Abstract: There are the handicaps as removing impurity and vaporizing solvent and reunited particle in the rut means of synthesis of zinc borate. These means do not meet the need of preparation of nano zinc borate. In this paper, a new way was researched for the preparation of nano zinc borate from ZnO and H₃BO₃. The results of XRD and SEM and XPS show that the zinc borate made from ZnO and H₃BO₃ by solid state rubbing reaction is an amorphism structure. The burning
charcoal test indicates that 38.9% of charcoal ratio of poplar wood powder treated with zinc borate made from ZnO and H₃BO₃ at 1:1 mole ratio, higher than 22.7% of charcoal ratio of the comparison. The compound fire retardant from zinc borate and ammonium polyphosphate has the complex effect of fire retardation. It is 44.5% the charcoal ratio of poplar wood powder treated with the compound fire retardant from zinc borate and ammonium polyphosphate at 50% mass ratio. The complex effect of fire retardation is 22.2%. Solid state reaction is a availability way of preparation of nano salt particle.

Key words: solid state reaction, nano zinc borate, fire retardant