scholarly journals Technological parameters determining the sintering process intensity

2021 ◽  
Vol 64 (3) ◽  
pp. 184-191
Author(s):  
S. G. Savel’ev ◽  
M. N. Kondratenko

The sintering intensity is an important factor determining techno-economic efficiency of sinter production which provides the blast-furnace process with the main type of agglomerated iron ore raw materials. The charge sintering rate depends on technological parameters of the sintering process. Therefore, a systematic study of sintering technological parameters, which determine its intensity, is of practical and scientific interest. Indicators of the sintering process intensity are considered that assess it from both the mechanical and heat engineering positions. It is shown that in its purest form the sintering process intensity is characterized by the vertical agglomeration rate and combustion intensity of the sintering charge carbon. Two other indexes − the specific productivity for suitable sinter and intensity of heat output in the combustion zone – are less representative for the comparative estimation of sintering intensity, since their values depend on sintered mass strength and thermal effect of carbon combustion respectively. These factors go beyond the essence of the sintering intensity concept. Since content of fines of 5 – 0 mm at different sinter plants is not equal, representative performance comparison of sintering process is possible only taking into account the total amount of fines generated throughout the agglomerate transport path from sinter machine to blast furnace or the results of testing the agglomerate strength in a drum. A comprehensive systematic classification of techniques has been developed to intensify the sintering process based on the material-component principle using four levels of separation – objects, directions, paths and methods in which each subsequent level concretizes and develops the previous one. Its value is universality, which makes it possible to apply a systematization and separation system for almost all already known and future methods of sintering process intensification.

2010 ◽  
Vol 42 (3) ◽  
pp. 269-281 ◽  
Author(s):  
N.A. El-Hussiny ◽  
M.E.H. Shalabi

The Egyptian Iron and Steel Company generates a great amount of blast furnace flue dust. The recovery of metals and carbon from this flue dust becomes a very important demand due to the increase of the price of coke breeze and the decrease of the primary source of metals. At the same time, it make the environment more safe by decreasing pollution. Introducing these dust fines in the sintering process proves to be very harmful for different operating parameters. Thus, this study aims at investigating the production of pellets resulting from these fines, using molasses as organic binder and its application in sintering of iron ore. The sintering experiments were performed using flue dust as pellets as a substitute of coke breeze. The results revealed that, sintering properties such as inter strength increases with using the flue dust pellets, while productivity of both the sinter machine and sinter machine at blast furnace yard decreases. Also the vertical velocity of the sinter machine and the weight loss during the reduction of produced the sinter by hydrogen decrease.


Author(s):  
V. I. Nosenko ◽  
A. N. Filatov ◽  
G. A. Nechkin ◽  
V. A. Kobelev

To decrease viscosity of BF slag and improve its desulfurization ability during hot metal production a magnesia oxide is used, which is introduced into a blast furnace, as a rule, within iron ore sinter, as well as in the form of a fluxing additive. Dolomite, sometimes iron ore materials with increased magnesia content (for example, Kovdor concentrate, raw or roasted Bakal siderite) as well as magnesia-contained wastes, most often BOF slag, are usually used as a main source of magnesia oxide during iron ore sinter production. Brucite, which is widely used abroad, mainly in Japan during iron ore sinter production, is a very prospective magnesia flux. However, brucite was never used in sinter production in Russia. Main parameters and efficiency of its application were obtained under Japan raw materials conditions. However sinter chemical and mineral compositions at Russian and Japanese sinter plants considerably differ. In this connection studies on influence of the magnesia flux “Flumag M”, which is identical by its composition to brucite, on the process parameters of sinter burden sintering and pellets production were carried out. The estimation of application efficiency of “Flumag M” magnesia flux was made during typical sintering of NLMK sinter burden. It was determined, that partial and complete substitution of dolomite by the “Flumag M” magnesia flux in the NLMK sinter burden results in an increase of specific productivity of sintering process by 10–20% (comparative) and the sinter strength by 3–5% (comparative) correspondently. Laboratory experiments on “Flumag M” magnesia flux application, carried out in STI NITU “MISiS”, showed, that raw pellets with magnesia flux additives have higher compressive strength comparing with the pellets having dolomite additives. Impact strength and abrasion strength of roasted pellets is higher, comparing with those with dolomite. Optimal content of “Flumag M” flux in the pellets burden is 2%. The application of “Flumag M” magnesia flux enables to remove burden from the burden and increase strength of roasted pellets.


2010 ◽  
Vol 42 (2) ◽  
pp. 193-202 ◽  
Author(s):  
F.M. Mohamed ◽  
N.A. El-Hussiny ◽  
M.E.H. Shalabi

Coke breeze is the main fuel used in the sintering process. The value of -3+1 mm. represents the most favorable particle size for coke breeze in the sintering process. About 20% of total coke fines (-0.5 mm) are produced during different steps of preparation. Introducing these fines during the sintering process proves to be very harmful for different operating parameters. Thus ,this study aims at investigating the production of granules resulting from these fines using molasses as organic binder and its application in sintering of an iron ore. The results showed that the granules having the highest mechanical properties were obtained with 14.5 wt % molasses addition. The sintering experiments were performed by using coke breeze in different shapes (-3+1 mm in size, coke breeze without sieving and coke breeze granules -3+1 mm). The reduction experiments, microscopic structure and X-ray analysis for the produced sinter were carried out. The results revealed that, all sinter properties (such as shatter test, productivity of sinter machine and blast furnace, reduction time and chemical composition) for produced sinter by using coke breeze with size -3+1 mm and coke breeze granules were almost the same. The iron ore sinter which was produced by using coke breeze without sieving yielded low productivity for both sinter machine and blast furnace. Furthermore, using coke breeze without sieving in sintering of an iron ore decreases the vertical velocity of sinter machine and increases the reduction time.


2011 ◽  
Vol 43 (1) ◽  
pp. 21-31 ◽  
Author(s):  
N.A. El-Hussiny ◽  
F.M. Mohamed ◽  
M.E.H. Shalabi

This investigation deals with the effect of replacing some amount of Baharia high barite iron ore concentrate by mill scale waste which was characterized by high iron oxide content on the parameters of the sintering process., and investigation the effect of different amount of coke breeze added on sintering process parameters when using 5% mill scale waste with 95% iron ore concentrate. The results of this work show that, replacement of iron ore concentrate with mill scale increases the amount of ready made sinter, sinter strength and productivity of the sinter machine and productivity at blast furnace yard. Also, the increase of coke breeze leads to an increase the ready made sinter and productivity of the sintering machine at blast furnace yard. The productivity of the sintering machine after 5% decreased slightly due to the decrease of vertical velocity.


Author(s):  
O. Yu. Kichigina

At production of stainless steel expensive alloying elements, containing nickel, are used. To decrease the steel cost, substitution of nickel during steel alloying process by its oxides is an actual task. Results of analysis of thermodynamic and experimental studies of nickel reducing from its oxide presented, as well as methods of nickel oxide obtaining at manganese bearing complex raw materials enrichment and practice of its application during steel alloying. Technology of comprehensive processing of complex manganese-containing raw materials considered, including leaching and selective extraction out of the solution valuable components: manganese, nickel, iron, cobalt and copper. Based on theoretical and experiment studies, a possibility of substitution of metal nickel by concentrates, obtained as a result of hydrometallurgical enrichment, was confirmed. Optimal technological parameters, ensuring high degree of nickel recovery out of the initial raw materials were determined. It was established, that for direct steel alloying it is reasonable to add into the charge pellets, consisting of nickel concentrate and coke fines, that enables to reach the through nickel recovery at a level of 90%. The proposed method of alloying steel by nickel gives a possibility to decrease considerably steel cost at the expense of application of nickel concentrate, obtained out of tails of hydrometallurgical enrichment of manganese-bearing raw materials, which is much cheaper comparing with the metal nickel.


Author(s):  
N. S. Tsarev ◽  
V. I. Aksenov ◽  
I. I. Nichkova

To neutralize the waste pickling solutions and rinsing water, resulting from cleaning metal products s surface of rust by acids solutions, lime is used. Being cheap, this method of sewage neutralization has considerable drawbacks. Forming in the technological pipes strong gypsum depositions and low specific productivity of the equipment for sediment dewatering are most significant of them. Characteristic of aggressive industrial sewage, formed at pickling of ferrous metals presented. Methods of elimination of drawbacks of industrial sewage neutralization by lime considered, including stabilization of neutralized industrial sewage and control of properties of the sediment formed. It was noted, that stability of the circulating water can be provided by accelerating of crystallization of the forming gypsum sediments by introducing in it fine priming powder and heating the neutralized water up to 65-70 °С followed by thermal softening of a part of circulating water, removed out of the circulating system. It was shown, that the heating of the water and the ongoing changes of the composition and properties of the sediment result in decrease of filtration resistance 2-3 folds, increase of deposition speed 3-4 folds and decrease the sediment volume 1.5-2 folds comparing with lime neutralization in cold water. Calculated dozes of lime at the heating were taken the same as at the regular lime neutralization. Elimination of the circulating water oversaturation by bi-water gypsum can be reached also by addition into the water of powder-like gypsum pulp - priming powder for microcrystals of the gypsum, followed by aeration during 30-40 min. This method was tested under industrial conditions. Technological properties of the forming sediment can be improved by sediment treatment by flocculants and preliminary heating of the neutralized water up to 65-70 °С. Control of technological properties of the sediment is done by addition of flocculants and heating of the neutralized water. Recommendations for improving operation of the neutralization facilities presented with indicating particular technological parameters of the equipment operation for sewage and sediment treatment. 


2019 ◽  
Vol 70 (11) ◽  
pp. 3835-3842
Author(s):  
Mihai Dumitru Tudor ◽  
Mircea Hritac ◽  
Nicolae Constantin ◽  
Mihai Butu ◽  
Valeriu Rucai ◽  
...  

Direct use of iron ores in blast furnaces, without prior sintering leads to a reduction in production costs and energy consumption [1,2]. Fine-grained iron ores and iron oxides from ferrous wastes can be used together with coal dust and limestone in mixed injection technology through the furnace tuyeres. In this paper are presented the results of experimental laboratory investigations for establishing the physic-chemical characteristics of fine materials (iron ore, limestone, pulverized coal) susceptible to be used for mixed injection in blast furnace. [1,4]. The results of the experimental research have shown that all the raw materials analyzed can be used for mixt injection in blast furnace.


2021 ◽  
Vol 7 (5) ◽  
pp. 56
Author(s):  
Yimin Yang ◽  
Xiaoying Li ◽  
Ziyu Liu ◽  
Dianjun Hu ◽  
Xin Liu ◽  
...  

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.


2021 ◽  
Vol 13 (14) ◽  
pp. 7706
Author(s):  
Tova Jarnerud ◽  
Andrey V. Karasev ◽  
Chuan Wang ◽  
Frida Bäck ◽  
Pär G. Jönsson

A six day industrial trial using hydrochar as part of the carbon source for hot metal production was performed in a production blast furnace (BF). The hydrochar came from two types of feedstocks, namely an organic mixed biosludge generated from pulp and paper production and an organic green waste residue. These sludges and residues were upgraded to hydrochar in the form of pellets by using a hydrothermal carbonization (HTC) technology. Then, the hydrochar pellets were pressed into briquettes together with commonly used briquetting material (in-plant fines such as fines from pellets and scraps, dust, etc. generated from the steel plant) and the briquettes were top charged into the blast furnace. In total, 418 tons of hydrochar briquettes were produced. The aim of the trials was to investigate the stability and productivity of the blast furnace during charging of these experimental briquettes. The results show that briquettes containing hydrochar from pulp and paper industries waste and green waste can partially be used for charging in blast furnaces together with conventional briquettes. Most of the technological parameters of the BF process, such as the production rate of hot metal (<1.5% difference between reference days and trial days), amount of dust, fuel rate and amount of injected coal, amount of slag, as well as contents of FeO in slag and %C, %S and %P in the hot metal in the experimental trials were very similar compared to those in the reference periods (two days before and two days after the trials) without using these experimental charge materials. Thus, it was proven that hydrochar derived from various types of organic residues could be used for metallurgical applications. While in this trial campaign only small amounts of hydrochar were used, nevertheless, these positive results support our efforts to perform more in-depth investigations in this direction in the future.


2021 ◽  
Vol 7 (3) ◽  
pp. 32
Author(s):  
Noorina Hidayu Jamil ◽  
Mohd. Mustafa Al Bakri Abdullah ◽  
Faizul Che Pa ◽  
Mohamad Hasmaliza ◽  
Wan Mohd Arif W. Ibrahim ◽  
...  

The main objective of this research was to investigate the influence of curing temperature on the phase transformation, mechanical properties, and microstructure of the as-cured and sintered kaolin-ground granulated blast furnace slag (GGBS) geopolymer. The curing temperature was varied, giving four different conditions; namely: Room temperature, 40, 60, and 80 °C. The kaolin-GGBS geopolymer was prepared, with a mixture of NaOH (8 M) and sodium silicate. The samples were cured for 14 days and sintered afterwards using the same sintering profile for all of the samples. The sintered kaolin-GGBS geopolymer that underwent the curing process at the temperature of 60 °C featured the highest strength value: 8.90 MPa, and a densified microstructure, compared with the other samples. The contribution of the Na2O in the geopolymerization process was as a self-fluxing agent for the production of the geopolymer ceramic at low temperatures.


Sign in / Sign up

Export Citation Format

Share Document