FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
{See Section 10 and Rule 13)
1 TITLE OF THE INVENTION :
A SYSTEM FOR PRODUCING ALUMINIUM SHOTS/CUBES FOR USE IN STEEL MAKING AND A PROCESS THEREOF.
2 APPLICANT (S)
Name : STEEL AUTHORITY OF INDIA LIMITED.
Nationality : A Govt, of India Enterprise;
Bhilai Steel Plant, Bhilai, State of Chattisgarh,India.


3 PREAMBLE TO THE DESCRIPTION
COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.


FIELD OF THE INVENTION
The present invention relates to an Al melting furnace and manufacturing Al shots for use in steel melting process for deoxidation. More particularly, the invention relates to a gas fired mechanized coke-oven gas fired melting furnace with special type burners in order to achieve higher productivity and low cost of Aluminium shots of required quality produced following the process of the invention. The Al melting furnace and the process followed therein is also adapted to produce aluminium shots of varied shapes such as spherical or cubes. The present invention is thus particularly directed to providing for fast melting with little oxide generation for better yield, favourable designing of burners and melting furnace which would make production of shots, cost effective and fuel efficient. Also, importantly, the present invention would provide for a mechanized system of generation of Aluminium shots whereby the production can be faster with reduced manual labour thereby making the process of shot production highly efficient justifying wide application of such Al melting systems in steel plants to meet the requirements of deoxidisers.
BACKGROUND OF THE INVENTION
It is well known in the existing art of steel Melting process that Aluminum shots of selective quality/purity and of approximately 10mm size (dia.) in near spherical shapes are required to be added to the melt in preferred weight proportion to contribute to the function of deoxidation. These steel shots are thus required in huge quantities and on regular basis to match the continuous rate of steel melting/production. It is also experienced that the existing general process of making aluminium shots involves melting scrap aluminium/ingots in small crucibles in batches, using coke and oil fired furnaces which are less energy efficient and low yield process. Shots produced by pouring molten metal manually through a cup with shieved bottom such that the droplets of molten aluminium are allowed to solidify on a disc rotated manually and finally collecting the shots manually. The conventional crucible based melting process using coke or furnace oil as fuel to melt aluminium thus having the limitation of low production capability and low yield. The total process being cumbersome and manually operated result in high cost of production and unsafe working condition for operators.
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There has been thus a persistent need to develop a mechanized process involving energy efficient furnace operation for melting aluminium and pouring into shots of desired quality, size and quantity on a continuous, safe, reliable and cost effective manner. The equipment and process of producing aluminium shots primarily intended to be used for deoxidation in steel melting in large steel plants would thus be capable to meet the continuous volume and quality requirements for such aluminium shots at less cost involving less manpower.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide a mechanized coke-oven gas fired melting furnace in order to improve the productivity and yield of the production of aluminium shots for addition during steel melting as deoxidiser.
Another object of the present invention is directed to a system of manufacturing Al shots, involving a cheaper fuel e.g. coke-oven gas fired melting furnace wherein the process for aluminum melting and converting to shots could be achieved in desired quantity and quality fit to cater to steel melting requirements as deoxidiser, on a faster, consistent, safe and reliable basis.
A further object of the present invention is directed to said melting furnace wherein provision of mechanized furnace tilting, rotating disc and pouring tray favour higher productivity at less cost with involvement of least manpower.
A still further object of the present invention is directed to said mechanized melting furnace adapted to produce aluminium shots for use in steel melting wherein the operation is safe and less hazardous.
A still further object of the present invention directed to said gas-fired and mechanized melting furnace for production of aluminium wherein the aluminium melting is cost effective by using coke-oven gas burnt in special energy efficient burners for faster melting and pouring into shots on mechanized rotating disc/tray.
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SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided a system for producing aluminium shots/cubes for use in steel making comprising:
a melting furnace with crucible;
means adapted to tilt the melting furnace;
a trough/tray having sieved bottom below the melting furnace such as to pour molten metal directly from the furnace to the trough /tray and producing shots in large quantities;
a rotating disc below the trough/tray such that the molten aluminium metal from the tray fall on said rotating disk and convert into shots/cubes ; and means for cooling and collecting the shots/cubes thus obtained.
Another aspect of the present invention is directed to said system for producing aluminium shots wherein said furnace is adapted to be heated indirectly with coke oven gas burners.
A still further aspect of the present invention directed to said system for producing
aluminium shots wherein said means adapted to tilt the furnace comprises:
providing the melting furnace on a main frame with a tilting arrangement comprising of
rope , pulley and hand winch.
According to yet another aspect of the present invention directed to said system for
producing aluminium shots wherein the trough/tray is fixed below the melting furnace to
take molten aluminium metal directly into trough.
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A still further aspect of the present invention directed to said system for producing aluminium shots wherein the rotating disk is rotated with electro mechanical drive.
According to a still further aspect of the system of the present invention for producing aluminium shots, is comprising means to blow compressed air through pipe with nozzles to cool and collect the shots from the rotating disk.
An yet further aspect of the present invention is directed to a system for producing aluminium shots wherein the tray with sieved bottom comprise heating arrangement adapted for perfect formation of large quantity of shots.
Another important aspect of the present invention is directed to a process for the manufacture of aluminium shots/cubes for steel making using the system comprising:
providing the aluminium ingots/scraps in the melting furnace to obtain the molten metal;
tilting the furnace to pour the molten metal into the trough/tray and allowing the molten metal droplets to fall on the rotating disk and solidify to covert to shots ;
blowing compressed air to cool and collect the shots in containers.
A further aspect of the present invention is directed to said process for the manufacture of aluminium shots/cubes wherein high efficiency coke oven gas burner is used for faster melting.
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The present invention and its advantages and objectives are described in greater details with reference to the following accompanying exemplary non-limiting figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1: is the illustration of the flow-diagram of Al melting process of the invention in gas fired mechanized melting furnace and tilting/pouring arrangement for production of Al shots according to the present invention.
Figure 2: is the illustration of the schematic arrangement of the gas fired mechanized tilting furnace for aluminium melting and the disc and tray arrangement for pouring and converting in to shots.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES
The present Invention is thus directed to developing a mechanized furnace and associated system for Aluminium melting and converting to Al shots for use as deoxidiser in steel melting, maintaining desired quality and quantity requirements, involving minimum manual labour. The method of Al melting and pouring of A! shots according to the present invention and the process of execution, ensure safety avoiding operational hazards. More importantly, due to improvement in production and yield through improved design of Gas burners, use of cheaper fuel, tilting of furnaces and rotation of disc mechanism or pouring tray for shots makes the process faster and lower the cost of production.
Main features of the present invention are as follows -
A) Fast melting with little oxide generation, resulting in better yield.
B) Design of burners and melting furnace is very much energy efficient and cost
effective and cost of fuel is minimized by using in-house coke-oven gas for
furnace firing .
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C) Tilting mechanism of melting furnace and mechanized rotation of Disc, result in higher productivity.
Reference is first invite to accompanying Figure 1 that illustrates the flow diagram for the Al melting shot production according to the present invention. It is clearly apparent from said Figure 1 that the Aluminium ingots of requisite quality is charged in the melting furnace and the heat of melting and holding required melting temperature is effectively achieved by installing highly efficient burners that are adapted to use the coke-oven gas as the cheap fuel. Thus obtaining molten aluminium for pouring economically in the melting furnace according to the invention, that ensure faster melting with little oxide generation, resulting in improved yield of the furnace. The molten aluminium is poured by tilting mechanism through the Trough, heated by gas burner at desired temperature to maintain desired fluidity of melt before being poured on mechanized rotating disc such that the droplets of molten aluminium are cooled by compressed air to be converted into shots collected in pouring trays.
Reference is now invited to accompanying Figure 2 that illustrate a preferred embodiment of the system according to the invention for Aluminium melting comprising the coke-oven gas fired melting furnace with energy efficient special burners and mechanized tilting mechanism. It is clearly apparent from the accompanying Figure 2, that illustrate that a Melting Furnace (2) which is mounted on a fabricated main frame (1) having a tilting arrangement. Aluminium ingots/scrap are charged into the melting furnace (2), a CI crucible(3)(not shown) and the charge is heated indirectly with the help of specially designed coke oven gas burners(4)(not shown) of said melting furnace(2) facilitating metal pouring after melting, operatively by the action of said tilting by winding of rope(6)r over a pul)ey(5) and hand winch (7). The combination of the melting furnace of the invention and the cast iron crucible proved to be suitable for melting aluminium scrap of large size such as 1Mx1M.
The Trough (8) is fixed below the melting furnace (2) to take molten aluminium metal directly into trough (§). Molten metal droplets formed through trough(8) fall on rotating disc (9) which is rotated at desired speed by the operation of an electro- mechanial drive(lO). The rotating disc (9) is arranged below the trough for Aluminium metal droplets to fall on the disc surface to get solidified and converted into aluminium shots
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and then cooled and collected by the blow of compressed air blown through pipe (11) into containers for shipment to steel melting shop or store.
The melting process using the above system of arrangement of mechanized furnace and supporting equipments has been found to be very much suitable for making shots including aluminium cubes also, both being used for de-oxidation purpose in steel melting process. The process is further capable of producing aluminium shots of desired quality and quantity to meet the requirement of deoxidation in steel melting.
Thus the distinct advantageous features obtained in the mechanized melting and pouring arrangement/system according to the present invention for production of aluminium shots for use in steel melting as deoxidiser, are as following:
a. Pouring of molten metal from melting furnace to tray with seived bottom has been
mechanized thus replacing manual labour.
b. Tray with sieved bottom along with heating arrangement in trough allow perfect
formation of shots and production in large quantities.
c. Disc rotation mechanism has favoured reduction in manual labour and ensuring
safety avoiding operational hazards.
d. Collection of Aliminium shots is done by blowing compressed air through nozzles
that serve the dual purpose of cooling as well as collecting shots.
e. Highly efficient burners are designed and installed in the melting furnace to favour
rapid heating using coke-oven gas as fuel for faster melting of aluminium, thus
increasing productivity.
f. Maintaining the consistent quality of shots by ensuring faster melting with little
oxide generation, resulting in improved yield of the furnace.
It is thus possible by way of the present invention to achieve means for rapid melting of aluminium ingots and relatively larger size of scrap, in a coke-oven gas fired furnace with high efficiency burners installed therein, at a faster rate with little oxide generation. Also a mechanized powered tilting arrangement of the melting furnace favour pouring of melt through the trough/tray with sieved bottom to the rotating disc in the form of metal(AI) droplets of desired size and shape. The process in the furnace has the in built capacity to attain desired quality of melt as well as the aluminium shots on conversion thereafter. The shots received on a electromechanically driven rotating disc receiving the hot
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droplets are subjected to compressed air sprayed through nozzles to simultaneously effect cooling as well as collecting in containers. The system and the process of Al melting and pouring into shots being largely mechanized according to the embodiment of the present invention thus reduce involvement of manual labour, avoid operational hazard, ensure quality and quantity requirements of shots on continuous basis for catering to the need for deoxidation in steel melting while at the same time cost of production of Al shots are reduced to considerable extent due to such mechanization and use of in-house coke-oven gas as the source of cheap fuel for heating the Al ingots/scrap in melting furnace using energy efficient burners. Thus the present invention is capable to deliver equipment and process for production of Al shots at a faster and economic manner maintaining work safety and reliability so as to favour its wide scale operation and application in large steel plants to meet the sustained requirements of deoxidisers for steel melting process.
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WE CLAIM:
1. A system for producing aluminium shots/cubes for use in steel making comprising:
a melting furnace with crucible;
means adapted to tilt the melting furnace;
a trough/tray having sieved bottom below the melting furnace such as to pour molten metal directly from the furnace to the trough/tray and producing shots in large quantities;
a rotating disc below the trough/tray such that the molten aluminium metal from the tray fall on said rotating disk and convert into shots/cubes ; and means for cooling and collecting the shots/cubes thus obtained.
2. A system for producing aluminium shots as claimed in claim 1 wherein said furnace is adapted to be heated indirectly with coke oven gas burners.
3. A system for producing aluminium shots as claimed in anyone of claims 1 or 2 wherein said means adapted to tilt the furnace comprises:
providing the melting furnace on a main frame with a tilting arrangement comprising of rope , pulley and hand winch.
4. A system for producing aluminium shots as claimed in anyone of claims 1 to 3 wherein
the trough/tray is fixed below the melting furnace to take molten aluminium metal
directly into trough.
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5. A system for producing aluminium shots as claimed in anyone of claims 1 to 4 wherein
the rotating disk is rotated with electro mechanical drive.
6. A system for producing aluminium shots as claimed in anyone of claims 1 to 5
comprising means to blow compressed air through pipe with nozzles to cool and collect
the shots from the rotating disc.
7. A system for producing aluminium shots as claimed in anyone of claims 1 to 6 wherein the tray with sieved bottom comprise heating arrangement adapted for perfect formation of large quantity of shots
8. A process for the manufacture of aluminium shots/cubes for steel making using the system as claimed in anyone of claims 1 to 6 comprising:
providing the aluminium ingots in the melting furnace to obtain the molten metal;
tilting the furnace to pour the molten metal into the trough/tray and allowing the molten metal droplets to fall on the rotating disc, and solidify to covert to shots ; blowing compressed air to cool and collect the shots in containers.
9. A process for the manufacture of aluminium shots/cubes as claimed in claim 8
wherein high efficiency coke oven gas burner is used for faster melting.
10. A system for producing aluminium shots/cubes for use in steel making and a process
involving the same substantially as herein described and illustrated with reference to the
accompanying figures.
Dated this 16th Day of July, 2008 Anjan Sen
Of Anjan Sen & Associates (Applicants Agent)
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