In this study, the use of a crystallization separation process for copper removal from wastewater in a fluidized-bed reactor (FBR) was investigated. Supersaturation played a significant role in the copper removal process and was affected by the concentration of added carbonate, the influent copper concentration, and the position of carbonate reagent dosing. The experimental results showed that the limited influent copper concentration in the FBR was 20 mg/L, and that the optimum molar ratio of [C-T]/[Cu2+] was 2. Under these conditions, the total copper removal efficiency reached 87%. Furthermore, scanning electron microscope (SEM) analysis indicated that when homogeneous nucleation occurred, some precipitate was coated onto the sand surface and mechanical stability was reduced.