Characteristics of Site from Scientific Analysis of Iron By-product Excavated from Osong in Cheongju, Korea

The characteristics of the sites were identified through scientific analysis of by-products excavated from Osong site in Cheongju, and regional characteristics were investigated by comparing the by-products of Jincheon Songdu-ri, Jincheon Gusan-ri, and Cheongwon Yeonje-ri site at the same time. In the total Fe and deoxidation agent by smelting, direct smelting total Fe is 33.16-59.01 wt%, and deoxidation agent is 20.58-51.54 wt%, and Osong sites correspond to this. The compound analysis result indicated that fayalite and wüstite, oliven are the main compounds in slag. Furthermore, the microstructure analysis result confirmed the presence of fayalite and wüstite in the slag. In particular, two of the four samples have high CaO content, and Kirschsteinite was detected as a result of XRD analysis, and Kirschsteinite was also confirmed in Raman micro-spectroscopy analysis. This is a major feature of the slag of Osong sites in Cheongju used in this analysis, and it is estimated that the ingredients contained in the original ore have been eluted. In the case of locally close Jincheon Songdu-ri, Jincheon Gusan-ri, and Cheongwon Yeonje-ri, the overall amount of total Fe and deoxidation agent were similar, and as a result of comparing rare earth elements, it is estimated that there is no significant difference in raw materials. Through these results, the Osong sites in Cheongju produced iron by direct smelting using raw ore containing Kirschsteinite with high CaO content, and similar iron-making process characteristics were confirmed in all four sites.