Method for preparing superfine even Fe2O3

Abstract

This invention discloses a method for preparing uniform nanoscale Fe3O4. The method comprises: adjusting the pH value of ferrous salt solution or waste acid solution containing ferrous ions to 8.7-10 with NaOH, adding H2O2 at room temperature to prepare amorphous delta-FeOOH precursor, adding ferrous salt solution at a delta-FeOOH / ferrous salt mol. ratio of (1.32-1.92):1, adjusting the pH value to 8-13 with NaOH, refluxing under boiling for 1.5-2.5 h, filtering the product, washing with water, washing with diluted ammonia solution, and drying to obtain spherical Fe3O4 nanopowder. The particle sizes of the Fe3O4 nanopowder are 30-70 nm, and can be artificially controlled. The Fe3O4 nanopowder has high crystallinity. The method has such advantages as simple process, short reaction time, mild reaction conditions, abundant raw material, and no pollution.

Description

technical field [0001] The invention relates to a method for preparing nano-Fe 3 o 4 method, especially a liquid-phase rapid preparation of ultra-fine uniform nano-Fe 3 o 4 Methods. Background technique [0002] Fe 3 o 4 It is an ancient and traditional magnetic material, and it is also the earliest non-metallic magnetic material. Due to its many advantages and special properties, it has always been valued in the field of magnetic material research and application. With the informatization of society and the application of nanotechnology, people's synthesis of it gradually transitions from micron, submicron to nanometer size. This miniaturized nanotechnology has created conditions for the development of many fields. Due to the size effect of nanoparticles, different sizes of Fe 3 o 4 Magnetic nanoparticles often exhibit different magnetic properties. Therefore, for Fe with controllable particle size 3 o 4 The synthesis of magnetic materials has become a research h...

AI Technical Summary

Problems solved by technology

For example: D.K.Kim. used the co-precipitation method to obtain nano-Fe with a particle size of 13-60nm and different magnetic properties after surface treatment with sodium oleate. 3 o 4 (J.Magnetism MagneticMater.2001, 225, 30-36); An Lijuan et al. used co-precipitation method, and used oleic acid and sodium dodecylbenzene sulfonate as double-layer surfactants for surface modification, and obtained particle size 10nm stable water-dispersible nano-Fe 3 o 4 (Acta Chemical Journal of Chinese Universities, 2005, 26 (2), 366-369); Wang Hanbin etc. also adopt co-precipitation method, add citrate to control nano-Fe 3 o 4 The growth of Fe, with a particle size of less than 5nm 3 o 4 - particles, but the crystallization of the sample is not ideal (Journal of Inorganic Chemistry, 2004, 20(11), 1279-1283); in addition, Shufeng Si et al. 3 .6H 2 O and Fe powder are used as precursors. In the presence of oleic acid and dodecylamide, monodisperse Fe with a particle size of 5.2-12.7nm is obtained by hydrothermal synthesis at 180°C for different times. 3 o 4 Powder; Lai Qiong Yu et al. Fe(NH 4 ) 2 (SO 4 ) 2 .6H 2 O as raw material, with H 2 o 2 As an oxidant, and treated with a surfactant, Fe with a particle size of 8-10nm was obtained. 3 o 4 Particles; but with Fe 2+ As a raw material, add alkali to control the pH value, and use air to oxidize the obtained Fe 3 o 4 The particle size is generally larger

In recent years, although in Fe 3 o 4 Significant progress has been made in nano-preparation and modification, but there are still two typical problems: (1) the raw materials for preparation are expensive, the cost is high, and the preparation process is relatively complicated; (2) for nano-Fe 3 o 4 Modification of the surface of the sample can reduce the grain size of the sample and improve the dispersion of the sample, but it will lead to nano-Fe 3 o 4 decline in magnetic properties