Influence of the initial granulometric composition of solid fuel on its final size in sintering

Abstract

The ease of sintering and the quality of the sinter obtained largely depend on the technical composition (content of ash, volatiles, sulfur, and moisture) and granulometric composition of the solid fuel and the method by which it is introduced in the batch. In granulometric terms, the basic requirement on sintering coke fines is a minimum content of fractions smaller than 0.5 mm and larger than 3 mm [1]. In the present work, we investigate the influence of the initial size of the solid fuel (coke fines) on the final yield of the <0.5 mm fraction. Preliminary sifting of the <0.5 mm fraction from the fuel increases the sintering productivity by 17‐38% (rel.), improves the mechanical strength of the sinter [3, 4], and reduces its content of fines (0‐5 mm) [5], according to laboratory research at OAO ZapadnoSibirskii Metallurgicheskii Kombinat (ZSMK) [12] and the data in [2]. At most Russian sinter plants, the preparation of solid fuel includes storage, crushing, pulverization, and subsequent supply to the batch department [6]. Crushing of the fuel in conical units is accompanied by slight increase in the < 0.5 mm fraction in the fuel mixture. Thus, in the ZSMK sinter shop, equipped with a KMD1750 conical crusher (discharge slot 9‐11 mm), the content of the <0.5 mm fraction is 9.1‐10.7% greater after crushing, despite the significant fluctuation in granulometric composition of the initial fuel. Pulverization of the solid-fuel in four-drum crushers generates most of the <0.5 mm fraction. Pulverization of the solid fuel is evaluated in terms of the factor where M 1 and M 2 denote the content of the 0‐0.5 mm fraction in the initial fuel and in the pulverized fuel, respectively, %. In production conditions, on account of the considerable duration of sampling, sample preparation, and sifting and the elevated moisture content of the small fractions, ongoing determination of the content of the J 100 M 2 M 1 ‐ 100 M1