Drying and dehydration of calcium aluminate cement (CAC)-bonded castables is critical to their industrial performance. However, internal pressure build-up during heating can impede vapor removal, affecting mass transport. This preferentially drives steam towards cooler areas, increasing internal vapor pressure and potentially causing spalling under severe hydrothermal conditions.

We investigated hydrate evolution in CAC-bonded castables under simulated conditions using autoclave treatments. These treatments replicate the hydrothermal environments experienced during industrial heating on a laboratory scale.

We are using Raman spectroscopy, a non-destructive technique for analyzing mineral and amorphous phases as well as liquids, to analyze alumina-based CAC matrix castables containing two different liquefiers after autoclave treatment at different temperatures. Complementary research focuses on X-ray diffraction (XRD) of the matrix compositions and the pore size distribution of the finished castables using mercury intrusion porosimetry.