MgO对12CaO·7Al_2O_3晶体结构及其氧化铝浸出性能的影响

Effect of MgO on the Crystal Structure and Alumina Leaching Property of 12CaO·7Al_2O_3

应用XRD、EDS等手段,研究了MgO对12CaO.7Al2O3(C12A7)晶体结构及其氧化铝浸出性能的影响。结果表明:在掺杂量小于2%的情况下,MgO会固溶入C12A7晶体中,但不会影响该体系的物相组成。MgO在C12A7晶体中的饱和固溶量不超过1%,其余的MgO以方镁石形式单独析出。固溶机理为离子半径相对较大的Mg2+取代了晶胞中离子半径相对较小的Al3+,引起了晶胞的扩胀,晶面距d值的变大。当MgO含量小于2%时,随着MgO掺杂量的增大,C12A7的氧化铝浸出率出现了小幅度的下降,但均在90%以上,对浸出性能影响不大。

The effect of MgO on the crystal structure and alumina leaching property of 12CaO · 7Al2O3 （C12A7）is studied by XRD and EDS. The results show that if the adding amount of MgO is below 2% , MgO can be dissolved in C12A7 in the form of solid solution, but it will not influence the phase composition of the system. The saturated solid solution amount of MgO in C12A7 is below 1% , and the other MgO is precipitated in the form of periclase singly. The mechanism of solid solution is that Mg^2＋ whose ionic radius is bigger replaces Al^3＋ whose ionic radius is smaller and this causes the expansion of crystal cellular and increase of interplanar spacing d value. When the content of MgO is below 2%, the alumina leaching rate of C12A7 decreases a little with the increase of adding amount of MgO, but it has little effect on the leaching property for the leaching rates are all above 90%.