随着耐火材料对氧化镁质量要求的提高,采用低品位菱镁矿制备高纯氧化镁引起广泛关注.对海城某菱镁矿矿石进行轻烧-氯化铵浸出,获得MgCl2和CaCl2等的浸出液,取等体积该浸出液采用氨水沉淀法制备氢氧化镁,在反应时间为60 min,反应温度为45℃,氨水浓度为8 mol/L及搅拌速度为500 r/min的条件下,制备的氢氧化镁沉淀量达到最大值.将制备的氢氧化镁置于马弗炉中进行焙烧,在焙烧时间为30 min及焙烧温度为500℃的条件下,可制得纯度高达99.84％ 的氧化镁.激光粒度分析显示氧化镁的中位径(D50)为50.21μm,其中在0.500～100μm范围内粒径占95％,分散性好.%With the improvement of the quality requirements of the refractories to magnesium oxide, prepation of high-purity magnesium oxide from low-grade magnesite has attracted wide attention. A magnesite ore in Haicheng was lightly burned, and the product was leached by ammonium chloride. MgCl2 and CaCl2 were mainly contained in the leach solution and magnesium hydroxide was prepared from the equal volume leaching solution by ammonia precipitation method. The precipitation of magnesium hydroxide could reach the maximum when the reaction conditions are as follows: time of 60 min, temperature of 45 ℃, ammonia concentration of 8 mol/L and stirring speed of 500 r/min. The prepared magnesium hydroxide was put into the muffle furnace for roasting. Magnesium oxide with purity up to 99.84％ could be prepared at the calcination time of 30 min and calcination temperature of 500 ℃. The results of laser particle size show that the median diameter (D50) of magnesium oxide is 50.21 μm, the particle size accounts for 95％ in the range of 0.500-100 μm and the dispersibility is good.
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