Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration

Rare earth elements materials production from apatite ores

The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics

Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing

The features of extraction of rare earth elements (REE) were considered from hydrate-phosphate precipitates of REE of apatite processing by nitric acid technology. The preliminary purification of nitrate solution of REE from impurities of titanium, aluminum, iron, uranium and thorium was suggested to obtain stable solutions not forming precipitates. Washing the extract was recommended with the evaporated reextract that allows to obtain directly on the cascade of REE extraction the concentrated solutions suitable for the separation into groups by the extraction method. Technical decisions were suggested for the separation of REE in groups without the use of salting-out agent

Hydride-dehydride fine zirconium powders for pyrotechnics

In this paper, the possibility of obtaining fine zirconium powders by the hydrogenationdehydrogenation method is studied. The main parameters of the technological process that allow obtaining fine zirconium powders for pyrotechnics are determined. Hydrogenation and dehydrogenation of the samples are carried out in a rotating quartz tube placed in a furnace at temperatures of 380◦C and 850◦C, respectively. Zirconium hydride is milled using tungsten carbide balls to eliminate the presence of impurities. Thus it is possible to obtain a fine zirconium powder with a number-average particle size of 4.527 +- 2.650 Um and a specific surface area of 0.231 m2/g from the initial electrolytic zirconium powder with a number-average particle size of 220 Um and a specific surface area < 0.1 m2/g. The allowed relative error of measuring the specific surface area is +- 5%. Hence it is possible to reduce the particle size of zirconium powder by 54.6 times without changing the composition

Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration

Advanced of rare earth fluorides technology

The thermochemical processes of synthesis and purification of rare earth metals fluorides through the transfer of fluoroammonium complexes were discussed. By differential thermal calorimetry the temperature maxima of rates of formation and decomposition of complex compounds were defined and the values of the apparent activation energy processes were determined. It is possible the use of fluoroammonium systems to develop the preparation of anhydrous fluorides of rare earth metals.</jats:p

Determination of Au(III) and Ag(I) in Carbonaceous Shales and Pyrites by Stripping Voltammetry

Techniques of stripping voltammetry (SV) determination of silver and gold in pyrites and carbonaceous matter are developed. The problem of quantitative transfer of the analytes into the solution is solved. For this purpose, the ore matrix of carbonaceous shales was decomposed by mineral acids in autoclaves at high pressures. The element to be determined from the sample matrix was separated by extraction. Ag(I) ions from the solutions were extracted in the form of a dithizonate complex in CCl4. Au(III) ions were extracted by diethyl ether. The extracts were decomposed thermally. The dry residue was dissolved in the background electrolyte, and the element was determined by the SV method. The graphite electrode (GE) impregnated with polyethylene was used as a working electrode in the SV determination of silver. The SV determination of gold was carried out using a GE modified by bismuth. The limits of detection (LOD) of Ag(I) and Au(III) contents were equal to 0.016 mg L&#8722;1 and 0.0086 mg L&#8722;1, respectively. The results of SV determination of gold and silver in standard samples, pyrites, and carbonaceous shales were presented. The silver content in the pyrite was 13.6 g t&#8722;1, and in carbon shale it was 0.34 g t&#8722;1. The concentration of gold in the pyrite of the Kirovsko&#8315;Kryklinskaya ore zone was 1.15 g t&#8722;1, while in carbonaceous shales it was 2.66 g t&#8722;1. The obtained data were consistent with the data of atomic emission spectroscopy (AES) and inductively-coupled plasma mass spectrometry (ICP&#8315;MS). The error of determination of elements by stripping voltammetry was calculated as ranging from 10 to 6 g t&#8722;1 (less than 12%) in pyrite and carbonaceous material when determining the silver content, and from 1 to 3 g t&#8722;1 (less than 22%) when determining the gold content in pyrite and carbonaceous matter

Rare earth elements materials production from apatite ores

The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics

Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing

The features of extraction of rare earth elements (REE) were considered from hydrate-phosphate precipitates of REE of apatite processing by nitric acid technology. The preliminary purification of nitrate solution of REE from impurities of titanium, aluminum, iron, uranium and thorium was suggested to obtain stable solutions not forming precipitates. Washing the extract was recommended with the evaporated reextract that allows to obtain directly on the cascade of REE extraction the concentrated solutions suitable for the separation into groups by the extraction method. Technical decisions were suggested for the separation of REE in groups without the use of salting-out agent