2, 20120-1, No.1, pp.1, Vol. 1gnal of Minerals & Materials Characterization & EngineerinJour jmmce.org Printed in the US A. All rights r e served
1
Parameters Affecting the Pr odu ct ion of High Carbon Ferromanganese i n
Closed Submerged Arc Furnace
Mamdouh Eissa*, Hoda El-Faramawy*, Azza Ahmed, Saeed Nabil
and Hossam Halfa
Steel and Ferroalloys Department, Central Metallurgical Research and Development
Institute (CMRDI), P. O. Box 87, Helwan, Cairo, Egypt,
* Corresponding Authors: [e-mail], [e-mail]
ABSTRACT
This study has been performed to investigate the different parameters affecting on the
production of high carbon ferromanganese in closed submerged arc furnace. The analysis of
industrial data revealed that using manganese ores with low Mn/Fe ratio necessitates hi gher
amount of Mn-sinter in the charge. Using Mn-blend with higher Mn/Fe ratio reduces the
coke consumption and this leads to reducing the electrodes consumption. The reco very of Mn
ranges between 70 and 80 %. Much higher basic slag has slight effect on Mn- recovery.
However, as slag basicity increases, the MnO- content of slag decreases. The manganese
content of produced HCFeMn depends mainly on Mn/Fe ratio of Mn-blend. For obtaining
HCFeMn alloy containing minimum 75%Mn, it is necessary to use Mn-blend with Mn/Fe
ratio of higher than 6. A model for determination of the amount and composition of off-gases
has been derived based on the chemical composition and material balance of the input raw
materials and the produced alloy and slag. By using this model, the amount of off-gases was
found to increase by increasing both Mn-blend and coke consumption.
Key words: Ferromanganese, closed Furnaces, carbothermic reduction, Slag basicity
1. INTRODUCTION
At Sinai Manganese Company (SMC), Abu Zenimam, standard high-carbon ferromanganese
(HCFeMn) for the domestic and exported markets is smelted in 21 MVA three phase
submerged electric arc furnace as closed top unit. The closed top submerged arc furnace has
the following advantages comparing with open furnace: less power consumption, kwh/ton
and higher productivity. On the other hand, the requirements for ore used in closed top

2 2 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
furnace are more restricted, e.g. free oxygen must be less than 10% and less friable ore.
Otherwise, crust may be formed leading to occurrence of explosion.
The proper economic production of ferromanganese performance will be improved by
selecti ng the prop er raw mater ials s uitab le for t he closed top submerged arc furnace, applying
the best material balance for the raw materials and enhancing the smelting condition. The
result will be lower consumption of raw materials, reduced specific energy consumption,
good furnace operation, higher alloy quality and lower production cost. Thus, it is of prime
importance to examine the different parameters affecting on the production of high carbon
ferromanganese in closed submerged arc furnace.
2. EXPERIMENTAL PROCEDURE
In the high carbon ferromanganese making process at SMC, different local manganese ores
and imported manganese sinter are blended along with the reducing agent (coke) and flux
materials (dolomite and limestone) are mixed outside of the furnace (often called charge
mix ). The different raw mat erials compo nents are weighed out bas ed on chemical an alysis of
the ores, sinter, fluxes and coke and on the desired composition of alloy and slag. It is desired
to obtain standard high carbon ferromanganese alloy containing at least 75% Mn and
minimum content of phosphorus.
The raw materials mix is transported to hoppers above the furnace from where it is fed by
gravity through chutes passing through the furnace cover.
In the submerged arc furnace, the electrodes are buried deep in the furnace burden and the
reduction reaction takes place near the tip of the electrodes. The current flow between
electrodes creates the intensive heat needed for the high temperature and energy required for
the reduction reactions.
Charge mix is added periodically and the metal and slag are collected during tapping at
appropriate intervals (often at 30 Mw). Produced slag and metal are tapped from the same
tap-hole.
3. RESULTS & DISCUSSION
3.1 Statistical Analysis of Collected Data
The real operating data for producing high carbon ferromanganese at SMC were collected
and statistical analysis of collected data has been conducted to evaluate the different
parameters affectin g on the production process.
The material balance for producing one ton high carbon ferromanganese has been calculated
and an example of the material balance is summarized in Table 1.

Vol.11, No.1 Comparative Study of the Kinetics 3
The electric are s teelmak ing furnace operat es as a batch m elti ng process prod ucing batches of
molten steel known "heats". Thus, it is easy to determine the input and output of every heat.
On the other hand, the closed top submerged arc furnace for producing high carbon
ferromanganese operates by continuous process. The charge mix is added periodically and
the metal and slag are collected during tapping at appropriate materials (often every power
consumption of 30Mw). Consequently, the tapped metal and slag are not the output of input
charge mix esp ecial l y when changing the charge materials composition or if the charge mix is
subjected to modification. For that reason, the material balance calculations were done for
periods of one month, or periods of some operations days working with constant charge mix.
Table 1: Material balance for producing one ton of HC-FeMn alloy
Raw
materials Kg MnO
2
MnO Fe Fe
2
O
3
SiO
2
Al
2
O
3
CaO MgO Na
2
O BaO P
2
O
5
C CO
2
CO H
2
O
Mn-ore1
976
458.4 206 118.6 83.3 24.4 26.4 13.7 3.416 27.13 2.235 7.12
Mn-ore2 392 166.7 78.8 68.99 43.1 9.016 8.04 3.53 1.254 5.88 0.763 2.55
Mn-sinter 653 130.6 382 42.9 50.4 25.47 1.96 1.18 2.612 2.612 1.137 4.83
Dolomite 245 2.132 11.9 3.185 72 46.8 107 1.27
Limestone 140 0.742 5.74 1.022 72.2 0.98 58 0.56
Coke 458.3 0.34 7.975 23.9 17.01 1.55 0.13 0.033 394 4.58
Electrodes
16.9
16.9
Elect.casing 0.708 0.708
Sum 2882 755.7 667 0.71 241.3 218 80.1 182 66.3 7.28 35.62 4.17 411 165 20.9
Kmol 8.69 9 .4 0.013 1.51 3.64 0.79 3.25 1.64 0.117 0.232 0.029 34.2 3.76 1.16
Products Kg Mn Fe MnO FeO SiO
2
Al
2
O
3
CaO MgO C CO
2
CO H
2
O
FeMn 1000 752 173 70
Slag 690 129.9 5.87 182 80.05 185 63.8
Gases
1024
278
725
20.9
Losses 168
Sum 2882 752 173 129.9 5.87 182 80.05 195 53.8 70 278 725 20.9
Kmol 13.67 3.09 1.83 0.08 3.03 0.78 3.48 1.35 5.83 6.32 25.9 1.16
Metal composition (%) Slag composition (%) Gas composition (kmol)
Mn Fe C P Si MnO FeO CaO MgO SiO
2
Al
2
O
3
CO
2
CO H
2
O
75.2
17.3
7
0.18
0.18
18.8
0.85
26.8
9.2
26.3
11.6
6.32 25.9 1.16
3.2 Effect of Different Parameters
3.2.1 Raw Materials
3.2.1.1 Mn- Ores
Blends of local manganese ores and imported manganese sinter are used at SMC for
producing the high carbon ferromanganese. The local manganese ores are law and medium
grades with Mn/Fe ratio ranges between 3 and 5.5.
Manganese to iron ratio is very important in the ferromanganese production process. Mn /Fe
weight ratio of 7.5 is required for production standard ferromanganese alloy with 78 % Mn

4 4 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
[1]. Furthermore, the local manganese ores vary widely in their content of manganese, iron,
silicon, alumina, lime, magnesia, potassium and sodium oxides, barium oxide and
phosphorus.
Mixtures of two Mn- ores are usually used to be blend with Mn-si nter. The charged Mn-ores
mixture amounts to 890 - 1890 kg per ton produced alloy (average 1375 kg/ton) with Mn/Fe
ratio ranges between 3.3 and 5.5 (average 4.08).
3.2.1.2 Mn-Sinter
Mn-sinter is suited for use in ferromanganese furnaces, since it is mechanically strong and
thermally stable, allowing the gas to disperse evenly throughout the preheating and pre-
reduction zone. Moreover, the requirements for ore used in closed top furnace are more
restricted, i.e. excess oxygen must be less than 10 %. To adjust this vital parameter in closed
top furnaces, excess oxygen, Mn-sinter is used in the charge mix. Excess ox ygen is defined as
the difference between the actual amount of oxygen chemically bounded to manganese and
the theoretically amount of oxygen assuming the total amount of manganese being present in
the monoxide MnO state.
At SMC, Mn-sinter is used to increase the Mn-Fe ratio of the blend and reduce the excess
oxygen. Mn-sinter has a higher Mn /Fe ratio ranges between 9.3 and 12.6, and the charged
amount ranges between 385 and 870 kg per one ton produced ferromanganese alloy (average
642 kg/ton). This amount represents 22 to 45% of the Mn- blend (average 32.2%).
By adding Mn –sinter into the Mn–ores mixture, the Mn /Fe ratio of Mn-blend increases to
4.5 – 6.4 (average 5.4) and the Mn-blend amounts to 1745 - 2430 kg per ton produced
ferromanganese alloy (average 1998 kg/ton).
Furthermore, addition of Mn-sinter reduces the excess oxygen, Figure1. As Mn/Fe ratio of
local Mn-ores increases, the Mn-sinter weight per one ton produced HCFeMn decreases,
Figure 2, and Mn-sinter% in the Mn-blend decreases, Figu re 3 .

Vol.11, No.1 Comparative Study of the Kinetics 5
0
1
2
3
4
5
6
7
8
9
10
20 25 30 35 40 45 50
Mn-Sinter % in Mn-blend, w t%
Excess oxygen, %
Figure1: Mn-si nt er % in Mn-blend versus excess oxygen
0
100
200
300
400
500
600
700
800
900
1000
33.5 44.5 55.5 6
Mn/Fe ratio of Mn-ores
Sin ter wt (Kg ) / ton FeMn
Figure 2: Mn/Fe ratio of Mn-ores versus Mn-sinter wt/ton FeMn

6 6 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
0
10
20
30
40
50
33.5 44.5 55.5 6
Mn/Fe ratio of Mn-ores
Mn-sinter % in Mn-blend, wt%
Figure 3: Mn/Fe ratio of Mn-ores versus Mn-sinter% in Mn-blend
3.2.1.3 Reducing Agent
Coke is added as a source of carbon for ore reduction. The interior of a furnace producing
high carbon ferromanganese consists of two main zones with different characteristics: the low
temperature pre-reduction zone, and the high temperature coke bed zone. As the raw
materials move down in the pre-reduction zone, the higher oxides of manganese are pre-
reduced in solid state to Mn3O4 and preferably further to MnO by CO gas formed in the crater
zone. The extent of the simultaneously running Boudouard reaction (CO2+C = 2CO) is
responsible for the variation in carbon. After further reheati ng, th e pre-reduced ore and added
fluxes start melting at temperatures of about 1250oC to 1300oC. The coke remains solid, so
below this area there is a permanent coke bed [2]. The melting together of ores and fluxes and
reduction of MnO dissolved in the slag phase take place in the coke bed. The coke bed starts
approximately at the tip of the submerged electrodes. It constitutes a permanent reservoir of
coke. The relative amount of coke in the charge mix determines whether the coke bed
increases, decr eases or stab le in siz e. In addition to being the ch emical reduct ant it i s also th e
heating element of the process where the electric current runs and ohmic energy is produced.
The coke consumption ranges between 400 - 550 kg/ton HCMnFe (average 462 kg/ton).
The coke consumption increases as the Mn-blend weight increases, Figure 4, and Mn/Fe of
the Mn-bl end decreas es, Figure 5.

Vol.11, No.1 Comparative Study of the Kinetics 7
0
100
200
300
400
500
600
700
1700 1800 1900 2000 2100 2200 23002400 2500
Mn-blend weight (Kg) / ton FeMn
Coke consumption (Kg) / ton FeMn
Figure 4 : Mn-blend weight per ton FeMn versus coke consumption
0
100
200
300
400
500
600
4.5 55.5 66.5
Mn/Fe ratio of blend
Coke wt (Kg) / ton FeMn
Figure 5: Mn/Fe ratio of Mn-blend versus coke consumption

8 8 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
3.2.1.4 Flux Materials
Limestone and dolomite are used as flux materials. These basic fluxes are added to give the
slag suitable chemical properties, smelting temperature and viscosity in order to secure good
furnace operation and a high manganese reco very [1].
The amount of added limestone and dolomite depends on the required CaO and MgO to
attain the specific slag basicity.
The flux consumption per ton HCFeMn ranges between 200 and 450 kg (average 340 kg).
About two third of this amount is dolomite and the other third is limestone.
The flux consumption is correlated with the basicity and SiO2 content of Mn-blend, Figures
6-8 . As the silica amount or percent in Mn-blend increase, the flux addition increases. On the
other hand, as the basicity of Mn-blend increases, the flux addition decreases.
0
100
200
300
400
500
600
80100 120 140 160 180 200 220
SiO2 wt in the blend (Kg) / ton FeMn
Flux wt (Kg) / ton FeMn
Figure 6: SiO2 weight in Mn-blend per ton FeMn versus coke consumption

Vol.11, No.1 Comparative Study of the Kinetics 9
0
100
200
300
400
500
5678910 11
SiO2 % in the blend, wt%
Flux wt (Kg) / ton FeMn
Figure 7 : SiO2 % in Mn-blend versus flux consumption per ton FeMn
0
100
200
300
400
500
0.2 0.3 0.4 0.50.6 0.7
Basicity of Mn-blend, (CaO + MgO) / SiO2
Flux wt (Kg) / ton FeMn
Fig.8: Basicity of Mn-blend versus flux consumption per ton FeMn
3.2.2 Electrodes
The electrodes of three-phase electric furnace are made of carbonaceous material, and they
consumed during normal production. The consumption is usually large near the tip of the

10 10 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
electrode where the temperature is high and the reactants are more active. To keep the
electrode tip at the same position it is therefore necessary to prolong the electrode regularly.
The electrodes consumption per ton HCFeMn ranges between 8 and 37 kg (average 17.5 kg).
The electro des consumption increases as the coke consumption per ton HCFeMn increases,
Figure 9.
3.2.3 Electrodes Casing
Electrodes casing is a low carbon steel and is consumed with the consumption of electrodes.
The electrodes casing consumption ranges between 0.4 and 1.3 kg / ton HCFeMn (average
0.6 kg/ton
0
5
10
15
20
25
30
35
40
350 400 450 500 550 600 650
Coke consumption (Kg) / ton FeMn
Electrodes consumption (Kg) / to FeMn
Figure 9: Coke consumption versus electrodes consumption per ton FeMn
3.3. Products
3.3.1 High Carbon Ferromanganese
The quality of high carbon ferromanganese depends mainly on the content of manganese and
phosphorus. The phosphorus content of standard HCFeMn is < 0.2 %. Most of the
phosphorus in the ore remains in the finished product. The recovery of phosphorus is high
(average 98%) and decreases with increasing the slag basicity as shown in Figure 10.
However, due to the relatively low phosphorus content of Mn-blend, the phosphorus content
in the produced HCFeMn is low of average 0.18 %. The recovery of Mn ranges between 70
and 80 % (average 75 %). In smelting of high carbon ferromanganese, manganese recovery
was found to increase b y increas in g s lag bas ici ty [3-10] and decreasing slag viscosity [5,6].

Vol.11, No.1 Comparative Study of the Kinetics 11
Figure 11 illustrates slight effect of much higher basic slag on Mn- recovery. In the range of
the basic slag used, the negative higher viscosity of much higher basic slag [11] hinders the
positive effect of increasing the activity of manganese oxide in the slag melt due to existing
of higher content of basic oxides CaO and MgO. The manganese content of produced
HCFeMn depends mainly on Mn/Fe ratio of Mn-blend as shown in Figure 12.
For obtaining HCFeMn alloy containing minimum 75%Mn, it is necessary to use Mn-blend
with Mn/Fe ratio of higher than 6.
The recovery of iron is higher than the recovery of manganese. Its average is about 96%. In
the range of basic slag used, slag basicity has insignificant effect on iron recovery, Figu re 13.
The silicon content in the metal is very low (average 0.18 %) as a result of high slag basicity
and low operating temperature, leading to low Si recovery of only 2 %, Figu re 14 .
0
10
20
30
40
50
60
70
80
90
100
110
120
1.2 1.25 1.3 1.35 1.4 1.45 1.5
Slag Basicity, (CaO + MgO) / SiO2
Phosph o ru s r eco very,%
Figure 10: Slag basicity versus phosphorus recovery

12 12 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
0
10
20
30
40
50
60
70
80
90
100
1.2 1.25 1.3 1.35 1.4 1.45 1.5
Slag Basicity, (CaO + MgO) / SiO2
Manganese Recover y,%
Figure11: Slag basicity, (CaO + MgO) / SiO2, versus manganese recovery
60
65
70
75
80
4.5 55.5 66.5
Mn/Fe Ratio of Blend
Mn Content in FeMn Alloy,%
Figure12: Mn / Fe ratio of Mn-blend versus manganese content in FeMn

Vol.11, No.1 Comparative Study of the Kinetics 13
0
10
20
30
40
50
60
70
80
90
100
110
120
1.2 1.25 1.3 1.35 1.4 1.45 1.5
Slag Basicity, (CaO + MgO) / SiO2
Iron Reco very,%
Figure 13: Slag basicity, (CaO + MgO) / SiO2, versus iron recovery
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
1.2 1.25 1.3 1.351.4 1.45 1.5
Slag Basicity, (CaO + MgO) / SiO2
Sil iconi Reco very,%
Figure 14: Slag basicity, (CaO + MgO) / SiO2, versus silicon recovery
3.3.2 Slag
Besides manganese and iron oxide, the manganese ores contain SiO2, Al2O3, CaO, MgO,
Na2O, BaO and P2O5. Coke ash also contains SiO2, Al2O3 and smaller amount of CaO and

14 14 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
MgO. In addition, CaO- and MgO- containing fluxes (dolomite and limestone) are added to
the raw materials mixture. These oxides will end up in the slag phase.
Most of iron oxi des are reduced while Mn-oxides are partially reduced from the slag to form
the metal phase. Less SiO2 is reduced because silicon is more stable than MnO2. Even more
stable oxides are CaO, MgO and Al2O3. These oxides are considered to be irreducible, and
they maintain their mutual ratio in the slag during the reduction process. The amount of slag
produced per ton HCFeMn ranges between 460 and 940 kg (average 661kg).
The amount of slag weight depends on the amount of Mn-blend, Figu re 15 . This can be
attributed to increase of gangue materials and irreducible oxides which enter the slag phase.
In addition, limestone and dolomite are added in the charge mix to adjust the slag basicity.
The formula of mass ratio (CaO+MgO)/ SiO2 is often used to express the slag basicity. As
much amount of limestone and dolomite are added the produced slag weight increases,
Figure 16.
During the period of collected data, high slag basicity is used to increase the manganese
recovery. The MnO–content of slag ranges between 16 and 28% (average 20%) depending
primarily on slag basicity, Figure 17. As slag basicity increases, the MnO- content of slag
decreases.
0
100
200
300
400
500
600
700
800
900
1000
1700 1800 1900 2000 2100 2200 2300 2400 2500
Mn-blend weight (Kg) / ton FeMn
Slag weight (Kg) / ton FeMn
Figure 15: Mn-blend weight versus slag weight per ton FeMn

Vol.11, No.1 Comparative Study of the Kinetics 15
0
100
200
300
400
500
600
700
800
900
1000
100 150 200250 300 350 400450 500
Flux weight (Kg) / ton FeMn alloy
Slag weightt (Kg) / ton FeMn alloy
Figure 16: Flux weight versus slag weight per ton FeMn
0
5
10
15
20
25
30
1.2 1.25 1.3 1.351.4 1.45 1.5
Slag basicity, (CaO + MgO) / SiO2
MnO% in slag, wt%
Figure 17: Slag basicity, (CaO + MgO) / SiO2, versus MnO % in slag

16 16 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
3.3.3 Gases
The amount and analysis of the gases leaving the furnace is not available at SMC due to
unavailability of measuring devices. Assumptions have been made in order to calculate the
amount and composition of the gases. It is assumed that the temperature of the gases at the
furnace top, which is in excess of 200oC, being high enough for evaporation of moisture from
charge as soon as the materials fall into the furnace. Evaporation of moisture is very rapid.
Thus, all H2O (l) enters the furn ace leav es as H2O (g) with the off-gas.
The other constituents of gas phase are CO and CO2. By determining the amount of carbon
and oxygen in gases, the amount of CO and CO2 can be calculated.
The carbon amount in CO and CO2 mixture in off-gas can be calculated by subtraction the
carbon contained in the produced HCFeMn from the sum of carbon contained in the added
coke, fluxing materials and consumed electrodes,
C {CO+CO2} = C ( C oke) + C (electrodes) + C (flu x) – C (alloy) (1)
The oxygen amount in CO and CO2 mixture in off-gas can be calculated by subtraction the
oxygen contained in the produced slag from the oxygen contained in the raw materials (local
Mn-Ores, Mn-Sinter, limestone, dolomite and coke ash),
O {CO+CO2} = O (Raw materials) – O (slag) (2)
The sum of carbon and oxygen in (CO +CO2) mixture equals the sum of CO and CO2 in off-
gas:
C {CO+CO2} + O {CO+CO2} = {CO +CO2} in gases (3)
Consequently, the total weight of gases can be calculated:
Gases weight = CO + CO2 + H2O (4)
Carbon / oxygen ratio is calculated and correlated with CO2/ (CO+CO2) as shown in Fig (18).
The following equation is fitting this relation:
CO2 / (CO+CO2) wt ratio = -266.67 (C/O) + 200 (5)
The amount of gases per one ton HCFeMn ranges between 855 and 1316
kg (average 1016 kg). The CO2 / (CO+CO2) wt ratio ranges between 0.05 and 0.45 (average
0.25)
Figures (19 -21) reveal increasing the amount of gases per one ton HCFeMn by increasing
both Mn-blend and coke and sum of Mn-blend and coke, respectively. This can be attributed
to the higher oxygen and carbon in the charge mix.

Vol.11, No.1 Comparative Study of the Kinetics 17
y = -266.67x + 200
-10
0
10
20
30
40
50
60
70
80
90
100
110
0.3 0.4 0.5 0.60.7 0.8
Carbon:oxygen wt ratio in CO-CO2 mixture
CO2 / (CO + CO2), wt%
Figure18: Carbon: oxygen ratio versus CO2 % in CO – CO2 mixture
0
200
400
600
800
1000
1200
1400
1700 1800 1900 2000 2100 2200 2300 2400 2500
Mn-blend weight (Kg) / ton FeMn
Gases weight (Kg) / ton FeM n
Figure 19: Mn-blend wt versus gases wt per ton FeMn

18 18 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
0
200
400
600
800
1000
1200
1400
350 400450 500 550600 650
Coke consumption (Kg) / ton FeMn
Gases weight (Kg) / ton FeMn
Figure 20: Coke consumption versus gases wt per ton FeM n
Figure 21: Sum of Mn-blend and coke wt versus gases wt per ton FeMn
0
200
400
600
800
1000
1200
1400
2100 22002300 2400 2500 2600 2700 2800 2900 3000
(Mn-blend+Coke) wt (Kg) / ton FeMn
Gases wt (Kg) / ton F eM n

Vol.11, No.1 Comparative Study of the Kinetics 19
3.3.4 Losses
From material balance calculations, weight losses up to 350 kg per one ton produced
HCFeMn has been detected (average 162 kg). The average weight losses represent about
5.5% of the charge mix. These weight losses could be attributed to materials losses in
handling and charging process, dust leaving the furnace with the off-gas, weight errors and
metal lost in slag and in crushing to the suitable sizes.
4. CONCLUSIO NS
From the results of analysis of industrial data for producing HC-FeMn in closed submerged
arc furnace, the following conclusions can be deduced:
• As Mn/Fe ratio of local Mn-ores increases, t he M n-sint er weight per one ton produced
HCFeMn decr eases , and Mn-sinter% in the Mn-blend decreases.
• The coke consumption increases as the Mn-blend weight increases and Mn/Fe of the
Mn-blend decreases.
• As the silica amount or percent in Mn-blend increase, the flux addition increases. On
the other hand, as the basicity of Mn-blend increases, the flux addition decreases.
• The electrodes consumption increases as the coke consumption per ton HCFeMn
increases .
• Most of the phosphorus in the ore goes to the finished product. The recovery of
phosphorus is high of about 98% and slightly decreases with increasing the slag
basicity. For producing standard HCFeMn containing < 0.2 % P, charging of Mn-
blend with low phosphorus content is required.
• The recovery of Mn ranges between 70 and 80 %. Much higher basic slag has slight
effect on Mn- recovery. The negative higher viscosity of much higher basic slag
hinders the positive effect of increasing the activity of manganese oxide in the slag
melt due to existing of higher content of basic oxides CaO and MgO.
• The manganese cont ent of produced HCFeMn depends mainly on Mn/Fe ratio of Mn-
blend. For obtaining HCFeMn alloy containing minimum 75%Mn, it is necessary to
use Mn-blend with Mn/Fe ratio of higher than 6.
• The recovery of iron is higher than the recovery of manganese. Its average is about
96%. In the range of basic slag used, slag basicity has insignificant effect on iron
recovery.
• The silicon content in the produced alloy is very low (average 0.18 %) as a result of
high slag basicity and low operating temperature, leading to low Si recovery of only 2
%.
• The amount of produced slag depends on the amounts of Mn-blend and fluxing
materials.
• The MnO–content of slag depends primarily on slag basicity, as slag basicity
increases , t he Mn O- con ten t of sl ag decreases .

20 20 Mamdouh Eissa, Hoda El-Faramawy Vol.11, No.1
• A model for determination of the amount and composition of off-gases has been
derived based on the chemical composition and material balance of the input raw
materials and the produced alloy and slag.
• The amount of off-gases increases b y increas ing bot h Mn-blend and coke amounts.
• In the production process, about 5.5% of the charge mix weight is lost due to
materials losses in handling and charging process, dust leaving the furnace with the
off-gases , weight errors and metal lost in slag and in crushing to the suitable sizes.
ACKNOWLEDGEMENT
This work is a part of complex study carried out through a project financed by the Science
and Technological Development Fund (STDF), Egypt. The authors would like to
acknowledge STDF due to their financial support and all facilities they offered to perform
this work. Cordial thanks and deep appreciation are due to Eng. Mohamed Abdel Samie
Chairman & Managing Director of Sinai Manganese Company (SMC), for his
encouragement, sound support and providing technical data. The counterparts of SMC
offered all facilities and required data for performing this study. Special thanks and gratitude
are due to all members in Steel and Ferroalloys Department, CMRDI and technical staff of
SMC Company.
REFERENCES
[1] Ol sen S. E., Tangstad M. and Lindstad T., 2007, Production of Manganese Ferroalloys,
P. 247, SINTEF and Tapir Academic Press, Trondheim
[2] Tan gstad M. , 1996, The Hi gh Carb on Ferroman ganese Process-Coke Bed Relations,
PhD Thesis, 49, Department of Metallurgy, The Norwegian Institute of Technology,
Trondheim
[3] V.I. Nikoleav, 1974, Steel in the USSR, pp. 299-302
[4] N. Chernyatin, V. G. Mizin, I.A. Kopyrin and E. A. Simonova, 1981, Stal, 9, pp. 38-44
[5] Y. Kamel, T. Miyazaki, H. Yamaoka, 1993, ISIJ International, 33 , No.2, pp. 259-266
[6] X. Bi et al, 1993, Ironmaking and Steelmaking, 20, No. 6, pp.476-481
[7] P.A.Kravchenko et al, Steel in Translation, 38(2008), No. 9, pp. 764-760
[8] V.P. Vorob,ev, A. D. Godunov and V. Ignat,v, 2009, Steel in Translation, 39, No.3,
pp.243-247
[9] R. Kononov, O. Ostrovski and Ganguly, 2009, ISIJ International, 49, No.8, pp. 1099-
1106
[10] V.Tathavadkar, V.Singh, P.K.Mishra, P. Mallick and B. D. Nanda, 2010, Ironmaking
and steelmaking, 37, No. 2, pp.103-111.
[11] Slag Atlas, 1981, Ed. Verein Deutscher Eisenhuttenleute, Verlag Staheisen GmbH,
Dusseldorf, p. 282.