Utilization of the post-filtration lye from the SCS method of soda production

The mutual solubility of salts in the NaVO₃-NaNO₃-H₂O system was investigated at 293 - 323 K temperature range by the method of isothermal saturation of solutions. A fragment of the solubility polytherm for that system was plotted, based on the obtained data. The investigated system is a part of the quaternary NH₄NO₃-NaVO₃-NH₄VO₃-NaNO₃ system, and it is necessary for plotting the solubility isotherm as a planar projection according to Janecke, since it defines one edge of its square. Knowledge of the isotherm for that quaternary system is necessary to determine the optimal utilization conditions for the post-filtration lye, formed during the soda production from NaNO₃ by the Solvay method, using NaVO₃.