Stable Tetrahedron NaBO2–Na2CO3–Na2WO4–K2WO4of the Quaternary Reciprocal System Na,K∥BO2,CO3,WO4

Abstract

By differential thermal analysis using the calculation-experimental method, the phase diagram of the quaternary system NaBO₂–Na₂CO₃–Na₂WO4–K₂WO₄ was studied, and the coordinates of ternary eutectics and two quaternary eutectics were determined: E₁^□ (530°C, 5.6% NaBO₂, 30% Na₂CO₃, 55.3% Na₂WO₄, 9.1% K₂WO₄). It was shown that the calculated and experimental data on the coordinates of the quaternary eutectics agree satisfactory.