Caustic calcined magnesia light calcined powder

The magnesite, brucite and magnesium hydroxide extracted from seawater or brine are calcined at about 800~1000 ° C to decompose and discharge CO2 or H2O, that is, light-burned magnesium powder (Caustic calcined magnesia), activated magnesium oxide is also It is called light-burned magnesia, caustic magnesia or light-burned magnesia, commonly known as bitter earth powder. Light burned magnesia powder has loose texture and high chemical activity. It can not only be used to manufacture magnesia cement, magnesite building materials, thermal insulation materials, etc., but also an intermediate product of high-quality magnesia produced by two-step calcination.

Light burning powder use

When magnesite is heated, equiaxed periclase appears around 600°C; at 650°C, equiaxed periclase disappears, and non-equiaxed periclase is produced; at 850°C, equiaxed periclase appears disappear completely. These periclase lattices have high surface energies due to the presence of point defects and dislocations. The lattice of MgO is not much more water than the lattice group of MgCO3, so the inter-lattice pores increase, the porosity is high, the specific surface area is large, and it has high activity.

Light burned magnesium powder is light yellow or light brown powder, the particle size is mostly below -100 mesh, the periclase crystal is very small (<3μm), the true specific gravity is 3.07~3.22, the bulk density is 0.8~1.2g/cm3, and the refractive index is 1.68 ~1.70, large lattice constant (α=0.4212), many lattice defects, brittle texture, porous structure, high reactivity, easy to carry out solid-phase reaction or sintering, and hardening with water to produce Mg(OH)2. Bonding ability. The light-burned magnesia powder calcined from magnesite has a volume shrinkage of about 5%; usually 3% to 5% of CO2 remains due to incomplete decomposition.

The light burning temperature and light burning time of magnesite have certain influence on the activity of light burning magnesia powder. The magnesite was calcined at 600, 650, 700, 750, 800, 850 and 900 ℃ respectively, and the calcination temperature of 700, 750 and 800 ℃ within 15~90 minutes had no obvious effect on the activity of light-burned magnesium powder; 600, 650, 850, 900 ℃ have a particularly significant effect on the activity. When calcined at 600 and 650 ℃, the activity increases significantly with the prolongation of time; when calcined at 850 and 900 ℃, the activity decreases significantly with the prolongation of hydrocarbon calcination time.