Abstract

Samples of clays suspected to be bentonite were obtained from Ashaka, Tongo and Potiskum, Nigeria and a commercial bentonite obtained from Kofar Ruwa market, Kano State were investigated for some of their physicochemical properties. These determinations were carried out on the wet beneficiated clay samples. The results were compared with results obtained from other studies on bentonite clays. The moisture content, pH, density and swelling power were between 4 to 7%, 7.78 to 9.89, 1.21 to 1.82 g/cm3 and 10 to 13 ml/2 g, respectively. Cation exchange capacity (CEC) was between 61 and 72 meq/100 g; Ca2+ and Na+ were the main exchangeable cations (20.87 to 39.752 and 26.55 to 33.18 meq/100 g, respectively) with calcium ion as the dominant. The chemical composition of the clays indicates high percentages of CaO 1.155 to 14.850 wt%. The silica and alumina contents of the samples were in the ranges of 40.705 to 49.873 wt% and 14.856 to 16.744 wt%, respectively. Fe2O3 content of the samples was in the range of 4.802 to 5.606 wt%. The results of the physicochemical analysis of the samples when compared with the results from other studies on bentonite may suggest that the samples are bentonite clays.

Key words: Bentonite, montmorillonite, smectite, cation exchange capacity (CEC), swelling power, chemical composition.