轻烧菱镁石粉对低硅含镁球团矿孔隙和强度的影响

本文研究了向两种铁精粉和膨润土中添加不同质量分数的轻烧菱镁石粉对球团矿孔隙、强度和物相的影响.研究结果表明:轻烧菱镁石粉平均粒径较小,结晶水和MgCO₃质量分数高(分别为3.94%和8.59%),对球团矿性能影响较大.轻烧菱镁石添加量由1.5%增加到3.5%时,焙烧球孔隙率由11.12%升高到15.95%,大气孔(孔径大于5μm)的体积分数由8.94%升高到36.61%,且分布均匀化程度降低;同时,球团矿变得“疏松”,固结指数由60.45%降低到43.00%,预热球和焙烧球强度分别降低79.3N和247.6N;球团矿中的铁酸镁和磁铁矿相质量分数增加,赤铁矿相再结晶减弱.适量增加球团矿中轻烧菱镁石粉的配比,可使球团矿孔隙率、大气孔和高熔点物相增多,进而提高球团矿的还原和软熔滴落等性能.

Effect of light burnt magnesite powder on pore and strength of low silicon magnesium pellet

Effect of different mass fractions of light burnt magnesite powder on the pores,strength and phase of pellets Ls investigated in this paper by adding magnesite powder into two kinds of iron fine powder and bentonite.The results indicate that the average particle size of light burnt magnesite powder is small but the crystal water and MgC0₃ content(3.94% and 8.59%)is high,which influences the performance of pellets.When the addition of light burnt magnesite increases from 1.5% to 3.5%,the porosity of the roasted pellets increases from 11.12% to 15.95%.Meanwhile,the proportion of large pores(diameter is above 5μm)increases from 8.94% to 36.61%,and the homogenization degree of larger pores distribution reduces.Moreover,the pellets become loose.The consolidation index reduces from 60.45% to 43.00%,and the strength of preheated pellets and roasted pellets decrease 79.3 N and 247.6 N respectively.In addition,the mass fraction of magnesium ferrite and magnetite phase in the pellets increases,and the recrystallizarion of the hematite phase becomes weakened.The increased proportion of activated light-burned magnesite can increase the internal porosity,large pores and liigh melting point phases of the pellets,thus improving the metallurgical properties of the pellets,and the metallurgical properties of the pellets such as the reduction and the softening dropping property of the burden can be improved.