Research Information System
MEHRAN UNIVERSITY RESEARCH JOURNAL OF ENGINEERING AND TECHNOLOGY, vol.44, no.3, pp.94-105, 2025 (ESCI)
Oltu-stone, a semi-precious stone found in the Oltu district of Erzurum, Turkey, is frequently used in the making of decorative ornaments. Approximately 90-95% of the Oltu-stone mined, consisting of substandard Oltu-stone because of mineral impurities and small fragment sizes, is considered Oltu-stone waste (OW). This waste is either discarded or burned, resulting in economic losses. The utilization of Oltu-stone waste (OW) as an alternative to standard Oltu-stone (SO) could reduce such losses. In order to see if Oltu-stone waste can be used as an alternative to standard Oltu-stone, it must first be cleaned of its inorganic impurities. After that, the cleaned Oltu-stone properties should be determined to compare their characteristics with standard Oltu-stone. In this study, the petrographic and chemical characteristics of cleaned Oltu-stone obtained by dense medium separation (float-sink method) were determined. The results indicated that the cleaned Oltu-stone was liptinite-rich coal with a small amount of huminite content. Also, it shows contorted suberinite cellular structure and has varying resinite content. Due to high liptinite content, cleaned Oltu-stone has a high volatile matter, i.e., 63-65%. The inorganic impurities in the Oltu-stone wastes were mainly quartz, calcite, pyrite, and clay mineral. After cleaning, most inorganics were separated, although pyrite and silicate minerals remained in trace amounts within the cellular structure. The FTIR results show the predominance of aliphatic hydrocarbons, low aromaticity, and low apparent maturity. It was determined that the cleaned Oltu-stone wastes have similar characteristics to the standard Oltu-stone and can be utilized for further processing as an alternative source.