Some observations on the production of iron powder by atomization

Abstract

The use of metal powders is progressively increasing. The properties of a metallic powder depend on the technique of its production: amongst the methods available, atomization of liquid metal has been extensively used. For studying the factors affecting production of metallic iron powder by the atomization of a molten pig iron stream, this investigation was conducted. The effects of variation in the size and shape of the nozzle for discharging atomizing agents like air, water and steam at different pressures on the degree of atomization, particle shape, etc., were studied. Several types of jets, impinging on the molten metal stream in different ways and from different directions were tried. The effect of temperatures of the molten metal on atomization was also investigated. As foundry grade pig iron had to be employed because of limitations in the melting facilities available, the silicon contents of the final metal powders were high. Attempts to reduce the silicon content by using oxygen as the atomizing agent proved abortive. The granulometry of various sieve fractions was found to be significantly influenced by the process parameters. Although the flowability of the metal powder produced was satisfactory, it could not be employed satisfactorily for cutting and scarfing purposes because of the high silicon contents. However, the determination of the extent of influence of the process parameters studied in this investigation could assist in producing almost pure iron powder by an appropriate choice of the starting materials. (J. Goswami, S.B. Ghosh, A.B. Chatterjea and V.A. Altekar)