A Novel Technique for Making Cold Briquettes for Charging in Blast Furnace

Abstract

Abstract. Different metallurgical wastes are generated during pyro processing of iron ore, which is used for making sponge iron or hot metal and for producing steel. Apart from these wastes, coke fines are generated during the coke making, and iron ore fines are generated during mining of iron ore. Although iron ore fines are used for making pellet after beneficiation still, it generates a huge quantity of iron ore waste during beneficiation with comparatively lower iron content. In the present study, briquettes are made by a stiff extrusion process from metallurgical waste like iron ore fines and coke fines with the addition of Portland cement as a binder and clay as a rheology modifier. Physical properties of the briquettes are evaluated, and reducibility of the briquettes is studied in comparison to lumpy iron ore. Phase analysis and microstructural analysis of the briquettes and lumpy iron ore are carried out after firing at different temperatures in the simulated blast furnace condition. Physical and mineralogical properties are correlated with the reducibility of the briquettes and lumpy iron ore. Briquettes made by a stiff extrusion process show a better mechanical strength fired at a different temperature to take the load of burden and better reducibility than lumpy iron ore. The briquettes after self-curing are charged to a 23 mt3 blast furnace which shows encouraging results.

Suitability of Auger Pressing Briquettes for Blast Furnace Use Based on Laboratory Tests

“…It is noteworthy that the briquette appeared to swell more without the 40 min isotherm at 1100 • C than with it. The result may be due in part to measurement inaccuracies, but it is also in line with the study on stiff extrusion briquettes by Mohanty et al [14] who observed a swelling index of 19% at 1000 • C but found it to drop sharply with a rise in temperature. At 1400 • C, the swelling index was only 4%.…”

“…Cold bonded briquetting is a well-known agglomeration method in which a binder, often bentonite, is added to a mixture of fine-grained materials to be recycled. There are three basic briquetting technologies: vibro-pressing, roller pressing, and stiff extrusion [14]. Vibro-pressing or punch-and-die pressing is the oldest high-pressure agglomeration technology and is used in various industries.…”

“…In the field of roller pressing, Köppern is one of the market leaders in the manufacture and supply of machinery and plants for the processes of briquetting, compaction, and comminution [18]. The third technique, i.e., extrusion technology, was first applied in an industrial scale by J.C. Steele & Sons in 1993 at the metallurgical plant of Bethlehem Steel Corp. in Pennsylvania, USA [14].…”