The Swelling Properties of Bentonites

A study on the swelling properties of bentonites produced in Japan was carried out and the following conclusions were obtained:(1) When bentonite was mixed with pure water, there was a difference in the swelling between bentonite "A" (produced in Yamagata-ken) and bentonite "B" (produced in Gunma-ken).(2) The bentonite having higher swelling ability (A) took more time to swell completely than the bentonite having lower swelling ability (B).(3) Effect of NaCl: In NaCl solution the swelling was reduced substantially. The reduction of swelling depends on the concentration of NaCl and also on the kind of bentonite.(4) Effect of surfactant: Bentonite A was not affected by all kinds of surfactants, but bentonite B was affected by the anionic surfactant and its swelling ability was increased about 20%.(5) Effect of CMC: The swelling property was not affected by CMC.