Air may be easily incorporated by vigorous mechanical stirring, with the help of surfactants, of activated geopolymer-yielding suspensions. The cellular structure is stabilized by the viscosity increase caused by curing reactions, configuring an “inorganic gel casting”. The present paper is aimed at extending this approach to mullite foams, obtained by the thermal treatment of engineered alkali activated suspensions. “Green” foams were first obtained by gel casting of a suspension for Na-geopolymer enriched with reactive γ-Al₂O₃ powders. Sodium was later extracted by ionic exchange with ammonium salts. In particular, the removal of Na⁺ ions was achieved by immersion in ammonium nitrate solution overnight, with retention of the cellular structure. Finally, the ion-exchanged foams were successfully converted into pure mullite foams by application of a firing treatment at 1300°C, for 1 hour. Preliminary results concerning the extension of the concept to mullite three-dimensional scaffolds are presented as well.

中文翻译：

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由工程碱活化悬浮液制成的高度多孔莫来石陶瓷

在表面活性剂的帮助下，活化的产生地聚合物的悬浮液通过剧烈的机械搅拌可以很容易地掺入空气。通过固化反应引起的粘度增加来稳定细胞结构，从而构成“无机凝胶浇铸”。本文旨在将这种方法扩展到莫来石泡沫塑料，该泡沫塑料是通过对工程化碱活化悬浮液进行热处理而获得的。“绿色”泡沫体首先通过悬浮的凝胶浇铸的Na-地质聚合物富集的具有反应性的γ-Al得到_2成ö ₃粉末。随后通过与铵盐的离子交换来提取钠。特别是去除Na ⁺通过将其浸入硝酸铵溶液中过夜以保持细胞结构来获得离子。最后，通过在1300℃下进行1小时的烧成处理，将离子交换泡沫成功地转化为纯莫来石泡沫。还提出了有关将该概念扩展到莫来石三维支架的初步结果。