Hydroxy-Chromium Smectite

C. Volzone, A. M. Cesio, R. M. Torres Sánchez and E. Pereira
Centro de Tecnología de Recursos Minerales y Cerámica (CETMIC) Cno. Centenario y 506, CC49 (1897), M. B. Gonnet, Argentina

Abstract: Hydroxy-chromium solutions were prepared from chromium nitrate solutions by adding NaOH with OH/Cr = 2.

The solutions were treated at 20°C and 60°C. The hydrolysis times were from 1 to 100 days. Polymeric species in hydrolyzed chromium solutions were followed by visible absorption spectra within the range 325–800 nm and by pH measurement. OH-Cr-smectite with high d(001) spacing (2.07 nm) was obtained when hydroxy-chromium solution was prepared at 60°C and with 1-day hydrolysis. When this sample was heated up to 350°C the basal spacing collapsed at 1.8 nm.

The samples were characterized by X-ray diffraction and N2 adsorption-desorption isotherms.

Key Words: Cross-linked smectites • Pillared smectites • Polymeric Cr species

Clays and Clay Minerals; December 1993 v. 41; no. 6; p. 702-706; DOI: 10.1346/CCMN.1993.0410608
© 1993, The Clay Minerals Society
Clay Minerals Society (www.clays.org)