Experimental study of iron-bentonite interactions; Analytical results of experimental sample conducted over a period of 10 years at room temperature

Sasamoto, Hiroshi   ; Suyama, Tadahiro

For the better understanding of phenomena caused by iron-bentonite(smectite) interactions, experimental samples conducted over a period of 10 years at room temperature with mixture of distilled water, iron and bentonite (an iron/bentonite mass ratio of 1) were analyzed to identify the alteration behavior of smectite. Major results are summarized below. (1)The color of bentonite changed to grey-green or grey-black with interaction of iron material. The pH and Eh values of solution after the experiment also changed to more alkaline and reducing (pH around 11.5, Eh -284 mV vs. SHE) comparing with the initial condition. (2)Results of X-ray diffraction (XRD) analysis, Scanning Electron Microphotograph (SEM) and Transmission Electron Microphotograph (TEM) observation suggested that no alteration was occurred and the initial Na-type smectite would be remained.