Home PageTechnologyCase StudiesProfileContactSecure area

Ferrochromium

The ferrochromium industry generates appreciable tonnages of metallic fines falling into the zero to 10mm size range, which are derived from their product alloy crushing and screening plants. Such dusts, besides presenting localized environmental problems, are difficult to reprocess in conventional submerged-arc electric furnaces.  At the same time, this industry also generates chromite ore fines, which, due to their lower chromium contents, are uneconomic to process by the conventional smelting route. Consequently, AMRT in a joint cooperation with one of South Africa’s major ferrochromium producers, Samancor, has successfully demonstrated that an acceptable grade of ferrochromium can be produced by smelting a combination of these two types of fines material, namely metallic fines and chromite fines, together with a carbonaceous reducing agent and slag modifying agents in a melt reduction furnace. The following table presents an array of some typical results that were obtained.

AMRT melt reduction furnace technology as applied to smelting a mixture of metallic ferrochromium fines and chromite ore fines generated by Samancor, South Africa

 

Furnace inputs

Furnace outputs

 

Chromite fines
(%)

Metallic fines
(%)

Metal
(%)

Slag
(%)

Gas
(% by volume)

Cr

30.4

48.8

54.0

3.1

 

Fe

20.3

33.7

38.6

0.05

 

Si

 

4.5

0.3

 

 

Al

 

0.01

0.00

 

 

Mn

0.2

 

0.1

0.2

 

SiO2

3.2

 

 

32.0

 

CaO

0.3

0.5

 

23.7

 

MgO

10.1

3.0

 

16.5

 

Al2O3

14.9

2.5

 

21.8

 

TiO2

0.8

 

 

1.0

 

P

 

0.03

0.01

 

 

S

 

0.04

0.01

 

 

C

 

5.8

7.0

 

 

CO2

 

 

 

 

28.8

H2O

0

0

 

 

0.0

 

The reactions involved were:

FeCr2O4 + 2Si = Fe + 2Cr + 2SiO2

FeCr2O4 + 4C = Fe + 2Cr + 4CO

which drew 1870 kWh per metric ton of metallic-ore fines mixture.

Examples of materials that have been produced by or processed in AMRT’s melt reduction furnaces are:

Copper

Cobalt

Nickel

Tin

Zinc and lead oxide and sulphides

Ferrochromium

Ferromanganese

Ferrotitanium

Precious metal-bearing wastes

Ancillary processes and procedures associated with AMRT’s furnace operations

 
 
AMRT © 2008