Characterization and assessment of Okpella metacarbonate deposit in Nigeria

The metacarbonate deposits in the southern Nigeria intercalated with calc-silicate gneiss, intrusive granite and migmatite gneiss rocks are of Proterozoic age. The study focused on examining the suitability of the metacarbonate via characterisation for industrial applications. This study is based on X-ray diffractometry (XRD), scanning electron microscopy (SEM), polarizing/reflected light microscopy, chemical and differential thermal analysis/thermal gravimetric analysis (DTA/TGA). The calcite is the dominant phase while silica is the subordinating component of the metacarbonate. The metacarbonate is characterized with limited water absorption, appreciable compressive strength, high loss of ignition and bulk specific gravity. Quicklime calcined at 900, 1100 °C for 60, 90 and 120 min of soaking time were unreactive due to incomplete calcination and densification of the pore surface of the produced quicklime. However, the quicklime calcined at 1000 °C exhibited high reactivity after complete thermal decomposition associated with its unique microstructure. Marble has affluent industrial applications attributed to its established microstructure, chemical composition and thermal decomposition behaviour.