| 摘要 |
PURPOSE:To obtain high-purity magnesia clinker having high bulk density, by calcining natural magnesite having a specific composition, adding silica, etc. thereto, and grinding and calcining the mixture. CONSTITUTION:A natural magnesite composed of >=97.5% of MgO, 0.8-2.0% of CaO, trace -0.15% of SiO2, <=0.3% of Fe2O3, <=0.15% of Al2O3 and <=0.1% of B2O3 (based on wt% after ignition) is calcined at about 700-1,400 deg.C to form magnesium oxide. The magnesium oxide is added with amorphous silica, silica gel or a silicon compound capable of giving SiO2 by calcination, and the mixture is ground after or during the addition of the silicon compound. The amount of the silicon compound is selected to give an SiO2 content of 0.12-1.0% after calcination. The ground mixture is calcined at about 1,900-2,100 deg.C to obtain a high-purity magnesia clinker having a bulk density of >=3.48g/cm<3>. |
