Trans-Purification of spent carbide via pressure pot into reusable limes: An economical approach

Abstract

About 20-30 kg of spent carbides is averagely generated per panel beater daily in Nigeria (West Africa). In this study, pure limes (quicklime and slaked lime) from spent carbide were obtained via lime cycle – calcination/ hydration. The spent carbide (wet) was collected from the panel beater's workshop at Yaba College of Technology, Lagos, Nigeria. 400 g to 600 g from these sieved particles were subjected to calcination at temperature ranges 950℃ and 1000℃. Slaking or hydration of 20 g of the calcined spent carbide was conducted in a pressure pot by varying water to sample ratio at separate times (30, 60, and 90 minutes). The obtained limes, CaO were characterized only by FTIR, and Ca (OH)2 was characterized by XRD and FTIR. The XRD spectrum of the synthesized slaked limes showed major peaks around 18o to 71.8o (2θ) with a dominant peak (011) plane at 34.1o (2θ). The crystallite size was found to be 56.55 nm, 56.56 nm, and 42.42 nm for samples A90, A60, and A30, respectively. FTIR spectroscopy of prepared samples (A30 and A60) showed sharp peaks viz-a-viz sample A90 at wave number 3637 cm-1 which is assigned to the presence of O―H stretching. The observed FTIR peak bands of the synthesized CaO at temperatures of 950oC (B950) and 1000oC (B1000) were found between the range of 1401.47 cm-1 and 998.92 cm-1, the presence of water molecules on the surface of the powder this also noticed in commercial CaO.