关键词: 耐火材料, 工艺流程, 菱镁石, 轻烧温度, 氧化镁, 烧结, 体积密度

Abstract: Magnesia was used as starting material to prepare MgO specimens the way it was lightly roasted at 850°C for 2 hr to form MgO which was then hydrated, ground, filtered, extracted and dried to become Mg(OH)2 from which the powdered MgO with different activities were obtained at different temperature and, finally, the φ20 mm × 10 mm cylindrical MgO or magnesia specimens were provided through briquetting and sintering. How the fineness of powdered magnesia due to grinding, briquetting pressure and light roasting temperature affect the bulk density of sintered magnesia were investigated through tests. The results showed that both the grinding operations before and after the light roasting at 600°C of Mg(OH)2 to become powdered magnesia affect significantly the bulk density of sintered magnesia, while the briquetting pressure affects it not much. So, high-density magnesia can be obtained under the conditions that there are two grinding operations mentioned above, the briquetting pressure to form specimens is 200 MPa and sintering at 1 600°C for 3 hr. Such a magnesia shows TO (MgO) = 97.5%, w(CaO):w(SiO2)>2 and bulk density = 3.47g/cm³.