低温水熱反応による黒曜石からの粘土鉱物の生成 (その4) : 硝酸溶液中での粘土鉱物の生成

概要

論文の詳細を見る
Experimental syntheses of clay minerals from obsidian were performed in 0.01N and 0.001N HNO_3 solutions at 150℃ and 200℃ for 1 to 60 days. Formation and transformation processes of the clay minerals during the reactions were examined by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, infrared absorption spectroscopy, and X-ray photoelectron spectroscopy. At 200℃ reaction, a small amount of boehmite was formed at the early stage, and spherical kaolinite appeared and grew successively as reaction proceeded in 0.01N HNO_3 solution. On the other hand, a flaky smectite was mainly formed in 0.001N HNO_3 solution. At 150℃ reaction, boehmite, allophane, spherical halloysite, and platy kaolinite were produced in both 0.01N and 0.001N HNO_3 solutions. Based on a stability diagram for the system of Na_2O-Al_2O_3-SiO_2-H_2O, it was found that the spherical and platy kaolinites and smectite were formed as a stable phase, whereas allophane and halloysite appeared as a metastable phase. In this paper, we discussed the following problems: 1) formation conditions of kaolinite and smectite, 2) formation conditions of spherical and platy kaolinites, and 3) formation conditions of kaolinite and halloysite.
日本粘土学会の論文
1995-03-28