Title of Invention	HIGH DIMENSIONAL CORED WIRES CONTAINIG DE-SULPHURISING AGENT (S) FOR REMOVING SULPHUR FROM HOT METAL AND PROCESS FOR PREPARING THE SAME
Abstract	High dimensional cored wires containing de-sulphurising agent(s) for removing sulphur from hot metal, characterized in that said wires contain sulphur - removers or de-sulphurising agent(s) formed from cold rolled steel sheet, said sulphur - removers or de - sulphurising agent(s) being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of said cored wires varying between 19 and 40 mm, and the coated de-sulphurising agent(s) filled in the core in is held in place in compacted form by the seaming locks provided during formation of the said cored wires by being pressed and drawn after filling, to generate gas for dispersing the said de - sulphurising agent(s) throughout the hot metal and promote intimate mixing, better reaction and removal of sulphur from hot metal as sulphides.

Title of Invention

HIGH DIMENSIONAL CORED WIRES CONTAINIG DE-SULPHURISING AGENT (S) FOR REMOVING SULPHUR FROM HOT METAL AND PROCESS FOR PREPARING THE SAME

Abstract

High dimensional cored wires containing de-sulphurising agent(s) for removing sulphur from hot metal, characterized in that said wires contain sulphur - removers or de-sulphurising agent(s) formed from cold rolled steel sheet, said sulphur - removers or de - sulphurising agent(s) being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of said cored wires varying between 19 and 40 mm, and the coated de-sulphurising agent(s) filled in the core in is held in place in compacted form by the seaming locks provided during formation of the said cored wires by being pressed and drawn after filling, to generate gas for dispersing the said de - sulphurising agent(s) throughout the hot metal and promote intimate mixing, better reaction and removal of sulphur from hot metal as sulphides.

Full Text	The present invention relates to the manufacture of high dimensional cored wires containing de - sulphuriser compounds for removing sulphur from "hot metal" and a process for making the same. More particularly this invention pertains to high dimensional cored wires filled with a granular or powdery sulphur removing material selected from the group of calcium carbide, calcium oxide (lime), calcium metal, magnesium, magnesium-aluminium alloy, and preferably fine granules of reactive powders having a coat of inorganic or/and organic material, or even without a coating and simple granules with the mixtures of such inorganic or organic materials and a process for preparing such high dimensional cored wires. The present invention constitutes an improvement in or modification of the invention described and claimed in my main Patent Application No.725/KOL/2006 dated 20.07.2006. In the complete specification of my said main Patent Application there is descirbed and claimed high dimensional cored wires containing oxygen removers formed from cold-rolled steel sheet, said oxygen remover or de-oxidant material being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of the said cored wires varying between 13 and 40 mm, preferably between 19 and 34 mm, and the coated de-oxidant material filled in the core is held in place in compacted form by the seaming locks provided during formation of the said cored wires after filling. The said main Patent Application also relates to a process for preparing high dimensional cored wires containing oxygen removers comprising the steps of- (a) slitting cold-rolled steel sheet of thickness varying between 0.2 and upto 1 mm and required width of 90-110 mm, providing for the double seaming locks; (b) feeding the slit coils into forming rolls which gives the slits the desired near round shape with diameter of 13 to 40 mm, preferably between 19 and 34 mm; (c) filling reactive aluminium powder/granules or other de-oxidants from bunkers or feeders into the blank spaces of the wire; (d) sealing the powder/granule filled wire, either singly or doubly, by the time it comes out of the last forming roll; (e) coiling the thus formed wire over a mandrel with inner diameter varying from 200 mm to 2.5 metres in diameter, generally of around 1 metre in diameter, depending on customer requirement; (f) applying a thin film of oil or anti-rust solution to the exposed surface or outer layer of the coil to prevent rust formation, and (g) strapping and/or wrapping the coils with plastic/stretch film for preventing moisture ingress and then placing over wooden or steel pallets for delivery to the customer. De-sulphurisation plays an important role in the process of iron making and for which calcium carbide with lime and hydrocarbon and magnesium or magnesium aluminium alloys with lime with or without hydrocarbons have been conventionally used. The term de-sulphuriser means a chemical compound, alloy or element which will remove the active sulphur present in the liquid metal and form a sulphide as its final product, usually as a distinct phase and easily separable from the liquid metal. Iron making is integral to the steel making process and de-sulphurisation of hot metal is an important processing step, which determiners the quality of steel. Sulphur, if present in iron and consequently steel in the active/elemnental form, will deteriorate the quality of steel and will also result in difficulties in steel making. The steel thus made will have lesser demand and consequetly lesser price realization. Steel makers are in regular search of a better and more economical method for removing sulphur in the steel. The existing process of de-sulphurisation involves pneumatic injection of the finely powdered de-sulphuriser reagent through a ceramic lance into the hot metal, involving either mono or co-injection of the reagents. That is either just calcium carbide based reagent is injected or both calcium carbide and magnesium-based reagents are co-injected simultaneously as per determined process. The process suffers from the following limitations : a) The calcium caride based reagent is highly explosive in nature and requires extensive and very elaborate safety precautions to be taken in its handling and storage. b) The reagent in the storage tanks requires regular purging with dry nitrogen to ensure that it does not settle down and jam the exit injection pipelines. c) An extensive and elaborate pollution control system needs to be installed to clean the oxide of nitrogen that are formed when the injected nitrogen surfaces from the molten metal and comes in contact with the oxygen in air. These fumes also contain some calcium carbide and other powder which also needs to be handled carefully so that no explosion takes place in the pollution equipment. d) The recovery of the reagent is also limited and is not more than 40-45% by wt. e) Explosive license is required for the whole de-sulphuriser plant and all the rules and regulations regarding working in an explosive area need to be observed meticulously. f) Investment in the plant and equipment are considerable. g) Plant requires considerable space and close monitoring. The present invention aims at overcoming the foregoing shortcomings of the prior art and carry out production of de-sulpurisation of hot metal more efficiently and effectively and with lower consumption of the reagents. The process has the objective of economizing the hot metal de-sulphurisation by cored wire injection by reducing the quantum of steel used as a sheath for encasing the powdery/granular de-sulphuriser reagents by using the higher dimension cored wire. This invention has also the objective to further enhance the recovery of the de-sulphuriser reagents, simultaneously reducing the quantum of consumpton and time of feeding of the de-sulphuriser to the liquid metal. A further object of the present invention is to provide a technique to use magnesium or magnesium-aluminium alloy scrap as de-sulphurisers after converting them into granules or calcium carbide powder/granules as desulphuriser reagent, mixed with lime and hydrocarbons, followed by coating with a material like graphite, low density polythene, polyamide, low molecular weight vinyl acetate polymer, talc, steatite, calcium silicide, powdered lime, hydrocarbons and the like to prevent fusion or adhesion of the granular particles into a single mass while being pressed and drawn in the wire as well as generate the required amount of gas when in contact with the moltel hot metal to ensure intimate mixing of the powdered reagent in the hot metal, resulting in good reaction and high sulphur removal. A still further object of this invention is to provide high dimensional cored wires containing de-sulphuriser granules coated with graphite which while being drawn, the contents become tightly packed, thereby imparting dimensional rigidity and stiffness to the wire. A further object of the invention is to impart thermal stability to the wire so that it remains cool for a longer time than thinner wires and is able to penetrate deeper into the hot metal and thus has better thermal stability to prevent deformation and which will eventually result in better action and recovery of the reagents. Another object of this invention is to provide high dimentional cored wires with a non-adherent coating of polymeric material on the inside surface of the said cored wires. Yet another object of this invention is to provide high dimentional cored wires containing de-sulphurising agents in granular form without coating but mixed with the aforementioned coating material (s) filled into the same wire. Still another object of the present invention is to provide a process for preparing high dimensional cored wires containing de-sulphurising agents in a granular form and coated with a protective coating to prevent sticking and fusing into a single mass while being pressed and drawn into wire. The foregoing objects are achieved by the present invention which pertains to high dimentional cored wires containing de-sulphurising agents for removal of sulphur from hot metal characterized in that said wires contain sulphur-removers or de-sulphurising agent(s) formed from cold rolled steel sheet, said sulphur-removers or de-sulphurising agent(s) being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of said cored wires varying between 19 and 40 mm, and the coated de-sulphurising agent(s) filled in the core is held in place in compacted form by the seaming locks provided during formation of the said cored wires by being pressed and drawn after filling, to generate gas for dispersing the said de-sulphurising agent(s) throughout the hot metal and promote intimate mixing, better reaction and removal of sulphur from hot metal as sulphides. The subject invention also relates to a process for high dimensional cored wires containing sulphur removers as defined above and comprising the steps of - a) slitting cold rolled steel sheet of thickness varying between 0.2 mm and upto 1 mm, and required width of 90-110 mm, providing for the double seaming locks; b) coating the slit coils with plastic or BOPP (bi-axially oriented poly propylene) film to prevent the reaction of the chemicals with the cold rolled steel strip; c) feeding the slit coils into forming rolls which gives the slits the desired near round shape with a diameter of 13 to 40 mm; d) filling reactive de-sulphuriser powder/granules or other de-sulphrisers such as herein described from bunkers or feeders into the empty spaces of the wire to ensure that the wire is tightly packed with the powders, this powder density varying for wires of different diameters; e) sealing the powder/granule filled wire, either singly or doubly by the time it comes out of the last forming roll; f) coiling the wire thus formed over a mandrel with inner diameter varying from 200 mm to 2.5 meters in diameter, generally of around 1.2 meter in diameter, depending on customer requirement; g) applying a thin film of oil or anti-rust solution to the exposed surface or outer layer of the coil to prevent rust formation, and h) strapping and/or wrapping the coils with plastic/stretch film for preventing moisture ingress and then placing over wooden or steel pallets for delivery to the customer. In the above process, even uncoated slit coils may be used, avoiding use of expensive 'BOPP' film, if the shelf life is short. The prererred diameter of rolls formed from the slit coils varies between 19 and 34 mm. As regards BOPP tape, it is being increasingly used since it is strong and does not tear easily like other plastic materials. An additional advantage with the BOPP tape is that at very high molten metal temperature, it would form gases which would help in stirring the hot metal ensuring enhanced removal of sulphur. The most frequently used de-sulphuriser is either metallic magnesium or calcium carbide. The former is generally coated with 5% CaO (lime) to reduce the risk of an accident, and for the latter during its handling, the area is purged with gaseous nitrogen. Oil and anti-rust solution appl'ed to the outer surface of the finished coil are obtained from petroleum fraction which are viscous and greasy, acting as an effective barrier against rust-forming agents. As pointed out earlier, de-sulphurisers may be selected from calcium carbide, and mixed with calcium oxide (lime), hydrocarbons or calcium metal, magnesium, magnesium-aluminium alloy, and preferably fine granules of reactive magnesium based regent or regents of calcium carbide powders having a coat of inorganic or/and organic metarial, preferably lime and hydrocarbons, or even without a coating and simple granules with the mixtures of inorganic or organic materials. Size of de-sulphuriser granules should optimally be around 10 mesh, but finer or coarser granules may just as well be used; however, care should be taken to prevent handling loss. While drawing the granular desulphuriser reagent -filled wire, the contents become tightly packed, imparting dimensional stability and stiffness to the wire, thereby ensuring ease of handling the coil. De-sulphurisation by changing the form of desulphuriser reagent addition, which is carried out by injecting high dimentional cored wire filled with highly reactive de-sulphurisation reagent in fine granular form and coated with an organic material like graphite for better recovery and achieving the optimum level of sulphur and with lesser consumption of the de-sulphurisation reagent are unique features of this invention. The coating is not limited to organic materials but can also include inorganic coating materials as well, like calcium oxide, talc, chalk powder, and the like. De-sulphurisation in accordance with the present invention can be carried out in hot metal at any stage it travels from the blast furnace to the steel making area as per requirement of the steel maker. A notable feature of this invention is to use scrap magnesium or magnesium aluminium alloy of any grade in granular or powdered form as the de-sulphurisers, suitably coated with organic or inorganic coating material as described hereinbefore. Use of scrap/waste magnesium or magnesium aluminium alloy effectively adds to the economy of the overall process. As an additional feature of this invention, i.e. winding of the powder-filled coil is subjected to 'coreless coiling' so that the coil can be uncoiled from inner diameter of the stationary coil generally called a flipping coil, either vertical or horizontal. The coil can also be made into a spool with a core made of either wooden, synthetic, metal or any such materials. The novel products of this invention, namely, high dimensional cored wire filled with fine granules of the de-sulphuriser reagents powder/granules coated with graphite and securely held inside, is provided with seaming locks. By 'high dimensional' it is implied that dimensions of the cored wire ranges between 13 mm and 40 mm, optimally between 19 mm and 34 mm, and the internal diam- eter of the wound wire over the mandrel vary between 200 mm to 2.5 meters and the weight of each coil may range between 1 MT to around 20 MT depending on customer, storage and handling requirements. The high dimension as stated has the technical advantage of providing thermal stability, which ensure deeper penetration of the wire into the melt thus resulting in better recovery of the reagents. The present invention will be further illustrated by the consumption data of the reagents as per the reduction in sulphur levels that has been achieved as mentioned in the table and the example given below. It is to be understood that the invention is not restricted to the results given therein. Various advantages of the products of the present invention may be briefly outlined as under : 1. An increasing amount of de-sulphuriser reagents can be filled per unit length of wire, and as more material is compacted per meter of wire of larger dimension, the cost of the steel sheathing becomes less. 2. There is substantial rise in the feeding rate, thereby saving feeding time and resulting in an enhanced time available for steel making. 3. Due to larger dimension, better rigidity and stiffness, the high dimensional wire allows for deeper penetration into steel, thereby resulting in better recovery and homogenization of the de-sulphurisers. 4. Coated fine granules of the de-sulphurisation reagents is used as filler material for making high dimensional cored wire resulting in an estimated 10-15% higher recovery than the conventional pneumatic injection system for reagents. 5. Since the de-sulphuriser reagent is steel sheathed cored wire and is also "flipping type", there is a saving on the transportation (since normal trucks can be used to transport the material, unlike explosive licensed storage tanks for the conventional de-sulphurisation reagent) and easier storage since it can be stored anywhere unlike in the de-sulphuriser reagent for the pneumatic injection system. The storage cost is drastically reduced and the shelf life is also higher since the de-sulphuriser reagent is encased in a tightly covered steel sheath and is water and moisture proof. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described experimental data are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and ambit as defined in the claims appended hereafter, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences or such meets and bounds, are therefore intended to be embraced by the appended claims. I Claim : 1. High dimensional cored wires containing de-sulphurising agent(s) for removing sulphur from hot metal, characterized in that said wires contain sulphur - removers or de-sulphurising agent(s) formed from cold rolled steel sheet, said sulphur - removers or de - sulphurising agent(s) being in finely divided granular or powdery form coated with a protective coating material such as herein described, the diameter of said cored wires varying between 19 and 40 mm, and the coated de-sulphurising agent(s) filled in the core in is held in place in compacted form by the seaming locks provided during formation of the said cored wires by being pressed and drawn after filling, to generate gas for dispersing the said de - sulphurising agent(s) throughout the hot metal and promote intimate mixing, better reaction and removal of sulphur from hot metal as sulphides. 2. High dimensional cored wires as claimed in Claim 1, characterized in that diameter of the said cored wires varies between 19 and 34 mm containing fine granules of magnesium based reagents or reagents of calcium carbide powders having a cost of inorganic or/and organic protective coating material such as herein described, preferably lime and hydrocarbons like plastic waste or graphite - based, coal - based or charcoal based carbon powder, or granules of de - sulphurising agent(s) without coating but mixed with one or more protective coating materials such as herein described, wherein the size of said granules is optimally around 10 mesh. 3. High dimensional cored wires as claimed in Claims 1 and 2, characterized in that as de - sulphurising agent there is employed prime or scrap metallic magnesium, magnesium-aluminium alloy, calcium carbide - based rea"gent, calcium oxide or calcium, wherein magnesium or magnesium-aluminium alloy is shredded and converted into granular/powdery form, followed by application of one or more of said inorganic and/or organic coating materials to prevent fusion or adhesion of granules at the time of being pressed and drawn in the form of wire. 4. High dimensional cored wires as claimed in Claims 1 to 3, characterized in that said protective inorganic coating materials are selected from the group of powdered lime (CaO), talc, steatite, lime stone dust, calcite and calcium silicide, and as organic coating material there is employed graphite, LDP (low density polyethylene), polyamide, low molecular weight vinyl acetate polymer, bi-axially oriented poly propylene (BOPP) or waste plastic powder. 5. High dimensional cored wires as claimed in Claims 1 to 4, characterized in that while drawing the said granular/powdery de - sulphuriser agent like prime or scrap magnesium or magnesium-aluminium alloy or calcium carbide based reagent coated with powdered lime and hydrocarbons in powder/granule filled wire, the contents become tightly packed imparting stiffness and dimensional stability to the wire, thereby ensuring ease of handling the coil. 6. High dimensional cored wires containing de - sulphurising agent (s) for removing sulphur from hot metal, substantially as herein described with particular reference to the illustrative Example. 7. A process preparing high dimensional cored wires containing sulphur removers as claimed in any of the preceding claims, characterized in that the said comprises the steps of - a) slitting cold rolled steel of thickness varying between 0.2 and 1 mm and required width of 90-110 mm providing for the double seaming locks; b) coating the slit coils with plastic or BOPP (bi-axially oriented poly propylene) film to prevent the reaction of the chemicals with the cold rolled steel strip; c) feeding the slit coils into the forming rolls which gives the slits the desired near-round shape a diameter of 13 to 40 mm; d) filling reactive de-sulphuriser reagent powder/granules or other de-sulphurisers such as herein described into the wire from bunkers or feeders into empty spaces of the wire to ensure that the wire is tightly packed with the powders, the powder density varying for wires of different diameters; e) sealing the powder/granule filled wire, wither singly or doubly, by the time it comes out of the last forming roll; f) coiling the thus formed wire over a mandrel with inner diameter varying from 200 mm to 2.5 meters in diameter, generally of around 1.2 meter in diameter, depending on customer requirement; g) applying a thin film of oil or anti-rust solution to the exposed surface or outer layer of the coil to prevent rust formation and h) strapping and/or wrapping the coils with plastic/stretch film for preventing moisture ingress and then placing over wooden or steel pallets for delivery to the customer. 8. A process as claimed in Claim 7, characterized in that the thickness of the cold-rolled steel sheet (DD and soft grade) is optimally 0.4 mm, diameter of the formed wire varies between 19 and 34 mm and weight of each of coil varies between 1 MT and 20 MT, depending on customer requirement. 9. A process for claimed in Claim 7 and 8, wherein winding of the de-sulphurisers filled coil is subjected to coreless winding thereby allowing the said coil to be unwinded or uncoiled from the inner diameter of the stationary coil. 10. A process for preparing high dimensional cored wires containing sulphur removers, substantially as hereinbefore described.

Full Text

The present invention relates to the manufacture of high dimensional
cored wires containing de - sulphuriser compounds for removing sulphur from
"hot metal" and a process for making the same. More particularly this invention
pertains to high dimensional cored wires filled with a granular or powdery
sulphur removing material selected from the group of calcium carbide, calcium
oxide (lime), calcium metal, magnesium, magnesium-aluminium alloy, and
preferably fine granules of reactive powders having a coat of inorganic or/and
organic material, or even without a coating and simple granules with the
mixtures of such inorganic or organic materials and a process for preparing
such high dimensional cored wires.
The present invention constitutes an improvement in or modification
of the invention described and claimed in my main Patent Application
No.725/KOL/2006 dated 20.07.2006. In the complete specification of my said
main Patent Application there is descirbed and claimed high dimensional cored
wires containing oxygen removers formed from cold-rolled steel sheet, said
oxygen remover or de-oxidant material being in finely divided granular or
powdery form coated with a protective coating material such as herein described,
the diameter of the said cored wires varying between 13 and 40 mm, preferably
between 19 and 34 mm, and the coated de-oxidant material filled in the core is
held in place in compacted form by the seaming locks provided during formation
of the said cored wires after filling.
The said main Patent Application also relates to a process for preparing
high dimensional cored wires containing oxygen removers comprising the steps
of-
(a) slitting cold-rolled steel sheet of thickness varying between 0.2
and upto 1 mm and required width of 90-110 mm, providing for the
double seaming locks;
(b) feeding the slit coils into forming rolls which gives the slits the
desired near round shape with diameter of 13 to 40 mm, preferably
between 19 and 34 mm;
(c) filling reactive aluminium powder/granules or other de-oxidants
from bunkers or feeders into the blank spaces of the wire;
(d) sealing the powder/granule filled wire, either singly or doubly,
by the time it comes out of the last forming roll;
(e) coiling the thus formed wire over a mandrel with inner diameter
varying from 200 mm to 2.5 metres in diameter, generally of around
1 metre in diameter, depending on customer requirement;
(f) applying a thin film of oil or anti-rust solution to the exposed
surface or outer layer of the coil to prevent rust formation, and
(g) strapping and/or wrapping the coils with plastic/stretch film for
preventing moisture ingress and then placing over wooden or steel pallets
for delivery to the customer.
De-sulphurisation plays an important role in the process of iron making
and for which calcium carbide with lime and hydrocarbon and magnesium or
magnesium aluminium alloys with lime with or without hydrocarbons have been
conventionally used. The term de-sulphuriser means a chemical compound,
alloy or element which will remove the active sulphur present in the liquid metal
and form a sulphide as its final product, usually as a distinct phase and easily
separable from the liquid metal. Iron making is integral to the steel making
process and de-sulphurisation of hot metal is an important processing
step, which determiners the quality of steel. Sulphur, if present in iron and
consequently steel in the active/elemnental form, will deteriorate the quality of
steel and will also result in difficulties in steel making. The steel thus made will
have lesser demand and consequetly lesser price realization. Steel makers are
in regular search of a better and more economical method for removing sulphur
in the steel.
The existing process of de-sulphurisation involves pneumatic injection of
the finely powdered de-sulphuriser reagent through a ceramic lance into the
hot metal, involving either mono or co-injection of the reagents. That is either
just calcium carbide based reagent is injected or both calcium carbide and
magnesium-based reagents are co-injected simultaneously as per determined
process.
The process suffers from the following limitations :
a) The calcium caride based reagent is highly explosive in nature
and requires extensive and very elaborate safety precautions to be
taken in its handling and storage.
b) The reagent in the storage tanks requires regular purging with
dry nitrogen to ensure that it does not settle down and jam the exit
injection pipelines.
c) An extensive and elaborate pollution control system needs to be
installed to clean the oxide of nitrogen that are formed when the injected
nitrogen surfaces from the molten metal and comes in contact with the
oxygen in air. These fumes also contain some calcium carbide and other
powder which also needs to be handled carefully so that no explosion
takes place in the pollution equipment.
d) The recovery of the reagent is also limited and is not more than
40-45% by wt.
e) Explosive license is required for the whole de-sulphuriser plant
and all the rules and regulations regarding working in an explosive
area need to be observed meticulously.
f) Investment in the plant and equipment are considerable.
g) Plant requires considerable space and close monitoring.
The present invention aims at overcoming the foregoing shortcomings of
the prior art and carry out production of de-sulpurisation of hot metal more
efficiently and effectively and with lower consumption of the reagents.
The process has the objective of economizing the hot metal
de-sulphurisation by cored wire injection by reducing the quantum of steel used
as a sheath for encasing the powdery/granular de-sulphuriser reagents by
using the higher dimension cored wire.
This invention has also the objective to further enhance the recovery of
the de-sulphuriser reagents, simultaneously reducing the quantum of
consumpton and time of feeding of the de-sulphuriser to the liquid metal.
A further object of the present invention is to provide a technique to use
magnesium or magnesium-aluminium alloy scrap as de-sulphurisers after
converting them into granules or calcium carbide powder/granules as
desulphuriser reagent, mixed with lime and hydrocarbons, followed by coating
with a material like graphite, low density polythene, polyamide, low molecular
weight vinyl acetate polymer, talc, steatite, calcium silicide, powdered lime,
hydrocarbons and the like to prevent fusion or adhesion of the granular
particles into a single mass while being pressed and drawn in the wire as well as
generate the required amount of gas when in contact with the moltel hot metal
to ensure intimate mixing of the powdered reagent in the hot metal, resulting in
good reaction and high sulphur removal.
A still further object of this invention is to provide high dimensional
cored wires containing de-sulphuriser granules coated with graphite which
while being drawn, the contents become tightly packed, thereby imparting
dimensional rigidity and stiffness to the wire.
A further object of the invention is to impart thermal stability to the
wire so that it remains cool for a longer time than thinner wires and is able to
penetrate deeper into the hot metal and thus has better thermal stability
to prevent deformation and which will eventually result in better action and
recovery of the reagents.
Another object of this invention is to provide high dimentional cored wires
with a non-adherent coating of polymeric material on the inside surface of the
said cored wires.
Yet another object of this invention is to provide high dimentional cored
wires containing de-sulphurising agents in granular form without coating but
mixed with the aforementioned coating material (s) filled into the same wire.
Still another object of the present invention is to provide a process for
preparing high dimensional cored wires containing de-sulphurising agents in
a granular form and coated with a protective coating to prevent sticking and
fusing into a single mass while being pressed and drawn into wire.
The foregoing objects are achieved by the present invention which
pertains to high dimentional cored wires containing de-sulphurising agents
for removal of sulphur from hot metal characterized in that said wires contain
sulphur-removers or de-sulphurising agent(s) formed from cold rolled steel sheet,
said sulphur-removers or de-sulphurising agent(s) being in finely divided granular
or powdery form coated with a protective coating material such as herein
described, the diameter of said cored wires varying between 19 and 40 mm,
and the coated de-sulphurising agent(s) filled in the core is held in place in
compacted form by the seaming locks provided during formation of the said
cored wires by being pressed and drawn after filling, to generate gas for
dispersing the said de-sulphurising agent(s) throughout the hot metal and
promote intimate mixing, better reaction and removal of sulphur from hot metal
as sulphides.
The subject invention also relates to a process for high dimensional
cored wires containing sulphur removers as defined above and comprising
the steps of -
a) slitting cold rolled steel sheet of thickness varying between 0.2 mm
and upto 1 mm, and required width of 90-110 mm, providing for the
double seaming locks;
b) coating the slit coils with plastic or BOPP (bi-axially oriented poly
propylene) film to prevent the reaction of the chemicals with the cold
rolled steel strip;
c) feeding the slit coils into forming rolls which gives the slits the
desired near round shape with a diameter of 13 to 40 mm;
d) filling reactive de-sulphuriser powder/granules or other
de-sulphrisers such as herein described from bunkers or feeders into the
empty spaces of the wire to ensure that the wire is tightly packed with the
powders, this powder density varying for wires of different diameters;
e) sealing the powder/granule filled wire, either singly or doubly by
the time it comes out of the last forming roll;
f) coiling the wire thus formed over a mandrel with inner diameter
varying from 200 mm to 2.5 meters in diameter, generally of around
1.2 meter in diameter, depending on customer requirement;
g) applying a thin film of oil or anti-rust solution to the exposed
surface or outer layer of the coil to prevent rust formation, and
h) strapping and/or wrapping the coils with plastic/stretch film for
preventing moisture ingress and then placing over wooden or steel pallets
for delivery to the customer.
In the above process, even uncoated slit coils may be used, avoiding use of
expensive 'BOPP' film, if the shelf life is short. The prererred diameter of rolls
formed from the slit coils varies between 19 and 34 mm.
As regards BOPP tape, it is being increasingly used since it is strong and
does not tear easily like other plastic materials. An additional advantage with
the BOPP tape is that at very high molten metal temperature, it would form
gases which would help in stirring the hot metal ensuring enhanced removal of
sulphur.
The most frequently used de-sulphuriser is either metallic magnesium or
calcium carbide. The former is generally coated with 5% CaO (lime) to reduce
the risk of an accident, and for the latter during its handling, the area is purged
with gaseous nitrogen.
Oil and anti-rust solution appl'ed to the outer surface of the finished coil
are obtained from petroleum fraction which are viscous and greasy, acting as an
effective barrier against rust-forming agents.
As pointed out earlier, de-sulphurisers may be selected from calcium
carbide, and mixed with calcium oxide (lime), hydrocarbons or calcium metal,
magnesium, magnesium-aluminium alloy, and preferably fine granules of
reactive magnesium based regent or regents of calcium carbide powders having
a coat of inorganic or/and organic metarial, preferably lime and hydrocarbons,
or even without a coating and simple granules with the mixtures of inorganic or
organic materials.
Size of de-sulphuriser granules should optimally be around 10 mesh, but
finer or coarser granules may just as well be used; however, care should be
taken to prevent handling loss. While drawing the granular desulphuriser
reagent -filled wire, the contents become tightly packed, imparting dimensional
stability and stiffness to the wire, thereby ensuring ease of handling the coil.
De-sulphurisation by changing the form of desulphuriser reagent
addition, which is carried out by injecting high dimentional cored wire filled
with highly reactive de-sulphurisation reagent in fine granular form and coated
with an organic material like graphite for better recovery and achieving the
optimum level of sulphur and with lesser consumption of the de-sulphurisation
reagent are unique features of this invention. The coating is not limited to
organic materials but can also include inorganic coating materials as well,
like calcium oxide, talc, chalk powder, and the like. De-sulphurisation in
accordance with the present invention can be carried out in hot metal at
any stage it travels from the blast furnace to the steel making area as per
requirement of the steel maker.
A notable feature of this invention is to use scrap magnesium or
magnesium aluminium alloy of any grade in granular or powdered form as the
de-sulphurisers, suitably coated with organic or inorganic coating material as
described hereinbefore. Use of scrap/waste magnesium or magnesium aluminium
alloy effectively adds to the economy of the overall process.
As an additional feature of this invention, i.e. winding of the powder-filled
coil is subjected to 'coreless coiling' so that the coil can be uncoiled from inner
diameter of the stationary coil generally called a flipping coil, either vertical or
horizontal. The coil can also be made into a spool with a core made of either
wooden, synthetic, metal or any such materials.
The novel products of this invention, namely, high dimensional cored wire
filled with fine granules of the de-sulphuriser reagents powder/granules coated
with graphite and securely held inside, is provided with seaming locks. By 'high
dimensional' it is implied that dimensions of the cored wire ranges between 13
mm and 40 mm, optimally between 19 mm and 34 mm, and the internal diam-
eter of the wound wire over the mandrel vary between 200 mm to 2.5 meters and
the weight of each coil may range between 1 MT to around 20 MT depending on
customer, storage and handling requirements. The high dimension as stated
has the technical advantage of providing thermal stability, which ensure deeper
penetration of the wire into the melt thus resulting in better recovery of the
reagents.
The present invention will be further illustrated by the consumption data
of the reagents as per the reduction in sulphur levels that has been achieved as
mentioned in the table and the example given below. It is to be understood that
the invention is not restricted to the results given therein.
Various advantages of the products of the present invention may be briefly
outlined as under :
1. An increasing amount of de-sulphuriser reagents can be filled per
unit length of wire, and as more material is compacted per meter of wire of
larger dimension, the cost of the steel sheathing becomes less.
2. There is substantial rise in the feeding rate, thereby saving feeding
time and resulting in an enhanced time available for steel making.
3. Due to larger dimension, better rigidity and stiffness, the high
dimensional wire allows for deeper penetration into steel, thereby resulting in
better recovery and homogenization of the de-sulphurisers.
4. Coated fine granules of the de-sulphurisation reagents is used as
filler material for making high dimensional cored wire resulting in an estimated
10-15% higher recovery than the conventional pneumatic injection system for
reagents.
5. Since the de-sulphuriser reagent is steel sheathed cored wire and
is also "flipping type", there is a saving on the transportation (since normal
trucks can be used to transport the material, unlike explosive licensed storage
tanks for the conventional de-sulphurisation reagent) and easier storage since it
can be stored anywhere unlike in the de-sulphuriser reagent for the pneumatic
injection system. The storage cost is drastically reduced and the shelf life is also
higher since the de-sulphuriser reagent is encased in a tightly covered steel
sheath and is water and moisture proof.
As the present invention may be embodied in several forms without
departing from the spirit or essential characteristics thereof, it should also be
understood that the above-described experimental data are not limited by any
of the details of the foregoing description, unless otherwise specified, but rather
should be construed broadly within its spirit and ambit as defined in the claims
appended hereafter, and therefore all changes and modifications that fall within
the meets and bounds of the claims, or equivalences or such meets and bounds,
are therefore intended to be embraced by the appended claims.
I Claim :
1. High dimensional cored wires containing de-sulphurising agent(s)
for removing sulphur from hot metal, characterized in that said wires contain
sulphur - removers or de-sulphurising agent(s) formed from cold rolled steel
sheet, said sulphur - removers or de - sulphurising agent(s) being in finely
divided granular or powdery form coated with a protective coating material such
as herein described, the diameter of said cored wires varying between 19 and
40 mm, and the coated de-sulphurising agent(s) filled in the core in is held in
place in compacted form by the seaming locks provided during formation of the
said cored wires by being pressed and drawn after filling, to generate gas for
dispersing the said de - sulphurising agent(s) throughout the hot metal and
promote intimate mixing, better reaction and removal of sulphur from hot metal
as sulphides.
2. High dimensional cored wires as claimed in Claim 1, characterized
in that diameter of the said cored wires varies between 19 and 34 mm
containing fine granules of magnesium based reagents or reagents of calcium
carbide powders having a cost of inorganic or/and organic protective coating
material such as herein described, preferably lime and hydrocarbons like
plastic waste or graphite - based, coal - based or charcoal based carbon powder,
or granules of de - sulphurising agent(s) without coating but mixed with one or
more protective coating materials such as herein described, wherein the size of
said granules is optimally around 10 mesh.
3. High dimensional cored wires as claimed in Claims 1 and 2,
characterized in that as de - sulphurising agent there is employed prime or
scrap metallic magnesium, magnesium-aluminium alloy, calcium carbide - based
rea"gent, calcium oxide or calcium, wherein magnesium or magnesium-aluminium
alloy is shredded and converted into granular/powdery form, followed by
application of one or more of said inorganic and/or organic coating materials to
prevent fusion or adhesion of granules at the time of being pressed and drawn
in the form of wire.
4. High dimensional cored wires as claimed in Claims 1 to 3,
characterized in that said protective inorganic coating materials are selected
from the group of powdered lime (CaO), talc, steatite, lime stone dust, calcite
and calcium silicide, and as organic coating material there is employed
graphite, LDP (low density polyethylene), polyamide, low molecular weight vinyl
acetate polymer, bi-axially oriented poly propylene (BOPP) or waste plastic
powder.
5. High dimensional cored wires as claimed in Claims 1 to 4,
characterized in that while drawing the said granular/powdery de - sulphuriser
agent like prime or scrap magnesium or magnesium-aluminium alloy or
calcium carbide based reagent coated with powdered lime and hydrocarbons
in powder/granule filled wire, the contents become tightly packed imparting
stiffness and dimensional stability to the wire, thereby ensuring ease of
handling the coil.
6. High dimensional cored wires containing de - sulphurising agent (s)
for removing sulphur from hot metal, substantially as herein described with
particular reference to the illustrative Example.
7. A process preparing high dimensional cored wires containing
sulphur removers as claimed in any of the preceding claims, characterized
in that the said comprises the steps of -
a) slitting cold rolled steel of thickness varying between 0.2 and 1 mm
and required width of 90-110 mm providing for the double seaming locks;
b) coating the slit coils with plastic or BOPP (bi-axially oriented poly
propylene) film to prevent the reaction of the chemicals with the cold
rolled steel strip;
c) feeding the slit coils into the forming rolls which gives the slits the
desired near-round shape a diameter of 13 to 40 mm;
d) filling reactive de-sulphuriser reagent powder/granules or other
de-sulphurisers such as herein described into the wire from bunkers or
feeders into empty spaces of the wire to ensure that the wire is tightly
packed with the powders, the powder density varying for wires of different
diameters;
e) sealing the powder/granule filled wire, wither singly or doubly, by
the time it comes out of the last forming roll;
f) coiling the thus formed wire over a mandrel with inner diameter
varying from 200 mm to 2.5 meters in diameter, generally of around
1.2 meter in diameter, depending on customer requirement;
g) applying a thin film of oil or anti-rust solution to the exposed
surface or outer layer of the coil to prevent rust formation and
h) strapping and/or wrapping the coils with plastic/stretch film for
preventing moisture ingress and then placing over wooden or steel pallets
for delivery to the customer.
8. A process as claimed in Claim 7, characterized in that the thickness
of the cold-rolled steel sheet (DD and soft grade) is optimally 0.4 mm, diameter
of the formed wire varies between 19 and 34 mm and weight of each of coil varies
between 1 MT and 20 MT, depending on customer requirement.
9. A process for claimed in Claim 7 and 8, wherein winding of the
de-sulphurisers filled coil is subjected to coreless winding thereby allowing the
said coil to be unwinded or uncoiled from the inner diameter of the stationary
coil.
10. A process for preparing high dimensional cored wires containing
sulphur removers, substantially as hereinbefore described.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=Rh9TbMv+6iXfwzz1sKNzWA==&loc=wDBSZCsAt7zoiVrqcFJsRw==

« Previous Patent

Next Patent »

Patent Number

279782

Indian Patent Application Number

1289/KOL/2009

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

31-Jan-2017

Date of Filing

28-Oct-2009

Name of Patentee

GODA SURYA NARAYAN

Applicant Address

BB-8, 7&8 AREA, CIVIL TOWNSHIP, ROURKELA - 769004, ORISSA, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	GODA SURYA NARAYAN	BB-8, 7&8 AREA, CIVIL TOWNSHIP, ROURKELA - 769004, ORISSA, INDIA

PCT International Classification Number

C23F4/04;C22B1/11;C23G1/08;C23F1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA