高铝熔渣物相析出演变规律研究

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.

Study on Evolution of Phase Precipitation in High Aluminum Slags

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.