Recovery of valuable components from basalt waste by sintering it with sodium carbonate

The sintering of basalt waste with sodium carbonate at 1000–1200°C followed by leaching of the sinter with water, a NaOH solution, or hydrochloric acid is reported. The most effective leaching agent is hydrochloric acid, with which all of the valuable components of basalt pass into solution and silicon can be selectively separated as silicic acid.     

Decomposition of aluminum oxynitride compounds in an air-vapor medium at 950°C

Aluminum oxynitride hydrolysis in wet air at a temperature of 950°C has been shown to lead to the formation of a phase whose composition lies beyond the Al₂O₃-AlN join in the Al-O-N system.     

Phase diagram of the As-S system

Thermodynamic modeling of phase equilibria is used to consistent p-T-x phase diagram of the As-S system. Experimental evidence is presented that As₂S₅ is a metastable phase at moderate pressures. Analytical expressions are derived for the subsolidus phase equilibria in the As-S system. It is shown for the first time that crystalline As₄S₃ sublimes congruently and that two liquid-vapor azeotropes exist in the As-S system.     

Behavior of impurity metals in the fusion of magmatic rocks with a mixture of sodium carbonate and calcium oxide

The method of physicochemical simulation is used to calculate the equilibrium compositions of SiO₂-Al₂O₃-(TiO₂)-CaO-MgO-Fe₂O₃-(MnO)-Na₂O-(Cr₂O₃)-(V₂O₅) systems in the temperature range of 1273–1473 K at various ratios of (Na₂CO₃ + CaO): rock. It is shown that the impurity metals are present in fusion products in the form of calcium polytitanate (Ca₃Ti₂O₇), manganese(II, III) oxide (Mn₃O₄), chromium(III) oxide (Cr₂O₃), and calcium orthovanadate (Ca₃V₂O₈).     

Use of chemical and metallurgical methods for processing of gabbro-basalt raw material

The recovery of silica and the mixture of iron and aluminum oxides, as well as associated valuable elements, from hydrochloric acid solutions obtained after the desalination of the products of the sintering of wastes of gabbro-basalt raw material with soda by hydrochloric acid has been experimentally studied. A scheme of the integrated utilization of gabbro-basalt raw material involving chemical and metallurgical methods has been suggested.     

High-temperature mass spectrometric vaporization study of the Bi-Sb-O system

The vapor composition in the Bi-Sb-O system has been determined by Knudsen cell mass spectrometry. We have calculated the individual mass spectra of the Bi₃SbO₆, Bi₂Sb₂O₆, and BiSb₃O₆ molecules and determined the partial pressures of all the vapor species identified. Bi₃SbO₇ and BiSbO₄ have been shown to sublime congruently. The results have been used to construct p-x sections for the pseudobinary oxide systems Bi₂O₃-BiSbO₄ and BiSbO₄-Sb₂O₄.     

Production of ceramic materials by the sintering of ground basalt

The process of the heating of ground basalt was studied. Based on the obtained results, samples of basalt ceramics without a binding agent were fabricated by sintering. The physicochemical properties of the obtained samples were investigated.     

Crystal-chemical aspect of formation of CdAs<Subscript>2</Subscript>-ZnAs<Subscript>2</Subscript> solid solutions

The initial stages of the formation of CdAs₂-ZnAs₂ solid solutions are analyzed in terms of crystalchemical energetics. Given that the bond enthalpies decrease in the order H (Zn-As)< H (Cd-As)< H (As-As), it is concluded that, most likely, CdAs₂-based solid solutions are substitutional and ZnAs₂-based solid solutions are interstitial, and that the thermochemical stability of the substitutional solid solutions is higher than that of CdAs₂ . The conclusions drawn from crystal-chemical analysis correlate with the reported x-ray diffraction, chemical analysis, resistivity, and Hall data for the solid solutions.Translated from Neorganicheskie Materialy, Vol. 41, No. 1, 2005, pp. 7–10. Original Russian Text Copyright © 2005 by Sanygin, Mikhailov, Palkina, Steblevskii, Kvardakov, Marenkin.     

Effect of iron content on the sintering of ground basalt into ceramics

Ground basalt from the Myandukha occurrence, Arkhangelsk oblast, was divided into magnetically enriched and magnetically deficient components by magnetic separation, and their chemical compositions were determined. We investigated the difference in thermal behavior between the two components using differential scanning calorimetry and thermogravimetry data and the mineralogical composition obtained by thermodynamic modeling of the basalt. The sintering behavior of the magnetic and nonmagnetic components of the ground basalt was examined, and some properties of the resultant ceramic materials were studied.     

Preparation and Properties of Thin InSb〈Te〉 Layers on Al2O3

Thin layers of Te-doped indium antimonide are produced on Al₂O₃ substrates by directional solidification. The effective distribution coefficient of Te is determined, and the electrical properties (resistivity, carrier mobility, and carrier concentration) of the layers are studied in the range 77–300 K. The mechanisms of carrier scattering governing the electrical properties of the layers are discussed.