Strontium extraction

SREX [Strontium extraction] A process for removing strontium-90 from aqueous wastes from nuclear fuel processing, by solvent extraction into a solution of 18-crown-6 in octanol. Developed by E. P. Horwitz at the Argonne National Laboratory, Chicago, IL, in 1990. 

Within the hexamers studied, (CA12) is the most efficient for strontium extraction, while (CA8) and (CA15) bearing bulkier groups on the upper rim display lower distribution ratios. In general, octamers show higher distribution ratios and selectivity... 

FIGURE 6.4 Test flowsheet for cesium and strontium extraction by crown mixture. 

Meikrantz, D.H., Todd, T.A., Riddle, C.L., Law, J.D., Peterman, D.R., Mincher, B.J., McGrath, C.A., Baker, J.D. Cesium and strontium extraction using a mixed extractant solvent including crown ether and calixarene extractants. Pat W02006016892 (Publ. 16-02-16-2006). 

Concerning strontium extraction, the principal radiolytic effect was a two- to threefold decrease (158). Schultz explained this effect by the polymerization of HDEHP with H2MEHP via hydrogen bonding, making HDEHP molecules either unavailable or less available for binding with strontium. According to Tachimori (163), the... 

THE STRONTIUM EXTRACTION BY 18C6 TO SC-COz IMPORTANCE OF INTERFACIAL PHENOMENA AND COUNTERIONS... 

THE STRONTIUM EXTRACTION BY CROWN ETHERS TO A ROOM -TEMPERATURE IONIC LIQUID. SOLVATION IN DRY VERSUS "HUMID" FORMS OF THE LIQUID, AND PARTITIONING AT THE AQUEOUS INTERFACE... 

For the crown ether strontium extractant, speculate how the active agent for separating strontium functions in this analysis. 

The experimental data showed that at 25 °C, the residual strontium concentration is apix-oximately the same in the 2.5 M sodium chloride solutions in the system NaCl-SrCV NaOH-H20, and NaCl-SrCl2-CaCl2-Na0H-H20. At 75 °C the degree of strontium extraction is twice that of the sodium calcium chloride solutions. 

Family of the scientist has presented documentar y materials to Academy of sciences in June 1974. Among them, the most important ar e manuscripts, typewritten copies about 100 scientific works of the scientist and working materials to them. Its includes articles, reports, monographs, the textbooks written by A.K. Babko during last 25 year s working writing-books with extracts, marks on various questions, abstracts of chemical literature responses and reviews on thesis of Ph.D. and doctor s degrees, on ar ticles, books, textbooks. For example, early works Product of solubility , To a technique of definition of strontium in minerals (1940-s), many unpublished works in 1940-1960, etc. 

In the past, dissociation of the nucleoprotein complex has been brought about by salt solutions or by heat denaturation,129 but, more recently, decomposition has been effected by hydrolysis with trypsin,126 or by the use of dodecyl sodium sulfate130 or strontium nitrate.131 Some virus nucleoproteins are decomposed by ethyl alcohol.132 This effect may be similar to that of alcohol on the ribonucleoproteins of mammalian tissues. If minced liver is denatured with alcohol, and the dried tissue powder is extracted with 10% sodium chloride, the ribonucleoproteins are decomposed to give a soluble sodium ribonucleate while the deoxyribonucleoproteins are unaffected.133 On the other hand, extraction with 10 % sodium chloride is not satisfactory unless the proteins have first been denatured with alcohol. Denaturation also serves to inactivate enzymes of the tissues which might otherwise bring about degradation of the nucleic acid during extraction. 

Interference effects begin to appear at higher magnesium or strontium molar ratios. Tsunogai et al. [157] found the interference of magnesium to be negative and, for strontium, interference is related to the extraction into the organic layer of the calcium GHA complex. They found a positive interference for strontium at twice the seawater molar ratios. Therefore, the interference of... 

Scheibler A process for extracting sucrose from molasses residues, based on the precipitation of strontium saccharate. Operated in Germany in the late 19th century. 

D. 2,3-Diamino pyridine (Note 12). In an apparatus for catalytic hydrogenation (Note 13) 56.4 g. (0.3 mole) of 2,3-diamino-5-bromopyridine suspended in 300 ml. of 4% sodium hydroxide solution is shaken with hydrogen in the presence of 1.0 g. of 5% palladized strontium carbonate (Note 14). When absorption of hydrogen is completed, the catalyst is removed by filtration, and, after saturation with potassium carbonate (about 330 g. is required), the resulting slushy mixture is extracted continuously with ether until all the precipitate completely disappears (usually about 18 hours, but this depends on the efficiency of the extraction apparatus). The ether is removed by distillation, and the residue of crude 2,3-diaminopyridine is recrystallized from benzene (about 600 ml. is required) using 3 g. of activated charcoal and filtering rapidly through a preheated Buchner funnel. The yield of 2,3-diaminopyridine, obtained as colorless needles, m.p. 115-116°, pKa 6.84, is 25.5-28.0 g. (78-86%) (Note 15). 

Strontium hydroxide [Sr(OH)j] is used to extract sugar from sugar beet molasses. It is also used in the manufacture of soaps, adhesives, plastics, glass, and lubricants that can be used in very high or low temperature environments. 

Fig. 5.5. Decomposition of Solar System abundances into r and s processes. Once an isotopic abundance table has been established for the Solar System, the nuclei are then very carefully separated into two groups those produced by the r process and those produced by the s process. Isotope by isotope, the nuclei are sorted into their respective categories. In order to determine the relative contributions of the two processes to solar abundances, the s component is first extracted, being the more easily identified. Indeed, the product of the neutron capture cross-section with the abundance is approximately constant for aU the elements in this class. The figure shows that europium, iridium and thorium come essentially from the r process, unlike strontium, zirconium, lanthanum and cerium, which originate mainly from the s process. Other elements have more mixed origins. (From Sneden 2001.)... 

E. O. Von Lippmann, Die Chemie der Zuckerarten, Vieweg and Sohn, Braunschweig, 2nd ed., pp. 588-596 (1895). (A list of species examined up to 1895, usually by extracting the plant with aqueous alcohol and precipitating any sucrose from the extract as the difficultly soluble strontium saccharate.)... 

Uranium mineral first is digested with hot nitric acid. AH uranium and radium compounds dissolve in the acid. The solution is filtered to separate insoluble residues. The acid extract is then treated with sulfate ions to separate radium sulfate, which is co-precipitated with the sulfates of barium, strontium, calcium, and lead. The precipitate is boiled in an aqueous solution of sodium chloride or sodium hydroxide to form water-soluble salts. The solution is filtered and the residue containing radium is washed with boiling water. This residue also contains sulfates of other alkahne earth metals. The sohd sulfate mixture of radium and other alkahne earth metals is fused with sodium carbonate to convert these metals into carbonates. Treatment with hydrochloric acid converts radium and other carbonates into chlorides, all of which are water-soluble. Radium is separated from this solution as its chloride salt by fractional crystallization. Much of the barium, chemically similar to radium, is removed at this stage. Final separation is carried out by treating radium chloride with hydrobromic acid and isolating the bromide by fractional crystallization. 

Strontium hydroxide is used in extracting sugar from beet sugar molasses... 

Elemental composition Sr 47.70%, S 17.46%, O 34.84%. Strontium sulfate can be characterized by x-ray crystallography. A nitric acid extract is analyzed for strontium. An aqueous solution (the salt is only slightly soluble) is filtered or decanted from insoluble material and measured by ion chromatography. 

System (2) has been described for the assay of corticosteroids (cortisone, hydrocortisone, prednisone, and prednisolone) in urine [141]. Prior to introduction into the GC system, the sample was eluted with 2 1 ethyl acetate-methanol, the extracts evaporated to dryness, and then oxidized with sodium bismuthate. Used in the method was a silanized column (132 cm X 5 mm) containing 2,2-dimethylpropane-l,3-diol adipate (0.65%) supported on celite, and operated at 230°C. The carrier gas was argon, and the detector used strontium 90-ionization. The standard deviation was 3.5 % (based on 47 determinations). 

Researchers at BNL claim that this technology may be used to extract metals such as cadmium, arsenic, lead, zinc, copper, magnesium, manganese, aluminum, barium, nickel, and chromium, as well as radionuclides such as uranium, thorium, plutonium, cobalt, cesium, and strontium. They state that the process offers the following advantages ... 

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