The strength of high water content clay stabilized by cement will be related closely with its microscopic structure. So microscopic structure of the stabilized high water content clay was observed by a scanning electron microscope and the pore diameter distribution of the stabilized part was measured by a mercury porosimeter.
As the result of the research, following were clarified.
1. The strength gain rate of the stabilized soil differed from the cement types. This difference would be made by the shapes and formation time of the reaction products.
2. The stabilized clay that was rich in soluble silica producted calcium-silicate hydrate for a long time, and this formation gained the strength of the stabilized soil.
3. There was a positive correlation between the strength of the stabilized soil and the content ratio of pores which were under 0.1 μm in diameter in the stabilized soil.

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The 2-mercaptobenzothiazole (MBT) -chalcopyrite system has been studied through adsorption and flotation tests. 2-Mercaptobenzothiazole (MBO) and 2-mercaptobenzimidazole (MBM) were also used in the test as a reference. The adsorption isotherms of MBT, MBO and MBM were determined in the wide pH range 3.0-12.0, with each collector being used alone. As a consequence, the adsorption amount shows that the MBT is largest, while MBM is smallest. The recovery of chalcopyrite in the flotation tests was as high as 80% at pH region around 4.0-10.0 when MBT was used alone. The characteristics such as meneral properties to be estimated, flotation results predicated, and changes in processing valuables evaluated are discussed on the view points of recovery-vs-time data in the flotation of chalcopyrite.

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Three coals from different localities (Datong, Wandoan and Illinois) were used in this study. Immersion time measurements were carried out to assess wettability of coal surface using 100-200 mesh coals. Flotation tests were conducted by introducing air, nitrogen and carbon dioxide gases, respectively. After sparging the gases into coal slurries, the slurries were chemically analyzed. For flotation and chemical analysis fine coals (mean particle size: about 30 pm) were used. Some of the coals were treated with 0.6 kgf/cm2 of carbon dioxide gas prior to the experiments. The collectors used were kerosene for Datong coal and heavy oil A for the other coals.
The hydrophobicity of three coals treated with carbon dioxide became slightly higher than that of untreated coals. When sparging carbon dioxide gas, the highest amounts of calcium and magnesium were dissolved from Datong and Wandoan coals and the amounts of bassanite and calcite in the coals were simultaneously decreased. By flotation with carbon dioxide, the maximum yield was obtained for the coals treated with carbon dioxide than the untreated coals, but the ash content of the froth products was high. For these froth products cleaner flotation with frother alone was carried out, and the ash content of clean coals was improved for Datong coal but not for Wandoan and Illinois coals. This was mainly caused by the difference in the liberation degree and flotation behavior of mineral matters in the coals, and the difference in the collectors used.

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