A stray-field imaging,CRAMPS and MQMAS study of the drying process of precasting materials used in a steel-making converter

Optimization of the drying process conditions in a steel-making converter in a steel works is very difficult since the process is off-line and time-consuming. However, it is important to optimize drying process conditions (temperature, surface active agents, etc.), as steam explosion can readily occur with insufficient drying time. To help understanding, we have demonstrated that we can monitor the drying of real refractory mortar with stray-field imaging. We chose, this method because of the possibility of detecting shortT ₂ components. This paper shows the effect of varying water content in different materials on the drying rate. In particular, we find that the free-water loss rate is relatively independent of water content. However the bound-water loss rate is more affected. Also, solid-state nuclear magnetic resonance (NMR) (¹H-CRAMPS and²⁷Al M(3 and 5)QMAS) studies are performed to clarify the change of chemical structure by drying treatment. It is clear that imaging and solid-state NMR give useful information to optimize drying conditions. With this data, we can adjust and optimize the drying process and time in steel works.