Synthesis and characterization of nano-zinc oxide from a continuous zinc carbonate process

摘要

A Na2CO3/Zn(NO3)2/H2O reactive crystallization system was used to prepare precursor of zinc oxide by using a pH-stat continuous double-jet feed crystallizer under a high shear-stirring-rate process. Process variables are the pH of the solution, the feed rate, and concentration of feed. The effect of pH on the formation of zinc compound was significant; the result showed that the product was zinc carbonate at pH of 9, while the product became zinc hydroxide at pH of 11. A TGA analysis for zinc carbonate showed that the decomposition temperature was at 250°C. Mean crystal sizes of zinc oxide can be determined by using Scherer's equation, and the effect of calcination temperature on the crystal size of zinc oxide can be expressed as Arrhenius' law. Characterization of zinc oxide powders was examined by using PL, SEM and BET, respectively. The result showed that the characterization of zinc oxide obtained in this work was close to that observed from commercial products.