Faujasite

• Faujasite -Na
• Faujasite -Ca
• Faujasite -Mg

As the three faujasite quite rare silicate mineral faujasite -Na, faujasite -Ca -Mg and faujasite are referred from the family of zeolites in summary. They have in common is the simplified chemical formula (Na, Ca0, 5, Mg0, 5, K ) x ( AlxSi12 - XO24 ) ‣ 16H2O, where the tail part is the predominant cation referred to ( Na for sodium, Ca for calcium, Mg for magnesium). The value of x in the above formula will usually vary from 3.2 to 3.8. By substituting potassium and strontium something may be included. Faujasite is crystallized in the cubic crystal system and occurs as small, usually colorless or white, well -formed crystals in an octahedron. Industrially synthesized faujasites are zeolite X and zeolite Y.

Etymology and history

Faujasite was described in 1842 by Augustin Alexis Damour first Sasbach the Emperor chair and was named in honor of the French geologists and volcanologists Barthelemy Faujas de Saint- Fond. The structure of faujasite was first reported in 1956.

Education and Locations

Faujasite, like many other zeolites also a typical product of hydrothermal conversion of basaltic volcanic rocks. Through the circulation of hot solutions the rock is gradually altered after the eruption, in Druze and fissures entrained solution freight in the precipitation. At the classical site of the emperor chair grows faujasite in free-standing crystals in druses in cavities Limburgit lava flows.

Species

Since the revision of the Zeolithnomenklatur by the International Mineralogical Association in 1998, three distinct mineral species can be distinguished, faujasite -Na, faujasite -Ca -Mg and faujasite. The type localities for faujasite -Na and Mg are still the quarries at Sasbach, for faujasite -Ca a drill core from Haselborn at Ilbeshausen / Vogelsberg is specified.

Crystal structure

The structure of faujasite is identical to that of the synthetic zeolite Y. The base member of the Faujasitgerüsts sodalite cages are connected to each other via hexagonal prisms. The pores are perpendicular to each other. The pore which is formed by a ring with 12 units, having a diameter of 7.4 Å is relatively large. The interior has a diameter of 12 Å and is surrounded by 10 sodalite cages. The unit cell is cubic with a length of 24.7 Å. Faujasite materials are characterized by a large surface area and a narrow pore size distribution in the range of 0.9 to 1.2 nm, and by a high thermal resistance.

Use

Unlike its synthetic counterpart zeolite Y, which is produced in large amounts of industrial, natural faujasite has no practical significance because of its rarity.