固液界面形成磁性超细粉及其机理探讨

A Preparation and Mechanism of Isomorphous Transformation to Ultra-fine Magnetite at Solid-solution Interface

利用钢铁厂的平炉尘与二价铁盐制备Fe3O4，反应体系用氮气保护以免悬浮体内的Fe3O4Fe2+被氧化。反应过程中未发现中间体，反应快，反应条件和缓。使Fe3O4吸附表面活性剂，以防止因表面能及磁性引起的团聚倾向，可获得粒径小于100nm的超细粉，其数量达总产物的60％以上。

Magnetite can be prepared from opendiearth dust using γ-Fe2O3 and Fe3O4 and thereare no such intermedia as FeOOH,Fe(OH) 3 in the process and therefore it react quickly.Particles are fined by adsorbing the surfactent so that particles smaller in size than 100nmaccount to 60% of magnetite. This method can prepare spinel ferrites contained in other metals.In this paper we study on the transformation mechanism and deduce that ferrite are formed byisomorphous transformation at solidsolution interface and the following formula γ-Fe2O3(s)+Fe2+(aq) + H2O = Fe3O4(s) + 2H+ (aq)