| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系所 === 101 === The study aims to use the dried process technology to produce the ZnO powder in the atmosphere. During the process of ZnO powder production, this technology could not only reduce the cadmium(Cd) and lead(Pb) but also decrease the aggregation from the materials as well as improve the process, such as the mixing impurity in the air. As a result, high-quality ZnO powder was produced with the narrow particle size and higher purity.
The goal of this experiment was to purify Zinc metal and to increase mass production with the methods of shiny metal fumace, reverberating fumace and parameter adjusting of smelting process. The purity was raised to 99.7 % and the content of Cd and Pb was decreased efficiently lower than 10 ppm(0.001 wt%) and 50 ppm(0.005 wt%) in the Zinc liquid. In addition, the nature air filling in the negative pressure piping system was designed to match with negative pressure motor, caliber, and the length of the piping. Furthermore, it optimized the parameter to shrink the ZnO powder particle size less than 230 nm and to produce efficiency of the powder deposition quantity in oxidization region.
Since the high-temperature oxidation process is a method of atmospheric processes, it occurred to be mixed with atmospheric impurity easily, resulting in production pollution and decreased powder purity. Therefore, a closed and isolated space was built in the half area of the oxidation furnace, in order to reduce the impurities of mixing zinc vapor with air, and to enhance the oxidation of zinc powder purity. However, since the zinc oxide powder has the agglomeration effect in the formative stage, the thermal convection was used at the joint of the exports and vacuum pumping tube in the oxidation furnace. Moreover, the different types of openings were applied to achieve an optimal design, so that the oxidation furnace outlet temperature was quickly decreased and the agglomeration effect was reduced. So as to reduce the cost of production and maintenance in the cooling system, the thermal convection was used to perform cooling of the vacuum pipe effectively. With this method, a uniform particle size of newly formed zinc oxide powder was produced, and the specific surface area was above 4.1 cm2/g.
|
|---|
