Enhanced Properties of Tailored Alumina–Magnesia-Based Dry Ramming Mixes by Calcium Magnesium Aluminate (CMA)

Abstract

To achieve the goal of “dual-carbon”, induction furnaces with high efficiency and energy-saving advantages are paid more attention in the foundry and metallurgy industries. The service life and safety of induction furnaces strongly depended on the lining because expansion and forward sintering could result in the erosion and slag resistance of the lining. Focusing on the tailoring properties of alumina–magnesia-based dry ramming mixes, calcined magnesia particles were replaced with the novel multi-component materials of calcium magnesium aluminate (CaO-MgO-Al2O3, CMA) with a size of 200 mesh. Properties such as the bulk density, apparent porosity, strength, and slag corrosion resistance of alumina–magnesia-based dry ramming mix containing CMA were evaluated contrastively. The results demonstrate that the penetration index of manganese-bearing slag in dry ramming mixes first decreased and then slightly increased with the addition of CMA. Meanwhile, the permanent linear change in dry ramming mixes was gradually reduced. When the addition of CMA reached 4 wt%, the strength of the dry ramming mixes was slightly greater than the reference, and the slag penetration index was just 75% of the latter.

Microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate in alumina castables

“…Recently, the French company Imerys has developed a composite material called calcium magnesium aluminate (CMA), which consists of 72.5 wt% spinel (MA), 16.5 wt% calcium aluminate (CA), and 9.0 wt% CA 2 with a low expansion coefficient. 17 CMA has emerged as a new additive and aggregate in the realm of refractory materials, demonstrating significant potential for various applications. Initially, CMA was used as a binder in ladle castables, as exemplified by Gehre et al's incorporation of CMA72 cement as a binder in corundum-spinel castables.…”