The present invention relates to an improved process for production of low phosphorous, low
manganese base iron metal through cold blast cupola furnace.
It is well known that in jobbing and spun pipe producing foundries, cupola is a very
commonly used versatile melting unit used for production of cast iron and ductile iron,
malleable iron castings.
At present there are a number of items which calls for low phosphorous, and low manganese
base iron metal which is presently produced through electric furnace route which is
expensive. Moreover, the rapid increase in electric steel making has led to widespread
concerns about a possible future shortage of scrap, the basic feed stock for most EAF plants.
The process will help in achieving reduced power consumption, tap to tap time and input
productivity.
It is the basic objective of the present invention to provide for process for production of low
phosphorous, low manganese, base iron metal through a simple and essentially cost-effective
route suitable for use in electric furnace to produce quality steel.
The another object of the present invention is to provide for method of manufacture of low
phosphorous, low manganese, base iron metal through cold blast cupola furnace which would
be cost-effective route and thus avoid the need of expensive pig iron.
Yet further object is to provide a process for manufacture of low phosphorous/low
manganese base iron metal through cold blast cupola furnace without oxygen enrichment
thereby making the process much more simple and cost-effective.
Yet further object is to provide for the process for production of low phosphorous, low
manganese, base iron metal through cold blast cupola furnace wherein the base iron metal
can be produced using conventional material/gadgets and thereby making the process and its
operation simple.
Yet further object is directed to the process of manufacture of low phosphorous, low
manganese, base iron metal through cold blast cupola furnace which would reduce power
consumption, tap to tap time and increase productivity.
Yet further object is directed to the process of manufacture of low phosphorous, low
manganese base iron metal through cold blast cupola furnace which can be directly utilised in
the electric arc furnace for production of steel casting apart from other specialised
applications.
Thus according to the present invention there is provided an improved process for production
of low phosphorous, low manganese, base iron metal through cold blast cupola furnace
comprising the following steps :
i) melting of higher percentage of steel scrap of upto 80% and H.B. iron with or without
pig iron in cold blast cupola furnace ;
ii) adding coke with low phosphorous, low ash content into said cold blast cupola ;
iii) subjecting the cupola metal to treatment in electric arc furnace with addition of
sponge iron and without addition of oxygen to thereby produce liquid steel (base
metal) having low manganese content of 0.14 to 0.15 to 0.02 to 0.04 and low
phosphorous content of 0.04 to 0.05 to 0.010 to 0.018.
Preferably, following the improved process of the invention the base metal obtained has low
silicon content of 0.01to 0.04 to Trace%.
The input charge into the cupola furnace comprise hot briqueted iron 20-
60%, steel scrap 20-70% and the balance pig iron. The coke charged in
the cupola is also of low ash and low phosphorous content of 0.13-0.15%
Importantly, the tapping temperature is maintained in the higher range of
1420-1450°C and deslagging is carefully attended for obtaining the clean
metal and the ladle is maintained red hot.
Preferably, the melting is completed in about 100-120 minutes with
reduced power consumption of 400-450 kw/ton. Following the above
process 50% of cupola metal can be treated with DRI sponge 50% without
any oxygen addition in the electric arc furnace to produce the liquid steel.
The fluidity of the metal is maintained in good condition and the
temperature of the metal maintained as high as 1420 to 1470°C.
Preferably in the above process of the invention the input charge material
should be selective and of known chemistry and to be used from same
batch. Also, low phosphorous, low sulphur charge mix should be used
alongwith low ash, low phosphorous, coke with the tapping temperature
maintained high (1420 - 1450°C), deslagging should be properly done for
obtaining clean metal and the ladle should be red hot, preferably with
arrangement for facility for quick analysis of base metal.
The details of the invention its objects and advantages are explained
hereunder in greater detail in relation to the non-limiting exemplary
illustrations as per the accompanying figures wherein ;
Fig. 1 is a schematic illustration of a flow diagram illustrating the process
of the invention.
As illustrated in said figure a mix of Steel Scrap 0-80%, H.B. Iron 30 - 60% and Pig Iron 0 -
20% is used as the initial charge into the Cold Blast Cupola.
Thereafter, coke with low phosphorous and low manganese content is fed into the cold blast
cupola. From the cupola, the cupola metal 50% is transferred into the electric arc furnace
wherein further DRI sponge 50% is added in the EAF. The chemical analysis of the input raw
material used are detailed hereunder in Table-1

In the electric arc furnace without use of any additional oxygen, the metal is subjected to
melting in order to obtain the liquid steel.
Following the above process several trials were carried out using a 5T Arc Furnace and the
results are represented in Table 2 hereunder:

It would thus be evident from the above that by way of the improved process it is now
possible to produce low phosphorous, low manganese, base iron metal through cold blast
cupola furnace having a carbon in the range of 3.1 to 3.5%, silicon 0.42 to 0.52%, Manganese
0.16 to 0.27%, sulphur 0.05 to 0.06% and phosphorous 0.05 to 0.07%.
It is thus possible by way of the above process of the invention to provide for
i) melting of higher percentage steel scrap (70%) and H.B. Iron in cold blast cupola
furnace;
ii) production of low silicon (0.3-0.6) low manganese (0.17-0.27) base iron metal from
cold blast cupola furnace without oxygen enrichment;
iii) utilization of low Si, low Mn base iron metal for subsequent production of steel
castings in foundry.
The production of good quality base iron metal will open a new horizon for captive and
jobbing foundries as many people are not aware of this type development and this has got
enormous potential for current cost competitive market.
In jobbing foundries for grey irons and steel castings production where
cupola and Arc furnace are there, the cupola hot metal can be directly
utilised in the electric are furnace for production of steel castings. This
can also be used for extra low carbon, low silicon steel for special
applications.
WE CLAIM
1. An improved process for production of low phosphorous, low manganese, base iron
metal through cold blast cupola furnace comprising the following steps :
i) melting of higher percentage of steel scrap of upto 80% and H.B. iron with or without
pig iron in cold blast cupola furnace ;
ii) adding coke with low phosphorous, low ash content into said cold blast cupola ;
iii) subjecting the cupola metal to treatment in electric arc furnace with addition of
sponge iron and without addition of oxygen to thereby produce liquid steel (base
metal) having low manganese content of 0.14 to0.15 to 0.02 to 0.04 and low
phosphorous content of 0.04 to 0.05 to 0.010 to 0.018.
2. An improved process as claimed in claim 1 wherein the base metal obtained has low
silicon content of 0.01 to 0.04 to Trace%.
3. An improved process as claimed in anyone of claims 1 or 2 wherein the input charge into
the cupola furnace comprise hot briqueted iron 20-60%, steel scrap 20-70% and the
balance pig iron.
4. An improved process as claimed in anyone of claims 1 to 3 wherein the coke charged in
the cupola is also of low ash and low phosphorous content of 0.13-0.15%.
5. An improved process as claimed in anyone of claims 1 to 4 wherein the tapping
temperature is maintained in the higher range of 1420-1450°C.
6. An improved process as claimed in anyone of claims 1 to 5 wherein deslagging is
carefully attended for obtaining the clean metal and the ladle is maintained red hot.
7. An improved process as claimed in anyone of claims 1 to 6 wherein the melting is
completed in about 100-120 minutes with reduced power consumption of 400-450
kw/ton.
8. An improved process as claimed in anyone of claims 1 to 7 wherein 50% of cupola metal
is treated with DRI sponge 50% without any oxygen addition in the electric arc furnace
to produce the liquid steel.
9. An improved process as claimed in anyone of claims 1 to 8 wherein the fluidity of the
metal is maintained in good condition and the temperature of the metal maintained as
high as 1420 to 1470°C.
10. An improved process substantially as herein described and illustrated with reference to
the accompanying figures and examples.

The present invention relates to an improved process for production of low
phosphorous, low manganese hot metal through cold blast cupola
furnace. The improved process comprising melting of higher percentage of
steel scrap of upto 80% and H.B. iron with or without pig iron in cold
blast cupola furnace ; adding coke with low phosphorous, low ash content
into said cold blast cupola ; subjecting the cupola metal to treatment in
electric arc furnace with addition of sponge iron and without addition of
oxygen to thereby produce liquid steel (base metal) having low manganese
content of 0.14/0.15 to 0.02/0.04 and low phosphorous content of
0.04/0.05 to 0.010 to 0.018. Preferably, following the improved process of
the invention the base metal obtained has low silicon content of
0.01/0.04 to Trace%. The invention thus provides a method of
manufacture of low phosphorous, low manganese hot metal through cold
blast cupola furnace without oxygen enrichment thereby making the
process much more simple and cost-effective to avoid the need of
expensive pig iron.