ABSTRACT
The use of the sonoluminescence spectroscopy for the determination of main components in concentrated aqueous solution of alkali metal halides is examined. In concentrated RCl solutions (R = Li, Na, K; C = 100-600 g · dm-3) the sonoluminescence intensity is inversely proportional to ultrasound frequency in the range from 2 Hz up to 5 Hz. In the CsCl case the inverse proportionality is disturbed at ultrasound frequencies higher than 3 MHz. This is the limiting value for the accurate analysis of the concentrated solutions of cesium chloride. The increase of initiating ultrasound frequency leads to a decrease of the main component determination in highly concentrated (more than 300 g c dm-3) natural and artificial solutions. Nevertheless, the metrological characteristics of the results of the main substance determination in these solutions improve. The routines of express determination of the main substance in concentrated saline solutions were developed.
ABSTRACT
Alumina solubility in chloride-fluoride melts of KCl-NaCl-NaF mixtures with ratios of 0.425:0.425:0.15 (I), 0.38:0.38:0.24 (II), and 0.35:0.35:0.30 (III) (molar fractions) was investigated in the 973-1123 K temperature range using the isothermal saturation method. Al2O3 solubility in the ionic melts studied was shown to be on the order of 0.06 g kg(-1) for system I, 0.12 g kg(-1) for system II, and 0.14 g kg(-1) for system III at 1073 K. All the "Al2O3 + melt" systems were found to demonstrate negative deviations from the ideal solutions. The solubility of Al2O3 in all the melts increases with the temperature increase; however, the dependences of -log N(Al2O3) versus T(-1) were characterized by the slopes (2.6 +/- 0.4) x 10(3) K (I and II) and (2.4 +/- 0.6) x 10(3) K (III), which were considerably less than the slope predicted by the Shreder-Le Chatelier equation (approximately 5.8 x 10(3)).
ABSTRACT
The reaction of carbonate ion dissociation in molten CsI and NaI was studied in the temperature range from the melting point to 800 (CsI) and 830 degrees C (NaI) by a potentiometric method with the use of a membrane oxygen electrode as an indicator one. The dissociation constant of CO(3)(2-) in the molten iodides was found to increase with the temperature. pK values for CsI are 4.47 (650 degrees C), 4.23 (700 degrees C), 3.89 (750 degrees C), 3.44 (800 degrees C); those for NaI are 4.68 (700 degrees C), 4.39 (750 degrees C), 4.17 (800 degrees C), 3.92 (830 degrees C). The plots of pK vs reverse temperature are linear. Carbonate stability in molten CsI is lower than that in the NaI due to lower stability of Cs(2)CO(3) compared with Na(2)CO(3).
