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Ettringite is the most common and prominent member of the AFt group (X in this case denoting sulfate), and often simply called Alumina Ferrite tri-sulfate (AFt). AFm: abbreviation for "alumina, ferric oxide, mono-substituted" or (Al 2 O 3 − Fe 2 O 3 − mono). It represents another group of calcium aluminate hydrates with general formula [Ca ...
Alum treatment begins with the addition of aluminum sulfate salt to a water body. Once added, the salt dissolves and dissociates, introducing Al(III) ions to the water. The aluminum ions participate in a series of hydrolysis reactions, forming different aluminum species across pH ranges. As more aluminum sulfate is added, water pH decreases.
Chondrite meteorite with calcium–aluminium-rich inclusions seen as white specks. A calcium–aluminium-rich inclusion or Ca–Al-rich inclusion (CAI) is a submillimeter- to centimeter-sized light-colored calcium- and aluminium-rich inclusion found in carbonaceous chondrite meteorites.
The following inclusion types can also be found in aluminium alloys: alumina needles (Al 2 O 3), nitrides (AlN), iron oxides (FeO), manganese oxides (MnO), fluorides (Na 3 AlF 6, NaF, CaF 2, …), aluminium borides (AlB 2, AlB 12), borocarbides (Al 4 C 4 B). Bone ash (Ca 3 (PO 4) 2) sometimes added to patch cracks in the trough can be found as ...
The main constituent, and also the most reactive phase, of calcium aluminate cements is the monocalcium aluminate (CaAl 2 O 4 = CaO · Al 2 O 3, also written as CA in the cement chemist notation). It usually contains other calcium aluminates as well as a number of less reactive phases deriving from impurities in the raw materials.
The necessary additional calcium is provided by the calcium hydroxide and calcium silicate hydrate in the cement paste; The effect of these changes is an overall loss of concrete strength. The above effects are typical of attack by solutions of sodium sulfate or potassium sulfate. Solutions containing magnesium sulfate are generally more ...
Calcium aluminates phase diagram Crystal structure of dodecacalcium hepta-aluminate, 12CaO·7Al 2 O 3 (C 12 A 7). [1] Calcium aluminates are a range of materials [2] obtained by heating calcium oxide and aluminium oxide together at high temperatures. They are encountered in the manufacture of refractories and cements.
Calcium aluminoferrite (Ca 2 (Al,Fe) 2 O 5) is a dark brown crystalline phase commonly found in cements. In the cement industry it is termed tetra-calcium aluminoferrite or ferrite. In cement chemist notation (CCN), it is abbreviated as C 4 AF meaning 4CaO· Al 2 O 3 · Fe 2 O 3 in the oxide notation. It also exists in nature as the rare ...