Comparison of Variables in Ion and Precipitate Flotation

Abstract

cipally to obtain the fastest dissolution, but also because a precipitate of A1F3 is much easier to redissolve than a precipitate of ZrF4. Fortunately, the rate of approach to conditions that form a precipitate of ZrF4 decreases as fluoride is consumed, so that the formation of ZrF4 is unlikely. The composition of the final dissolver solution is sufficiently stable if processed immediately. Zirconium and aluminum may gradually precipitate over a period of several weeks, making it necessary to centrifuge out the solids prior to solvent extraction if the process is delayed (3, 6, 7, 7 7 ) . No further adjustment in salting strength is required prior to solvent extraction. The zirconium fuel element dissolved faster in this test than in the laboratory because of a larger surface-to-weight ratio.The elements were dissolved a t 70' C. in 24 hours, including an 8to 9-hour period during which the solution was penetrating the oxide layer. The rate of corrosion of the Type 304L stainless steel averaged 10 to 15 mils per year in the liquid phase and <1 mil per year in the vapor phase. I n summary, the Alniflex process was shown to be an acceptable process for dissolving zirconium-uranium alloys in Type 304L stainless steel dissolvers.

The Removal of Radioactive Strontium from Aqueous Solutions by Foam Separation

“…Percentage removals were calculated by comparing the count rates of samples taken before and after flotation. This increase in the percentage removal is believed to be due to the partial formation of Strontium hydroxide species containing excess hydroxyl ions [24]. Of the four collectors tested, only Aerosol 18 showed appreciable removals; intensive investigations using this collector were, therefore, performed.…”

Removal of Trace Cd2+Using Continuous Multistage Ion Foam Fractionation: Part II—The Effects of Operational Parameters

“…Compressed air from an air compressor was introduced under the bottom tray and was regulated by a rotameter to have flow rates in the range of 30-100 dm 3 =min. The experiments were carried out at room temperature (25-27 C) because of the insignificant influence of temperature on foam fractionation performance (9,10). The foam was collected at the top of the column at different foam heights (30, 60, and 90 cm) from the liquid pool of the top tray.…”

“…Hence, at the top, the foam becomes dry while at the bottom it remains wet (7). Temperature has little effect on the separation efficiency of foam fractionation (8)(9)(10). However, despite many attractive features of foam fractionation, few papers on continuous ion foam fractionation for heavy metal removal have been published in the last decade (9,11).…”

Selective Elimination of Cadmium by Bubble Fractionation

“…(2), (3), (4) and (5) E=rs[CFLF (6) When CF{Mei) is equal to CF(Me2), the selective elimination ratio Es may be given by…”