高铝熔渣物相析出演变规律研究

摘要 以改善高铝渣浸出性能为目标，采用DSC实验和SEM-EDS检测方法，研究了高铝渣控温冷却过程中物相析出规律，考察了降温速率、n(CaO)/n(Al2O3)和MgO含量对铝酸钙渣物相析出演变规律的影响.结果表明:当降温速率加快时，熔渣凝固过程趋于更大程度的偏析，C2S相变愈不充分，粒度粗化，劣化了自粉行为和浸出条件;随着调高渣中n(CaO)/n(Al2O3)，C12A7的析出温度升高，物相析出活性按照CA→C12A7→C3A逐渐增强;当渣中含有MgO时，物相中出现C2MS2，不利于C2S物相转变，更为重要的是MgO富集在含铝物相中形成Q相，显著恶化氧化铝浸出率和收得率.
Abstract：To improve the leaching performance of high alumina slags， DSC and SEM-EDS analyses were employed to study the phase precipitation behaviors of high alumina slags during solidification with controlled cooling rates. The effects of cooling rate，n(CaO)/n(Al2O3) and MgO content on the evolution of phase precipitation were discussed. The results show that when the cooling rate increases， the solidification process tends to have severer segregation， the C2S phase transformation becomes more insufficient and the particle turns obviously coarse， so that the self-pulverization and leaching performance deteriorate. With the increase of n(CaO)/n(Al2O3) in the slags， the precipitation temperature of C12A7 rises and the activities of precipitation phases increase gradually as CA→C12A7→C3A. When the slags contains MgO， the phase of C2MS2 appears， which is detrimental to the phase transition of C2S. More importantly， MgO enriching in aluminum-bearing phase leads to the formation of Q phase， which deteriorates greatly the leaching and recovery rate of alumina.