| The cation exchange capacities of three kaolinitic clays of Indian origin were
determined in connection with the preparation of homo ionic forms of the clays for studies
on their thermal behaviour. Two inflexion points in the potentiometric titration of
H-form ofTravancore china clay was noticed, while the other two H-forms of Rajmahal
china clay and Ball clay exhibited only one inflexion point. Titration of H-forms of
these three clays in methanol-water mixture (methanol+ I% water) also showed the
same type of behaviour except that the inflexions occurred at lower amounts of alkali
than in water. On the basis of the results obtained in this study and evidence available
on the subject, the author considers that the two inflexion points in some of the H+kaolinites
may be due to H+ and AI+++ in the exchange complex which, at appropriate
concentrations give rise to the individual peaks. |
