Determination of soluble and insoluble zirconium in magnesium alloys

A method for the determination of soluble and insoluble zirconium is described. To differentiate between the two forms, two solutions are prepared, in one of which the insoluble zirconium remains in suspension ; in the other it is brought into solution with hydrofluoric acid. Zirconium is extracted by trioctyl phosphine oxide/petroleum ether and determined in the extract spectrophotometrically with pyridyl-azo-naphthol (PAN) as reagent.     

Determination of thorium in magnesium alloys that contain zirconium

Summary An indirect polarographic method for the determination of thorium in magnesium alloys that contain zirconium, zinc, and rare-earth elements is described. The method depends on the precipitation of thorium as the tetra (m-nitrobenzoate) and the polarographic determination of the m-nitrobenzoic acid that is equivalent to the amount of thorium that was so precipitated. The only interference, that of zirconium, is forestalled by the prior removal of the zirconium on an anion-exchange resin. The zirconium can easily be eluted quantitatively from the resin, for subsequent determination.The method avoids tedious separational procedures, and yields accurate and precise values for thorium in the alloys for which it was devised. It is also applicable to simpler substances.The authors gratefully acknowledge the grant from the Defence Research Board of Canada that made possible this investigation (Project D44-75-10-04).     

Determination of niobium and tantalum in binary alloys and zirconium alloys

Recent developments in the metallurgy of niobium, tantalum and zirconium have necessitated provision of analytical procedures for determining niobium and tantalum in the presence of each other and in the presence of zirconium. For this purpose, absorptioinetric procedures based on the formation of yellow coloured complexes, between pyrogallol and niobium or tantalum, have been critically examined. Direct absorptiometric procedures are described, which are suitable for determining niobium or tantalum in the range 2 to 7%; when either of these metals exceeds 7%, differential absorptiometric procedures are recommended. Corrections must lie made for absorption due to the presence of other metals which form complexes with pyrogallol. In tlie determination of niobium or tantalum up to 5%, the precision of the method is about ±0.05%. About 12 determinations can be made in a day, by one analyst.     

Analysis of bismuth base alloys : Ternary alloys containing uranium and neodymium or praseodymium

Procedures are described for the analysis of bismuth base alloys containing 0.2–5% of uranium and 0.2–5% of neodymium or praseodymium. Bismuth is first separated from a solution of the alloy in N nitric acid by extraction with diethylammonium diethyldithiocarbamate in chloroform, followed by the separation of uranium with the same reagent from an acetate buffered solution of pH 5.5–6.0. The uranium determination is completed by measuring the absorbancy of its diethyldithiocarbamate complex in chloroform. The neodymium or praseodymium is determined by titration with EDTA of the aqueous solution remaining after the separation of bismuth and uranium, using xylenol orange indicator in solutions of pH 5.6–5.8 EDTA is also used to determine the bismuth by direct titration of a separate aliquot of the sample solutions.     

Determination of small amounts of uranium in hafnium,zirconium and zircaloy-2

To meet specification requirements, selected methods for determining uranium have been examined and two satisfactory procedures have been developed for application to the analysis of reactor-grades of hafnium, zirconium and Zircaloy-2.These procedures are based on extraction of uranyl ions from a solution of the sample with a tri-n-butyl phosphate-iso-octane mixture. Following this extraction, uranium over the range 10–150 p.p.m. is determined by a spectrophotometric method, using dibenzoylmethane. For smaller amounts of uranium, down to about 0.5 p.p.m., the determination is completed by squarewave polarography.     

Ion exchange separations in the analysis of bismuth base alloys : Binary alloys with uranium and thorium

Procedures are described for the determination of uranium (0.001–10%) and thorium (0.05–10%) in binary mixtures with bismuth. A preliminary separation of the bismuth is effected by the passage of a hydrochloric acid solution of the sample through a column of Deacidite FF For thorium contents greater than 1%, the determination is completed volumetrically with EDTA using pyrocatechol violet as indicator, smaller amounts are determined absorptiometrically with thoronol Similarly the higher uranium contents are determined volumetrically after reduction to the tetravalent state with a lead reductor, and an absorptiometric method based on the coloured complex formed by tetravalent uranium with thoronol is used for the smaller amounts.     

Direct complexometric determination of magnesium in the presence of uranium, iron and aluminium

Conditions for the direct complexometric determination of magnesium in the presence of uranium, iron and aluminium are described. The method is based on the masking of uranium by hydroxylamine, and of iron and aluminium by triethanolamine. Methylthymol Blue is used as indicator for the EDTA titration of magnesium at pH 10.     

Determination of bismuth in ores, concentrates and non-ferrous alloys by atomic-absorption spectrophotometry after separation by diethyldithiocarbamate extraction or iron collection

Two simple, reliable and moderately rapid atomic-absorption methods for determining trace and minor amounts of bismuth in copper, nickel, molybdenum, lead and zinc concentrates and ores, and in non-ferrous alloys, are described. These methods involve the separation of bismuth from matrix elements either by chloroform extraction of its diethyldithiocarbamate (DDTC) complex, at pH 11.5–12.0, from a sodium hydroxide medium containing citric acid, tartaric acid, EDTA and potassium cyanide as complexing agents, or by co-precipitation with hydrous ferric oxide from an ammoniacal medium. Bismuth is ultimately determined, at 223.1 nm after evaporation of the extract to dryness in the presence of nitric and petchloric acids and dissolution of the salts in 20% v/v hydrochloric acid, or by dissolution of the hydrous oxide precipitate with the same acid solution, respectively. Results obtained by both methods are compared with those obtained spectrophotometrically by the iodide method after the separation of bismuth by DDTC and xanthate extractions.     

Physicochemical transformations in multicomponent melts containing uranium,zirconium, and iron oxides and calcium silicates and aluminates

The properties and crystallization nature of melts of the U⁴⁺–U⁶⁺–Zr⁴⁺–Fe²⁺–Fe³⁺–Ca²⁺–Si⁴⁺–Al³⁺–O^2– system were studied. It was found that the main factors changing the physicochemical characteristics of the melt are the concentration and valence state of uranium and the concentrations of iron oxide and silicon oxide. The results obtained in the analysis of the physicochemical properties of the multicomponent melt can be used in nuclear power engineering to preclude disintegration of a WWER type nuclear reactor in the course of a hypothetical severe reactor accident.     

氢化物发生电加热石英管原子吸收法测定包头铁矿中的砷、锑、铋

研究了氢化物发生原子吸收法测定包头矿中痕量砷、锑、铋的分析方法,试验确立了反应条件,建立了以KI、抗坏血酸、硫脲为还原体系,消除试样中共存元素的干扰,利用KMnO4消除锑对砷的干扰.砷、锑、铋的检出限可分别达到:0.15,0.28,0.15 ng/mL.方法已用于包头矿分析.     

Determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys by atomic-absorption spectrophotometry

A simple atomic-absorption spectrophotometry method is described for the determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys, with use of a single sample solution. The sample is dissolved in a mixture of hydrobromic acid and bromine, then fumed with sulphuric acid. The lead sulphate is dissolved in concentrated hydrochloric acid. The method is particularly suitable for the determination of silver and bismuth, which are co-precipitated with lead sulphate. The other elements can also be determined after removal of the lead sulphate by filtration.     

Ion exchange separation in the analysis of bismuth base alloys : Part II. Ternary alloys containing uranium and thorium

Procedures are described for the analysis of bismuth base alloys containing uranium and thorium in the range from 0.1 to 10%. The thorium is first separated by the passage of a solution of the sample in 5M hydrochloric acid through a column of Deacidite FF in the chloride form. For thorium contents greater than about 1%, the determination is completed volumetrically with EDTA using pyrocatechol violet as the indicator. Smaller amounts are determined absorptiometrically by the thoronol method. Uranium is recovered from the ion-exchange column in a quantity of 0.2M hydrochloric acid, bismuth still being retained by the column under these conditions. Uranium contents greater than about 1% are determined volumetrically after reduction to the tetravalent state with a lead reductor, whilst smaller amounts are determined polarographically using a tartrate base solution.     

分光光度法测定铝合金中的微量铋

研究了在75℃条件下偶氮氯膦(Ⅲ)在HClO4介质中与Bi(Ⅲ)显色生成稳定红色络合物测定微量铋的高灵敏方法。该络合物的最大吸收波长为510nm,摩尔吸光系数ε510=1.567×105L.mol-1.cm-1,Bi(Ⅲ)在0~0.60μg/mL范围内符合比耳定律。已用于铝合金样品中微量铋的测定。     

Paper chromatographic separation of thorium, zirconium and uranium

Summary The possibility of paper chromatographic separation of a number of elements (Th, U, Zr, Fe, Mg, Ni, Co, Ce, La, Y, Sm, Gd) has been studied, employing solvent mixtures containing tri-n-butyl phosphate (TBP) as principal constituent. Various factors that influence the R_f values have been investigated. It has been made possible to separate only thorium and uranium from the other elements including the rare earths and also from one another. Only thorium and uranium move under the conditions studied, the others remain stationary on the starting line. The solvent mixture methylisobutyl ketone-isobutyl alcohol-TBP (503812) shaken with 4 M HNO₃ proved to be a good mobile solvent for the separation of thorium and uranium. Thorium has also been separated from monazite extract. A single chromatogenic spray (-SNADNS-6) has been used for the detection of all the elements. Thorium, uranium and zirconium have also been quantitatively estimated after chromatographic separation by EDTA titration using the same dye.

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Zusammenfassung Die Möglichkeit der papierchromatographischen Trennung verschiedener Elemente (Th, U, Zr, Fe, Mg, Ni, Co, Ce, La, Y, Sm, Gd) mit tributylphosphathaltigen Laufmitteln ist untersucht worden. Hierbei wurde die Beeinflussung der R_f-Werte durch verschiedene Faktoren geprüft und eine Möglichkeit zur Trennung von Thorium und Uran voneinander sowie von anderen Metallen gefunden. Als Laufmittel hat sich am besten das Gemisch Methylisobutylketon-Isobutanol-Tributylphosphat (503812), äquilibriert mit 4 n Salpetersäure, bewährt. Nur U und Th wandern, alle anderen Elemente bleiben auf der Startlinie. Thorium konnte auch aus Monazitextrakt abgetrennt werden. -SNADNS-6 dient als einziges Nachweisreagens für alle genannten Metalle und wird auch als Indicator benutzt bei der komplexometrischen Titration von Zr, Th und U im Anschluß an die papierchromatographische Abtrennung.

     

Anion exchange separation of uranium, thorium and bismuth

Summary A method for the anion exchange separation of uranium, thorium and bismuth is described, using the strongly basic anion exchanger Dowex 1 X8. These three elements are simultaneously adsorbed on the resin (nitrate form) from a solution consisting of 96% n propanol and 4% 5 n nitric acid. The separation of thorium and bismuth from uranium is effected by washing the column with a mixture consisting of 80% methanol and 20% 5n nitric acid (elution of uranium). To separate thorium from bismuth the resin is then treated with a solution consisting of 80% methanol and 20% 6n hydrochloric acid whereby the thorium is eluted. Finally the bismuth is removed by washing the column with 1 n nitric acid. The experimental conditions for this separation scheme have been selected after the determination of the distribution coefficients of uranium, thorium, and bismuth in different mixtures of aliphatic alcohols with nitric and hydrochloric acid.

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Zusammenfassung Zur Trennung von Uran, Thorium und Wismut wird der stark basische Anionenaustauscher Dowex 1X8 verwendet. Aus einem Lösungsmittelgemisch von 96% n-Propanol und 4% 5n Salpetersäure werden die drei Elemente zusammen an dem Austauscher (Nitratform) adsorbiert. Mit einer Mischung von 80% Methanol und 20% 5n Salpetersäure wird sodann das Uran eluiert. Thorium wird mit einem Gemisch von 80% Methanol und 20% 6n Salzsäure ausgewaschen und schließlich wird mit 1 n Salpetersäure das Wismut von der Säule entfernt. Die Verteilungskoeffizienten der drei Metalle wurden in verschiedenen Gemischen von aliphatischen Alkoholen und Salz- sowie Salpetersäure bestimmt.

     

Determination of magnesium in nodular cast iron,using a chromatographic separation

Small amounts of magnesium present in solutions of cast iron can be separated by partition chromatography on cellulose columns. Magnesium may then be determined volumetrically. The method is rapid and gives results which appear acceptable for routine work No elaborate apparatus is required.     

Determination of uranium, iron, copper, and nickel in rock and water samples by MEKC

A micellar electrokinetic capillary chromatographic (MEKC) procedure has been developed for the separation and determination of dioxouranium (VI), iron(III), copper(II), and nickel(II) using bis(salicylaldehyde)propylenediimine (H2SA2Pn) as chelating reagent with a total run time of <3 min. Sodium dodecyl sulphate (SDS) was used as micellar medium at pH 8.1 with sodium tetraborate buffer (0.1 M). Uncoated fused silica capillary with effective length 38.8 cmx75 microm id was used with an applied voltage of 30 kV and photo-diode array detection at 228 nm. Linear calibrations were established within 0.045-1000 microg/mL of each element with detection limit within 15-122 ng/mL. The method was applied to the analysis of spring water and rock samples. The presence of uranium in rock and spring water samples was established within 1.58-1739.3 microg/g and 0.047-0.712 microg/mL with relative standard deviation within 0.9-2.1% and 1.3-2.6% respectively. Uranium ore and water samples were also assayed by the standard addition technique. Recovery of uranium was >98% with RSD up to 2.7%. Copper, nickel, and iron in their combined matrix were concurrently determined within RSD 0.6-3.6% (n=5) and the results obtained were compared with those of flame AAS.     

Determination of magnesium in iron by atomic absorption spectrophotometry

An atomic absorption spectrophotometric method for the determination of 0.001–0.10% magnesium in irons has been proposed. After suitable dissolution of the sample, 1500 p.p.m. of strontium is added to suppress aluminium interference and the solution is atomised in an atomic absorption spectrophotometer. The method is rapid, has high sensitivity, is free from interference and no preliminary separations are required.     

Determination of calcium,magnesium, and phosphate in the presence of iron and each other

Excess EDTA and MgSO₄ solution is added to a mildly acidic solution of the sample containing calcium, magnesium, iron, and phosphate ions. Addition of NH₄OH to this solution results in the precipitation of MgNH₄PO₄·6H₂O and various iron compounds. Calcium ions and a portion of the magnesium ions stay in the solution as the respective EDTA chelates. The mixture is adjusted to a known volume and filtered. The EDTA content of the filtrate with the exception of the EDTA tied up as calcium-EDTA chelate, is titrated with standard CaCl₂ solution at pH 12.5–13.0 in the presence of hydroxy naphthol blue indicator. The calcium content of the sample can be calculated from the result of this titration.