Abstract: The pure ZnSO₄ solution was obtained by low-grade ZnO ore as raw materials after the process of H₂SO₄ leaching and purification.Nanometer ZnO powders were prepared by direct precipitation method using NH₄HCO₃ as precipitator.The effects of various factors such as the mole ratio of NH₄HCO₃ to ZnSO₄,reaction temperature,reaction time,thermal decomposition temperature and time of basic zinc carbonate precursors on the particle size of nanometer powders  and the precipitation rate or the purity of ZnO were investigated systematically.XRD and SEM were used to characterize the structure and size of ZnO particle.The results show that the ZnO powders with hexagonal structure,spherical morphologies,40 nm of average crystal size and 97.5% of purity are obtained.The main technical indices of nanometer ZnO powders prepared by the above route met GB/T19589—2004 National Standard.The processes are simple and easy for industrialization.

Key words: low-grade zinc oxide ore, direct precipitation method, nanometer zinc oxide