When exposed to air and water, arsenopyriteArsenopyrite in tailings can oxidize, leading to a drop in pH and the release of harmful ions like Fe3+ and SO42−. This process can leach arsenicArsenic into the environment, which is a toxic elementElements posing significant risks to both biodiversity and human health. We investigated a more effective approach: using cobaltCobalt cementationCementation to eliminate particulate arsenopyriteArsenopyrite. In our study, we added zincZinc powder to a solution containing Co2+ and arsenopyriteArsenopyrite. The zincZinc oxidizes, releasing electrons that flow through the arsenopyriteArsenopyrite, reducingReducing Co2+ and depositing cobaltCobalt onto the arsenopyriteArsenopyrite particles. This cobaltCobalt-coated arsenopyriteArsenopyrite can then be recovered using magnetic separationMagnetic separation. We conducted an experiment using arsenopyriteArsenopyrite particles of three different size fractions: + 200 mesh, −200 + 352 mesh and −325 mesh. The removal rates we observed were 22.8, 81.19%, and an impressive 98.5%, respectively, indicating that we achieved over 98% removal for particles smaller than –325 mesh. Additionally, we explored how varying the amounts of arsenopyriteArsenopyrite and zincZinc, cobaltCobalt concentration, pH, temperature, and stirring speed affected the results. Our findings suggest that cobaltCobalt cementationCementation followed by magnetic separationMagnetic separation is a viable and effective method for removing particulate arsenopyriteArsenopyrite from tailings, contributing to better environmental management.