Zirconium Nitrate Research Articles

Atomic-absorption determination of copper impurities in zirconium salts using an air-acetylene flame

An AAS method is described for the direct determination of traces of copper in zirconium(IV) oxide chloride and nitrate. An interference study of the zirconium matrix is reported. Best conditions for the removal of the suppressive effect of zirconium on the copper signal by addition of hydrofluoric acid are described. Results obtained by analyzing commercial samples from different manufacturers are presented.

K absorption edge of zirconium in some of its compounds

Using a 1m radius bent crystal spectrograph, the X-ray K absorption edge of zirconium in zirconium metal, zirconium oxide, zirconium tetrachloride and in zirconium oxychloride has been studied. In all the compounds investigated, it has been observed that the absorption discontinuity shifts towards the high energy side with respect to the pure metal. The shift which is due to the change in the distribution of the valence electrons is a maximum in the case of zirconium nitrate. The relative magnitude of the shifts in the compounds studied are tentatively explained on the basis of considerations involving electronegativity and interatomic distances.

DISPERSION, MECHANICAL COMPOSITION, AND FRACTIONATION OF WEST INDIAN VOLCANIC YELLOW EARTH SOILS (ANDEPTS)

SummaryMethods of dispersion used in Japan and New Zealand for soils formed on recent volcanic ash (Andepts) which involved adjusting the pH of organic matterfree soil suspensions to 4 or 10·5 were not effective on similar soils in the Caribbean. Partial dispersion was obtained by adjusting the pH to between 2 and 3 but lower (down to pH 1) and higher (up to pH 11·1) pH values were ineffective. Substantial amounts of Al dissolved at pH 1–3 probably as a result of some disintegration of the allophanoid minerals. Zirconium nitrate solutions were very efficient in causing dispersion, a concentration of 12 me Zr being necessary for complete dispersion of 20 g samples of soil. Excess Zr did not adversely affect dispersion but resulted in depression of pH of the suspensions. The high ionic charge, small atomic radius, and low ionization potential of Zr apparently resulted in saturation of the cation exchange capacity and some isomorphous substitution of Al leading to a net positive charge of the clay and an increase in anion exchange capacity. This was considered to be responsible for dispersion.

Precipitation and complex solubility of zirconium sulfate

The solubility boundaries of systems obtained by mixing aqueous zirconium nitrate solutions with solutions of lithium-, potassium-, or magnesium-sulfate were determined as a function of pH. Distinct complex solubility ranges have been established in the excess of zirconium and sulfate salts, respectively.

Investigation of the sintering of zirconia

We investigated the sintering of zirconium dioxide as a function of the activity of the starting material. It was shown that preliminary firing or stabilization of zirconium dioxide reduces its capacity for densification at temperatures of up to 1500°C, while stabilizing it directly during sintering intensifies this capacity. The prestabilized zirconia has the lowest sintering rate. Introducing monoclinic unfired zirconia into the prestabilized material intensifies sintering; the optimal addition is 30%. It is established that the zirconia is sintered by volume diffusion of vacancies. We investigated the sintering of active zirconia obtained by decomposing zirconium nitrate. The greatest degree of densification is obtained with a preliminary short heat processing of the nitrate at 400°C. Activation is connected with the formation of metastable tetragonal and cubic modifications with defect crystal lattices. Increasing the heat-process temperature of the nitrate or prolonging the soak at 400°C, leading to the formation of stable monoclinic ZrO2 with an ordered crystalline lattice, impairs sintering. Incorporating small additions of active ZrO2 in the industrial material, and providing rapid firing in an oxidizing atmosphere, greatly increases the degree of sintering. Introducing stabilizing additives intensifies sintering. The maximum densification is obtained by the formation of 60–70% solid solution. Further increase in these additions reduces the shrinkage and densification of the specimens.

On the Identification of Hydroxamic Acids formed by Nitric Acid Degradation of Kerosene andi-Dodecane

Identification of hydroxamic acids in chemically degraded kerosene and i-dodecane with nitric acid has been carried out by ferric chloride test to characterize these acids, infrared spectroscopy, visible ray absorption spectroscopy, and extraction of fission products and zirconium nitrate. It is concluded from the above analytical results that small amounts of hydroxamic acids exist without doubt in both the degraded diluents. Their presence has also been evidenced from an examination of the chemical behavior of long chain alkyl hydroxamic acids such as stearyl hydroxamic acid. It is furthermore suggested that some of the precursors to the hydroxamic acids are olefines originally contained and/or formed by radiolysis of paraffines, naphtenes and aromatics in the diluent. With the use of octene-2, the process of formation of hydroxamic acid from olefine has also been estimated and is discussed on the basis of the results obtained.

Densification of ?active? zirconia powders during hot pressing

We studied the influence of temperature and heat process time for zirconium nitrate on the phase composition, dispersion of grains and crystalline lattice defects in the resulting zirconia, and also on its capacity for subsequent compaction during hot pressing. This capacity is connected with the formation, during a short heating period up to 400°C, of metastable tetragonal and cubic modifications having a highly defective crystalline lattice. We also studied the densification during hot pressing of active zirconia obtained by decomposing zirconium nitrate. During decomposition of zirconium nitrate at 400°C with a short soak we noted the formation of zirconium dioxide which was actively compacted at 1100°C and a pressure of 200 kg/cm2. We studied the influence of additions of CaO and the methods of adding it on the densification of active zirconia. An increase in the content of CaO leads to a reduction in the capacity of ZrO2 for compaction during hot pressing. It is necessary to introduce the additive to the nitrate before it decomposes. During hot pressing of active zirconia containing additions of CaO and Y2O3 at low temperatures (1100–1300°C) cubic solid solutions are not formed owing to the short process time, and the zirconia in the specimens consists of monoclinic form. Subsequent heating of the pressed specimens forms cubic solid solutions. It was found that the introduction of 10–20% additive of zirconia obtained by heat processing the nitrate to industrial ultrapure zirconium dioxide yields dense specimens with a reduction in the optimum pressing temperature of 200°C.

On the Preparation of Zirconium Glutarate Gels

Transparent and stable gels of zirconium glutarate were prepared by metathesis of sodium glutarate and zirconium nitrate solutions under controlled conditions. The gelling time ranged from 120 to 436 min at a bath temperature of 35 c- C. In the presence of dioxane, however, the gelling time was considerably reduced. Measurement of the H/sup +/ ion concentration of the gel- forming mixture showed that zirconium glutarate gels are obtained at the pH range 2 to 2.3, establishing the acidic nature of the gels. (P.C.H.)

Removal of niobium-95 from zirconium solutions with Vycor glass

A procedure was developed for separating Nb/sup 95/ from zirconium nitrate -nitric acid solutions containing Zr -Nb/sup95/ tracer by using the adsorption propertmes of glass. The results show that unfired Vycor glass powder will preferentially adsorb Nb/sup 95/ from high nitric acid solutions and may be used to remove such activlty from solutions containing Zr/sup 95/and Nb/sup 95/. The data are tabulated. (P.C.H.)

Solvent Extraction of Inorganic Nitrates with Diphosphonate Ester. I. Zirconium, Yttrium and Lanthanide Nitrates

The extractability of Zr, Y, Ce, Pm, Eu, and Lu was studied on the system between tetra-n-butyl ethylenediphosphonate (TBEDP) -kerosene and various nitric acid concentrations. The results obtained are plotted with results for extraction with TBP from nitric acid for comparison. The distribution ratios, which can increase when other nitrates are added to nitric acid, suggest that the extraction of zirconium by TBEDP depends on the nitrate ion concentration to some extent. The results also indicate that zirconium is extracted more readily from nitric acid solution containing aluminum nitrate than from pure nitric acid solution of the same total nitrate ion concentration. (P.C.H.)

The chemical stability of tributyl phosphate in some nitrate and chloride systems

BS>Preliminary studies have disclosed two factors about the chemical stability of TBP which are very impontant to the processing of nuclear fuels. First, the so-called acid catalyzed hydrolysis of TBP (equilibrated with 2 to 5 M acid) is not primarily a hydrolysis reaction, but a dealkylation reaction. Second, TBP is degraded quite rapidly by (a) a homogeneous reaction with extracted zirconium (nitrate or chloride) and by (b) a heterogensous reaction with solid zirconium compounds (nitrate or chloride). In both (a) and (b) either n-butyl nitrate or n-butyl chloride and insoluble zirconium organic phosphates are major products. (N.W.R.)

EFFECTS OF STRUCTURE OF N,N-DISUBSTITUTED AMIDES ON THEIR EXTRACTION OF ACTINIDE AND ZIRCONIUM NITRATES AND OF NITRIC ACID1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEFFECTS OF STRUCTURE OF N,N-DISUBSTITUTED AMIDES ON THEIR EXTRACTION OF ACTINIDE AND ZIRCONIUM NITRATES AND OF NITRIC ACID1T. H. Siddall IIICite this: J. Phys. Chem. 1960, 64, 12, 1863–1866Publication Date (Print):December 1, 1960Publication History Published online1 May 2002Published inissue 1 December 1960https://doi.org/10.1021/j100841a014RIGHTS & PERMISSIONSArticle Views392Altmetric-Citations137LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (468 KB) Get e-Alerts

The use of continuous extraction for the removal of interfering elements in the determination of calcium and magnesium

Solvent extraction with a continuous extractor has been used to separate Al, Be, Bi, Cd, Ce, Cr, Co, Cu, Ga, In, Fe, Pb, Hg, Mo, Ni, Tl, Th, Sn, Ti, W, U, V, Zn and Zr, from calcium and magnesium, before titration of the latter with ethanediaminotetraacetic acid. Most of these elements arc extracted at ca, pH 5.0 as their chelates with 8-hydroxyquinoline using chloroform. Be, Ce and Cr are not extracted under these conditions and are converted into their acetylacetonates, before extraction with chloroform. Manganese is not quantitatively removed by any of these processes and is precipitated as its hydrated dioxide by boiling the extracted solution with sodium chlorite. Phosphate, arsenate and selenate can be removed by precipitating them in acid solution with excess zirconium nitrate, and removing the latter with 8-hydroxyquinoline.

Tri- n-butyl phosphate as an extracting solvent for inorganic nitrates—I : Zirconium nitrate

The extraction of tracer zirconium by 19% v/v (0·69 M) tri- n-butyl phosphate (TBP) in kerosene has been studied from aqueous solutions consisting of (i) nitric acid, (ii) nitric acid plus an inextractable nitrate (sodium nitrate), and (iii) nitric acid plus an extractable nitrate (uranyl nitrate). The partition coefficients increase steeply with rising acidity, they are little affected by substitution of sodium nitrate for nitric acid, and they fall considerably on addition of uranyl nitrate to the system.

HETEROGENEOUS CHEMICAL REACTIONS IN THE SILENT ELECTRIC DISCHARGE. VIII

Abstract The chemical reactions in the silent electric discharge were studied when hydrogen reacted on the following inorganic solid substances. (1) Cupric nitrate. Reaction products:—ammonium salt, copper oxide, metallic copper, nitrite, nitrogen peroxide, nitric oxide, and ammonia. (2) Zirconium nitrate. Reaction products:—ammonium salt, zirconium oxide, nitrite, nitrogen peroxide, and nitric oxide. (3) Thallous nitrate. Reaction products:—nitrite, thallous hydroxide, metallic thallium, nitrogen peroxide, and ammonia gas. (4) Uranyl nitrate. Reaction products:—ammonium salt, uranous salt, uranium hydroxide, nitrite, and nitrogen peroxide. (5) Ferric nitrate. Reaction products:—ammonium salt, ferric hydroxide, nitrite, nitrogen peroxide, and nitric oxide. (6) Chromic nitrate. Reaction products:—ammonium salt, chromium hydroxide, and nitrite. (7) Calcium sulphite. Reaction products:—Calcium sulphide, calcium hydroxide, and hydrogen sulphide. (8) Sodium sulphite. Reaction products:—Sodium hydroxide, and hydrogen sulphide. The writer wishes to express his appreciation of a grant from the Imperial Academy towards the expenses of this research.