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Determination of Surface Areas of Mineral Powders by Adsorption Calorimetry1

Kenneth V. Ticknor
1990 Clays and clay minerals  
Adsorption calorimetry was used to develop a method for determining the surface area of lowsurface-area materials (< 1 m2/g), which required no pretreatment of the surface, such as outgassing at elevated temperatures. The method involved flowing heptane through a small amount of sample (0.15 to 1.0 g) in the flow cell of a commercial microcalorimeter. When thermal equilibrium was reached at the powder-heptane interface, pure heptane was replaced with a heptane carrier-solution containing 0.6
more » ... n containing 0.6 volume % n-butanol (n-BuOH) as the preferential adsorbate. The integral enthalpy of preferential saturation adsorption, AH,~, of n-BuOH on the surface was found to be a function of the BET surface area of the sample. An empirical relationship between AH" and BET surface area was determined over a surface area range of about three orders of magnitude (0.095 to 81 mE/g) by performing adsorption experiments on five a-alumina standard reference powders. The technique was applied to the determination of surface areas of untreated rock and mineral powders.
doi:10.1346/ccmn.1990.0380413 fatcat:dwkdafsgavduxg7pzyxmnvz6ji