Physicochemical and mineralogical characterization of spent and unspent cupels in Ghana; implication for recycling

• Comprehensive understanding of unspent and spent cupels from mine assay laboratories in Ghana. • Spent cupels retain high amount lead oxide with up to 45.1 wt% posing high risk of pollution. • Spent cupels can release hazardous lead into the environment. • Structural and mineralogical changes observed after cupellation. • Findings support recycling and regeneration of cupels to reduce environmental hazards. Ghana’s gold mining sector plays a crucial role in national economic development with fire assay method serving as a technique for accurate determination of precious metal content. One key component of this process is the use of cupels, a small porous ceramic material used in cupellation process to quantify the amount of Gold present in ore. As part of the process, lead metal is absorbed into the cupel in a form of lead oxide leaving gold and silver prill as a solid. This paper aims to analyse the physical, chemical and mineralogical features of both unspent and spent cupels from three mine assay laboratories in Ghana. Mass fraction showed significant negative correlation with unspent cupel weight (p=0.012) and positive correlation with weight difference. Lead was found to be averagely 28 wt% in spent cupels. Analytical techniques were used and the results revealed variations in mineral and elemental phase in unspent and spent cupel from the selected mine assay laboratories which influences the performance and also its environmental impact. Appreciable amount of lead was found to be contained in the spent cupels. Future studies are needed to control lead mobility in the soil and possible regeneration of cupels using green methods.