The Melting Point of Kalo2

The melting point of kalo2 is low, but it rapidly swells when ball-milled to produce the talc-like solid K12+6x Fe6Te4-x O27. Storing the kalo2 powder in air and annealing it substantially increases its ion conductivity. This is a consequence of a shorter diffusion path and increased surface area created by grinding. The result of these changes is a much more negative dP/dT slope and a more negative P-location of reaction (Qtz) than has been previously depicted. This may help to resolve the disagreements among previous experimental and topological studies of kaolinite-facies metamorphism and petrogenetic processes in granulite-facies systems. The article also discusses a problem with the interpretation of data sets on the fluid-absent, low-temperature dP/dT slopes of reactions (En) and (Phl). The authors propose that talc and anthophyllite equilibria are important in these systems.