Thorium Nitrate Research Articles

Production of lanthanon and thorium compounds from monazite. III. Preparation of pure thorium nitrate

AbstractA precipitation process is described for converting crude thorium oxalate or crude thorium phosphate into substantially pure thorium nitrate.The process is based on the use of a sulphuric acid‐oxalic acid mixture to ‘leach’ the bulk of the phosphate from a thorium oxalate complex. A phosphate concentrate can be treated similarly, but is first treated with oxalic acid to convert it into an oxalate complex. Residual phosphate and sulphate are removed from the acid‐treated products by precipitation of thorium oxalate under specified conditions. Residual lanthanons, together with any remaining impurities, are separated from thorium by precipitation of a granular form of thorium ‘peroxynitrate’. Variables in the process have been studied and material flow sheets, based on laboratory investigations, are presented. If mechanical losses are ignored the yield of thorium from monazite exceeds 90%.Application of the process to any type of thorium oxalate or phosphate concentrate is discussed, and details are given of the analytical determination in various thorium compounds of small quantities of phosphorus, cerium and mixed lanthanons.

The titration of Al with complexone III at a pH 3.5

A titration procedure for Al based on the reaction of Al and complexone III (disodium salt of ethylenediaminetetra-acetic acid, (“versene”) at pH 3.5–4.3 is described. After adding an excess of complexone the excess is back-titrated with thorium nitrate, using alizarin S as an indicator. The reaction is not exactly stoichiometric, but nevertheless quite reproducible, and an about 1% higher factor for Al should be used.

The titration of bismuth with complexone III at pH 2.0–2.8

A titration procedure for Bi is described; by adding an excess of complexone III (Versene) and back-titrating at pH 2.0–2.8 with standard thorium nitrate solution using alizarin-S as an indicator, it is possible to determine Bi with a precision of about 0.3%. By choice of the proper pH it is possible to eliminate most of the interfering elements, but at pH 2.0 Fe and Ni still interfere, and Cu only to a slight extent. Attention is drawn to the fact that it may be possible to determine Bi at pH 2.0 by direct titration with complexone III in the presence of much tartrate, using thiourea as an indicator. This method might be of value in the presence of Sn and Sb.

Liesegang rings of silver chromate

The colloidal behaviour of silver chromate in producing periodic precipitation, specially in agar agar medium, has been studied. Silver chromate does not form any stable colloidal solution in agar agar sol but it has been observed by us that its colloidal solution may be obtained in the presence of sodium citrate, disodium hydrogen phosphate, aluminium nitrate and thorium nitrate solutions. Further, Liesegang rings of silver chromate in agar agar gel are formed in the presence of these salts.

The microanalysis of fluorine-containing organic compounds. II. the determination of fluorine

The compound is decomposed by fusion with metallic sodium or potassium in a nickel bomb of special design, and the fluorine is titrated with thorium nitrate solution. Several modifications of this titration procedure were first examined as a means of completing the determination, but only one was found suitable, i. e. back-titration of a comparison solution with a standard sodium fluoride solution. When nitrogen and sulphur, which form cyanide and sulphide ions, are present, the procedure has to be modified slightly to overcome their interference.

The titration of complexone III with thorium nitrate at pH 2.8–4.3

The reaction between thorium and Complexone III (disodium salt of ethylene-diaminetetra-acetic acid) at pH 2.8–4.3 has been developed to a quantitative method. As indicator alizarin-S is used. In the first place the reaction is suitable to backtitrate an excess of Complexone III in the pH range mentioned and it is the basis for an Al, Ni and Bi determination still to be published; moreover, it probably presents the possibility of a simple determination of thorium.

The determination of fluorine in polytetrafluoroethylene

AbstractA method has been developed for the determination of fluorine in polytetrafluoroethylene. In this method the sample is fused with sodium peroxide in a Parr bomb and the aqueous extract of the melt is distilled with perchloric acid in the presence of silica. The fluoride in the distillate is titrated at a controlled pH of 3·0 with thorium nitrate solution using sodium alizarinsulphonate as indicator; the end‐point in the titration is determined by comparison with a colour standard containing thorium fluoride, cobalt sulphate and potassium dichromate. The thorium nitrate is standardized against pure sodium fluoride which has been submitted to the peroxide fusion and perchloric acid distillation process.

Rapid Separations of Protactinium and Uranium Radioisotopes from Cyclotron Bombarded Thorium Nitrate

Rapid Separations of Protactinium and Uranium Radioisotopes from Cyclotron Bombarded Thorium Nitrate

Coagulation Effects of Thorium Nitrate on Aqueous Sols of Silver Halides in Statu Nascendi. II. The Factors of Stabilization and the Effects of “Aging” of Thorium Nitrate Solution

Coagulation Effects of Thorium Nitrate on Aqueous Sols of Silver Halides in Statu Nascendi. II. The Factors of Stabilization and the Effects of “Aging” of Thorium Nitrate Solution

Coagulation Effects of Thorium Nitrate on Aqueous Sols of Silver Halides in Statu Nascendi. I. The Coagulation Curve and the Coagulation Value of Thorium Nitrate

Coagulation Effects of Thorium Nitrate on Aqueous Sols of Silver Halides in Statu Nascendi. I. The Coagulation Curve and the Coagulation Value of Thorium Nitrate

Thorium nitrate. V. Extraction from aqueous solution by organic solvents as a means of enriching mixed nitrates in thorium.

It was shown by the authors (J. Phys. and Colloid Chem.; 54: 954-957(Jun 1950) that the leaching of mixed solid thorium and rare earth nitrates with higher alcohols and ketones results in a considerable increase in the proportion of thorium nitrate. The present paper demonstrates that the last 10 to 20% of rare earth nitrates can be removed by a liquid-liquid extraction process. The only condition which is critical to the process is that the starting aqueous solution must be kept quite near to saturation with respect to thorium nitrate.

Variations in Absorption Spectrum of the Nitrate Group

Lithium, magnesium, calcium, aluminum, manganous, cobaltous, nickelous, cupric, zinc, cadmium and thorium nitrates, and nitric acid, show an absorption in tertiary butyl alcohol solution which is different from that of dilute aqueous solutions of nitrates. The most marked effects are shown by the transition elements with partially completed d shells. The variety of the spectra indicate that a single change, such as the rearrangement of the normally planar nitrate ion into a pyramidal form, cannot account for nitrate spectrum changes.

Thorium nitrate. IV. Leaching with higher alcohols and ketones as a means of enriching mixed nitrates in thorium.

Thorium nitrate. IV. Leaching with higher alcohols and ketones as a means of enriching mixed nitrates in thorium.

Note on the Solubility of Thorium Nitrate Tetrahydrate and Uranyl Nitrate Hexahydrate in Organic Solvents

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ON THE SOLUBILITY OF THORIUM NITRATE TETRAHYDRATE AND URANYL NITRATE HEXAHYDRATE IN ORGANIC SOLVENTS

The values reported by Yaffe for the solubilities of thorium nitrate tetrahydrate and uranyl nitrate hexahydrate in various organic solvents are compared with those previously reported by Templeton and Hall, the former being much lower than the latter. Some of the accessory experiments of Templeton and Hall are here presented in support of the position that their values more closely correspond to equilibrium than those of Yaffe.

SOLUBILITY OF URANYL NITRATE HEXAHYDRATE AND THORIUM NITRATE TETRAHYDRATE IN ORGANIC SOLVENTS AT 20 °C.

A study has been made of the solubility of uranyl nitrate hexahydrate and thorium nitrate tetrahydrate in various organic solvents at 20 °C. In all the solvents investigated no case was found where the thorium nitrate tetrahydrate was more soluble than the uranyl nitrate hexahydrate. Hydrocarbons do not dissolve either compound to an appreciable extent. Addition of a ketone, aldehyde, or alcohol group enhances the solubility considerably. The simpler the compound the greater the solubility of the nitrate in any given family.

Thorium Nitrate. III. The Distribution of Thorium Nitrate between Water and Certain Esters and the Nature of the Distribution Equilibrium.

Ethyl butyrate shows about the same properties for the solvent extraction of thorium nitrate from aqueous solution as alcohols and ketones of comparable molecular weight. Ethyl acetate was found to be miscible with aqueous solutions containing appreciable amounts of thorium nitrate, and therefore to be unsuitable as an extractant in the concentrated range. It has been shown that the effect of added nitric acid on the distribution of thorium nitrate between water and an organic solvent lends support to the view that the salt is more or less completely ionized in aqueous solution, and undissociated in the organic phase.

A COMPARISON OF THE DIRECT AND INDIRECT RADIOACTIVE METHODS FOR DETERMINING THE SURFACE AREA OF A STRONTIUM SULPHATE PRECIPITATE

The specific surface of a strontium sulphate precipitate, as determined by the direct radioactive method using Sr90, was found to be 12,800 sq. cm. per gm. The specific surface of the same strontium sulphate precipitate was also determined by the indirect method using ThB. Specific surfaces of 30,800 and 21,300 sq.cm. per gm. were obtained using ThB separated, from thorium nitrate, by the chemical separation and emanation methods, respectively. The factor of approximately 2 between the direct and indirect methods indicates that Paneth's theories, while probably correct in the main, may require some modification.

SOME EFFECTS OF THE ADMINISTRATION OF THORIUM NITRATE TO MICE

A method for the determination of microgram amounts of thorium in tissues by the use of the thorium isotope UX1 was developed.When an aqueous solution of thorium nitrate was administered orally to mice, the LD50 was found to be between 1.76 and 2.0 gm. of thorium per kgm. body weight. Mice supplied with a 0.1% solution of thorium nitrate as their only source of water exhibited a greater mortality than was found in a control group. The subcutaneous injection of 50 mgm. of thorium as a thorium nitrate solution into mice produced an acute, necrotizing, inflammatory reaction at the site of injection, but no other effects. The exposure of a group of mice to an aerosol of thorium nitrate solution on each of 90 days for 40 min. each day had no effect on their mortality. The average initial concentration of thorium for each exposure to the aerosol of thorium nitrate was 330 mgm. thorium per cu. m. of air and the average final concentration was 114 mgm. of thorium per cu. m. of air.Evidence was obtained that all the thorium administered orally as thorium nitrate solution to mice is excreted by way of the feces and that no absorption from the gastrointestinal tract takes place. It is suggested that thorium nitrate owes its oral toxicity to its local action on the mucosa of the gastrointestinal tract.No evidence was obtained that thorium was transported to the viscera and very little thorium was excreted after the subcutaneous injection of 0.5 mgm. of thorium as thorium nitrate solution into mice. Most of the thorium remained at the site of injection for at least seven days. The cutaneous application of 0.3 ml. of BAL (2,3-dimercaptopropanol) appeared to cause a slight increase in the excretion of thorium, but the distribution of thorium in the mouse was not affected by this treatment.A group of mice was exposed for 180 min. to an aerosol of thorium nitrate that gave a maximum concentration of 107 mgm. of thorium per cu. m. of air and a final concentration of 3 mgm. of thorium per cu. m. of air. After this treatment the average amount of thorium found in and on one mouse was 256 μgm. Most of this was on the skin and most was excreted by way of the feces within a few days. Less than 0.2 μgm. of thorium was found in the liver, kidneys, spleen, blood, or femurs, immediately after the exposure or one day later. The average amount of thorium found in the lungs of one mouse immediately after the exposure was 3.12 μgm. and this amount decreased slowly over a period of 35 days.

The Distribution of Thorium Nitrate between Water and Certain Alcohols and Ketones

The distribution of thorium nitrate has been determined at room temperature between water and each of the following solvents: isoamyl alcohol, n-hexyl alcohol, methyl isobutyl ketone, methyl n-amyl ketone, and methyl n-hexyl ketone. These five organic solvents appear to be the most promising for the liquid-liquid extraction of thorium nitrate from aqueous solutions also containing the nitrates of the rare earths and zirconium. The effect of added nitric acid has been ascertained on the systems containing n-hexyl alcohol and methyl n-hexyl ketone. Some preliminary extractions with methyl n-hexyl ketone are described to show the applicability of the conclusions drawn from these distribution data.