Effect of water-soluble magnesium lactate on the volume stability of refractory castables containing calcium aluminate cement.

A kind of organic magnesium salt, water-soluble magnesium lactate, was used as the MgO-precursor in new forms to identify the particular impact of additive dispersity on properties of calcium aluminate cement (CAC)-bonded castables, especially the volume stability. Magnesium lactate could dissolve in water in the mixing process, distribute uniformly, and decompose during heating, providing space for counterbalancing the expansion from in-situ calcium aluminates and MgAl₂O₄ spinel generation. Hence, in this study, CAC-bonded castables containing 0-1.2 wt% magnesium lactate were prepared. The volume stability and thermo-mechanical strength of castables were tested. Results show that the dissolution of magnesium lactate in water distinctly enhances the volume stability of castables. To understand the underlying mechanism of water-soluble magnesium lactate on the samples, phase compositions and microstructure development of castable matrices were examined. [ABSTRACT FROM AUTHOR]