Ceramics-Silikáty 21, (1) 3 - 11 (1977)

The heat of fusion of akermanite was determined at its melting temperature of 1727 K (ΔH_fus = 123.9 ± 3.2 [kJmol^-1]), as well as its fusion entropy (ΔS_fus = 71.7 [Jmol^-1K^-1]) and molar heats of crystalline and fused akermanite in the 1469 to 1696 K and 1741 to 1868 K temperature ranges respectively (C_p(c) = 0.2014 + 8.84 x 10^-5T [kJmol^-1K^-1], C_p(m) = 0.382 [kJmol^-1K^-1]). A solution obtained by dissolving the respective phase of akermanite in a mixture of hydrofluoric and nitric acids was selected as the base state for the determination of enthalpy increases ΔH. A solution and a drop calorimeter were employed in the measurements.