Rapid Determination of Surface Areas of Mineral Powders Using Adsorption Calorimetry1
P. P. S. Saluja, D. W. Oscarson, H. G. Miller, J. C. Leblanc, 1985. "Rapid Determination of Surface Areas of Mineral Powders Using Adsorption Calorimetry", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
Download citation file:
Adsorption-desorption calorimetry (ADCAL) was used to determine surface areas of 10 mineral powders, including 4 clay minerals, and carbon black. The method involved flowing a carrier liquid (pure heptane) through a small amount (< 0.4 g) of sample in the sorption cell of a commercial microcalorimeter. When thermal equilibrium was established, pure heptane was replaced by a heptane solution containing n-butanol (n-BuOH) as an adsorbate. The maximum integral enthalpy of adsorption of n-BuOH on the surface was assumed to be proportional to the surface area of the sample. The empirical proportionality constant was determined using a reference sample (SiO2 or kaolinite (KGa-l)) of known BET surface area.
Well-characterized powders of TiO2 (anatase) and very poorly crystalline SiO2, ZnO, and carbon black of known BET specific surface areas ranging from 24.3 to 0.64 m2/g were used as standards to determine the internal consistency of the method. A precision of ±4% was obtained; the specific surface areas determined by ADCAL were within ± 5% of the BET values. The method was applied to three nonex-panding clay minerals (a well crystallized (KGa-l) and a poorly crystallized (KGa-2) kaolinite and pal-ygorskite (PF1–1)), one expanding clay mineral (Wyoming montmorillonite (SWy-1)), and two minerals with low specific surface areas ( < 0.5 m2/g), olivine and microcline. Except for the expanding clay and the very low surface area microcline, the specific surface areas determined by ADCAL were within ± 4% of the BET values. The advantages of this method are that it is fast ( < 2 hr/sample), only a small amount of sample is required ( < 0.4 g), and it can be conducted at room temperature.
Figures & Tables
Proceedings of the International Clay Conference Denver, 1985
The papers included in this proceedings volume are representative of the research on clays being conducted in all parts of the world at the time of publication. Many of the subjects treated are controversial, and although some ideas expressed may not necessarily represent the views of the editors, the referees, or the publisher, they deserve to be brought to the attention of the international clay community.