-octylamine ln kerosene -- alcohol diluent were approximately equivalent with capryl alcohol, mixed decanols, or tridecanol in concentrations of 0.04 to 0.20 M alcohol. The coefficients decreased markedly when the alcohol concentration was increased to 0.3 and 0.5 M. With O.10 M nonylphenol or 0.04 dinonylphenol added to the solvent, coefficients were similar in magnitude to those obtained with 0.04 to 0.20 M alcohol modifier. Addition of nonylphenol or dinonylphenol in concentrations as high as 0.2 M, however, severely depressed uranium extraction. The effect of small concentrations of chloride and nitrate on thorium recovery by the Amex process from uranium-barren Blind River liquors was evaluated. The chloride or nitrate enters the liquor during ion-exchange recovery of uranium. The presence of chloride depressed thorium extraction but not sufficiently to interfere seriously with process performance. Nitrate interference, on the other hand, was severe, indicating that special provisions would be necessary for treating uranium-barren raffinates where nitrate elution is used in the ion- exchange process. Nitrate was extracted effectively, suggesting the possibility of nitrate recovery from the liquor prior to thorium extraction. In addition, a process for simultaneous recovery of thorium and nitrate by the Amex process appears economically attractive and is being given further study. Engineering Studies. The rate of uranium extraction from two synthetic sulfuric acid leach liquors by the Dapex solvent was proportional to the cube root of power input in mixers of three different sizes. The rate was nearly lndependent of the particular combinations of uranium concentration, phase ratio, and solvent strength. Scale-up of mixers by constant power input per unit mixer volume was demonstrated to be slightly consenvative for 6-, 12-, and 20-in. baffled tank mixers which are geometrically similar. (auth)