Equilibrium Study in the KNO₃ + NH₄NO₃ + H₂O System at Temperatures from 293.15 to 323.15 K

Abstract

A solid−liquid equilibrium (SLE) study was conducted in the ternary system KNO 3 + NH 4 NO 3 + H 2 O using the isothermal solution saturation method at temperatures of 293.15, 303.15, 313.15, and 323.15 K. The experimental data obtained were used to plot a section of the solubility polytherm of the investigated system and show the dependence of the densities of equilibrium solutions on their chemical compositions. It has been found that a complex salt of the formula K 0.25 (NH 4 ) 0.75 NO 3 is formed in the system at a temperature below 303.15 K.

Solubility Testing of the Five-Component KNO3 + NH4NO3 + KVO3 + NH4VO3 + H2O System at Temperatures of 293.15 and 313.15 K

“…Solutions represented by triple points are saturated with three salts. Owing to the presence of the double salt KNO 3 ·2NH 4 NO 3 ,, and two eutonic points E 2A and E 2B in the NH 4 + + K + + NO 3 – + H 2 O system at 293.15 K, three triple points P 2A , P 2B , and P 1 were obtained on the solubility isotherm diagram for the five-component system at this temperature. The composition of solid phases for individual triple points was confirmed by X-ray analysis and is presented in Figure .…”

“…Due to the low solubility of NH 4 NO 3 in saturated KNO 3 and NH 4 NO 3 solutions, a break on the ordinate axis was used to better illustrate the course of the curves. Eutonic points (E) for individual systems of salt pairs with a common ion are marked accordingly: E 1 : NH 4 NO 3 + NH 4 VO 3 + H 2 O E 2A , E 2B (293.15K) and E 2 (313.15K): NH 4 NO 3 + KNO 3 + H 2 O E 3 : KNO 3 + KVO 3 + H 2 O E 4 : NH 4 VO 3 + KVO 3 + H 2 O …”

“…The equilibrium tests of the KNO 3 + NH 4 VO 3 + H 2 O system were carried out using the isothermal saturation of solutions method at temperatures of 293.15 and 313.15 K. To prepare equilibrium solutions, their compositions were determined by the course of the appropriate branches of the isotherm. Eutonic solutions (E 1 , E 2 , E 2A , E 2B , E 3 , E 4 , E 5 ) − saturated with two salts were used as starting points, to which increasing amounts of the third salt were added until equilibrium solutions saturated with three salts (P 1 , P 2A , P 2B lub P 2 ) were obtained. The section of the isotherm between points P 2B and P 1 at a temperature of 293.15 K, as well as P 1 and P 2 at a temperature of 313.15 K, was determined by an analogous method.…”

“…As a result of existing threats, there is a constant requirement to investigate new low-waste technological solutions and develop production concepts that do not harm the natural environment. The SCS method provides an alternative to the conventional soda production method, enabling the production of sodium carbonate, gaseous chlorine, and ammonium-sodium nitrate in a single plant. − …”

“…After filtration, the precipitate is subjected to the calcination process (eq ). − 4 HNO 3 + O 2 + 4 NaCl ↔ 4 NaNO 3 + 2 Cl 2 + H 2 normalO NaNO 3 + NH 3 + CO 2 + H 2 normalO ↔ NaHCO 3 + NH 4 NO 3 2 NaHCO 3 → Na 2 CO 3 + CO 2 + H 2 normalO …”