Zonous Kaolinite bearing day, an Investigation on itsphysical-Chemical properties and Industrial applications.

Zonous Kaol ini te bea ring c lay de pos it is made by hydrothermal alteration of volcanic rocks mainaly of andesite ami dacite. Kao linit e , quartz and calci te are the main mineral co mposi tions. As quart z in the volcanic roc ks is cryptocrys talline, it is too dificult to seperat e it from kaol inite. The phys ical properties and chemica l composition of Zonous ceramic grade kaolinite bearing clay are directly related to its nature and geOlogical formation. The percenl age of SiOz in Zonous clay is highe r but the amount of Alz0 3 is lower th an Diamond kaolinte. For th is re ason the ceramic products of zonous cl ays have lower resistance to thermal shocks and modul e of rupture. High roughness, low plsticity and possible greater deformation during firing (Production of Ceramics) are o ther reasons for lim it ing the use of Zonous ceramic grade clays. The percentage of calcium oxide (CaO) in Zo no us clay is higer in co mparison wi th Diamond Kaolin hut pot asium oxide (KzO) whi ch plays as a nux in ceramic products is lower in zonous. The high pereentage of CaO which has a high melting point can raise the viscosity as a result lead to Crack in ceramic products. Fin ally with these colour pro pe rties, the Zonous ceramic grade kaolinite bearing clays , can be used as a fill er in pape r, paint and rubber industries.