DESC:FIELD OF INVENTION

? The present invention relates to killing of oxygen in steel during tapping from primary steelmaking furnace
? In particular, it relates to the development of a reagent which will partially or fully replace aluminium, which is added in the form of ingot, notch bar etc. during tapping and during subsequent processing of liquid steel
? It also relates to making the slag more conducive for refining by reducing lime consumption
? It also relates to reduction or elimination of slag conditioners like synthetic slag and fluorspar
? Thus it relates to significant reduction in steel making cost

BACKGROUND INFORMATION

? Currently the aluminium consumption in steel plants, using conventional de-oxidation practices varies between 1.5 and 4.0 kg/tonne of crude steel
? Addition of aluminium necessitates special treatment usually with calcium to produce clean steel
? Slag conditioners, like synthetic slag and fluorspar, which are environmentally hazardous materials are often added for making the slag conducive for refining
? There has always been a requirement for an alternate material which will be more efficient and cost effective for production of clean steel

OBJECTIVE

1. The main object of this invention is to reduce or eliminate aluminium consumption in steel making
2. Another object of this invention to reduce the alumina inclusion in steel
3. The third object of this invention is to reduce lime consumption
4. The fourth object of this invention is to reduce synthetic slag, fluorspar etc.
5. The fifth object of this invention to eliminate environmental hazards associated with use of materials like fluorspar
6. The sixth object of this invention to reduce requirement of special treatment of steel with calcium
7. The seventh object of this invention is to reduce total de-oxidation cost and thereby overall steel making cost

BRIEF DESCRIPTION OF THE INVENTION:

JAMIPOL has developed a deoxidizing reagent to meet the requirements of oxygen removal. The present invention relates to de-oxidation of steel during tapping from primary steelmaking furnace or during subsequent processing. To make the reagent efficient, metallic aluminium is blended with slag conditioner. This reagent composition is so adjusted that it reduces the addition of primary aluminum metal in the form of ingot, notch bar, cube, rod, wire etc. by 0.20-2.0 kg/tls (ton liquid steel) and reduces or eliminates use of synthetic slag, fluorspar etc. Further, the new reagent is cost effective. The chemical composition of deoxidizing reagent: Metallic Aluminium : 10-70%, Aluminium based compounds:20-60%, Lime:0-50%, other compounds: Rest

DETAILED DESCRIPTION OF THE INVENTION:

This new deoxidizing reagent is very effective in removing oxygen from liquid steel during tapping from primary steelmaking furnace and also during subsequent processing. This reduces consumption of primary aluminum metal in the form of ingot, notch bar, cube, rod, wire etc. by 0.20-2.0 kg/tls and lime consumption reduces by 0.75-1.5 kg/tls.

The development of new reagent involved industrial trials and outcome of the same is summarized below:

Industrial trials:
Trials were conducted in low carbon grade of 0.016- 0.028% C. The results obtained by using the new reagent is shown in the table

Table: Summary of Trial Results
S.No. Parameters UOM Conventional deoxidation practice Deoxidation with new reagent
1 Oxygen in Steel before addition of Deoxidizer Reagent ppm 600-800 600-800
2 Oxygen in Steel after addition of Deoxidizer Reagent ppm 3.10* 4.08*
3 Aluminium Consumption Kg/tls 2.19 1.62
4 New reagent Consumption Kg/tls - 1.24
5 Lime Consumption Kg/tls 3.90 2.91
*Oxygen level is within acceptable variation and considered to be in the same band

Trials showed following benefits-
? Reduction in Aluminium consumption by 26%
? Reduction in lime consumption by 25%
? Reduction in deoxidisation cost by 11% (over Rs 34 / tls)
,CLAIMS:WE CLAIM:

1. This innovative reagent is used for Deoxidizing of liquid steel during tapping of liquid steel from primary steelmaking unit.
2. The reagent as claimed in claim 1, is also used during subsequent processing of steel in ladle
3. The reagent as claimed in claim 1, wherein the said Deoxidizing reagent is composed of the following specification:
Metallic Aluminium: 10-70%,
Aluminium based compounds: 20-60%,
Lime: 0-50%,
Other compounds: Rest

4. The reagent as claimed in claim 1 reduces the aluminium consumption by 0.20-2.0 kg/tls
5. The reagent as claimed in claim 1 reduces the lime consumption by over 0.75-1.5 kg/tls
6. The reagent as claimed in claim 1 reduces the cost of deoxidizer by over Rs 30/tls.