TECHNICAL FIELD
The present disclosure relates to a process of production of high phosphorus pig iron. The said
process involves production of high phosphorus iron by employing basic oxygen furnace
(BOF) slag or Linz-Donawitz slag. The objective of the process of the present disclosure is to
not use prime raw material such as rock phosphate for the said production of high phosphorus
iron.
BACKGROUND OF THE DISCLOSURE
High phosphorus iron is generally produced by mini blast furnaces by using prime raw material
such as rock phosphate which provides phosphorus into the iron. Typically, mini blast furnaces
produce normal pig iron and phosphorus pig iron is produced in special batches/campaigns, in
which rock phosphate is added. However, this process of production of phosphorus iron has
disadvantages, such as-
. It generates intermediate range phosphors pig iron having 0.2% to 0.5% phosphorus
which apparently cannot be considered as prime product; and
. The raw material employed in the process, such as rock phosphate is expensive and is
not readily available.
Due to the non-availability of pig iron with high phosphorus content, there are instances of
importing Fe-P, a ferro alloy which provides phosphorus, which is further adding to the cost in
smelters, railways, automotive, etc.
Thus, there appears to be a need for a process which can mitigate the above noted limitations.
The present disclosure intends to overcome all the limitations observed in the art for the
production of pig iron with high phosphorus content.
SUMMARY OF THE DISCLOSURE
The present disclosure describes a process for producing pig iron having phosphorus content
in range of about 0.5% to 3.0%, said process comprising step of charging BOF slag or LD slag
along with component selected from a group comprising coke, nut coke, prime grade iron ore,
low grade iron ore, prime grade iron agglomerate, low grade iron agglomerate, or any
combination thereof, and flux, in to furnace to obtain the said pig iron.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the disclosure may be readily understood and put into practical effect, reference
will now be made to exemplary embodiments as illustrated with reference to the accompanying

figure. The figure together with detailed description below, are incorporated in and form part
of the specification, and serve to further illustrate the embodiments and explain various
principles and advantages, in accordance with the present disclosure where:
FIGURE 1 illustrates comparison of the process of the present disclosure and that of the
process available in the art (prior art).
DETAILED DESCRIPTION
The present disclosure relates to a process of producing pig iron with high phosphorus content.
The present disclosure relates to a process of producing pig iron with high phosphorus content
by employing process use wastes including but is not limited to steel plant waste such as basic
oxygen furnace (BOF) slag or Linz-Donawitz (LD) slag, waste of iron ore beneficiation process
and waste from Fe-Mn processing plant.
The present disclosure relates to a process of producing pig iron with high phosphorus content
without employing prime raw material, such as rock phosphate in the process.
The present disclosure relates to a process of producing pig iron with high phosphorus content,
wherein the said process is cost effective as it is not employing the prime raw material, such a
rock phosphate in the process.
The process of the present disclosure produces pig iron with high phosphorus content ranging
from about 0.5% to 3.0%. On the other hand, the process available in the art which employs
prime raw material yields pig iron with phosphorus content of about 0.5% to 1.5%. Thus, it is
apparent that the process of the present disclosure employing process use waste, such as steel
plant waste such as basic oxygen furnace (BOF) slag or Linz-Donawitz (LD) slag, waste of
iron ore beneficiation process and waste from Fe-Mn processing plant, produces pig iron with
higher phosphorus content ranging from 0.5% to 3.0%. The process of the present disclosure
employs waste material to generate the pig iron with higher phosphorus content unlike the
process available in the art which employs prime raw material, inferring that the process of the
present disclosure is highly economical, but still producing pig iron with higher phosphorus
content.

The process of the present disclosure for producing pig iron with high phosphorus content
comprises charging BOF slag or LD slag along with components selected from a group
comprising coke, nut coke, prime grade iron ore, low grade iron ore, prime grade iron
agglomerate, low grade iron agglomerate, or any combination thereof, and flux in the blast
furnace to obtain pig iron with high phosphorus content ranging from about 0.5% to 3.0%.
In another embodiment, the process of producing pig with phosphorus content of 0.5% to 3.0%
comprises steps of-
charging BOF slag or LD slag along with component selected from a group comprising
coke, nut coke, prime grade iron ore, low grade iron ore, prime grade iron agglomerate, low
grade iron agglomerate, or any combination thereof, and flux, in to furnace to obtain the said
pig iron; and
modulating parameters, such as adiabatic flame temperature, top gas temperature, coke
rate and wind volume for smooth burden descent, to a predetermined unit, to obtain the said
pig iron.
In an embodiment, the flux is quartzite.
In an embodiment, the BOF slag/LD slag in the process of the present disclosure is in an amount
ranging from about 20% to 90% w.r.t iron bearing material.
In another embodiment, the BOF slag/LD slag in the process of the present disclosure is in an
amount of about 20% w.r.t iron bearing material, about 30% w.r.t iron bearing material, about
40% w.r.t iron bearing material, about 50% w.r.t iron bearing material, about 60% w.r.t iron
bearing material, about 70% w.r.t iron bearing material, about 80% w.r.t iron bearing material
or about 90% w.r.t iron bearing material.
In an embodiment, the composition of the prime grade iron ore and low-grade iron ore is
provided in table 1 below-


In an embodiment, the low-grade iron ore employed in the process of the present disclosure
contains high amount of Al2O3 and SiO2. Such low-grade iron cannot be employed in the
process known in the art as it adversely affects the productivity and smooth operation.
However, the process of the present disclosure is designed such a way that upon employing
low-grade iron ore along with LD slag/BOF slag yields pig iron with high phosphorus content
in the range of about 0.5% to 3.0%.
In an embodiment, the process of the present disclosure produces pig iron having phosphorous
content of about 0.5%, about 1.0%, about 1.5%, about 2.0%, about 2.5% or about 3.0%.
In an embodiment, the composition of BOF slag/LD slag is provided in table 2 below-

In an embodiment, the BOF slag/LD slag employed in the process of the present disclosure
comprises CaO to SiO2 ratio in the range of about 2.8 to 3.8, wherein the CaO is in an amount
ranging from about 45% to 55% and SiO2 is in an amount ranging from about 13% to 18%.
In another embodiment, the composition of the LD slag may vary to some extent depending
upon the steel making operations and the source of raw materials and their corresponding
composition used during steel making process.
In an embodiment, in the process of the present disclosure slag is generated at higher quantities
and production of slag along with high phosphorus iron is dependent on LD slag in the burden
(charge) to the blast furnace.
In another embodiment, in the process of the present disclosure high phosphorus pig iron and
slag is generated in equal proportion when LD slag is employed in the process is about 40%
w.r.t the iron bearing material.
In another embodiment, the output from the process of the present disclosure comprises metal
(pig iron with high phosphorus content) to slag ratio of about 1:1.

In an embodiment, the process of the present disclosure ensures mass production of high
phosphorus iron in a cost-effective manner whilst recycling different wastes generated during
the process. Thus, the process of the present disclosure creates a circular economy paradigm.
In an embodiment, the pig iron with high phosphorus content produced by the process of the
present disclosure comprises carbon in an amount ranging from about 3% to 4%, silicon in an
amount ranging from about 1.0% to 2.5%, sulphur in an amount ranging from about 0.010% to
0.025%, phosphorus in an amount ranging from about 0.5% to 3.0% and iron in an amount
ranging from about 91.5% to 92.5%.
In an embodiment, in the process of the present disclosure in the blast furnace the ratio of pig
iron to slag changes from about 4:1 to 1:1. The process of the present disclosure involves
optimizing the furnace operating regime by modulating parameters, such as adiabatic flame
temperature, top gas temperature, coke rate and wind volume for smooth burden descent. The
process of the present disclosure also involves modification of casting practices, such as slag
pit management and slag granulation practice.
Additional embodiments and features of the present disclosure will be apparent to one of
ordinary skill in art based upon the description provided. The embodiments provide various
features and advantageous details thereof in the description. Descriptions of well-
known/conventional methods and techniques are omitted so as to not unnecessarily obscure the
embodiments. The examples provided herein are intended merely to facilitate an understanding
of ways in which the embodiments provided may be practiced and to further enable those of
skill in the art to practice the embodiments provided. Accordingly, the following examples
should not be construed as limiting the scope of the embodiments.
EXAMPLES
EXAMPLE 1: Process of producing high phosphorus pig iron
The example illustrates typical blast furnace operation with normal burden known in the prior
art and the process of the present disclosure (40% LD slag and 60% Iron ore) is given in the
table 3 below. The process of the present disclosure yields similar result with Mini Blast
Furnace (working volume of about 55 m3) and bigger blast furnace (working volume of about
1000 m3). Pig iron phosphorus varies with LD slag in the burden. Pig iron phosphorus is 1.1%,

WE CLAIM:
1. A process for producing pig iron having phosphorus content in range of about 0.5% to
3.0%, said process comprising step of charging BOF slag or LD slag along with
component selected from a group comprising coke, nut coke, prime grade iron ore, low
grade iron ore, prime grade iron agglomerate, low grade iron agglomerate, or any
combination thereof, and flux, in to furnace to obtain the said pig iron.
2. The process as claimed in claim 1, wherein the flux is quartzite.
3. The process as claimed in claim 1, wherein amount of the BOF slag or LD slag in the
process is ranging from about 20% to 90% with respect to iron bearing material.
4. The process as claimed in claim 1, wherein the BOF slag or LD slag comprises T.Fe at
about 18.7%, CaO at about 51%, SiO2 at about 15%, MgO at about 1.8%, Al2O3 at
about 1.1%, P2O5 at about 3.1%, MnO at about 0.6% and TiO2 at about 0.96%.
5. The process as claimed in claim 4, wherein ratio of CaO to SiO2 in the BOF slag or LD
slag is ranging from about 2.8 to 3.8.
6. The process as claimed in claim 1, wherein the phosphorus pig iron comprises carbon
in amount ranging from about 3% to 4%, silicon in amount ranging from about 1% to
2.5%, manganese in amount ranging from about 0.5% to 0.7%, sulphur in amount
ranging from about 0.010% to 0.025%, phosphorus in amount ranging from about 0.5%
to 3.0% and iron in amount ranging from about 91.5% to 92.5%.