Metallurgist, Vol. 60, Nos. 3–4, July, 2016 (Russian Original Nos. 3–4, March–April, 2016) 0026-0894/16/0304-0243 ©2016 Springer Science+Business Media New York 243 Translated from Metallurg, No. 3, pp. 29–32, March, 2016. Original article submitted January 14, 2016. BEHAVIOR OF EXTRUSION BRIQUETTES IN MIDREX REACTORS. PART 2 * I. F. Kurunov, 1 A. M. Bizhanov, 2 UDC 669.162:669.181.24 A. Kh. Wakeel, 3 and B. Mishra 4 Results are presented from tests involving the metallization of extrusion briquettes in an industrial reactor (Midrex process). The brex are made from screenings of oxidized pellets, partially metallized sludge, mill scale, and EAF dust with the use of two types of binders. The effect of the type of binder on the briquettes’ strength and degree of metallization is studied. Optical and electron microscopy are used to examine the structure of green briquettes and briquettes after their reduction. Keywords: pellets, metallization, finely dispersed wastes, briquetting, stiff vacuum extrusion, brex, magnesium binder, lime, testing, Midrex reactor, strength, porosity. In the first part of this investigation, an experiment was performed to observe how extrusion briquettes (brex) ob- tained from dispersed metallurgical waste products with the use of different binders behave in an industrial Midrex reactor [1]. The brex were placed inside rigid steel cages and charged into the reactor together with pellets. The cages were removed from the reactor at the end of the process, which made it possible to visually determine the physical condition of the reduced brex after being in the reactor and to study their composition and properties. The mechanical strength of the brex obviously did not play a key role in this case, since they were not subjected to the pressure of a column of charge materials and were not liable to deformation or mechanical fracture. In the second stage of tests, brex were placed in easily deformed gas-permeable steel packets. This made it possible to model the behavior of the brex under the conditions that exist in a Midrex reactor, with allowance being made in this case for the mechanical loads on the brex in the moving charge. Figure 1 shows the outward appearance of the steel cages and packets. With allowance for the results obtained in the first part of the investigation – which involved the use of four types of binders and four types of brex made from a mixture of screenings of oxidized pellets, partially metallized sludge, and scale [1] – in the second part we tested two types of brex made from mixtures of the same materials but with the addition of dust from an electric arc furnace (EAF). The binders were lime and a new magnesia-based material. The use of lime as a binder produced the best results in the first part of the investigation. To make the brex, we prepared two mixtures of pellet screenings (50.0%), partially metallized sludge (25.0%), mill scale (15.0%), sludge from the operation of electric steelmaking furnaces (5%), and the binder (5%). Lime was used as the binder in the first mixture (specimens of type 02-01) and the new material based on magnesium sulfate heptahydrate was used as the binder in the second mixture (specimens of type 02-02). The fractional composition of the components of the mixture was as follows: pellet screenings – 8% coarser than 6.30 mm, 60% within the range 0.15–6.30 mm, and 32% finer than 1 Novolipetsk Metallurgical Combine, Lipetsk, Russia; e-mail: kurunov_if@nlmk.com. 2 J. C. Steele & Sons, Inc., Statesville, NC, U.S.; e-mail: abizhanov@jcsteele.com. 3 Qatar Steel Company, Mesaieed State, Qatar; e-mail: wakeel@qatarsteel.com.qa. 4 DISIR, Rajgangpur, India; e-mail: bmishra@dalmiainstitute.in. * For Part 1 see Metallurgist, Nos. 3–4, 283–289 (2015). DOI 10.1007/s11015-016-0281-z