Prepration Of High-purity Ferric Oxide By Optimizing Ruthner Processing

Recently, the technology for producing top grade ferric oxide has been dominated by Japanese manufacturing enterprises, such as JFE, TESUTE. These foreign enterprises are holding the top grade ferric oxide market by controlling the technology. Compared with foreign enterprises, domestic soft magnetic ferric oxide field is seriously laggard. With rapid development of electrical components, it needs high quality soft magnetic ferric oxide, however, the quality of ferric oxide raw material has limited the development of soft magnetic ferrites in China. Spray roasting technology (Ruthner method) is a very important method to fabricate ferric oxide. However, the present production technology still has some problems, such as the low purity and the poor reactive activity.Therefore, this work focused on studying and optimizing Ruthner method. The optimized technology route is as follows, the pickling waste liquid was reacted by using dissolving pot, and then the20%ammonia was introduced into the solution to adjust pH value. The compressed air was gone into the solution for generating trivalent iron ions of solution, and then the flocculant was added into the reactive system. The flocculant could precipitate the SiO2impurity. The precipitation was removed from the acid liquid. At the same time, the impurities such as Al, P, Cr, Ni, were also removed. In this thesis, much effort was focused to develop an improved Ruthner method to fabricate high purity ferric oxide. The main results are as follows:The Si-removing and spray roasting technology were investigated, and the procedure parameters were optimized. The results show that the pH value and flocculation agent influence Si-removing effect, and the pH value of solution relates to addition of the ammonia and reaction time. The performance of roasted iron oxide relates to pickling waste liquid concentration, reaction temperature, pressure, ratio of air to gas, and oxygen content.In order to improve the quality of the ferric oxide, the traditional Ruthner method has been developed. The roasted iron oxide has further purified by using deionized water rinse technology. This process could remove some dissolving impurities, such as Cl, Ca, Na, and K. Finally, the fabricated iron oxide power was mechanically grinded to enhance the BET specific surface area, which could completely improve the activity of iron oxide. The ferric oxide prepared by this technology has high purity and good sintering activity, which can be applied to produce high quality soft magnetic ferrites.