Abstract:Nano-ZnO is a new type of high-function fine nano-material with wide application. The nano-ZnO particles prepared by hydrothermal method have high purity, good crystal shape and simple operation. There are many impurity elements in the zinc leaching solution containing zinc secondary resources, which has a great influence on the purity of the later products, among which the removal of copper and cadmium is more critical. In this paper, the zinc leaching solution containing zinc secondary resources was used as raw material, and copper and cadmium were removed by zinc powder replacement. Then, the purified zinc sulfate solution was used as zinc source, and ammonia water, sodium carbonate and sodium hydroxide were used as precipitants to prepare nano-ZnO by hydrothermal method. The effects of different process parameters on morphology of nano-ZnO were investigated. The results show that under the appropriate conditions, the concentrations of copper and cadmium ions in the leaching solution after zinc powder replacement are 0.0399mg·L-1 and 6.4162mg·L-1 respectively, which can be used to prepare nano-ZnO. The products prepared by using ammonia and sodium carbonate as precipitants are a mixture of ZnO and other crystals, which are irregular crystals of non-pure phase. Pure nano-ZnO can be prepared by using sodium hydroxide as precipitant. The optimum preparation conditions are as follows: the molar ratio of zinc to alkali is 1∶2, the reaction time is 1h, and the reaction temperature is 120℃. The prepared nano-ZnO presents a prism structure, the particle size is between 50~100nm, and the particle size distribution is uniform.
