Nano-zinc Oxide Preparation Of New Technology And Its Mechanism

This thesis is based on the domestic and the foreign references about the preparation of nanometer ZnO. The object is to focus on the industrial production. A new process involving mechanically activate method and direct precipitation approach were established.Based on the mechanism of the preparation of nanometer material by mechanically activate method, ZnO with good disperse properity and narrow particle size region was obtained for the first time by this way. An appropriate process was established through a systemic research on each factor. On the other hand, a proper additive was found too.The result of the experiment shows that the additive in this research work affect the preparation process greatly. It can not only improve the fluidity of raw materials, thus better the efficiency of ball milling, but also restrain the reunite between the particles, thus make the particle disperse very well. In addition, it can act as matrix which induce the diffuse solid state reaction to proceed in a fixed direction.On the basis of the systemic research on the mechanism of the preparation of nanometer particle by direct precipitation, a new process which can be easily industrialized was provided. An appropriate reaction equipment was used, the evenness and relative over-saturated solution of the concentration of reaction solution was sustained by a droping way which can control the flow rate of the reaction. The pH value of reaction solution was maintained by properly using amortize solution system; proper dispersant and protection reagent was appended and proper washing way was selected to eliminate or inhibit the agglomerate particles so as to make the product prepared by direct precipitation as good as that prepared by homogeneous precipitation method.After research, the results showed that the relative over -saturated solution, pH value of reaction solution, dispersant and protection reagent are the key affecting factors in the preparation. The appropriate preparation process was determined after systemic research on the rule of the effects of each factor by single factor experimental way. The effect of different types of surface activating agents on particles was investigated. The use of composite surfactant A. mixed, can inhibit the reunite of the particles, thus maintain the dispersibility of particles.The crystal type, morphology and partical size, the distribution of particle size and specific surface area, purity etc. of product was characterized by XRD, SEM, LPA, ICP-AES. The results show that the product with single crystal type can be prepared by solid and liquid way in this research. The purity of the product is more than 99%. Most of the particle are in ball-shape, only a little of them are in club-shape. The distribution of particles are even, the dispersibility is excellent, the average particle size is less than 50nm and the specific surface area of ZnO is more than 43m2/g.