| Montmorillonite is a slice-layer aluminum silicate. Since it was discovered in the 19th century, few attention has been paid on the kinetics of acid-dissolution of montmorillonite.This article investigated the effect of the important factors on the montmorillonite's cations acid-dissolution from experiments, and kinetics of acid-dissolution of montmorillonite had been studied. In the meanwhile the influences of hydrochloric acid-dissolution on the structure of montmorillonite were investigated and a better understanding was obtained on aqueous interaction between montmorillonite and acid.The leaching rate of Al2 O3 from montmorillonite was studied and the leaching kinetics of Al2 O3 can be represented by Flat plate-controlled by internal diffusion model and the relation between leaching rate (x) and reaction time (t) can be represented as (1-X)2 =-kt. The apparent activation energy for Al2 O3 leaching is about 24.3 kJ·mol-1.The surface area of acid-dissolved products increased to 144m2/g, then decreased. Few macropores had been found in the whole process. H+ metathesising the interbedded cations and octahedral cations caused the increase of micropore surface area but intensive acid-dissolution can destroy the crystal which will decrease the micropore surface area. Mesopores were piled by the montmorillonite slices and acid-dissolution will turn their slot shape to wedge shape. The rupture and separation of montmorillonite slices increase the mesopore surface area.
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