镁橄榄石质轻质球形骨料的制备

为了降低镁基轻质浇注料在受热过程中的收缩并提高其初始强度,以菱镁矿细粉、天然硅石粉、轻烧MgO和SiO_2微粉为原料,使用硫酸镁溶液为结合剂,采用圆盘造粒机成型料球,分别在1 400、1 420、1 450℃下保温3 h煅烧制备了镁橄榄石质轻质球形骨料。分别研究了结合剂浓度、原料配比和煅烧温度对骨料体积密度、显气孔率、料球强度的影响。结果表明:以质量分数分别为71. 1%的菱镁矿、24. 6%的硅石粉、3. 8%的轻烧镁粉和0. 5%的SiO_2微粉配料,加入w(MgSO_4)=15%的硫酸镁溶液为结合剂,经1 420℃保温3 h可以制备性能较佳的镁橄榄石质轻质球形骨料。

Preparation of spherical lightweight forsterite aggregates

This work aims at reducing the shrinkage of lightweight MgO-based refractory castables in the heating process and improving their green strength.Spherical lightweight forsterite aggregates were prepared using magnesite fine powder,natural silica powder,light-burned magnesia and silica fume as the starting materials,magnesium sulfate solution as the binder,shaping by a disc pelletizer,and calcining at 1400 ℃,1420 ℃,and 1450 ℃ for 3 h,respectively.The effects of the binder concentration,formulation and calcination temperature on the bulk density,apparent porosity and strength of the spherical aggregates were researched.The results indicate that the optimal spherical lightweight forsterite aggregates can be prepared by the formulation of 71.1 mass% magnesite,24.6 mass% silica powder,3.8 mass% light-burned magnesia and 0.5 mass% silica fume,the binder of magnesium sulfate solution (concentration of 15 mass%) and the calcination treatment at 1420 ℃ for 3 h.