Study On The Preparation Of Nanometer A-Fe₂O₃ By Sonochemistry Method

A new process with good respects and some value in production and application has been described in this paper, which can prepare nanometer α-Fe₂O₃ powders by chemical precipitation-oxygentation under ultrasonic. With the action of ultrasonic in the process of the oxygenation reaction, the products were prepared from raw materials of industry byproduct ferrous sulfate and industry grade ammonium bicarbonate. At the same time, a multiplex surfactant was used in this experiment and an appropriate pH value was adjusted. The effects of multiplicative technical factors on the properties of products, including the concentrations of reactants, oxygenation reaction temperature and time in this reaction system, calcination temperature and time, pH value of the system at the begin of oxygenation course, surfactant dosage and proportion and air flux, have been discussed with the help of single-element method. Moreover, the optimum technological conditions of preparing nanometer α-Fe₂O₃ powders have been given by using orthogonal test method and the formation mechanics has also been investigated. The structure and physical properties of products have been analyzed by XRD, TEM, BET and TG -DTA etc. The experimental result shows that the shape of nanometer α-Fe₂O₃ powders prepared under the optimum technological conditions is spherical and the products have narrow size distributions between 30nm and 50nm and their specific areas are 76.8m²/g. They can be applied to lots of special fields.