ISSN 0967-0912, Steel in Translation, 2008, Vol. 38, No. 12, pp. 1001–1002. © Allerton Press, Inc., 2008.Original Russian Text © I.S. Bersenev, R.A. Poluyakhtov, V.A. Gorbachev, M.P. Ershov, G.A. Zinyagin, Yu.G. Yaroshenko, 2008, published in “Stal’,” 2008, No. 12, pp. 14–16.

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1

Practically all the iron-ore deposits currentlyworked in Russia are magnetite deposits. However, theeasily accessible reserves are being depleted, and newsources of iron ore for ferrous metallurgy are required.One promising approach is the use of oxidized (hema-tite, limonite, martite, goethite) ore for sinter and pelletproduction.

At OOO NPVP TOREKS, research in 2007 and2008 addressed the production of high-quality iron-orepellets from hematite ores of different chemical compo-sition, including ore obtained by hydraulic extraction.Chemical analysis of samples reveals a high iron con-tent (64–68%), mainly in hematite form (1.3–6.8%FeO) and a low content of sulfur, phosphorus, andarsenic. Thus, these ores are promising for ferrous met-allurgy. However, appropriate technology for sinter andpellet production must be developed.

The first step is to investigate sinter production inthe Lebyazhinsk sinter plant at OAO VysokogorskiiGOK. In the experiments, the concentrate from wetmagnetic enrichment is gradually replaced by hematiteore containing 68.8% Fe

tot

, 1.35% FeO, 95.72% Fe

2

O

3

,0.52% CaO, 0.32% MgO, and 0.97% SiO

2

. The granu-lometric composition of the hematite ore is as follows:

The experimental results show that, when usinghematite ore, the iron content in the sinter increaseswith increase in its content in the batch (from 56.5%with no hematite ore to 62.5% with 59% hematite ore)and the melting point of the batch increases (Fig. 1),with simultaneous decrease in productivity of themachine (Fig. 2). This may be attributed to decrease in

1

The experimental work was conducted at the sinter plant at OOOChusovskoi Metallurgicheskii Zavod (under the direction ofR.R. Syrtlanov), in the sintering-pan equipment at OAOVysokogorskii GOK (under the direction of Ya.V. Shrainer), andat OAO Kachkanarskii GOK (under the direction of E.V. Ershov),with the participation of specialists V.I. Klein, A.A. Kutuzov, andD.N. Shipitsin from OOO NPVP TOREKS.

Fraction, mm >2.0 2.0–1.0 1.0–0.1 <0.1

Content, % 3.2 3.1 32.3 61.4

gas permeability of the bed because the hematite orehas a considerably lower aptitude for pelletization thanis typical of the concentrate. In addition, with increasein the content of hematite ore in the batch, more solidfuel is required for sintering, which is associated, inturn, with the lack of heat supply from magnetite oxi-dation for sintering. Analysis of blast-furnace smeltingat OAO Chusovskoi Metallurgicheskii Zavod showsthat the use of the sinter obtained may reduce coke con-sumption (to 4%) and slag yield (to 11%) and increasethe productivity (to 4%). However, the use of suchhematite ore at OAO Vysokogorskii GOK calls forimprovement in the technology so as to ensure satisfac-tory quality of the sinter and productivity of the sinter-ing machine. In particular, because of the poor pelleti-zation properties of the oxidized ore, the limestonemust be replaced by roasted lime (Fig. 3). The resultsshow that it is possible, in principle, to use hematite orein the production of iron-ore sinter. However, we areinterested not only in the sintering of multicomponentbatch with a relatively low content of hematite ores butalso in the production of sinter and pellets in which allthe iron ore is of hematite type.

Using Hematite Ore in Sinter and Pellet Production

1

I. S. Bersenev

a

, R. A. Poluyakhtov

a

, V. A. Gorbachev

a

, M. P. Ershov

a

,G. A. Zinyagin

b

, and Yu. G. Yaroshenko

c

a

OOO NPVP TOREKS, Yekaterinburg, Russia

b

ZAO Ob’’edinennaya Metallurgicheskaya Kompaniya, Moscow

c

Ural State Technological University–Ural Polytechnic Institute, Yekaterinburg, Russia

DOI:

10.3103/S0967091208120140

1240

605040302010

1140

1220

1200

1180

1160

11200

Content of hematite ore, %

Melting temperature,

°

C

Fig. 1.

Dependence of the temperature at which the batchbegins to melt on the content of hematite ore.

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STEEL IN TRANSLATION

Vol. 38

No. 12

2008

BERSENEV et al.

A promising trend is the use of rich hematite ore inpellet production. It is found that the pellet strength willonly be sufficient if the size of the material is <0.1 mmand the content of the <0.05 mm fraction is at least70%. Therefore, material with a specific surface of1200–1650 cm

2

/g is used in the production of labora-tory pellets from hematite ore. In tests, it is establishedthat the moisture content of the pellets from finelyground hematite ore is less than that of pellets of ironquartzites from the Kursk Magnetic Anomaly. Theexperimental pellets are roasted in laboratory condi-tions analogous to those in roasting machine 2 atMikhailovsk mining and enrichment facility. Thestrength of the roasted pellets is less than for regularMikhailovsk pellets. This means that the roasting con-ditions must be different in order to obtain high-qualitypellets from hematite ore and concentrates than formagnetite ore.

The metallurgical value of the pellets largelydepends on the iron content. However, Russian sinterplants usually produce pellets with no more than 58.0%Fe. At OOO NPVP TOREKS, sinter of a wide range ofbasicity has been produced in laboratory conditions soas to utilize batch in which hematite accounts for 100%of the iron ore. The iron content in the sinter producedis 64–67%, with a basicity of 0.70–2.42. The initial orecontains 67.9% Fe

tot

and 8.6% FeO; the basicity is 0.70.

As already noted, the sintering properties of the oremust be improved in order to produce high-qualitygranulated batch and satisfactory gas permeability ofthe bed. Two means of intensification of sintering areconsidered: the introduction of binder; and mechanicalactivation of the ore surface (by grinding). The use oflime with binding properties is only possible in limitedquantities, since there are few impurities in the ore, andit is inexpedient to increase the basicity above 2.5. Theuse of bentonite has also been proposed. However, itconsiderably intensifies clumping. (The mean clumpdiameter is increased by 45%). When using such batch,the gas permeability of the bed declines considerablyon account of the increased moisture content. The sec-ond means of improving the clumping properties iscrushing of the ore. With increase in specific surface by145 cm

2

/g, clumping increases by 21–30% (abs.) andthe mean clump diameter by 32–45%. Experimentalsintering of such batch shows that the solid-fuel con-sumption must be increased in order to ensure satisfac-tory sinter strength. The cake takes on a large-porestructure, and the FeO content is increased to 25–35%.

Our research confirms that the use of hematite ore inpellet production is promising. However, new technol-ogies must be developed, since Russian technologiesintended for pellet roasting and sintering of magnetiteore do not perform adequately with hematite ore.

63

706050403020100

57

62

61

60

59

58

56

Fe

tot

, %1.150

0.550

1.050

0.950

0.850

0.750

0.650

0.450

Prod

uctiv

ity, t

/(m

2

h)

Content of hematite ore, %

Fig. 2.

Dependence of the total iron content in the sinter andthe productivity of the machine on the content of hematiteore in the batch.

1.4

60

0.2

1.2

1.0

0.8

0.6

0.4

0 5040302010Content of hematite ore, %

Productivity

g

, t/(m

2

h)

Without lime

With lime

Fig. 3.

Dependence of the sintering productivity

g

on thecontent of hematite ore in the batch.