Abstract
The yellowish〜reddish brown residual soils are widely distributed in S. Korea. The residual soils have been widely used for the various applications. In the present study, the mineral and chemical compositions and other properties of some representative residual soils were investigated and compared according to parent rock type. Various applications of residual soils in Korea and the basic ideas of each application were introduced. The mineral and major element compositions of residual soils were different according to parent rock type, but the difference in the residual soils isn't significant compared with the difference in the parent rocks. Residual soils contain varying amounts of clay minerals such as kaolinite, illite and micas/vermiculite. The color and density as well as mineral and chemical compositions vary with particle size. The color and density become more reddish and higher, respectively, with decreasing particle size because of increasing amount of iron oxide. The amounts of clay minerals are increasing with decreasing particle size. These results are coincident with the variations in chemical compositions. The unique applications of residual soils are a characteristic feature in Korea unlike in other countries. The reddish residual soils have been widely used for various applications such as red tide reduction, construction materials, animal feeding, cosmetics, food, natural pigment and various healthy products. The main reasons of application are to use the properties of clay minerals contained in residual soil.
