Analysis of the Influence of the Degree of Reduction of Iron Ore Materials on the Shape and Location of the Cohesion Zone in a Blast Furnace

2021 ◽  
Vol 413 ◽  
pp. 157-166
Author(s):  
Andrey N. Dmitriev ◽  
Galina Yu. Vitkina ◽  
Roman V. Alektorov

The paper considers the theoretical foundations of softening of iron ore materials in a blast furnace (the so-called ‘cohesion zone’). The dependences of the temperature range of softening of iron ore materials (the temperatures of the beginning and ending of softening) on the degree of reduction are calculated and experimentally obtained. Physical modelling of the softening process of reduced iron ore materials was carried out using the Russian State Standard No 26517-85. The results of calculations of the location and shape of the cohesion zone in the blast furnace for iron ore materials with different metallurgical characteristics are presented.

2020 ◽  
Vol 2,2020 (2,2020 (125)) ◽  
pp. 5-9
Author(s):  
Vaniukov A ◽  
Kovalyov D ◽  
Vaniukova N ◽  
Khodyko I ◽  
Bezshkurenko O

The objective of the present work is to research a quantitate ratio of degree direct reduction inside of SRP and degree of indirect reduction outside of SRP on the top of the blast furnace.The reactions of direct and indirect reduction occurring during the heat treatment of self reducing pellets (SRP) have been studied. In this investigation Blast furnace (BF) sludge which contains particles of coke, has been included in the SRP blend as a source of solid reductant and iron bearing oxides. In the SRP as a part ot the blast furnace burden occur the reactions simultaneously: inside of SRP-direct reduction by Csolid; gasification of carbon and indirect reduction by CO; and outside of SRP-indirect reduction of iron bearing oxides by reducing gas coming from the hearth of blast furnace through the column of charged materials. The experimental setup is shown in Fig. 1. It con-sists of a electrical heating furnace, which can be moved up and down. The quartz tube passes through the furnace. The reaction zone is in the middle of the furnace. Neutral argon atmosphere is created and for indirect reduction argon changed - on hydrogen. Gases of argon, hydrogen are introduced into the furnace separately. Wire of nickel alloy chromosome joins the scales test. A thermocouple is located in the tube.The crucible of wire chrome-nickel was permeable.Metohd. The experiments was performed continuously from the start temperature (~200 ˚C) to the experimental temperature (500 ˚C; 700 ˚C; 900 ˚C; 1100 ˚C) in argon free environment. Upon reaching the desired temperature argon was replaced by hydrogen during 30 minutes. After that the reduced probe of SRP was cooled in argon. Results. The integrated degree of reduction is equal 100%, which includes 98,6 % direct reduction by solid carbon under temperatures 1100°C. The chemical analysis of the reduced SRP showed the degree of integrated reduction change from 85,79 % (900 °C) to 92,50 % (1000 °C) and 84,6% (1100°C) and metallization 83,30 % (900 °C), 89,90 % (1000 °C), 80,75 % (1100 °C).These data correspond to results of degree of reduction SRP depends on temperature


2013 ◽  
Vol 334-335 ◽  
pp. 375-380 ◽  
Author(s):  
A.N. Dmitriev ◽  
Yu.A. Chesnokov ◽  
Galina Yu. Vitkina

The technique of defining the minimum coke consumption in blast furnace smelting allows for the calculation of the reserve of coke economy on the basis of thermodynamic principles. In this reserve the constitutive role belongs to the reducibility of the iron ore materials (the agglomerate and pellets). In the present paper, the questions of the reduction kinetics of the iron ore materials and diffusion processes at reduction of iron from its oxides are considered. It is shown that the reducibility of the iron ore materials is the basic reserve of economy the scarce and expensive coke in the blast furnace smelting.


2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Zhulin Liu ◽  
Xuegong Bi ◽  
Zeping Gao ◽  
Yayu Wang

In this paper, carbon-containing pellets were prepared by using crop-derived charcoal made from agricultural residuals and iron ore concentrates, and their pelletizing performance and properties were studied. Experimental results showed that the strengths of pellets were related to the particle size of concentrates and the content of moisture, bentonite, and crop-derived charcoal fines in the pelletizing mixture and the temperature of roasting and reduction. That the granularity of raw materials was fine and the bentonite content increased was beneficial to the improvement of pellet strengths. The suitable molar ratio of carbon to oxygen was 1.0 and the proper proportioning ratios of moisture and binder were 8.0% and 6.5%, respectively. The pellet strengths increased accordingly with increasing the reduction temperature, and when the temperature reached 1200°C, accompanied by the fast reduction of iron and the formation of crystal stock, the dropping strength of product pellets was 15 times and the compressive strength was 1650 N; this may be improved by grinding of the concentrate, leading to acceptable strength for the blast furnace.


2020 ◽  
Vol 91 (11) ◽  
pp. 2000047 ◽  
Author(s):  
Anne Heikkilä ◽  
Mikko Iljana ◽  
Hauke Bartusch ◽  
Timo Fabritius

2021 ◽  
Vol 64 (11) ◽  
pp. 785-792
Author(s):  
A. N. Dmitriev ◽  
V. G. Smirnova ◽  
E. A. Vyaznikova ◽  
A. V. Dolmatov ◽  
G. Yu. Vit'kina

The burned pellets must retain the strength from the time they come off the roasting machine until they are loaded into the blast furnace. One indicator of the strength of burned pellets is the compressive strength, i.e., the maximum applied load at which the iron-ore pellet completely collapses. The paper studies the character of destruction of burned iron-ore titanomagnetite pellets of fraction 10 - 16 mm in the static compression test according to the Russian State Standard 24765-81. It is shown that the main type of destruction during the test is the emergence and development of plane cracks passing through the center of the magnetite core, where the maximum radial tensile stresses act or in the immediate vicinity. In some cases, the trajectory of one of the destructive cracks deviates from the above plane and envelopes the magnetite core. Obviously, this is due to the presence of a second area of tensile stress concentration at the boundary of the magnetite core and the hematite shell, formed during cooling of the pellets, due to differences in their mechanical and thermophysical properties. As a result, the final structure of pellets is characterized by the presence of two zones -peripheral hematite and central magnetite. The role of the relative size of the magnetite core on the compressive strength of burned pellets has been determined. It was established that the strength characteristics of the pellet increase with a decrease in relative size of the magnetite core. During the process of magnetite complete oxidation (when the whole volume of the pellet consists of hematite), the maximum level of the pellets compressive strength can be: the maximum destructive force - 3300 N, destructive energy - 0.55 J, mass destructive energy - 0.18 J/g.


2020 ◽  
Vol 2020 (2) ◽  
pp. 33-41
Author(s):  
Irina Merzlyakova ◽  
Aleksandr Feofanov

The article considers general problems of implementing the enterprise risk management procedure. One of the ways to solve the problems arising when meeting Russian state standard ISO 9001-2015 requirements concerning risk-oriented thinking is presented. A risk assessment control model aimed at coordinating all kinds of the enterprise departments activities, forming a clear algorithm of risk management procedure implementation and attracting a greater number of employees towards this activity is offered.


2018 ◽  
Vol 42 (3) ◽  
pp. 453-466
Author(s):  
Wei WANG ◽  
Pengfei YE ◽  
Xiaoli ZHOU ◽  
C WANG ◽  
Zekun HUO ◽  
...  

2021 ◽  
pp. 116971
Author(s):  
I.R.Souza Filho ◽  
Y. Ma ◽  
M. Kulse ◽  
D. Ponge ◽  
B. Gault ◽  
...  

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