Study of the isothermal kinetics of reduction of sinter from mill scale

Abstract

Studies of the isothermal kinetics of the reduction of sinter from mill scale were carried out at Zh. Abisheva Chemical and Metallurgical Institute (Karaganda). The influence of temperature and heating time on the degree of reduction of iron and other elements was studied in the Tamman furnace by the thermogravimetric method. The amount of reducing agent was taken in the experiments based on the stoichiometrically necessary amount of carbon for the complete reduction of iron oxides by more than 60%, as well as for the carburization of the resulting metal to 2.0% C. To obtain the kinetic characteristics of the reduction of the studied materials, depending on the temperature and duration of the process, processing of the received data array according to the models developed especially for these cases. The results of experimental data processing according to the Gistling-Brownstein model are presented. As a general assessment, this model with a sufficiently high correlation (R not less than 0.9) describes the studied process, which confirms its diffusion character. Analyzing the calculated data of the activation energy, one can assume the diffusion nature of the inhibition of the reduction reaction of all the materials under study. The value of the activation energy of the process shows that the agglomerate with dolomite (fluxed agglomerate) has the highest reducibility. During the frontal reduction of oxides of iron and other elements with carbon, a slag shell is formed around the grains of materials, which consists mainly of acidic oxides of barren rock, non-metallic inclusions of lightweight scrap and reducing agent ash and has a high viscosity. Its thickness depends on the composition of the material, temperature, time and degree of reduction.

Research of the production of iron ore sinter from bauxite processing waste

“…On the other hand, excessive consumption of fuel causes the development of high temperatures, which will cause excessive melting of the sinter and a decrease in mechanical strength, such as with an increase in fuel up to 11%. It is necessary to have such a fuel consumption at which the agglomerate would have good mechanical strength and would not be strongly melted [ [21], [22]]. These studies were carried out in order to determine the appropriate fuel consumption for such a sinter.…”

“…It is in this fineness range that many man-made wastes and the material under study (iron sands) fall, the granulometric composition of ferrous sands is presented in Table 2. The aspiration dust of steelmaking was used as a clay component to improve the compressibility of the charge [21]. The use of aspiration dust had a favorable effect on pelletization, which accelerates with an increase in the number of nuclei in the charge.…”

“…The use of aspiration dust had a favorable effect on pelletization, which accelerates with an increase in the number of nuclei in the charge. Pelletization was also facilitated by the use of return in the charge, in which the bulk has the presence of the smallest particles [ [20], [21], [22]]. Mixing of the mixture was carried out in a drum mixer.…”

“…The agglomeration of ore materials makes it possible to involve various technogenic wastes in metallurgical processing [20], such as screenings of ores, sludge, mill scale, flue, and aspiration specks of dust [21], and pyrite cinders. The agglomerated high-quality charge prepared for smelting will make it possible to utilize existing waste, improve the operation of furnaces, reduce dust removal, reduce the specific consumption of coke, and increase metal smelting.…”

Processing of low-quality manganese-containing raw materials to obtain pellets for production ferromanganese alloys. Review

“…При агломерации мелочи марганцевого сырья расходуется значительное количество кокса. Для уменьшения расхода кокса рекомендуется частичная замена его на углеводородсодержащие материалы [27,28]. Проведены исследования по агломерации марганецсодержащего сырья при соотношении кокса и нефтебитуминозной породы 1:1 и 1:2.…”