Abstract: Abstract:The crystallization process of copper removal by sodium carbonate was investigated in a seeded fluidized bed reactor. The influence of pH value of the precipitation agent on the copper conversion and removal efficiency was tested. The results indicated that 99.0% copper removal efficiency was achieved, while the fine generation efficiency was decreased by 0.5%-1.0% under conditions of influent copper 200 mg/L, pH value of precipitation agent 10.2 and optimal recycle flow rate. The sizes of the fine particles were uniform and present as rod-like. The crystal was identified as basic copper carbonate by X-ray diffraction (XRD). With pH of the reagent increased to 12.2, the removal efficiency of copper decreased to 95.0% and the crystals showed unclear crystallization characteristics, low degree of crystallization and irregular size. The XRD results indicated the fine fraction were a mixture of copper hydroxide, basic copper carbonate and calcium carbonate.