Title of Invention	"A PROCESS FOR NITROGEN REMOVAL IN ELECTRIC ARC FURNACE STEEL"
Abstract	# ABSTRACT A PROCESS FOR NITROGEN REMOVAL IN ELECTRIC AND FURNACE STEE' The present invention relates to a process for nitrogen removal in electric and furnace steel by utilization of direct reduced iron (DRI) fines. The process is useful in iron and steel industries where good quality bar and flat product is produced through electric arc furnace route. Novelty of the present invention is that the nitrogen removal is found up to about 25 ppm for high carbon steel (0.8 - 1.2%) by DRI fines injection where initial nitrogen level was 150 - 200 ppm. This is because, FeO in DRI fines and C in bath react to form CO bubbles and increases the activity coefficient of nitrogen in steel. 15

Title of Invention

"A PROCESS FOR NITROGEN REMOVAL IN ELECTRIC ARC FURNACE STEEL"

Abstract

# ABSTRACT A PROCESS FOR NITROGEN REMOVAL IN ELECTRIC AND FURNACE STEE' The present invention relates to a process for nitrogen removal in electric and furnace steel by utilization of direct reduced iron (DRI) fines. The process is useful in iron and steel industries where good quality bar and flat product is produced through electric arc furnace route. Novelty of the present invention is that the nitrogen removal is found up to about 25 ppm for high carbon steel (0.8 - 1.2%) by DRI fines injection where initial nitrogen level was 150 - 200 ppm. This is because, FeO in DRI fines and C in bath react to form CO bubbles and increases the activity coefficient of nitrogen in steel. 15

Full Text	Another objective of the present invention is to provide a process for nitrogen removal in electric arc furnace steel by utilizing DRI fines. Accordingly, the present invention provides a process for nitrogen removal in electric arc furnace steel which comprises: i) melting steel scrap in the temperature ranging between 1525 - 1575°C for a period of 15 - 30minutes, ii) increasing carbon content of the molten bath in the range of 0.8 to 1% by known method, maintaining temperature in the range of 1600- 1675°C and keeping bath depth of the molten metal in the range of 3 - 8 cm, iii) injecting DRI fines of size in the range of -40 to -100 mesh into the molten bath in the ratio ranging between 1:10 to 1:6 for a period of 4 - 10 minutes and maintaining flow rate in the range 8-15 liter per minute, iv) decreasing carbon content ofthe said molten bath in the range of 1 to 0.1% by known method, v) pouring carbon reduced molten steel for ingot casting. In an embodiment ofthe present invention used steel scrap may have C : 0.1 - . 4%, Si 0.2 - 0.5%, Mn : 0.2 - 0.5%, S : 0.02 - 0.04%, P : 0.02 - 0.04% In still embodiment of the present invention the injected DRI fines in steel bath may have FeO: 20 - 25%, A2O3: 1- 2°/0, S: 0.01 -0.02%, C: 0.3 - 1% In another embodiment of the present invention, the carbon content of the molten bath may be increased by adding coke having composition - Fixed carbon : 75- 87%, Volatile Matter : 1- 2%, Ash : 10 to 18% 6 We Claim: 1. A process for nitrogen removal in electric arc furnace steel which comprises: i) melting steel scrap in the temperature ranging between 1525 - 1575°C for a period of 15- 30 minutes, ii) increasing carbon content of the molten bath in the range of 0.8 to 1% by known method, maintaining temperature in the range of 1600 - 1675°C and keeping bath depth of the molten metal in the range of 3 - 8 cm, iii) injecting direct reduced iron (DRI) fines of size in the range of -40 to -100 mesh into the molten bath in the ratio ranging between 1:10 to 1:6 for a period of 4 - 10 minutes and maintaining flow rate in the range 8-15 liters per minute, iv) decreasing carbon content of the said molten bath in the range of 1 to 0.1% by known method, v) pouring carbon reduced molten steel for ingot casting. 2. A process as claimed in claim 1, wherein the used steel scrap has C : 0.1 - 0.4%, Si : 0.2 - 0.5%, Mn : 0.2- 0.5%, S : 0.02 - 0.04%, P : 0.02-0.04%. 3. A process as claimed in claims 1-2, wherein the injected DRI fines in steel bath has FeO: 20 - 25%, A2O3: 1-2%, S: 0.01 -0.02%, C: 0.3- 1%. 4. A process as claimed in claim 1, wherein the carbon content of the molten bath is increased by adding coke having composition - Fixed carbon : 75- 87%, Volatile Matter : 1- 2%, Ash lOto 18% Dated this 13* February 2006 Scientist, IPMD,CSIR 14

Full Text

Another objective of the present invention is to provide a process for nitrogen removal in electric
arc furnace steel by utilizing DRI fines.
Accordingly, the present invention provides a process for nitrogen removal in electric arc
furnace steel which comprises:
i) melting steel scrap in the temperature ranging between 1525 - 1575°C for a period of 15 -
30minutes,
ii) increasing carbon content of the molten bath in the range of 0.8 to 1% by known method,
maintaining temperature in the range of 1600- 1675°C and keeping bath depth of the molten
metal in the range of 3 - 8 cm,
iii) injecting DRI fines of size in the range of -40 to -100 mesh into the molten bath in the
ratio ranging between 1:10 to 1:6 for a period of 4 - 10 minutes and maintaining flow rate in
the range 8-15 liter per minute,
iv) decreasing carbon content ofthe said molten bath in the range of 1 to 0.1% by known
method,
v) pouring carbon reduced molten steel for ingot casting.
In an embodiment ofthe present invention used steel scrap may have C : 0.1 - . 4%, Si
0.2 - 0.5%, Mn : 0.2 - 0.5%, S : 0.02 - 0.04%, P : 0.02 - 0.04%
In still embodiment of the present invention the injected DRI fines in steel bath may have FeO:
20 - 25%, A2O3: 1- 2°/0, S: 0.01 -0.02%, C: 0.3 - 1%
In another embodiment of the present invention, the carbon content of the molten bath may be
increased by adding coke having composition - Fixed carbon : 75- 87%, Volatile Matter : 1- 2%,
Ash : 10 to 18%
6

We Claim:
1. A process for nitrogen removal in electric arc furnace steel which comprises:
i) melting steel scrap in the temperature ranging between 1525 - 1575°C for a period of
15- 30 minutes,
ii) increasing carbon content of the molten bath in the range of 0.8 to 1% by known
method, maintaining temperature in the range of 1600 - 1675°C and keeping bath
depth of the molten metal in the range of 3 - 8 cm,
iii) injecting direct reduced iron (DRI) fines of size in the range of -40 to -100 mesh into
the molten bath in the ratio ranging between 1:10 to 1:6 for a period of 4 - 10 minutes
and maintaining flow rate in the range 8-15 liters per minute,
iv) decreasing carbon content of the said molten bath in the range of 1 to 0.1% by
known method,
v) pouring carbon reduced molten steel for ingot casting.
2. A process as claimed in claim 1, wherein the used steel scrap has C : 0.1 - 0.4%, Si : 0.2 -
0.5%, Mn : 0.2- 0.5%, S : 0.02 - 0.04%, P : 0.02-0.04%.
3. A process as claimed in claims 1-2, wherein the injected DRI fines in steel bath has FeO:
20 - 25%, A2O3: 1-2%, S: 0.01 -0.02%, C: 0.3- 1%.
4. A process as claimed in claim 1, wherein the carbon content of the molten bath is increased
by adding coke having composition - Fixed carbon : 75- 87%, Volatile Matter : 1- 2%,
Ash lOto 18%
Dated this 13* February 2006
Scientist,
IPMD,CSIR
14

Documents:

396-del-2006-Abstract-(08-08-2013).pdf

396-del-2006-abstract.pdf

396-del-2006-Claims-(08-08-2013).pdf

396-del-2006-claims.pdf

396-del-2006-correspondence-others 1.pdf

396-del-2006-Correspondence-Others-(08-08-2013).pdf

396-DEL-2006-Correspondence-Others.pdf

396-del-2006-Description (Complete)-(08-08-2013).pdf

396-del-2006-description (complete).pdf

396-del-2006-form-1.pdf

396-del-2006-form-18.pdf

396-del-2006-form-2.pdf

396-del-2006-Form-3-(08-08-2013).pdf

396-del-2006-form-3.pdf

396-del-2006-form-5.pdf

396-del-2006-gpa.pdf

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Patent Number

265460

Indian Patent Application Number

396/DEL/2006

PG Journal Number

09/2015

Publication Date

27-Feb-2015

Grant Date

25-Feb-2015

Date of Filing

13-Feb-2006

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH.

Applicant Address

ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	J.PAL	NATIONAL METALLURGICAL LABORATORY BURMAMINES, JAMSHEDPUR-831 007 INDIA.
2	M.C. GOSWAMI	NATIONAL METALLURGICAL LABORATORY BURMAMINES, JAMSHEDPUR-831 007 INDIA.
3	S. GHOSH	NATIONAL METALLURGICAL LABORATORY BURMAMINES, JAMSHEDPUR-831 007 INDIA.
4	MANOJ KUMAR	NATIONAL METALLURGICAL LABORATORY BURMAMINES, JAMSHEDPUR-831 007 INDIA.

PCT International Classification Number

C21C 5/40

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA