Four-component reciprocal system Na,K∥F, CO3, WO4

The four-component reciprocal system Na,K∥F, CO3, WO4 has been studied using differential thermal analysis in combination with projective and differential geometry. The a priori prediction of the crystallization path (CP) shows six quaternary invariant points; of them, three are eutectics and the others are peritectics. The dominant exchange and complexing reactions have been recognized. The following four-component systems have been studied: (NaF)2-(KF)2-K2CO3-K3FWO4 (1), (NaF)2-K2CO3-K2WO4-K3FWO4 (2), (NaF)2-Na2CO3-Na2WO4-K2WO4 (3),, and (NaF)2-Na2CO3-K2CO3-K2WO4 (4); the coordinates of all quaternary invariant points have been determined.