Abstract

Setting behavior of calcium aluminate bonded refractory castables can vary in different environments, due to different dissolution and hydrate precipitation rates, as well as different mineralogical structure of hydrates that form as a function of temperature. It is quite common that a given castable will have an excessively long setting time at low temperatures, while inversely, having a too short workability and setting at high temperatures.

In this paper, a mineral based deflocculating active compound is used in an alumina spinel type castable that stabilizes the setting behavior over the temperature range 5°C to 35°C. A comparative study with a non-doped reference material is conducted, reviling the impact from the active compound on the hydration mechanisms across the temperature range.

Differential Scanning Calorimetry, X-Ray Diffraction and SEM observations are used to describe the different hydration behavior of the reference and doped castables, and to understand how the temperature stabilizing effect is achieved.