Dehydration of the washed potassium acetate complex of halloysite

TLDR: Wiewiora and Brindley as mentioned in this paper investigated the relationship between the different hydration states of halloysite-water complexes which were formed by washing various intercalation complexes of the mineral and compared with the drying behavior of naturally hydrated haUoysite.

Abstract: INTRODUCTION MANY alkali ynetal salts of short chain fatty acids have a strong affinity towards the formation of interlayer complexes with kaolin minerals (Weiss et al., 1963). The complexes of kaolin minerals with potassium acetate, KOAc, in particular have been the subject of much investigation: e.g., Wada (1959, 1961, 1965); Deeds et al. ( 1966); Wiewiora and Brindley (1969). One of the observations made in these studies is that the removal of intercalated KOAc by washing results in different products for the different kaolin minerals. Halloysites have the spacing of the fully hydrated form (10.1 A) restored when intercalated KOAc is removed in this way, regardless of whether they had been intercalated with the salt while in this form (Wada, 1961). Nacrite also forms a water complex as a result of the washing of its KOAc complex (Wada, 1965; Deeds et al., 1966). The nacrite hydrate formed in this way has a basal spacing of 8.4 A. Kaolinite and dickite do not form water complexes following intercalation with KOAc and the subsequent removal of the salt by washing, although it has been observed that the original structural order of kaolinite may not be preserved by these treatments (Wiewiora and Brindley, 1969). This report concerns a part of an investigation of the relationship between the different hydration states of halloysite (Churchman et al., 1972). The behavior on drying of halloysite-water complexes which were formed by washing various intercalation complexes of the mineral were compared with the drying behavior of naturally hydrated haUoysite.