煅烧温度对菱镁矿尾矿制备MgO-MgAl_(2)O_(4)-Mg_(2)SiO_(4)复相多孔材料性能的影响

Effect of calcination temperature on properties of MgO-MgAl_2O_4-Mg_(2)SiO_(4) complex porous materials prepared from magnesite tailings

以菱镁矿尾矿和二次铝灰为原料,按m(菱镁矿尾矿)∶m(二次铝灰)=7∶3配料,混料、成型后分别经1200、1300、1400和1500℃煅烧,制备了MgO-MgAl_(2)O_(4)-Mg_(2)SiO_(4)试样,并研究了煅烧温度对其性能的影响。结果表明:随着煅烧温度的升高,试样的体积密度和线收缩率随之增大,常温耐压强度基本呈增大的趋势,而显气孔率相应减小;当煅烧温度从1300℃升高到1400℃时,显气孔率变化尤为明显,分析认为这与镁铝尖晶石的形成有关。在满足显气孔率超过40%的条件下,试样经1300℃煅烧后的常温耐压强度较高。因此,最佳煅烧温度为1300℃。

MgO-MgAl_2O_4-Mg_(2)SiO_(4) specimens were prepared by mixing raw materials according to m(magnesite tailings)∶m(secondary aluminum ash)=7∶3,shaping,and calcining at 1200,1300,1400 and 1500℃,respectively.The effect of the calcination temperature on the properties of the prepared specimens was studied.The results show that with the increase of the calcination temperature,the bulk density and the linear shrinkage of the specimens increase,the cold compressive strength basically increases,while the apparent porosity decreases accordingly;when the calcination temperature increases from 1300℃to 1400℃,the apparent porosity of the specimens changes significantly.This is related to the formation of magnesium aluminate spinel.Under the condition of the apparent porosity exceeding 40%,the specimens calcined at 1300℃has a higher cold compressive strength.Therefore,the optimum calcination temperature is 1300℃.