THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT

The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by methods isothermal saturation, mass spectrometry inductively coupled plasma (ICP–MS) X-ray phase analysis. It noted that solubility both trioxide depends large extent on temperature. Thus, 700 °C, equilibrium concentration increases an average 1.7 times, its values increase 3.9 times.
 Based results obtained spectrometry, it found content (in calculation pure metal) sodium contact at different temperatures within error definition has approximately same values. indicate favor fact dissolution proceeds through stage formation tungstate. is possible may be formed this case, but no direct evidence been found. At higher than 750 almost all loaded turns into This gives grounds for asserting salt mainly form tungstate.
 give reason consi­der mentioned oxy­gen-containing compounds produces homogeneous phases ternary system CaCl2–NaCl–CaWO4, which 700÷800 satisfactorily described dependence ln S = 8.331 – 14057/T.