1) On the basis of a series of chemical composition as well as of the thermal dehydration behavior of the Yamagata-bentonite, the author proved a primary substance of bentonite-itself and also figured the microstructure of it. The samples used in the present research were the following 26 sorts:
Group 1. Kaolin, Pyrophillite, Natural and artifical silica gels (5 kinds).
Group 2. Raw bentonite and its related rock (5 kinds).
Group 3. A typical good bentonite and its fractional sediments (7 kinds).
Group 4. A good bentonite and its fractional sediments (9 kinds).
A proviso: group 3 and 4, each of which contains one purified with electrolysis respectively.
2) Arguing against the already known three different conclusions or formulae of Japanese acid-clay, the author showed that the primary substances of acid-clay and of bentonite should be identical.
3) The author showed a typical composition of the Yamagata-bentonite and a standard characteristic thermal dehydration curve of bentonite-itself, and argued that the bentonite-itself is nothing but the so-called montmorillonite. The stated chemical composition is the following: H
2O SiO
2 Al
2O
3 Fe
2O
3 CaO MgO Alk. Per cent 7.83 60.71 21.58 4.03 0.88 3.05 1.97 Mol. ratio 2.05 4.76 1.00 0.12 0.07 0.36 0.10
The dehydration curve is such that it can be cut into three distinct parts, i.e., S-shaped (room temp. -150°C, corresponding to reversible moisture), striaight (150°-550°, to ad-and chemi-sorped moisture by Si
2O
3(OH)
2 layer) and hook-like shaped (550°-1000°, to structural water) part. But, in another words, the curve cnn be taken to correspond to such a pyrophillite-curve as that be cut and replaced its lower half with an equivalent half of typical silica-gel curve.
4) In the end, the author arrived at the conclusion that at least the montmorillonite from the Yamagata-bentonite should certainly be a pile of the leaf-like crystallite of pyrophillite, a pyrophillite such that the outermost layer of Si
2O
3(OH)
2 of it being highly activated on account of some (may be correspond to about 30% of Si
2O
3(OH)
2) discordance in the arrangement of atoms within the Si-lattice layer. Where, say in addition, the activated layer is highly silica-gel-like in character, hence it seems reasonable to think the X-ray diffraction spectra from the layer might be far from distinction.
The structural formula which the author induced is the following one: [Al
2(Si
4O
10)(OH)
2)]⋅
xSiO
2⋅Aq. or [Al
2(Si
4O
10)(OH)
2]⋅Aq.
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