Solubility in the NaNO3-NH4NO3-KNO3-H2O system

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

“…The results of the study of the mutual solubility of salt in the studied system indicate the salting-out effect of potassium nitrate­(V) on ammonium nitrate­(V) and the salting-in effect of ammonium nitrate­(V) on potassium nitrate­(V). At 293.15 K, the formation of the double salt K 0.25 (NH 4 ) 0.75 NO 3 was observed, which is consistent with the literature. − However, contrary to what some authors report, − no other mixed salts were observed at higher temperatures.…”

“…There are many publications describing studies on solid phases appearing in the studied system. The outlined differences are primarily due to the tendency of potassium nitrate­(V) and ammonium nitrate­(V) to create metastable states in the form of solid solutions. − Some authors confirm the existence of double salts; however, there is no consensus on their stoichiometry and the temperatures at which they appear. − Some studies indicate the formation of double salts composed of 3KNO 3 ·NH 4 NO 3 and two rows of solid solutions at 298 K, − but there are also reports of double salts: 2KNO 3 ·NH 4 NO 3 and KNO 3 ·2NH 4 NO 3 . Other authors describe solid phases that are in fact solid solutions: K 0.75 (NH 4 ) 0.25 NO 3 and K 0.67 (NH 4 ) 0.33 NO 3 …”

“…The solid phase composition was analyzed for selected experimental points using a Philips X-Pert PRO powder diffractometer. To determine the composition of the solid phases, the diffractometric data obtained were compared with appropriate standards in the “Powder Diffraction File”. − …”