Abstract
Sepiolite of Spanish origin contained both calcite and dolomite which were detected by X-ray diffraction, infrared spectroscopy and thermal gravimetry-diffrential thermal analysis. These impurities were eliminated by treating with the dilute hydrochloric acid aqueous solution (0.59mol/1) without the decomposition of sepiolite itself. The specific surface area increased by the elimination of the impurity with dilute hydrochloric acid.
