Although the clay mineralogist is bringing
some order out of chaos in the classification of clays we are faced with
rather a large number of trade names when we come to study the
literature of clay catalysts. I shall name some of the better known
ones, beginning with the kaolinitic group, The clays of this group
have not been much used in catalysis and are not cursed with strange
nomenclature. Dickite, nacrite, and halloysite are not worked
commercially, so we are left with the familiar china clays and ball
clays of commerce. These are clays with a 7 Angstrom unit basal
spacing of the lattice. The 10 Angstrom unit clays or illite group
includes attapulgite, which is the clay mineral of Florida fuller's
earth, Floridin, Florex, and Florigel, the products of Florida and
Georgia in the United States. (I should add that Florite is a bauxite
catalyst made by the same company). These clays in granulated and
powder form are the most important clay catalysts in the world.
They are not known to exist in Britain in commercial quantities;
some Russian clays seem to be similar.
The 14Angstrom clays, or montmorillo