含铝铁酸钙CFA的生成行为

 含铝铁酸钙(CFA)是生成复合铁酸钙(SFCA)的一种重要前驱化合物,为了揭示CFA的生成路径和反应机理,采用压块-焙烧法并结合XRD和SEM-EDS等检测方法,研究不同烧结温度下CaO-Al₂O₃-Fe₂O₃三元系中的矿相生成和元素迁移规律。CFA生成行为研究结果表明,首先在低温条件下(＜750 ℃)生成铁酸二钙(C₂F),升温至800~950 ℃时C₂F与Fe₂O₃反应生成铁酸一钙(CF),然后在900~950 ℃的烧结温度区间内Al₂O₃与CaO反应生成铝酸半钙(CA₂),并在CF-CA₂-Fe₂O₃三元界面处开始生成CFA,最终对CA₂形成了具有针状结构的CFA产物包裹层。

Formation behavior of calcium ferrite containing aluminum

Calcium ferrite containing aluminum (CFA) is an important precursor compounds in the formation of silico-ferrite of calcium and aluminum (SFCA). In order to reveal the formation behavior and reaction mechanism of CFA,the samples of sinter were prepared by adopting the method of briquetting-sintering,then XRD and SEM-EDS were used to investigate the mineral formation and element migration in the CaO-Al₂O₃-Fe₂O₃system at different sintering temperatures. The results show that CFA was generated through three-stage reaction. Firstly,dicalcium ferrite (C₂F) was formed at low sintering temperature (<750 ℃),and then with the sintering temperature rising to 800-950 ℃,C₂F reacts with Fe₂O₃ to generate calcium ferrite (CF). Secondly,Al₂O₃ reacts with CaO to generate semi-calcium aluminate (CA₂) after the sintering temperature rises to 900-950 ℃,and then CFA was generated at the ternary interface of CF-CA₂-Fe₂O₃. Finally,the acicular CFA product layer was formed around CA₂.