Separation of Rare Earths from Thorium Nitrate

La détermination de la température optimale de précipitation de l'iodate de thorium

“…Les mtthodes de determination analytique du thorium dans les minerais et les produits mttallurgiques thoriferes sont assez nombreuses et leur choix dtpend de multiples facteurs tels que la prtcision dtsirte, l'importance de la teneur, la nature et l'importance des autres tltments, la rapiditt tventuellement exigte, le prix des appareillages ntcessaires (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Les proctdts les plus courallts sont la gravimttrie par l'iodate ou par le thiosulfate (I, ll), la titrimttrie par le molybdate ou l'oxinate, la colorimttrie par l'acide arsCnophCnylazonaphtol-disulfonique (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), la fluorimttrie par l'amino-hydroxyanthraquinone (12), la spectrophotomttrie par l'acide dimtthyl aminophtnylarsinique (2,4), la fluorescence, la polarographie et l'analyse spectrale (1, 7, 1 l), la complexomttrie (8,9), l'tchange ionique et l'extraction liquide-liquide (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23).…”

“…Les proctdts les plus courallts sont la gravimttrie par l'iodate ou par le thiosulfate (I, ll), la titrimttrie par le molybdate ou l'oxinate, la colorimttrie par l'acide arsCnophCnylazonaphtol-disulfonique (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), la fluorimttrie par l'amino-hydroxyanthraquinone (12), la spectrophotomttrie par l'acide dimtthyl aminophtnylarsinique (2,4), la fluorescence, la polarographie et l'analyse spectrale (1, 7, 1 l), la complexomttrie (8,9), l'tchange ionique et l'extraction liquide-liquide (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23).…”

Isolation of Rare Earth Elements. Chlorination-Volatilization Procedure

“…Until 1948 (14) the most difficult step in the isolation of the group was the removal of thorium. Recently, several improved procedures have included a solvent extraction using penta-ether (dibutoxy ethylene glycol) and 8-quinolinol-chloroform extraction steps (12), but the reagent penta-ether was not readily available commercially (it is now understood that this reagent is available from the Roberts Chemical Inc., RobertsRd.,Nitro, W. Va.) (IS). A solvent extraction procedure employing tributyl phosphate-carbon tetrachloride and thenoyltrifluoroacetone extraction (22) (the thenoyltrifluoroacetone in the quantities used is expensive and requires troublesome pH adjustments), and a cellulose column method involving the use of 12.5% v./v.…”

Ion Exchange Separation and Spectrographic Determination of Some Rare Earths in Beryllium, Uranium, Zirconium, and Titanium Metals, Alloys, and Oxides. Collection with Calcium and Magnesium Fluoride and Ion Exchange Separation

“…thermal neutron cross sections (europium, dysprosium, gadolinium, and samarium) in metals and oxides used in nuclear technology have been reviewed by Lerner and Pinto (8). They include methods based on the coprecipitation of the rare earth oxalates with thorium (5, 7) and removal of the thorium by 8quinolinol extraction (7) or cation exchange (S).…”

“…solved the problem of quantitatively precipitating the rare earths by employing thorium as a carrier and ammonium fluoride as a precipitating agent, leading to the formation of a precipitate such as NHjThFs.HzO which quantitatively carries the rare earths. The thorium carrier is later removed by 8-quinolinol extraction (7). Wood and Turner (9) recently recommended ammonium fluoride as a precipitating agent.…”