Abstract: Superfine zinc oxide(ZnO) powder was obtained by using coarse ZnO particles as raw material with wet grinding process.Properties of both grinding and ungrinding ZnO particles were characterized by SEM and Malvern laser granularity analyzer.Influences of different types and dosage of grinding adis,pH,solid content,and grinding time on grinding effect were investigated.Optimum grinding conditions were obtained as follows:grinding speed was 3 000 r/min，solid content was 15%(mass fraction),pH=11,amount of PEG20000 was 0.5%(mass fraction),and time was 40 min.Under those conditions superfine active ZnO powder which was about 6 μm in d₅₀ and 10 μm in d₉₀ was prepared.

Key words: zinc oxide, sand mill, ulltra-fine grinding, grinding aid, viscosity