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

In gold ore fire assay, litharge (PbO) is used as a fluxing agent to collect gold from the sample. This process produces a slag that retains residual lead and other impurities. Improper disposal of this slag in landfills can result in lead leaching into the environment, posing ecological risks. This study quantified the annual fire assay slag output from a typical Ghanaian laboratory, characterised its elemental composition, assessed lead mobility in rainwater, and investigated leaching efficiency using three acid lixiviants (HCl, HNO₃, and CH₃COOH). X-ray fluorescence (XRF) analysis indicated up to 18% Pb content. Rainwater leaching tests recorded a peak lead concentration of 198 mg/L within seven days, significantly exceeding World Health Organization and Environmental Protection Agency limits (0.01 mg/L). The most effective leaching condition achieved 71.67% Pb removal using 2 mol/L HNO₃ at a 20% w/v solid–liquid ratio.