enrichment of reduced siderite ore to produce concentrate for electrosteel smelting

ISSN 0967�0912, Steel in Translation, 2011, Vol. 41, No. 6, pp. 492–498. © Allerton Press, Inc., 2011.Original Russian Text © S.G. Melamud, V.V. Shatsillo, I.A. Dudchuk, A.A. Mushketov, E.V. Bratygin, B.P. Yur’ev, 2011, published in “Stal’,” 2011, No. 6, pp. 4–9.

492

If siderite�ore concentrate obtained by X�ray sepa�ration is reduced by the steam�conversion products ofnatural gas (by hydrogen) or by coke fines, almost100% reduction is possible. However, the reducedproduct contains a high proportion of barren rock(including nonreactive coal and ash), which reducesthe efficiency of smelting. On reductive roasting, theinitially nonmagnetic siderite ore acquires magneticproperties on account of the conversion of most of theiron from carbonate to metallic form. This permitsmagnetic separation by familiar methods in moderatefields (64–80 kA/m) so as to separate the metallicphase from the oxides of the rock and the unreducediron. On removing most of the barren rock from thesiderite, its value considerably increases.

The composition of the reduced siderite ore is asfollows: 42.0 wt % Fetot; 30.7 wt % Femet; 9.7 wt %FeO; 5.2 wt % Fe2O3; 6.0 wt % Cso; 6.4 wt % Ctot;7.8 wt % CaO; 11.6 wt % MgO; 15.0 wt % SiO2; 6.0 wt %Al2O3; 1.6 wt % MnO; 0.6 wt % Stot. The degree ofreduction is 73.0%.

Dry magnetic separation is undertaken at a fieldstrength of 120 kA/m on the PBS�90/25 and PBS�63/50 separators at OAO Uralmekhanobr. The speedvaries from 78 to 21 rpm for drums of the first type andfrom 80 to 26 rpm for drums of the second kind. Theintermediate size class 3–6 mm is obtained on aPBSTs�63/50 centrifugal magnetic separator (speed96 rpm; field strength 120 kA/m).

In dry magnetic separation, the goal is to extractthe coal that has not been consumed in reductiveroasting and to convert some of the barren rock intoenrichment tailings. The loss of iron with the tailingsmust be minimal. To this end, the initial ore is sub�jected to dry magnetic separation on a PBS�90/25 sys�tem in two stages (with reprocessing of the nonmag�

netic product) for most effective conversion of themagnetic component to magnetic products. The opti�mal drum speed is 78 rpm in the first stage and 21 rpmin the second (reprocessing of the nonmagnetic prod�uct from the first stage). A simplified diagram of theprocess is shown in the figure.

For the initial size class 0–50 mm, separationyields 44% tailings with relatively low iron content andincreases the total iron content from 33.2 wt % in theinitial reduced ore to 53.6 wt % in the total concen�trate, with increase in the metallic�iron content from23.1 to 38.7 wt %. Table 1 shows the chemical compo�sition of the products of dry magnetic separation in thesize classes 0–50 and 0–6 mm.

Hence, dry magnetic separation permits practicallycomplete transfer of the remaining coal to the tailings(99.1–99.9% extraction), both for the initial particlesize and after crushing to 0–6 mm. Crushing the sid�erite ore to 0–6 mm concentrates 50–52% of the silicaand alumina in the tailings. At the same time, separa�tion of the uncrushed ore (0–50 mm) permits thetransfer of no more than 30% of the barren rock to thetailings. For both the 0–50 mm and 0–6 mm sizeclasses, MgO is present in conglomerates with iron.Therefore, it passes to the magnetic fraction, and itscontent in the tailings is 1.2–2.8%.

Thus, to remove coal residues, dry magnetic sepa�ration may be undertaken for reduced siderite ore ofthe initial size class (0–50 mm). In that case, the con�centrate will contain 53–54% Fetot, around 40% Femet,13–14% SiO2, and 4–5% CaO. In the case of dry mag�netic separation without subsequent enrichment, theneed for preliminary crushing will depend on therequired slag composition. With a total slag basicity ofone, which ensures desulfurization of the metal andcontinuous slag runoff, there is no need for crushing.

Enrichment of Reduced Siderite Ore to Produce Concentrate for Electrosteel Smelting

S. G. Melamuda, V. V. Shatsillob, I. A. Dudchukb, A. A. Mushketova, E. V. Bratygina, and B. P. Yur’evc

aOAO Uralmekhanobr, Yekaterinburg, RussiabOOO NPRO Ural, Yekaterinburg, Russia

cUral Federal University, Yekaterinburg, Russia

Abstract—An enrichment technology for reduced siderite ore has been developed for the production of con�centrate that may be used in steel smelting. The technology includes dry and wet magnetic separation. Con�ditioned briquets may be produced from reduced siderite�ore concentrate and used in arc furnaces as a partialor complete replacement for scrap or hot metal.

DOI: 10.3103/S0967091211060076

STEEL IN TRANSLATION Vol. 41 No. 6 2011

ENRICHMENT OF REDUCED SIDERITE ORE TO PRODUCE CONCENTRATE 493

Increasing the basicity entails adding lime, inquantities proportional to the remaining silica con�tent. Therefore, for such melts and for subsequent wetmagnetic separation, it is expedient to send the moreacidic barren rock to the enrichment tailings. Theconcentrate from dry magnetic separation of thecrushed ore contains 58–59% Fetot and 43–44% Femet.

Given that the goal in wet magnetic separation ofthe concentrate from dry magnetic separation is toincrease the iron content by sending oxides (MgO,SiO2, CaO, and Al2O3) and S to the tailings, concentratefrom dry magnetic separation of size class 0–6 mm issent for further processing in a continuous wet�enrich�ment system. Counterflow PBM�13/38 separators areused for wet magnetic separation (field strength80 kA/m). In enrichment, the initial supply, the mag�netic and nonmagnetic products, and the discharge ofthe mills and the spiral classifier are selected. The con�tent of Fetot, Femet, FeO, MgO, SiO2, Ctot, S, P, CaO,and Al2O3 in the enrichment products is determined.

The system for wet magnetic separation includesthe following processes:

⎯crushing of the intermediate product in thestage�I ball mill, with subsequent screening of the milldischarge to obtain the 3–6 and 0–3 mm classes;

⎯wet magnetic separation of class I (0–3 mm), toobtain tailings 1 and magnetic product 1;

⎯passage of magnetic product 1 through a spiralclassifier (with a 0.071 mm screen), to obtain sand anddischarge;

⎯wet magnetic separation II of the 0–0.071 mmclass, to obtain the final iron concentrate and tailings;

⎯crushing of sand from the classifier in the stage�II ball mill to 0–1.0 mm;

⎯wet magnetic separation III of the dischargefrom the stage�II ball mill to obtain iron concentrateand tailings.

Table 2 summarizes the results of wet magneticenrichment. Analysis indicates that a relatively smallball mill cannot completely crush the reduced productto the required size (0–0.071 mm). Therefore, incrushing, concentrate 1 (sample 21) of size class 0–3 mm is obtained in stage I and concentrate 2 of sizeclass 0–1 mm (sample 23) in stage II. The total gran�

ular concentrate is a mixture of small beads (contain�ing 88.3% Fetot and 76.83% Femet) and flattened metalstructures with slag inclusions.

The large�grain concentrate (0–3 mm) contains76.4% Fetot and 67.5% Femet and fewer beads, onaccount of unseparated slag inclusions. Their presence

is indicated by the higher content of silicon (Si =

7.06%; Si = 2.62%) and magnesium oxide

(MgO0–3 = 6.05%; MgO0–1 = 3.86%).

After discharge of the tailings, the 0–3 mm productfrom stage�I wet magnetic separation is classified at a

O20–3

O20–1

Initial ore (0–50 mm)

M

78 rpm

N

T

Crushing (0–6 mm)

To WMS

M

M

78 rpm

N

N

DMS II

СМС I

DMS I

T

Dry magnetic separation (simplified diagram): DMS, drymagnetic separation; M, magnetic product; N, nonmag�netic product; T, tailings; WMS, wet magnetic separation.

DMS II

Table 1. Chemical composition, %, of total concentrates and tailings from dry magnetic separation

Enrichment product Fetot Femet FeO MgO CaO SiO2 Ctot Al2O3

Concentrate of size class, mm:

0–50 53.62 38.73 10.26 11.30 4.80 13.20 0.47 3.7

0–6 58.40 43.61 9.61 11.54 4.60 10.49 0.17 3.5

Tailings of size class, mm:

0–50 7.57 3.46 5.28 1.64 5.30 7.67 68.00 3.6

0–6 9.14 3.50 6.58 2.76 5.60 11.02 59.40 3.6

Initial ore 33.25 23.12 8.06 7.05 5.00 10.76 30.34 3.8

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MELAMUD et al.

0.071 mm screen and sent for stage�II separation. Thesmall (<0.071 mm) concentrate (sample 27) consistsof sponge iron, with impurities from the barren rock.The total iron content and metallic�iron content in thesmall concentrate is practically the same in the enrich�ment of small and large samples. According to Table 2,

≈ 80% and ≈ 70%. The yield ofsponge�iron concentrate is 15%.

Table 3 presents the total enrichment of the con�centrate from wet magnetic separation with 58.4%Fetot and 43.6% Femet initially; Table 4 presents the

Femet0–0.071 Femet

0–0.071

chemical composition of the products. The magneticconcentrates of classes 0–1 and 0–0.071 mm from wetmagnetic separation are satisfactorily enriched, with83% Fetot and 72% Femet. The content of componentsfrom the barren rock is typical for metalized pellets:3.5% SiO2 and 1.3% Al2O3. The elevated MgO content(4–6%) is due to the characteristics of the initial sid�eroplesite and cannot be significantly reduced. At thesame time, the FeO content in the reduced concen�trates from wet magnetic separation (4–10%) consid�erably exceeds that expected from laboratory experi�

Table 2. Production of iron concentrates of different quality and class size

Enrichment product Yield, %, from ore

Content, wt % Extraction, %

Fetot Femet Fetot Femet

Screening (3 mm class)

>3 mm class (21)* 8.28 64.34 58.00 16.02 20.80

0–3 mm class 40.65 57.19 40.66 69.82 71.49

Discharge from stage�I ball mill 48.93 58.40 43.61 85.94 92.28

Wet magnetic separation (0–3 mm class)

Magnetic product (22) 28.37 71.55 58.00 61.05 71.17

Nonmagnetic product (23) 12.28 24.00 0.60 8.86 0.32

Screen residue (0–3 mm) 40.65 57.19 40.66 69.82 71.49

Classification of magnetic product (22) (0.071 mm class)

Sand, >0.071 mm (26) 8.75 84.66 73.11 22.28 27.67

Discharge, <0.071 mm (25) 19.62 65.70 51.26 38.77 43.50


Wet magnetic separation of classification discharge (25)



Classification discharge (25) 19.62 65.70 51.26 38.77 43.50

Wet magnetic separation of classification sand (26)



Sand (26) 8.75 84.66 73.11 22.28 27.67

* The sample number is given in parentheses.

Table 3. Total characteristics in the continuous production of iron concentrate

Enrichment product Yield, %, from ore

Content, wt % Extraction, %

Fetot Femet Fetot Femet

Screen residue (>3 mm) 8.28 64.34 58.09 16.02 20.80

Magnetic product, mm

0–1 8.32 88.30 76.83 22.10 27.65

0–0.071 14.45 79.40 69.06 34.51 43.17

Nonmagnetic product 17.78 24.75 0.85 13.29 0.68

Initial product 48.93 58.40 43.61 85.94 92.28



ments and may be attributed to the deficiencies of therotary furnace employed.

The 3–6 mm residue at the screen, which is notsubjected to wet magnetic separation because it cannotbe crushed, does not differ greatly in compositionfrom the dry�separation concentrate and is notenriched when using a small continuous system. Sub�sequently, in processing large samples on industrialequipment, it is crushed, and its magnetic fraction ishardly different from that for the 0–1 mm class.

Reduced 0–1 mm and 0–0.071 mm concentratesfrom wet magnetic separation are briquetted, sincetheir introduction in the electrofurnace in powderform may lead to intense release of material at theelectrodes and within the shop.

Prior to industrial testing, the briquetting technol�ogy is refined in laboratory conditions. Two types ofbinder are tested: lignosulfonate and quicklime.Lignosulfonate is the commonest binder in refractoryproduction at OAO Magnitogorskii MetallurgicheskiiKombinat (MMK), where an industrial batch wastested. Lime is a promising binder, since it replaces theflux in electrofurnaces and is easily assimilated bymelting.

In terms of chemical and granulometric composi�tion, the concentrate for briquetting corresponds tothe 0–0.071 mm magnetic product. The first binderemployed is granulated lignosulfonates binder fromSolikamsk paper plant. The second binder is quick�lime obtained by roasting high�altitude limestone. Thelime contains 85% active CaO, and its size matchesthat of the concentrate from wet magnetic separation(90% of the <0.071 mm class).

As a result of holding of the batch with heating to40°C, conditioned briquets with 5.0–5.4% lignosul�fonate in the dry mass are obtained. The best results

are obtained when using lignosulfonate. The charac�teristics of the corresponding briquets are as follows:moisture content 4.25%; compressive strength156 N/briquet initially and 2700 N/briquet after dry�ing; the briquets withstand being dropped four timesfrom a height of 1.0 m in the initial state and 11 timesfrom 1.5 m after drying.

Such briquets may be produced on a rotary pressand transported to the straightening system. Note thatthe strong briquets with lignosulfonate have a signifi�cant deficiency. The aqueous solution of lignosul�fonate contains acidic cations, and the pH of themedium is no more than 4.0. This leads to oxidation ofthe metallic iron and impairs the briquet quality.Therefore, in the next series, the lignosulfonate isreplaced with quicklime. The resulting briquets are oflower quality: moisture content 8.0%; compressivestrength 100 N/briquet initially and 1200 N/briquetafter drying; the briquets withstand being droppedthree times from a height of 0.3 m in the initial state (asagainst 19 times for lignosulfonate) and three timesfrom 1.5 m after drying (as against 11 times for ligno�sulfonate).

Despite the heat liberation on slaking, the bri�quettes with lime are not heated as much as those withlignosulfonate. This indicates that there is practicallyno oxidation of the metal iron in the basic lime solu�tion. At the same time, the strength of the dry briquets(1200 N/briquet) is quite sufficient to permit loadingin the electrofurnace. Briquets of this strength evenwithstand dropping from the blast�furnace’s chargehole.

Thus, laboratory experiments show that thereduced concentrate from wet magnetic separationmay be briquetted by means of lignosulfonate or lime.In the latter case, the briquets are not oxidized and do

Table 4. Chemical composition of enrichment products obtained in continuous equipment

Element

Content of elements in products, wt %

screen residue (>3 mm)

magnetic product (0–1 mm)

magnetic product (0–0.071 mm)

nonmagnetic product (total)

initial concentrate from dry magnetic

separation

Fetot 64.34 88.30 79.40 24.75 58.40

Femet 58.09 76.83 69.06 0.85 43.61

FeO 5.54 3.98 9.78 13.97 9.61

MgO 8.25 3.86 5.82 21.27 11.54

CaO 4.38 – 0.25 11.00 4.60

SiO2 11.53 2.62 4.08 18.86 10.49

A12O3 3.16 – 1.31 4.84 3.50

Ctot – – – 0.65 0.17

Stot 0.47 – 0.29 0.74 0.50

Ptot 0.02 – 0.02 0.04 0.02

496


MELAMUD et al.

not contain harmful sulfur impurities. Industrial testshave been confined to briquets with lignosulfonates onthe roller press at OOO Ogneupor. The 50�kg condi�tioned briquets obtained are characterized by com�pressive strength of around 3000 N/briquet and meetthe requirements of steelmaking.

Experimental laboratory melts of the briquets in aninduction furnace employ a charge consisting of castiron (3 kg) and metal scrap (7 kg). After stabilization ofthe bath, portions of reduced siderite briquets are intro�duced in the molten metal (containing 1.5–2.0% C);briquets with lignosulfonate and lime binder areemployed. Metal and slag samples are taken at differ�ent periods (during melting of the iron and scrap, atbriquet addition). To obtain slag of optimal composi�tion, the calculated quantity of lime is added during

the melt. Table 5 shows the chemical composition ofthe metal and slag.

The heating effect and metal discharges are less ifthe lignosulfonate briquets are replaced with lime bri�quets (corresponding to 90% reduction), and the FeOcontent is no more than 6%. Near�optimal smeltingconditions are employed, while the metal compositionis close to that for structural steel. The MgO content inthe slag (MgOact = 19.3%) is higher than the calculatedvalue (MgOcalc = 11.0%), on account of solution of thefurnace lining.

For the arc furnaces at OAO MMK, we recom�mend the use of 5–10% fluxed briquets instead ofsome of the metal scrap, with the continuous supply offriable materials to the liquid metal, at a rate of0.5%/min. This reduces the content of harmful impu�rities such as Cu and Zn and maintains the S andP content at satisfactory levels.

To permit more extensive use of Bakal ore, not onlybriquets but concentrate obtained by dry magneticseparation are used in the arc furnaces. Sand and limeare added to the batch in laboratory melts of reducedconcentrate pieces obtained by dry magnetic separa�tion, so as to obtain slag of the required viscosity.Graphite powder is added to reduce the iron oxides. Amagnesium crucible is used for the melts. In the cruci�ble, we charge the concentrate obtained by dry mag�netic separation (55–56%), as well as lime (90% CaO)and sand (85% SiO2) so as to form slag of satisfactorymobility. Table 6 presents the chemical compositionand yield of the products.

Despite the elevated MgO content, the slag is suffi�ciently fluid. The melt proceeds without problems,with stable arc combustion. The composition of themetal ingots differs from the composition of the metalsmelted in an induction furnace in terms of the con�tent of carbon (2.6%, rather than 0.8%) and sulfur(0.07%, rather than 0.04%). The increased carboncontent is due to the excessive graphite combustion(added to enhance arc stability), and the sulfur con�tent is due to the low basicity of the slag and its largercontent in the initial batch consisting of concentratefrom dry magnetic separation.

Obviously, the metal obtained when using reducedconcentrate from dry magnetic separation may replacehot metal in the arc furnaces at OAO MMK.

The next step is to verify the laboratory results inindustrial conditions, on the DSP�3000 furnace at theYuzhuralmetallplyus plant; the bath can accommo�date 3 t of metal batch. The concentrate from dry mag�netic separation (0–50 mm size class) contains 47.0%FeOtot, 28.2% Femet, 15.8% FeO, 9.2% Fe2O3, 7.2%CaO, 10% MgO, 16.1% SiO2, 5.7% Al2O3, 1.7%MnO, 1.6% C, and 0.5% S. We may consider theresults for melts 1 and 2. The batch for melt 1 contains3.2 t of concentrate from dry magnetic separation. Thefluxes are limestone and foundry sand. The FeO isreduced using electrode cullet (94 kg/t of concen�

Table 5. Chemical composition of metal and slag on smelt�ing steel with the addition of reduced briquets made fromBakal siderite ore

Characteristic

Value for briquets with lignosul�fonates when the briquet

content is, %

Value for briquets

with lime

5 8 10 15

Chemical compo�sition of metal, %

C 0.91 0.82 0.67 0.13

Si 0.02 0.02 0.01 0.01

Mn 0.32 0.41 0.28 0.24

S 0.035 0.043 0.033 0.055

P 0.032 0.018 0.021 0.033

Cr 0.065 – 0.053 0.040

Ni 0.071 – 0.062 0.057

Cu 0.115 – 0.095 0.093

Chemical compo�sition of slag, %

CaO 22.70 15.40 21.00 17.70

SiO2 29.00 27.70 19.10 15.20

MgO 17.00 19.30 – 22.10

MnO 16.10 – 20.20 20.80

Al2O3 6.13 9.68 4.10 4.69

Fetot 5.19 11.40 16.00 14.20

Femet 0.26 — 1.21 0.55

FeO 4.41 2.51 16.30 15.30

Fe2O3 2.16 – 3.08 2.56

S 0.08 0.076 0.20 0.34

P2O5 0.044 0.080 0.15 0.17



trate). The arc burns in ordinary conditions for 10–12 min. The current flows in the melt for 3 h. The sandis introduced after complete melting of the bath,before discharge. The fluidity of the slag permits itstransfer from the furnace to the ladle and then to theslag pot. The metal (total mass 860 kg) is dividedbetween two molds. Some of the metal (around 20%)remains in the furnace and forms the seed for the sec�ond melt. Accordingly, the total metal yield is 1075 kg;this is 215 kg more than the metallic�iron content inthe concentrate from dry magnetic separation. Hence,half of the iron from the oxides is reduced to the metalby the carbon cullet.

In melt 1, the slag contains 14.5% MgO and 7.2%Fetot. Its basicity is CaO/SiO2 = 0.9. By calculation, itsmass is 2890 kg. Hence, the loss of iron is 14%. This isdue to the incomplete (60%) reduction of the concen�trate from dry magnetic separation and its inefficientenrichment in the 0–50 mm size class. Obviously, onrefining the technology, the degree of reductionreaches 80–90%, and the slag yield falls to 1.0–1.5 t/tof metal. The lack of iron oxides permits more com�plete extraction of iron in the steel, and the losses fallto the regular level of 5–7%. Despite the poor qualityof the concentrate from dry magnetic separation, thesteel produced contains 94% the metallic iron and1.9% carbon. Because of the low slag basicity, the sul�fur content is 0.54%.

In melt 2, the content of electrode cullet is reduced(40 kg/t of concentrate). Although the metal losseswith the slag are still 15%, the carburization of themetal is halved. In addition, in melt 2, the sulfur con�tent falls from 0.54% (slag 1) to 0.39%. Hence, it isinexpedient to raise the carbon content significantlyabove the stoichiometric level in order to reduce theiron oxides, since this leads to contamination of themetal.

Comparison of the laboratory and industrial datafor the smelting of concentrate from dry magnetic sep�aration leads to the following conclusions.

(1) The carbon content in industrial melt 2 is80 kg/t of iron, as against 180 kg/t in the laboratory tri�als. This is associated with carburization of the labora�tory metal to 2.6–2.8% (as against 0.87% for theindustrial metal).

(2) Thanks to the high level of reduction of the lab�oratory concentrate (Femet/Fetot = 9.4%) and the lowslag content, the metal losses with the slag may bereduced to the usual level for electrosmelting (4.4%).This confirms that most of the iron losses in the indus�trial melts are due to the low levels of reduction of theconcentrate from dry magnetic separation, on accountof the use of inappropriate equipment.

(30 The sulfur content in the metal in the labora�tory is less than 20% of that in the industrial trials andapproaches that in hot metal: 0.05–0.07%. This isassociated with the lower sulfur content in the labora�tory concentrate (0.26% S) than in the industrial con�

centrate (0.50% S) and the lower sulfur content per 1 tof metal when using enriched concentrate from drymagnetic separation.

Thus, the laboratory and industrial data forreduced concentrates obtained in the dry magneticseparation of siderite ore show that, in electrofur�naces, it is possible in principle to obtain an interme�diate product from magnesia containing 10–12%MgO. Obviously, optimal performance requires thesatisfaction of two conditions: 1) the degree of reduc�tion must be 85–90% [1]; 2) the conditions in theenrichment of the reduced ore (particle size, magneticfield strength, drum speed, etc.) must ensure maxi�mum discharge of the barren rock top tailings and a

Table 6. Chemical composition of metal and slag whensmelting reduced concentrate from dry magnetic separation(in an arc furnace) and yield of smelting products

Characteristic

Value for

melt 2 with lower

basicity

melt 3 with enhanced basicity

Chemical composition of metal, %

C 2.85 2.59

Si 1.19 0.69

Mn 0.44 0.35

S 0.076 0.073

P 0.024 0.014

Chemical composition of slag, %

Fetot 4.69 3.98

Femet 3.28 2.79

FeO 1.17 0.84

Fe2O3 0.71 0.77

CaO 22.50 28.00

SiO2 37.30 37.00

MgO 27.40 23.80

MnO 2.17 2.06

Al2O3 2.88 2.26

P 0.012 0.011

S 0.16 0.19

Product yield, g:

metal 145 135

slag 97 134

residue in crucible 130 125

all products 372 394

total consumption without graphite

388 400

498


MELAMUD et al.

total iron content of 65–75% in the concentrate fromdry magnetic separation [2].

CONCLUSIONS

An enrichment technology for reduced siderite orehas been developed; the concentrate obtained may beused in smelting steel. The new technology includesdry and wet magnetic separation of reduced sideriteore, the production of conditioned briquets fromreduced concentrate, and the smelting of briquets andreduced concentrate pieces in an arc furnace. The

replacement of some of the metal scrap or hot metal byreduced siderite ore is recommended.

REFERENCES

1. Vusikhis, A.S., Heat Treatment and PyrometallurgicalEnrichment of Siderite Ore, Cand. Sci. Dissertation,Institute of Metallurgy, Ural Branch, Russian Academyof Sciences, 1994.

2. Leont’ev, L.I., Vatolin, N.A., Shavrin, S.V., and Shu�makov, N.S., Pirometallurgicheskaya pererabotka komple�ksnykh rud (Pyrometallurgical Processing of ComplexOre), Moscow: Metallurgiya, 1997.

enrichment of reduced siderite ore to produce concentrate for electrosteel smelting

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