Due to increasing interest in reducing CO2 emissions, new hydraulic binders are emerging, many of which contain significant amounts of iron and aluminum oxides. The reactivity of such binders can be activated using CaCl2. It thus appears essential to investigate mixed Al/Fe-Cl hydrates to better characterize the hydration products and hydration processes of these new hydraulic binders. AFm-Cl phases with varying proportions of Al3+ and Fe3+ trivalent cations were synthesized and characterized. Carbonation of AFm-Cl samples is unavoidable at ambient atmosphere and leads to phases with Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O general composition (samples were synthesized for x = 0, 0.17, 0.33, 0.50, 0.67, 0.83 and 1). A complete solid solution between the two Ca2Al(OH)6·Cl0.7(CO3)0.15·2H2O and Ca2Fe(OH)6·Cl0.7(CO3)0.15·2H2O endmembers was demonstrated. Two hydration states were identified with characteristic interlayer distances of about 7.8 Å and 6.8 Å for, respectively, the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O hydrate and the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15 dehydrated phase. Thermal studies indicated a similar succession of thermal events for Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O regardless of the nature of the trivalent cation; the presence of iron however decreasing the degradation temperatures. Finally, the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O phase was investigated in the presence of carbonate anions, showing a progressive exchange of chloride for carbonate within the interlayer to form Ca2Al1-xFex(OH)6·(CO3)0.5·3H2O before degrading into calcite.

中文翻译：

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AFm-Cl 系统的研究：Fe-Al 固溶体、热行为和碳化


由于人们对减少二氧化碳排放的兴趣日益浓厚，新的液压粘结剂不断涌现，其中许多含有大量的铁和铝氧化物。这种粘合剂的反应性可以使用 CaCl2 激活。因此，研究混合的 Al/Fe-Cl 水合物以更好地表征这些新型水硬性粘合剂的水化产物和水化过程似乎至关重要。合成并表征了具有不同比例的 Al3+ 和 Fe3+ 三价阳离子的 AFm-Cl 固定相。在环境气氛中，AFm-Cl 样品的碳化是不可避免的，并导致 Ca2Al1-xFex（OH）6·Cl0.7（CO3）0.15·2H2O 一般组成（样品合成为 x = 0、0.17、0.33、0.50、0.67、0.83 和 1）。两者之间的完整固溶体 Ca2Al（OH）6·Cl0.7（CO3）0.15·2H2O 和 Ca2Fe（OH）6·证明了 Cl0.7（CO3）0.15·2H2O 端元。确定了 Ca2Al1-xFex（OH）6·Cl0.7（CO3）0.15·2H2O 水合物和 Ca2Al1-xFex（OH）6·Cl0.7（CO3）0.15 脱水相。热研究表明，Ca2Al1-xFex（OH）6·Cl0.7（CO3）0.15·2H2O 与三价阳离子的性质无关;然而，铁的存在降低了降解温度。最后，得到 Ca2Al1-xFex（OH）6·在碳酸盐阴离子存在下研究了 Cl0.7（CO3）0.15·2H2O 相，显示夹层内氯离子与碳酸盐的逐渐交换形成 Ca2Al1-xFex（OH）6·（CO3）0.5·3H2O 后降解为方解石。