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Volume 5 (1966)
- Issue 3-4 Pages 49-
- Issue 1-2 Pages 2-
Volume 5, Issue 1-2
Displaying 1-3 of 3 articles from this issue
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Takeshi MATSUI1966 Volume 5 Issue 1-2 Pages 2-13
Published: April 01, 1966
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSThe clay mineralogical composition of soils could not be regarded as products of a single genetic process, but be done as those of any composite processes. It may be reasonable to induce from reliable examples of the clay mineralogical identification of Japanese soils that such composite genetical processes are able to be resolved into two different cycles of processes, that is, the geological cycle and the bio-hydrological cycle.
The geological cycle means a series of skelton forming processes through the weathering, denudation, transportation, deposition and diagenesis during the geological time-scale. These processes develop evolutionally as shown in Fig. 2. The essential clay minerals and their elemental lattice structures in soils are nothing else but those which have been formed and/or inherited through this cycle of processes, in other words, under the influences of Dokuchaev's time factor of soil formation.
The bio-hydrological cycle means a series of modificatory processes to the skeletons formed through the preceding cycle. It mainly consists of such processes as the partial collapse, ion-exchange in a broad sense and the effect of organic matter. The ion-exchange phenomena include the release of fixed cation such as K+ in illite, hydration and dehydration, as well as the formation of complex with hydroxyl-Al, organic compounds, etc., at the interlayer spaces of the three layered lattice minerals. Consequently, these minerals are turned into each other, passing through the transitional mixed-layered phases. It should be stressed that such interchange phenomena of three layered lattice minerals could serve as the most useful indicators to the recent pedogenesis, on account of their high sensibility to the change of environment.View full abstractDownload PDF (1138K) -
Hajime TANAKA1966 Volume 5 Issue 1-2 Pages 14-24
Published: April 01, 1966
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSJapanese colloidal earth is a weathering product of volcanic ashes whose mineralogical main component is allophane, and chemically it is an amorphdous clay rich in almina content.
Many studies have hitherto been carried out on the adsorption capcity of this earth, and it has already been utilized as an industrial material for adsorbent and by hygroscopic substances.
In this report, to study the surface properties of this clay, the alumina gel, on the surface and in the interior of the clay has been treated with sulphuric acids of various concentrations and the changes of the conditions of the surface have been examined by the following methods.
(1) Measurement of specific surface area (by BET method).
(2) Measurement of pore distribution (by Kelvin method).
(3) Measurement of the heat of wetting.
As a result, the values of specific surface area were found to be 274m2/g, 172m2/g, 308m2/g, and 334m2/g for purified Japanese colloidal earth, 3%acid treated earth, 20% acid treated earth, and 35% acid treated earth, respectively. It was inferred that there exists on the surface of Japanese colloidal earth an alumina gel which increases the adsorptive surface area. The measured values of the heat of wetting showed a similar tendency and it was concluded from these results that Japanese colloidal earth consists of an alumina gel and a silica gel, which are on the surface and have high adsorption capacity, and a nucleus of silica-alumina gel.View full abstractDownload PDF (752K) -
Shigekazu UDAGAWA1966 Volume 5 Issue 1-2 Pages 25-37
Published: April 01, 1966
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSMullite formed in the fired kaolinite was studied by X-ray powder method and was discussed from the structural viewpoints. The formation temperature of mullite is greatly influenced with the time of heat treatment. For the heat treatment of 100 hrs, mullite develops at temperature as low as 900°C. Accurate measurements of the lattice constant of mullites formed at temperatures beween 1100°C and 1480°C were made by slow scanning with silicon as an internal standard. The lattice parameter c decreases very slightly with the increase of firing temperature, and the parameter b increases up to 1200°C and finally obtains almost constant value at or above 1200°C. On the other hand, the parameter a decreases with the increase of temperature, and the largest change is observed in the parameter a among the three parameters a, b and c. These progressive changes of the lattice constant were discussed on the basis of the mechanism of kaolinite-mullite reaction series proposed by Brindley et al. The axial ratio (a/b) of mullites formed from kaolinite increases successively with the decrease of firing temperature. This phenomenon indicates that mullites formed at lower temperatures approach more closely to tetragonal symmetry as compares with mullites formed at higher temperatures. However, in the fired kaolinite, there was not such tetragonal mullite as reported to be formed from coprecipitated Al2O3-SiO2 gels and natural allophanes. It was confirmed that the alumino-silicate formed in the fired kaolinites is not sillimanite but mullite by using the relationship between unit cell volume and cell edge c established by Agrell and Smith.View full abstractDownload PDF (925K)
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