KNUST Research Week and Scientific Conference: Empowering Researchers to Achieve Impactful Outcomes

Waste cupels from fire assay methods are considered as hazardous wastes because they are heavily contaminated with lead oxide (PbO) after cupellation therefore posing environmental hazards and disposal challenges. This work deals with the recovery of lead from used/spent cupels and transforming it into lead oxide suitable for reuse in the cupellation process and other applications. The spent cupels are collected from Intertek, Ghana, crushed and grinded into a powder and sieved to a size of 75 microns and characterized using X-Ray fluorescence (XRF) and X-Ray diffraction (XRD). It was leached with acetic acid solutions at concentrations (1 M), (2 M) and (4 M) respectively at a Solid: liquid ratio of 1:4 ml and 1:8 ml. The results indicated that Pb recovery efficiently increased with increased acid concentration, with 4 M acetic acid at a 1:4 ml S/L ratio yielding up to 88 % recovery. Leachate was treated with ammonium carbonate (NH4CO3) to precipitate lead carbonate (PbCO3), which was dried at 100°C and calcined between 350 and 365 °C in a furnace to obtain PbO. The formation of well-crystallized tetragonal litharge with a small amount of orthorhombic massicot was confirmed by phase analysis. This study illustrates a sustainable way of recycling fire assay laboratory waste and repurposing the product into valuable materials thereby reducing environment hazards and promoting a circular economy.