Effect of Acid Treatment for Sepiolite

Abstract

The mechanism of dissolution of Mg²⁺ from sepiolite by treating with aqueous solution of hydrogene chloride was studied. Sepiolite used was a pure one of α-type from Korea.
X-ray diffraction patterns of specimens treated with constant treating time (1hr) do not differ from non-treated powder up to 1N concentration. Above 1N, the inten-sities of diffraction peaks decrease with increasing acid concentration. X-ra diffrac-tion patterns of the specimens treated with 3N concentration from lhr to 9hrs change with a similar tendency to those treated from 3N to 1ON for 1hr and that treated with 3N concentration for 26hrs shows that this specimen is amorphous. Weight losses from 195° to 420°(W₂) and from 670° to 830°(W₄) which is caluculated by choosing 195° as a weight basis decrease with increasing degree of the acid treat-ment. It is clarified from the chemical analysis that Mg²⁺ included in the structure of sepiolite dissolves easily by the treatment with dilute acid solution.
These results show that Mg²⁺ dissolves from the structure of sepiolite by acid treatment, accompanied with this, dehydration of bounded water occurs and as a result the structure of sepiolite changes.