| Clays, both china and plastic, dominate the ultimate performance of
the whiteware. industry. The rheology of clay-water systems/pastes
is governed by the finer fractions or the colloidal particles. The evaluation
of the clay fineness using Stokes Law is time consuming for the
whiteware manufacturer, especially in the small-scale sector in this
country, who desires quick information which need not be very
accurate. Clay minerals have the characteristics of absorbing certain
ions and retaining them in an exchangeable state, i.e. these ions are
exchangeable for other ions by treatment in an aqueous solution.
Worrall developed a method using the above information. The method
is inexpensive, quick and accurate enough for practical purposes.
The method has been used to determine the specific surface areas of
quite a number of clays used in this country in the whiteware Industry.
To ascertain the efficacy of the method, clays douched with sulphuric
and phosphoric acids were evaluated and results have been discussed. |
