(東北大學材料與冶金學院，沈陽 110819)
摘 要: 采用石灰燒結法處理低品位含鋁資源提取氧化鋁，研究在n(CaO)/n(Al2O3)為1、燒結溫度為1350℃條件下，氧化鋁以α-氧化鋁、莫來石和鈣鋁黃長石賦存形式的物料與石灰燒結后熟料礦相、晶體穩(wěn)定性和在碳酸鈉溶液中氧化鋁浸出性能。結果表明：以α-氧化鋁為原料時，Ca12Al14O33優(yōu)先生成，并進一步結合Al2O3轉化成CaAl2O4。熟料礦相為CaAl2O4、Ca12Al14O33、γ-Ca2SiO4和β-Ca2SiO4，CaAl2O4和Ca12Al14O33晶胞體積較大，在碳酸鈉溶液中，晶體穩(wěn)定性較差，氧化鋁的浸出率為91.60%；以莫來石或鈣鋁黃長石為原料時，Ca2+逐步取代晶格中Si4+位置并與Al3+結合生成鋁酸鈣，分離出的Si4+與CaO生成Ca2SiO4，而Ca12Al14O33或Ca3Al2O6的生成造成CaO不足，導致部分Ca2Al2SiO7不能被轉化，熟料礦相為CaAl2O4、Ca12Al14O33、γ-Ca2SiO4、β-Ca2SiO4和Ca2Al2SiO7，CaAl2O4和Ca12Al14O33晶胞體積較小，與碳酸鈉反應時活性稍差，氧化鋁的浸出率低于80%。
關鍵字: CaAl2O4；Ca12Al14O33；Ca2Al2SiO7；氧化鋁；熟料；晶體穩(wěn)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
