|
Friedel's salt is an anion exchanger mineral belonging to the family of the layered double hydroxides (LDHs). It has affinity for anions as chloride and iodide and is capable to retain them to a certain extent in its crystallographical structure. ==Composition== Friedel's salt general formula is: :Ca2Al(OH)6(Cl, OH) · 2 H2O. In the cement chemist notation, considering that :2 OH− ↔ O2− + H2O, and doubling all the stoichiometry, it can also be written as follows: :3CaO·Al2O3·CaCl2 · 10 H2O Friedel's salt can also be considered as an AFm phase in which chloride ions have replaced sulfate ions and is formed in cements initially rich in tri-calcium aluminate (C3A). :2 Cl− + 3CaO·Al2O3·CaSO4 · 10 H2O → 3CaO·Al2O3·CaCl2 · 10 H2O + SO42− It plays a main role in the retention of chloride anions in cement and concrete. However, Friedel's salt remains a poorly understood phase in the CaO-Al2O3-CaCl2-H2O system, and is critical for the stability of salt-saturated Portland cement-based grouts. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Friedel's salt」の詳細全文を読む スポンサード リンク
|