C for calcium aluminate
Time for the next card in the COFERMIN quartet. After Aluminum Oxide (A) and Bentonite (B), we now turn our attention to this versatile material that plays an important role across multiple industries.
Calcium aluminate is a technically versatile material used both as a high-temperature-resistant binder in refractory applications and as a slag former in metallurgy. But let’s start with its chemical composition.
Chemically speaking, it is a mixture of substances produced by burning or sintering raw materials—predominantly calcium carbonate, aluminum oxide, silica, and iron oxide—at high temperatures (above 1,200 °C). The resulting compounds are embedded in a crystalline mass. A common base formula is CaAl₂O₄, though there are many more chemical compounds that fall under the term “calcium aluminate.” What they all share is high temperature resistance, with melting points typically above 1,400 °C depending on the phase. Variations are found in reactivity, which makes it possible to tailor calcium aluminate precisely to the requirements of specific applications.
In industrial use, calcium aluminate appears in different forms.
As a granulated slag-forming material in the steel industry, calcium aluminate is used to effectively bind sulfur and other impurities. By specifically influencing the slag composition, it helps reduce the chemical load on refractory linings, minimizing wear. Thanks to its microporous structure, it dissolves quickly and evenly into the slag, boosting the efficiency of metallurgical processes.
As a binder—also known as high-alumina cement—it develops high strength within just a few hours and is largely resistant to acids and sulfates (with the exception of mineral acids). It is an essential additive in monolithic refractory linings, such as in steel ladles and high-temperature furnaces. Calcium aluminate cement reaches compressive strengths within hours that conventional cement often takes days to achieve. Additionally, it does not form lime-bearing phases, which increases chemical stability.
Calcium aluminate is produced either via the energy-intensive melting process or the more efficient sintering process. Both deliver high quality, but the melting process ensures exceptional purity. In the traditional melting process, temperatures above 1,600 °C prevent the formation of unwanted residual phases. Modern sintering processes also allow flexible composition control while lowering energy consumption.
COFERMIN supplies tailor-made calcium aluminates, fine-tuned to your specific industrial requirements. Our raw materials come from trusted sources that meet high quality standards. Through our global network and strong supply partnerships, we ensure reliable deliveries even under fluctuating market conditions. In addition, we provide in-depth advice on application and handling, including optimal dosing for metallurgical use.
And of course, a quick look at our quartet categories:
- Economics: Closely linked to the steel and construction industries, moderate growth (~5% p.a.)
- Refractoriness: High, suitable for applications above 1,400 °C
- Country of Origin: China
- Sustainability: Medium, reduces fluorine use in the steel industry
- REACH Registration: Required only for fused material; sintered material is exempt
