As a leading global supplier of caustic calcined, deadburned and electrofused magnesia products (CCM, DBM and EFM) for use in the refractory, chemical, agricultural, environmental and hydrometallurgical sectors, QMAG is committed to creating solutions that make a sustainable difference.
Caustic calcined magnesia (CCM) is a chemically reactive material commonly used in various industries. The versatile material is produced by calcining magnesite (MgCO3) at temperatures higher than 600 °C, a process that drives off carbon dioxide (CO2) to leave only MgO, a magnesia product also known as CCM.
QMAG selectively mines its sizeable Kunwarara deposit of high-quality cryptocrystalline magnesite to produce a range of different CCM grades, which are calcined in multiple state-of-the-art hearth furnaces and separated in several screening stages. The final product can be granular or finely ground using highly precise milling and particle size classification systems.
Thanks to their lower MgO content, granular and milled grades of CCM are not only found in fertilizers, animal nutrition and other agricultural applications, but are also used to optimise chemical properties in steel and iron fluxing processes as well as for pH and pollution control in pulp, paper and water-treatment plants.
QMAG’s HGCCM, higher in MgO content and more reactive, is a finely milled magnesia product vital for sophisticated applications like rare earth, nickel and cobalt precipitation processes. These metals and minerals are critical for the growing EV battery market.
HGCCM is also used as an input feed for producing QMAG’s deadburned magnesia (DBM) and electrofused magnesia (EFM).
To ensure our deadburned magnesia (DBM) satisfies the high demands of refractory applications, our high-grade caustic calcined magnesia (HGCCM) is first finely milled, then hydraulically briquetted and finally fed into vertical shaft kilns for sintering.
The sintering process itself takes place at temperatures between 1,700 and 2,300 °C and results in a non-reactive, hard, dense and stable material called sintered or deadburned magnesia (DBM). QMAG prides itself in producing deadburned materials of the highest quality and consistency, with grades typically characterised by high density, a large periclase crystal size and low boron content. In addition, most DBM grades benefit from a controlled ratio of CaO to SiO2, which in turn ensures a high melting point of secondary phases (predominantly dicalcium silicate [Ca2SiO4]). Seen together, these properties make QMAG’s deadburned magnesia ideal for a large number of products typically used in refractory applications.
Further heating and fusing of high-grade caustic calcined magnesia (HGCCM) in an electric arc furnace at temperatures of more than 2,800 °C produces electrofused magnesia (EFM), a material of very high density that is ideal for highly demanding refractory applications.
Characterised by secondary phases of highly refractory dicalcium silicate (Ca2SiO4) and very large periclase crystals, EFM is extremely well suited for producing premium quality and long-lasting refractory products used in the manufacture of steel, in slag contact areas and in welding consumables.