Preparation method of nano alpha-Fe2O3

Abstract

The invention discloses a preparation method of nano alpha-Fe2O3 and belongs to the crossing field of chemical engineering and materials. Ferric salt, alkali, water, an organic solvent and other raw materials are pre-mixed in a supergravity rotating packed bed, a uniformly mixed precursor suspension is put in a hydrothermal kettle for heating, and nano alpha-Fe2O3 is obtained through washing, centrifugation, drying and other steps. The micromixing characteristic can be strengthened on the basis of the supergravity rotating packed bed, micromixing of a ferric salt solution and an alkaline solution is strengthened through the supergravity rotating packed bed, so that rapid and homogeneous nucleation of a reaction system is realized, a precursor suspension containing uniform crystal nucleusesis obtained, a solvothermal method is adopted in the later crystallization process, the product morphology and size are effectively regulated by changing the rotating speed of the rotating bed, the solvent type, the concentration of the alkaline solution and other parameters, and 15-30 nm nano alpha-Fe2O3 with regular particle morphology, good dispersity, small size and uniform particle size distribution is prepared.

Description

technical field [0001] The invention belongs to the interdisciplinary field of chemical industry and materials, and relates to a method for preparing nano-α-Fe by using supergravity technology. 2 o 3 Methods. Background technique [0002] α-Fe 2 o 3 It is an n-type semiconductor with a band gap, and it is the most stable ferrite; due to its low cost, strong stability and corrosion resistance, it has the characteristics of magnetism, high transparency, and a wide range of acidity adsorption. It is widely used in recording devices, anti-corrosion agents, catalysts and gas sensors, and sewage treatment. Nano α-Fe 2 o 3 The grain size and shape of the crystal largely determine its various physical and chemical properties, which in turn determine the performance and application of its products. Such as: rod-shaped, spindle-shaped α-Fe 2 o 3 Particles have higher residual magnetization and coercivity; hollow spherical nano-α-Fe 2 o 3 Based on its small density and large...

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Problems solved by technology

Among them, the gas-phase method and the solid-phase method have disadvantages such as harsh conditions, complicated equipment, high energy consumption, and low yield. It is difficult to realize industrialization, and it is difficult to effectively control the particle shape and size.

Among the liquid phase methods, the sol-gel method is complex to operate and requires strict process control; the template method has a low reaction rate and has the problem of template removal; the reaction-precipitation method is simple to operate, mild in conditions, and has good particle properties, and can mass produce nano Granules, but the traditional reaction precipitation method takes a long time for microscopic mixing, that is, the formation of crystal nuclei and grain growth are carried out at the same time. In addition, heat treatment processes such as calcination are required, which may easily cause irregular product morphology, uneven particle size distribution, and serious product agglomeration. Phenomenon; the hydrothermal method / solvothermal method mainly controls the crystallization process of the product, and the prepared nanoparticles have high crystallization integrity and regular shape. In addition, the product does not need to be calcined at high temperature, and the product has good dispersibility, but it cannot control the crystal nucleation process.

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