(东北大学材料与冶金学院，沈阳 110819)
摘 要: 采用石灰烧结法处理低品位含铝资源提取氧化铝，研究在n(CaO)/n(Al2O3)为1、烧结温度为1350℃条件下，氧化铝以α-氧化铝、莫来石和钙铝黄长石赋存形式的物料与石灰烧结后熟料矿相、晶体稳定性和在碳酸钠溶液中氧化铝浸出性能。结果表明：以α-氧化铝为原料时，Ca12Al14O33优先生成，并进一步结合Al2O3转化成CaAl2O4。熟料矿相为CaAl2O4、Ca12Al14O33、γ-Ca2SiO4和β-Ca2SiO4，CaAl2O4和Ca12Al14O33晶胞体积较大，在碳酸钠溶液中，晶体稳定性较差，氧化铝的浸出率为91.60%；以莫来石或钙铝黄长石为原料时，Ca2+逐步取代晶格中Si4+位置并与Al3+结合生成铝酸钙，分离出的Si4+与CaO生成Ca2SiO4，而Ca12Al14O33或Ca3Al2O6的生成造成CaO不足，导致部分Ca2Al2SiO7不能被转化，熟料矿相为CaAl2O4、Ca12Al14O33、γ-Ca2SiO4、β-Ca2SiO4和Ca2Al2SiO7，CaAl2O4和Ca12Al14O33晶胞体积较小，与碳酸钠反应时活性稍差，氧化铝的浸出率低于80%。
关键字: CaAl2O4；Ca12Al14O33；Ca2Al2SiO7；氧化铝；熟料；晶体稳定性；浸出性能
（School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China）
Abstract:The mineral phases, crystal stability and alumina leaching property in sodium carbonate of sintered clinker were studied using α-alumina, mullite and gehlenite as alumina-existing materials when the molar ratio of CaO to Al2O3 is 1 at 1350℃ by extracting alumina from the low-grade alumina containing resources by the lime sintering method. The results show that Ca12Al14O33 generates firstly, then it reacts with Al2O3 to form CaAl2O4. The sintered clinker is comprised of CaAl2O4, Ca12Al14O33, γ-Ca2SiO4 and β-Ca2SiO4 when using α-alumina as material. The unit cell volume of CaAl2O4 and Ca12Al14O33are larger with poor crystal stability in sodium carbonate solution, and the alumina leaching rate is 91.60%. Ca2+ replaces the lattice position of Si4+ and reacts with Al3+ to form calcium aluminates, and then, the separated Si4+ reacts with CaO to form calcium silicates. The formation of Ca12Al14O33 or Ca3Al2O6 causes the shortage of CaO, resulting in that Ca2Al2SiO7can not be transformed completely. The mineral phases are CaAl2O4, Ca12Al14O33, γ-Ca2SiO4, β-Ca2SiO4 and Ca2Al2SiO7 when using mullite or gehlenite as alumina-containing materials. The unit cell volumes of CaAl2O4 and Ca12Al14O33 are smaller with good crystal stability in sodium carbonate solution, and the alumina leaching rate is lower than 80%.
Key words: CaAl2O4; Ca12Al14O33; Ca2Al2SiO7; Al2O3; sintered clinker; crystal stability; leaching property
