KODOS 망간단괴의 SiO₂-CaO-MnO 상관관계와 분포양상

Abstract

SiO2 and CaO are added to decrease the smelting temperature in the reduction-smelting method for manganese nodule processing. These elements are components of the manganese nodules and might be very important controlling factors in the processing due to the locally variable content. The 707 chemical data of manganese nodules acquired from 1994 to 2001 in KODOS(KOrea Deep Ocean Survey) area were used for the hierarchical cluster analysis. The chemical data were classified by the morphological types, and the averages of the chemical data for each station were classified by the facies groups and the localities. All data are plotted on the SiO2-CaO-MnO phase diagram at 1773oK to compare with the best compositional area in the nodule smelting. Variations and distributions of SiO2 and CaO in KODOS nodules were also reviewed. The mineral phases assigned by the cluster analysis are CFA(Carbonate Fluorapatite), Fe-oxide, Al-silicate, and Mn-oxide. MnO contents are generally higher than SiO2 contents in most of the morphological types except for the Is- and It-type. The Dt- and Tt-type show wider range and the E-types show high anomaly in their CaO contents. The stations which belong to facies group A and B show generally higher MnO contents than SiO2 contents, however, the stations of facies group C and D show wide range in their MnO and SiO2 contents. It seems to be very important to control the SiO2 contents in the processing because of the wide range in the northern area. The additions of approximately 10 wt.% CaO and 10 wt.% SiO2 are recommended for the northern area, whereas, the additions of approximately 10 wt.% CaO and 20 wt.% SiO2 are recommended for the southern area.