CA1151421A - Tuyere for injecting powdered products into molten metal - Google Patents
Tuyere for injecting powdered products into molten metalInfo
- Publication number
- CA1151421A CA1151421A CA000368304A CA368304A CA1151421A CA 1151421 A CA1151421 A CA 1151421A CA 000368304 A CA000368304 A CA 000368304A CA 368304 A CA368304 A CA 368304A CA 1151421 A CA1151421 A CA 1151421A
- Authority
- CA
- Canada
- Prior art keywords
- supply line
- tuyere
- terminal portion
- carrier gas
- flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/46—Details or accessories
- C21C5/4606—Lances or injectors
- C21C5/4613—Refractory coated lances; Immersion lances
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
ABSTRACT
A tuyere or lance for injecting powdered products in a flow of carrier gas into molten metal, comprising a supply line with the terminal portion having made through the wall thereof at least one opening for withdrawing a part of the carrier gas from the mainstream flow. The tuyere also has a gas escape channel communicating with said opening the axis of which extends at an angle to the axis of said supply line, so that the axis of the mainstream flow of the carrier gas and the axis of the flow of the part with-drawn from the mainstream flow extend at an angle to each other. The invention enables to draw away a part of the carrier gas from the supply line, and thus to raise up the concentration of the powdered product in the mainstream flow.
A tuyere or lance for injecting powdered products in a flow of carrier gas into molten metal, comprising a supply line with the terminal portion having made through the wall thereof at least one opening for withdrawing a part of the carrier gas from the mainstream flow. The tuyere also has a gas escape channel communicating with said opening the axis of which extends at an angle to the axis of said supply line, so that the axis of the mainstream flow of the carrier gas and the axis of the flow of the part with-drawn from the mainstream flow extend at an angle to each other. The invention enables to draw away a part of the carrier gas from the supply line, and thus to raise up the concentration of the powdered product in the mainstream flow.
Description
1:151421 The present invention relates to metallurgy, and more particularly it relates to apparatus for treating molten metal with powdered products.
The invention can be utilized most advantageously in treating molten metal in iron and steel teeming ladles, and also in steel-making units, such as open-hearth furnaces, converters, electric furnaces, etc.
The invention can be also utilized in non-ferrous metallurgy.
There are known constructions of tuye~res or blowing lances for treating molten metal with powdered products in a gas flow, including a supply line from which the powdered product is introduced into the metal together with its carrier gas (cf- the US Patent No. 3,891,196, Int.Cl. C21C
7/100, dated June 24, 1975).
With the tuyere or blowing lance being of this construction, there has been experienced a considerable degree of carrying away the fine particles with ascending gas bubbles from the molten metal body into the atmosphere of the unit.
There is further known a device for blowing powdered products into molten metal with separation of the powdered products from the carrier gas, including a supply line with the bent end portion incorporating a separating baffle at its outlet (cf. the Czechoslovak Patent No. 130,274, Cl- 18 b 7/100, published December 15, 1968).
In this construction the powdered product fed in the flow of the carrier gas, while passing the bent portion of the supply line, is urged by thP centrifugal forces toward the outer portion of the curvilinear channel. It is practically pure carrier gas which flowsadjacent to the inner portion of curvilinear duct and is being cut off the flow .. . . . . . . .. ...
~5142-~
with high concentration of the powdered product by the ' separating baffle.
Thus, the separation of the flow takes place within the curvilinear portion of the supply pipe line wherein solid particles are urged toward the outermost part of the curvi-linear channel by the centrifugal forces, while practically pure carrier gas flows adjacent to the innermost portion of the channel. However, notwithstanding the incorporation of the separating baffle or partition, the whole body of the carrier gas passes through the outlet of the supp~y line, entering the melt is a single stream with non-uniform distribution of fine particles across its cross-section.
The known construction is characterized by a con-siderable hydrodynamic resistance of the curvilinear portion of the channel, which reduces the kinetic energy stored by the stream and results in less deep penetration of the solid particles into the molten metal, which reduces the volume of the molten metal directly contacting the powdered product.
It is an object of the present invention to step up the efficiency of using powdered products in metallurgical processes.
It is another object of the invention to provide for separation of a part of the stream of the carrier gas, and thus to step up the concentration of the powdered product in the gas flow penetrating the molten metal.
It is yet another object of the invention to reduce the resistance of the tuyere to passage therethrough of the stream of the carrier gas with entrained powdered product.
It is a further object of the present invention to provide for directing a part of the carrier gas away, avoiding its contact with the molten metal.
,~
~ , , . .. , , . ... , . - -- ---" l~S1421 These and other objects are attained in a tuyere for injecting powdered products in a flow of a carrier gas into molten metal, comprising a supply line the end portion of which is adapted for separating a part of the carrier gas flow from the mainstream flow, wherein, in accordance with the invention the end portion of the supply line has in the wall thereof at least one opening adjoined by a gas escape channel of which the axis extends at an angle to the axis of the supply line.
The provision of the opening enables to withdraw a part of the stream of the carrier gas from the supply line to step up the concentration of the powdered product in the main-stream flow downstream of the opening.
The arrangement is such that the carrier gas with-drawn through the opening in the supply line would not mix with the mainstream flow issuing from the outlet of the supply line.
Consequently, the disclosed tuyere provides for more efficient utilization of powdered products supplied into the melt for various reasons (carbonization, deoxidation, alloying of the metal, desulfurization of the metal in ladles, etc-, while reducing the amount of the powdered product finding its way into the atmosphere; furthermore, it enables to use inexpensive and readily available gases as the carrier gas, e.g. compressed air~
It is expedient that th~ opening should be in the form of at least one annular slit.
The slit-like shape of the opening minimizes the entrainment of fine particles in the carrier gas withdrawn from the mainstream flow in the supply line.
It is preferable that the terminal portion of the supply pipe should narrow down toward the outlet thereof, otherwise the velocity of the mainstream flow would significantly decrease on account of the part of the carrier gas having been withdrawn, which would reduce accordingly the depth of penetra-, .,_ .. , .. . ~ .. . . . ..
~51421 tion of the stream of the carrier gas with the powdered productentrained therein into the molten metal, thus affecting the efficiency of utilizing the powdered product.
Should it be necessary to avoid interaction of the withdrawn part of the carrier gas with the molten metal, it is expedient that a casing be mounted externally of the supply line, coaxially therewith, to define with the supply line an annular gap through which the part of the carrier gas can be withdrawn from the mainstream flow.
In one embodiment of the invention the opening in the tuyere through which the part of the carrier gas is with- -drawn is defined as a gap between the end face of the terminal portion of the supply line and the internal wall of the narrowing-down terminal portion of the casing, located at some distance downstream of the end face of the supply line and having an outlet coaxial with the supply line of a diameter not in excess of the diameter of the outlet of the supply line.
It is expedient that in the tuyere the gas escape channels should be so arranged that their axes should extend at an acute angle to the axis of the supply line, with their outlets facing the molten metal being treated.
In one embodiment of the invention, the tuyere has partitions or baffles mounted in the terminal portion thereof to separate the gas escape channels from the main channel of the supply line, these partitions or baffles having a varying thickness increasing toward the outlets of the gas escape channels, with the main channel being of a cross-section varying from circular in the area adjoining the inlets of the escape channels to slit-like at the outlet of the main channel.
Gwing to the varying thickness of the partitions or baffles, the withdrawn part of the carrier gas penetrates the molten metal at an angle relative to the mainstream flow.
,. . , ., ., ,. ,,. , . . _ ,_ , . . ... _ ,.
It can be seen from the abovesaid that in every embodiment of the tuyere in accordance with the invention the fine particles-of the powdered product would not alter the directicn of their motion throughout the length of the supply ,, line, whereas in the structure of the prior art the separation of the part of the carrier gas from the mainstream flow takes place within the curving portion of the supply line offering a significant local resistance to the flow, whereby a substantial amount of kinetic energy is lost by the fine particles.
Moreover, in every embodiment of the disclosed tuyere the withdrawn part of the carrier gas would not interact in the molten metal with the mainstream flow.
The invention will be further described in connection with embodiments thereof, with reference being made to the accompanying drawings, wherein:
Fig. 1 schematically shows a tuyere with two annular rows of openings for withdrawal of a part of the carrier gas, and with the narrowing terminal portion of the supply line, Fig. 2 shows schematically a perspective, partly broken-away view of a tuyere with annular slits and a gas escape channel defined by a specifically provided casing, Fig. 3 shows schematically a tuyere with a slit for withdrawing a part of the carrier gas, defined as a gap between the end face of the terminal portion of the supply line and the casing;
Fig. 4 shows schematically a tuyere with baffles in the terminal portion thereof:
Fig. 5 is a sectional view taken on line V-V of Fig. 4:
Fig. 6 shows a tuyere in accordance with Fig. 2 in its operating position of treating molten metal 11514Zl in a steel-teeming ladle.
Referring now to the drawings, a tuyere or lance for injecting powdered products into molten metal includes a supply line 1 (Fig. 1) having at one end thereof a connection (not shown) for communicating the tuyere with a line leading from a pneumatic conveying unit supplying powdered products in a flow of a carrier gas into the molten metal, e.g.
supplying desulfurizing agents in a flow of compressed air.
The terminal portion of the supply line 1 adapted to contact the molten metal is provided with a series of openings 2 which in the embodiment being described serve essentially as gas escape channel 3 through which a part of the carrier gas is drawn away from the mainstream flowing through the tuyere.
Owing to this part of the carrier gas having been drawn away, the concentration of the powdered product in the mainstream flow is stepped up in the supply line 1 downstream of the openings 2.
In the embodiment illustrated in Fig. 1 there are two annular rows of the openings 2 in the supply line 1.
However, it should be understood that a different arrangement of the openings would not alter the essence of the invention.
The terminal or end portion of the supply line 1 is shaped as a truncated cone 4 narrowing down toward the outlet.
This provides for an increased velocity of the mainstream flow issuing from the tuyere, and. hence, for deeper penetration into the molten metal of the flow of the powdered product entrained in the carrier gas. '-In another embodiment, the openings 2 (Fig. 2) in the supply line 1 are in the form of several substantially annular slits- The slits-like shape of the openings 2 offers the advantage of minimizing the amount of fine particles of the powdered product carried away by the carrier gas withdrawn from the mainstream flow.
~- 6 --. ,.
.. , _ . .. _. . . . _ ... ....
. . .
1~51421 In this embodiment there is a casing 5 mounted externally of the supply line 1, coaxially therewith, to define with this supply line 1 an annular gap 6 through which the part of the carrier gas, withdrawn from the mainstream flow, is led away. This construction enables to draw away the part of the carrier gas along this annular gap or channel 6, to avoid its interaction with the molten metal, which in a number of practical applications, e.g. in the case of treating molten metal in a ladle, is essential from the point of view of minimizing molten blowouts, of using inexpensive compressed air as the carrier gas and of stepping up the efficiency of utilizing some of the powdered product, e.g.
deoxidizing and desulfurizing agents, etc.
In another embodiment, likewise incorporating the casing 5 (Fig. 3), the opening 2 for drawing away a part of the carrier gas is defined by an annular gap (being in this embodiment the gas escape channel 3) between the end face of the supply line 1 and the internal wall of the narrowing terminal portion 7 of the casing 5, ending in an outlet 8 coaxial with the supply pipe 1.
Alternatively, the terminal portion of the supply line 1 can be arranged as illustrated in Figs. 4 and 5, with its cross-section altering from circular in the area of the inlets of the gas escape channels to slit-like at the outlet (see Fig. 5). Thus, the terminal portion of the tuyere is divided by baffles 9 into the central channel through which the main-stream flcw with the high concentration of the powdered product is adapted to flow, and side channels for drawing away a part of the carrier gas. The central channel is a continuation of the supply line 1. The baffles 9 have their thickness increasing toward the outlets of the gas escape channels. It should be pointed out that the provision of the tuyere either with water 11514Z~
cooling means, or with refractory heat protection means, or with both would not alter the essence of the invention.
The disclosed tuyere illustratedin Fig. 2 is operated in the following manner for treating molten steel in a ladle with powdered desulfurizing compositions (e~g. lime and fluorspar) supplied in a stream of compressed air ~see Fig. 6), a displacement mechanism (not shown) is operated to position the tuyere approximately 0.5 m above the molten metal level, the supply of compressed air from the compressor into the supply line 1 is turned on, the tuyere is dipped into the molten metal to a 1.5 m, depth and the feed of the powdered desulfurizing composition from the pneumatic conveying unit is initiated. Thus, the powdered composition in the flow of the carrier gas, i.e. compressed air, is fed into the supply line 1 of the tuyere, with part of the compressed air advancing through the supply line 1 being drawn away through the slit-like open-ings 2, into the gas escape channel 3 adjoining these openings 2, to flow through the gap 6 defined between the supply line 1 and the casing 5 into the atmosphere above the molten metal level, to be collected therefrom by a hood (not shown) positioned above the ladle and to be directed into a system cleaning the air from sus-pended fine particles.
While the part of the carrier gas is led away through the openings 2, the fine particles continue their motion by the kinetic energy stored through the supply line 1 in the stream of compressed air, to penetrate the molten metal at a higher concentration than at the inlet of the tuyere.
With the feed of the powdered product terminated, the supply line 1 is blasted with compressed air, the tuyere is withdrawn from the molten metal, and the feed of com-pressed air to the tuyere is turned off.
~ ~51421 The employment of the herein disclosed tuyere orlance, e.g. for treating molten steel in a ladle, enables:
- to step up the efficiency of utilization of powdered products injected into molten metal with the aims of desulfuriza-tion, deoxidation, alloying and carbonization, - to cut down the production cost of steel, - to reduce the percentage of fine particles carried away from molten metal by the carrier gas' - to minimize blowouts of molten metal from a ladle in the course of the blasting, and to conduct the treatment in a ladle being filled with steel teemed from a steel-making unit.
_ g _
The invention can be utilized most advantageously in treating molten metal in iron and steel teeming ladles, and also in steel-making units, such as open-hearth furnaces, converters, electric furnaces, etc.
The invention can be also utilized in non-ferrous metallurgy.
There are known constructions of tuye~res or blowing lances for treating molten metal with powdered products in a gas flow, including a supply line from which the powdered product is introduced into the metal together with its carrier gas (cf- the US Patent No. 3,891,196, Int.Cl. C21C
7/100, dated June 24, 1975).
With the tuyere or blowing lance being of this construction, there has been experienced a considerable degree of carrying away the fine particles with ascending gas bubbles from the molten metal body into the atmosphere of the unit.
There is further known a device for blowing powdered products into molten metal with separation of the powdered products from the carrier gas, including a supply line with the bent end portion incorporating a separating baffle at its outlet (cf. the Czechoslovak Patent No. 130,274, Cl- 18 b 7/100, published December 15, 1968).
In this construction the powdered product fed in the flow of the carrier gas, while passing the bent portion of the supply line, is urged by thP centrifugal forces toward the outer portion of the curvilinear channel. It is practically pure carrier gas which flowsadjacent to the inner portion of curvilinear duct and is being cut off the flow .. . . . . . . .. ...
~5142-~
with high concentration of the powdered product by the ' separating baffle.
Thus, the separation of the flow takes place within the curvilinear portion of the supply pipe line wherein solid particles are urged toward the outermost part of the curvi-linear channel by the centrifugal forces, while practically pure carrier gas flows adjacent to the innermost portion of the channel. However, notwithstanding the incorporation of the separating baffle or partition, the whole body of the carrier gas passes through the outlet of the supp~y line, entering the melt is a single stream with non-uniform distribution of fine particles across its cross-section.
The known construction is characterized by a con-siderable hydrodynamic resistance of the curvilinear portion of the channel, which reduces the kinetic energy stored by the stream and results in less deep penetration of the solid particles into the molten metal, which reduces the volume of the molten metal directly contacting the powdered product.
It is an object of the present invention to step up the efficiency of using powdered products in metallurgical processes.
It is another object of the invention to provide for separation of a part of the stream of the carrier gas, and thus to step up the concentration of the powdered product in the gas flow penetrating the molten metal.
It is yet another object of the invention to reduce the resistance of the tuyere to passage therethrough of the stream of the carrier gas with entrained powdered product.
It is a further object of the present invention to provide for directing a part of the carrier gas away, avoiding its contact with the molten metal.
,~
~ , , . .. , , . ... , . - -- ---" l~S1421 These and other objects are attained in a tuyere for injecting powdered products in a flow of a carrier gas into molten metal, comprising a supply line the end portion of which is adapted for separating a part of the carrier gas flow from the mainstream flow, wherein, in accordance with the invention the end portion of the supply line has in the wall thereof at least one opening adjoined by a gas escape channel of which the axis extends at an angle to the axis of the supply line.
The provision of the opening enables to withdraw a part of the stream of the carrier gas from the supply line to step up the concentration of the powdered product in the main-stream flow downstream of the opening.
The arrangement is such that the carrier gas with-drawn through the opening in the supply line would not mix with the mainstream flow issuing from the outlet of the supply line.
Consequently, the disclosed tuyere provides for more efficient utilization of powdered products supplied into the melt for various reasons (carbonization, deoxidation, alloying of the metal, desulfurization of the metal in ladles, etc-, while reducing the amount of the powdered product finding its way into the atmosphere; furthermore, it enables to use inexpensive and readily available gases as the carrier gas, e.g. compressed air~
It is expedient that th~ opening should be in the form of at least one annular slit.
The slit-like shape of the opening minimizes the entrainment of fine particles in the carrier gas withdrawn from the mainstream flow in the supply line.
It is preferable that the terminal portion of the supply pipe should narrow down toward the outlet thereof, otherwise the velocity of the mainstream flow would significantly decrease on account of the part of the carrier gas having been withdrawn, which would reduce accordingly the depth of penetra-, .,_ .. , .. . ~ .. . . . ..
~51421 tion of the stream of the carrier gas with the powdered productentrained therein into the molten metal, thus affecting the efficiency of utilizing the powdered product.
Should it be necessary to avoid interaction of the withdrawn part of the carrier gas with the molten metal, it is expedient that a casing be mounted externally of the supply line, coaxially therewith, to define with the supply line an annular gap through which the part of the carrier gas can be withdrawn from the mainstream flow.
In one embodiment of the invention the opening in the tuyere through which the part of the carrier gas is with- -drawn is defined as a gap between the end face of the terminal portion of the supply line and the internal wall of the narrowing-down terminal portion of the casing, located at some distance downstream of the end face of the supply line and having an outlet coaxial with the supply line of a diameter not in excess of the diameter of the outlet of the supply line.
It is expedient that in the tuyere the gas escape channels should be so arranged that their axes should extend at an acute angle to the axis of the supply line, with their outlets facing the molten metal being treated.
In one embodiment of the invention, the tuyere has partitions or baffles mounted in the terminal portion thereof to separate the gas escape channels from the main channel of the supply line, these partitions or baffles having a varying thickness increasing toward the outlets of the gas escape channels, with the main channel being of a cross-section varying from circular in the area adjoining the inlets of the escape channels to slit-like at the outlet of the main channel.
Gwing to the varying thickness of the partitions or baffles, the withdrawn part of the carrier gas penetrates the molten metal at an angle relative to the mainstream flow.
,. . , ., ., ,. ,,. , . . _ ,_ , . . ... _ ,.
It can be seen from the abovesaid that in every embodiment of the tuyere in accordance with the invention the fine particles-of the powdered product would not alter the directicn of their motion throughout the length of the supply ,, line, whereas in the structure of the prior art the separation of the part of the carrier gas from the mainstream flow takes place within the curving portion of the supply line offering a significant local resistance to the flow, whereby a substantial amount of kinetic energy is lost by the fine particles.
Moreover, in every embodiment of the disclosed tuyere the withdrawn part of the carrier gas would not interact in the molten metal with the mainstream flow.
The invention will be further described in connection with embodiments thereof, with reference being made to the accompanying drawings, wherein:
Fig. 1 schematically shows a tuyere with two annular rows of openings for withdrawal of a part of the carrier gas, and with the narrowing terminal portion of the supply line, Fig. 2 shows schematically a perspective, partly broken-away view of a tuyere with annular slits and a gas escape channel defined by a specifically provided casing, Fig. 3 shows schematically a tuyere with a slit for withdrawing a part of the carrier gas, defined as a gap between the end face of the terminal portion of the supply line and the casing;
Fig. 4 shows schematically a tuyere with baffles in the terminal portion thereof:
Fig. 5 is a sectional view taken on line V-V of Fig. 4:
Fig. 6 shows a tuyere in accordance with Fig. 2 in its operating position of treating molten metal 11514Zl in a steel-teeming ladle.
Referring now to the drawings, a tuyere or lance for injecting powdered products into molten metal includes a supply line 1 (Fig. 1) having at one end thereof a connection (not shown) for communicating the tuyere with a line leading from a pneumatic conveying unit supplying powdered products in a flow of a carrier gas into the molten metal, e.g.
supplying desulfurizing agents in a flow of compressed air.
The terminal portion of the supply line 1 adapted to contact the molten metal is provided with a series of openings 2 which in the embodiment being described serve essentially as gas escape channel 3 through which a part of the carrier gas is drawn away from the mainstream flowing through the tuyere.
Owing to this part of the carrier gas having been drawn away, the concentration of the powdered product in the mainstream flow is stepped up in the supply line 1 downstream of the openings 2.
In the embodiment illustrated in Fig. 1 there are two annular rows of the openings 2 in the supply line 1.
However, it should be understood that a different arrangement of the openings would not alter the essence of the invention.
The terminal or end portion of the supply line 1 is shaped as a truncated cone 4 narrowing down toward the outlet.
This provides for an increased velocity of the mainstream flow issuing from the tuyere, and. hence, for deeper penetration into the molten metal of the flow of the powdered product entrained in the carrier gas. '-In another embodiment, the openings 2 (Fig. 2) in the supply line 1 are in the form of several substantially annular slits- The slits-like shape of the openings 2 offers the advantage of minimizing the amount of fine particles of the powdered product carried away by the carrier gas withdrawn from the mainstream flow.
~- 6 --. ,.
.. , _ . .. _. . . . _ ... ....
. . .
1~51421 In this embodiment there is a casing 5 mounted externally of the supply line 1, coaxially therewith, to define with this supply line 1 an annular gap 6 through which the part of the carrier gas, withdrawn from the mainstream flow, is led away. This construction enables to draw away the part of the carrier gas along this annular gap or channel 6, to avoid its interaction with the molten metal, which in a number of practical applications, e.g. in the case of treating molten metal in a ladle, is essential from the point of view of minimizing molten blowouts, of using inexpensive compressed air as the carrier gas and of stepping up the efficiency of utilizing some of the powdered product, e.g.
deoxidizing and desulfurizing agents, etc.
In another embodiment, likewise incorporating the casing 5 (Fig. 3), the opening 2 for drawing away a part of the carrier gas is defined by an annular gap (being in this embodiment the gas escape channel 3) between the end face of the supply line 1 and the internal wall of the narrowing terminal portion 7 of the casing 5, ending in an outlet 8 coaxial with the supply pipe 1.
Alternatively, the terminal portion of the supply line 1 can be arranged as illustrated in Figs. 4 and 5, with its cross-section altering from circular in the area of the inlets of the gas escape channels to slit-like at the outlet (see Fig. 5). Thus, the terminal portion of the tuyere is divided by baffles 9 into the central channel through which the main-stream flcw with the high concentration of the powdered product is adapted to flow, and side channels for drawing away a part of the carrier gas. The central channel is a continuation of the supply line 1. The baffles 9 have their thickness increasing toward the outlets of the gas escape channels. It should be pointed out that the provision of the tuyere either with water 11514Z~
cooling means, or with refractory heat protection means, or with both would not alter the essence of the invention.
The disclosed tuyere illustratedin Fig. 2 is operated in the following manner for treating molten steel in a ladle with powdered desulfurizing compositions (e~g. lime and fluorspar) supplied in a stream of compressed air ~see Fig. 6), a displacement mechanism (not shown) is operated to position the tuyere approximately 0.5 m above the molten metal level, the supply of compressed air from the compressor into the supply line 1 is turned on, the tuyere is dipped into the molten metal to a 1.5 m, depth and the feed of the powdered desulfurizing composition from the pneumatic conveying unit is initiated. Thus, the powdered composition in the flow of the carrier gas, i.e. compressed air, is fed into the supply line 1 of the tuyere, with part of the compressed air advancing through the supply line 1 being drawn away through the slit-like open-ings 2, into the gas escape channel 3 adjoining these openings 2, to flow through the gap 6 defined between the supply line 1 and the casing 5 into the atmosphere above the molten metal level, to be collected therefrom by a hood (not shown) positioned above the ladle and to be directed into a system cleaning the air from sus-pended fine particles.
While the part of the carrier gas is led away through the openings 2, the fine particles continue their motion by the kinetic energy stored through the supply line 1 in the stream of compressed air, to penetrate the molten metal at a higher concentration than at the inlet of the tuyere.
With the feed of the powdered product terminated, the supply line 1 is blasted with compressed air, the tuyere is withdrawn from the molten metal, and the feed of com-pressed air to the tuyere is turned off.
~ ~51421 The employment of the herein disclosed tuyere orlance, e.g. for treating molten steel in a ladle, enables:
- to step up the efficiency of utilization of powdered products injected into molten metal with the aims of desulfuriza-tion, deoxidation, alloying and carbonization, - to cut down the production cost of steel, - to reduce the percentage of fine particles carried away from molten metal by the carrier gas' - to minimize blowouts of molten metal from a ladle in the course of the blasting, and to conduct the treatment in a ladle being filled with steel teemed from a steel-making unit.
_ g _
Claims (10)
1. A tuyere for injecting powdered products in a flow of a carrier gas into molten metal, comprising a supply line;
a terminal portion of said supply line having made through the wall thereof at least one opening for drawing away a part of the gas carrier from the mainstream flow; a gas escape channel adjoining at least one said opening having its axis extending at an angle to the axis of said supply pipe, so that the axis of the mainstream flow and the axis of the flow of the withdrawn part of the carrier gas extend at an angle to each other.
a terminal portion of said supply line having made through the wall thereof at least one opening for drawing away a part of the gas carrier from the mainstream flow; a gas escape channel adjoining at least one said opening having its axis extending at an angle to the axis of said supply pipe, so that the axis of the mainstream flow and the axis of the flow of the withdrawn part of the carrier gas extend at an angle to each other.
2. A tuyere as claimed in Claim 1, wherein said opening is in the form of at least one substantially annular slit.
3. A tuyere as claimed in Claim 1, wherein said terminal portion of said supply line is narrowing down toward the outlet thereof.
4. A tuyere as claimed in Claim 1, wherein a casing is arranged externally of said supply line, coaxially there-with, to define with said supply line an annular gap for draw-ing away a part of the carrier gas flow from the mainstream flow thereof.
5. A tuyere as claimed in Claim 4, wherein said casing has a narrowing terminal portion, said opening for withdrawing a part of the carrier gas flow being defined by a gap between the end face of said terminal portion of said supply line and the internal wall of said narrowing terminal portion of said casing, located at some distance downstream of the end face of said terminal portion of said supply line and defining an outlet coaxial with said supply line, the diameter of this last-mentioned outlet being not in excess of the diameter of the outlet of said supply line.
6. A tuyere as claimed in Claim 3, having a plurality of said gas escape channels of which the respective axes extend at acute angles to the axis of said supply line, their respective outlets facing the molten metal being treated.
7. A tuyere as claimed in Claim 6, having baffles mounted in said terminal portion of said line, to separate said gas escape channels from the main channel of said supply line, said baffles having each the thickness increasing toward the respective outlets of said gas escape channels, the main channel of said supply line having its cross-section varying from essentially circular in the area of the respective inlets of said gas escape channels to slit-like at the outlet of said supply line.
8. A tuyere as claimed in Claim 2, wherein said terminal portion of said supply line is narrowing down toward the outlet thereof.
9. A tuyere as claimed in Claim 8, wherein a casing is arranged externally of said supply line, coaxially therewith to define with said supply line an annular gap for drawing away a part of the carrier gas flow from the mainstream flow thereof.
10. A tuyere as claimed in claim 9, wherein said casing has a narrowing terminal portion, said opening for withdrawing a part of the carrier gas flow being defined by a gap between the end face of said terminal portion of said supply line and the internal wall of said narrowing terminal portion of said casing, located at some distance downstream of the end face of said terminal portion of said supply line and defining an outlet coaxial with said supply line, the diameter of this last-mentioned outlet being not in excess of the diameter of the outlet of said supply line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000368304A CA1151421A (en) | 1981-01-12 | 1981-01-12 | Tuyere for injecting powdered products into molten metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000368304A CA1151421A (en) | 1981-01-12 | 1981-01-12 | Tuyere for injecting powdered products into molten metal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1151421A true CA1151421A (en) | 1983-08-09 |
Family
ID=4118890
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368304A Expired CA1151421A (en) | 1981-01-12 | 1981-01-12 | Tuyere for injecting powdered products into molten metal |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1151421A (en) |
-
1981
- 1981-01-12 CA CA000368304A patent/CA1151421A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |