Development of briquette modifier composition to increase the stability of grinding media in iron ore fine grinding mills

Abstract

Recently, there has been a trend towards the use of modifiers in the form of briquettes produced by pressing highly dispersed materials with a binder. The choice of a rational composition of the briquette-modifier will improve the properties of cast irons and steels by increasing the assimilation of the modifying components and facilitating their introduction into the melt. Therefore, the possibility of using briquetted materials for modifying and alloying cast iron to improve melt quality, considered in this paper, is relevant. A literature analysis was carried out on the methods of producing briquettes. The influence of the main technological parameters of briquettes production on their quality characteristics is studied. It was found that the main limitation of the use of briquette modifiers is their high dissolution temperature (more than 1450 °C). The paper considers the possibility of reducing the briquette dissolution temperature by introducing the magnesium-aluminium alloy MAGR into its composition, which helps to accelerate the dissolution due to the internal rupture of the briquette from thermal shock. The rational composition of the modifier, which includes nanodispersed titanium carbonitride powder (35-40%), granular MAGR alloy (5-10%) and dispersed cast iron chips (the rest), was determined by laboratory tests. The proposed composition of the briquettes is appropriate in terms of the optimum dissolution temperature (12500C) and increasing the rate of interaction of the briquette reagents with the melt. The experimental briquette modifiers were tested in industrial conditions at PJSC ArcelorMittal Kryvyi Rih. According to the results of the research, it was found that the use of the developed briquette-modifier in the manufacture of cast iron grinding balls increases their operational stability by 18-30%, which made it possible to reduce the cost of ore grinding.