Friedel's salt
Friedel's salt is a mineral compound that forms in concrete when chloride- containing solutions penetrate . It is produced by the reaction of the chloride ions with calcium aluminates contained in the concrete and has the composition 3 CaO · Al 2 O 3 · CaCl 2 · 10 H 2 O. It is the best known and probably the most stable chloride phase in cement stone. The compound is named after its discoverer, the French mineralogist Georges Friedel .
Friedel's salt is formed in concrete by the reaction of monosulfate (3 CaO · Al 2 O 3 · CaSO 4 · 12 H 2 O) when chloride-containing solutions, for example de-icing salt solution, enter . The chloride ion displaces the sulfate ion from the salt .
In the presence of carbon dioxide , chloride is displaced from the salt to form a carbonate . Friedel's salt is not stable even in the presence of sulfate ions ; it reacts to form ettringite .
It was first made by French mineralogist and crystallographer Georges Friedel in 1897 .
Individual evidence
- ↑ a b Association of German Cement Works, p. 114. (PDF; 1.4 MB)
- ↑ a b H. Dahme, M. Setzer: Investigation of the chloride sorption taking into account the carbonation , University of Duisburg-Essen (PDF; 63 kB)
- ↑ www.annales.org
- ↑ mindat.org: Friedel's Salt: Friedel's Salt mineral information and data. , accessed July 19, 2017.