CA1053908A - Method for refining of metal - Google Patents
Method for refining of metalInfo
- Publication number
- CA1053908A CA1053908A CA217,974A CA217974A CA1053908A CA 1053908 A CA1053908 A CA 1053908A CA 217974 A CA217974 A CA 217974A CA 1053908 A CA1053908 A CA 1053908A
- Authority
- CA
- Canada
- Prior art keywords
- metal
- slag
- discharge
- poured
- refining
- 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.)
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
METHOD FOR REFINING OF METAL
Abstract of the Disclosure The herein-proposed method consists in that half of a given amount of fluid slag is poured off on a metal stream before a discharge of the first 20% of the metal is over, and the remaining amount of the slag is poured off during the entire period of the discharge of the rest 50% of the metal.
The present invention ensures a high degree of metal refining.
Abstract of the Disclosure The herein-proposed method consists in that half of a given amount of fluid slag is poured off on a metal stream before a discharge of the first 20% of the metal is over, and the remaining amount of the slag is poured off during the entire period of the discharge of the rest 50% of the metal.
The present invention ensures a high degree of metal refining.
Description
~s~
I`~IETHOD FOR REFINING OF MET~L
The present invention relates to the production of metals and, more specifically, to a method for refining of metal bv a fluid slag.
A method has previously been proposed for refining of metal by the fluid slag, consisting in that the metal is poured o~f on the slag which is in a ladle or some other capacity. When a stream of the metal hits the slag the metal mixes with the latter, as a result the metal refining occurs.
Under this method the refining process mainly occurs in the first half of the dischar~e of metal when -the kinetic energy of a stream is suf'ficiently great. In the second half of the metal discharge, as the height of the fall of the metal s-tream diminishes and the pressure of the outflow of the stream drops down, the refining process sharply slows down or ceases altogether. This is a shortcoming of this method.
In the second half of the discharge the refinery slag, as a rule, still possesses a sufficiently high refining capacity which, however, is not used because of a small inter-face of the reacting phases.
Known in the art is a refining method according towhich, for increasing the interface and! consequently, for raising the efficiency slag is poured off on a metal stream in ~he first hal~ of the metal discharge period.
However, as it is~mentioned, in the first half of metal discharge, due to the stream's great kinetic energy, the interface of phases is big, An increase in the degree of the phase m~xing, due to collision of the streams of slag and metal, will raise but little the eficiency of treatment.
The main object of the present invention is to develop a method for refining of metal b~ fluid slag, which would ~ ~)s3~
ensure the efficiency of metal treatment~
Said and other o~jects of the invention are achieved through a method for refining of metal by fluid slag, envisaging the discharge of slag on a stream of metal under which, accord-ing to the invention, half of a given amount of slag is poured off before the discharge of the first 20% of metal is over, the remaining amount of the slag is poured off during the entire period of the discharge of the rest 50~ of the metalO
The essence of the herei~proposed method consists in the following.
It is proposed that about half of the entire given amount of the refinery slag be poured off on the stream of the discharyed metal before the discharge of the firs-t 20% of the metal is over.
Due to a ~ig kinetic energy of the metal stream and also due to an additional mixing of the slag and metal~ because of collision of the streams, the discharge of the first 50% of the whole of metal results in a sufficiently big interface and, consequentlyr in a high refining efficiency.
During the discharge of the rest 50% of the metal the energy of the metal stream decreases; at this time it is proposed that the refinery slag be poured off on the metal stream.
In comparison with the known methods, the present method makes it possib].e to increase considerably the interface of phases and to make use of a still high refining capacity of the slag. As a whole, due to a combined discharge of the slag and metal during the discharge of the first portion of the metal and, especially, during the discharge of the rest 50% of the metal, the efficiency of refining increases, as compaxed to the known methods~
. .... .
~lt53~8 The advantages of theherei~propose~ method can be seen more specifically from the following examples.
Example l.
To re~ine medium-carbon steel intended for important applications, which is melted in a 140-ton open-hearth furnace, 4.5 tons of the fluid refinery slag were prepared.
Preparation of the slag consists in mel-ting initial materials in an electric furnace, overheating the slag to l,650-1,700, and in discharging it into a special ladle where-from the slag is poured off through a lip of the ladle.
When steel is being poured off from a furnace the discharge of the slag begins immediately in a stream in such a way that the latter would hit the stream of the discharged metal.
A~ter roughly 10% of the whole amount of the metal, i.e. about 14 tons, is poured off the discharge of the slag is discontinued. At this time half of the whole amount of the sla~, that is, ahout 2.2 - 2.3 tons, is discharged. This amount of slag i5 enough for developing a big inter~ace due to a high kinetic energy of the metal stream which falls from a height of 4-5 m at the beginning of discharge and from a height of
I`~IETHOD FOR REFINING OF MET~L
The present invention relates to the production of metals and, more specifically, to a method for refining of metal bv a fluid slag.
A method has previously been proposed for refining of metal by the fluid slag, consisting in that the metal is poured o~f on the slag which is in a ladle or some other capacity. When a stream of the metal hits the slag the metal mixes with the latter, as a result the metal refining occurs.
Under this method the refining process mainly occurs in the first half of the dischar~e of metal when -the kinetic energy of a stream is suf'ficiently great. In the second half of the metal discharge, as the height of the fall of the metal s-tream diminishes and the pressure of the outflow of the stream drops down, the refining process sharply slows down or ceases altogether. This is a shortcoming of this method.
In the second half of the discharge the refinery slag, as a rule, still possesses a sufficiently high refining capacity which, however, is not used because of a small inter-face of the reacting phases.
Known in the art is a refining method according towhich, for increasing the interface and! consequently, for raising the efficiency slag is poured off on a metal stream in ~he first hal~ of the metal discharge period.
However, as it is~mentioned, in the first half of metal discharge, due to the stream's great kinetic energy, the interface of phases is big, An increase in the degree of the phase m~xing, due to collision of the streams of slag and metal, will raise but little the eficiency of treatment.
The main object of the present invention is to develop a method for refining of metal b~ fluid slag, which would ~ ~)s3~
ensure the efficiency of metal treatment~
Said and other o~jects of the invention are achieved through a method for refining of metal by fluid slag, envisaging the discharge of slag on a stream of metal under which, accord-ing to the invention, half of a given amount of slag is poured off before the discharge of the first 20% of metal is over, the remaining amount of the slag is poured off during the entire period of the discharge of the rest 50~ of the metalO
The essence of the herei~proposed method consists in the following.
It is proposed that about half of the entire given amount of the refinery slag be poured off on the stream of the discharyed metal before the discharge of the firs-t 20% of the metal is over.
Due to a ~ig kinetic energy of the metal stream and also due to an additional mixing of the slag and metal~ because of collision of the streams, the discharge of the first 50% of the whole of metal results in a sufficiently big interface and, consequentlyr in a high refining efficiency.
During the discharge of the rest 50% of the metal the energy of the metal stream decreases; at this time it is proposed that the refinery slag be poured off on the metal stream.
In comparison with the known methods, the present method makes it possib].e to increase considerably the interface of phases and to make use of a still high refining capacity of the slag. As a whole, due to a combined discharge of the slag and metal during the discharge of the first portion of the metal and, especially, during the discharge of the rest 50% of the metal, the efficiency of refining increases, as compaxed to the known methods~
. .... .
~lt53~8 The advantages of theherei~propose~ method can be seen more specifically from the following examples.
Example l.
To re~ine medium-carbon steel intended for important applications, which is melted in a 140-ton open-hearth furnace, 4.5 tons of the fluid refinery slag were prepared.
Preparation of the slag consists in mel-ting initial materials in an electric furnace, overheating the slag to l,650-1,700, and in discharging it into a special ladle where-from the slag is poured off through a lip of the ladle.
When steel is being poured off from a furnace the discharge of the slag begins immediately in a stream in such a way that the latter would hit the stream of the discharged metal.
A~ter roughly 10% of the whole amount of the metal, i.e. about 14 tons, is poured off the discharge of the slag is discontinued. At this time half of the whole amount of the sla~, that is, ahout 2.2 - 2.3 tons, is discharged. This amount of slag i5 enough for developing a big inter~ace due to a high kinetic energy of the metal stream which falls from a height of 4-5 m at the beginning of discharge and from a height of
2-3 m by the middle of discharge.
During the discharge of from lO to 50~ of the whole amount of metal slag is not discharged. The discharge of the remaining part of the refinery slag (about half of the whole amount - 2.2 - 2.3 tons) begins when the discharge of the rest 50~ o~ the metal is resumed. q`he slag is discharged so that the-stream of the slag would hit the metal stream. The slag is being poured off during the entire period of the discharge of the rest 50% of the metal.
At this time the collision of the streams of the re-acting phases also results :in a sufficiently bi~ interface, and the refining capacity of slag is used to the utmost.
~;35~
As a ~hole, the efficiency oE refining increases by 20 - 50%, as compared to the known methods. To achieve the same degree of refining the consumption of slag can be reduced to 3-4 tons.
Example 2.
For treating low-carbon high-alloy (e.g., stainless) steel melted in a 25-ton electric furnace 1.5 tons of refinery calcareous-aluminous slag were prepared.
Slag is prepared by smelting lime and alumina in an electric furnace. The slag is overheated to 1,700, and the necessary amount is discharged into a special ladle with a pouring lip.
With the appearance of the first portions of metal in a steel-teçming ladle the discharge of refinery slag begins through the lip of the ladle in such a way that the slag stream would hit the metal stream. During the entire period of discharge the height of the fall of the metal stream is kept constant (3 - 4m)~ due to lowering the steel-teeming ladle whlch is positioned on hooks of a crane.
After the discharge of the irst 20~ of metal the discharge of the slag is discontinued; at this time about half of the whole amount of the slag, that is, 0.7 - 0.8 tons, is poured off.
Ater this the discharge of the slag is interrupted;
the discharge of the slag is again resumed when the discharge of the rest 50% of metal begins.
The slag is likewisa discharged so that the stream of the slag would hit the metal stream. The slag is being poured off during the entire period of the discharge of the rest sn~ of the metal, at this time about half of the whole amount of the slag, i.a., 0.7 - 0.8 tons, is poured o~f as well. In this case the ef~iciency o~ desulphuration of the metal can be raised to 70 -:: .:: .. . . . . . . .. .
~(~S~90~
85~, as against 50 - 60% in accordance with the kno~n method.
Thus, to achieve the same degree oE desulphuration -50 -60%, about one ton oE slag can be -ta]cen For refining and not 1.5 tons.
Example 3.
For treating steel intended for important applications, e.g., for main gas pipelines, which is melted in a 300-ton open-hearth furnace, nine -tons of the refinery slag are prepared.
The slag is prepared by burning 9.5 tons of exo-thermic mixture in a separate ladle with a pouring lip.
lQ With the appearance o E a metal stream in a steel-teeming ladle the discharge of refinery slag begins by means of tilting a special ladle in such a way that the slag stream would hit the metal stream. A~ter the discharge of the first 15~ by weight of the whole of the metal, that is, after about 20 tons of the metal are discharged, the discharge of the slag is discontinued. At this time about 4.5 tons o~ the slag are ladled out.
Duriny the discharge of subsequent 130 tons of the metal the slag is not ladled out. At this time the refining process proceeds due to developing an interface, as a result of the collision of t-he metal and slag streams. During this .
perlod the height of the ~all of the metal stream changes from 5 - ~7 m to 3 - 4 m, i.e., the kinetic energy of the metal stream remains high.
During the discharge o E the rest 150 tons of the metal, that is, o~ 50% by weight o~ the whole melt, the discharge of the slag is again resumed in a stream so that the stream of the slag hits the metal stream~
~ At this stage 4.5 tons of the slag are likewise ladled out~during the entire remaining period of discharge.
~ Refining result~ in reducing the content o:E sulphur by 50 - ~0~ The concelltration of sulphur in finishecl me tal is : :
.:
within the limits of 0.010 - 0.017%, as against 0.020 - 0.040%
initially. If refining had been carried out according to a usual method 12 -tons of slag would have been required to achieve the same results, that is, the consumption of slag dwindled by 1.3 - fold; and outlays on steel refining wil.l, correspondingly, go down.
~ 6 -
During the discharge of from lO to 50~ of the whole amount of metal slag is not discharged. The discharge of the remaining part of the refinery slag (about half of the whole amount - 2.2 - 2.3 tons) begins when the discharge of the rest 50~ o~ the metal is resumed. q`he slag is discharged so that the-stream of the slag would hit the metal stream. The slag is being poured off during the entire period of the discharge of the rest 50% of the metal.
At this time the collision of the streams of the re-acting phases also results :in a sufficiently bi~ interface, and the refining capacity of slag is used to the utmost.
~;35~
As a ~hole, the efficiency oE refining increases by 20 - 50%, as compared to the known methods. To achieve the same degree of refining the consumption of slag can be reduced to 3-4 tons.
Example 2.
For treating low-carbon high-alloy (e.g., stainless) steel melted in a 25-ton electric furnace 1.5 tons of refinery calcareous-aluminous slag were prepared.
Slag is prepared by smelting lime and alumina in an electric furnace. The slag is overheated to 1,700, and the necessary amount is discharged into a special ladle with a pouring lip.
With the appearance of the first portions of metal in a steel-teçming ladle the discharge of refinery slag begins through the lip of the ladle in such a way that the slag stream would hit the metal stream. During the entire period of discharge the height of the fall of the metal stream is kept constant (3 - 4m)~ due to lowering the steel-teeming ladle whlch is positioned on hooks of a crane.
After the discharge of the irst 20~ of metal the discharge of the slag is discontinued; at this time about half of the whole amount of the slag, that is, 0.7 - 0.8 tons, is poured off.
Ater this the discharge of the slag is interrupted;
the discharge of the slag is again resumed when the discharge of the rest 50% of metal begins.
The slag is likewisa discharged so that the stream of the slag would hit the metal stream. The slag is being poured off during the entire period of the discharge of the rest sn~ of the metal, at this time about half of the whole amount of the slag, i.a., 0.7 - 0.8 tons, is poured o~f as well. In this case the ef~iciency o~ desulphuration of the metal can be raised to 70 -:: .:: .. . . . . . . .. .
~(~S~90~
85~, as against 50 - 60% in accordance with the kno~n method.
Thus, to achieve the same degree oE desulphuration -50 -60%, about one ton oE slag can be -ta]cen For refining and not 1.5 tons.
Example 3.
For treating steel intended for important applications, e.g., for main gas pipelines, which is melted in a 300-ton open-hearth furnace, nine -tons of the refinery slag are prepared.
The slag is prepared by burning 9.5 tons of exo-thermic mixture in a separate ladle with a pouring lip.
lQ With the appearance o E a metal stream in a steel-teeming ladle the discharge of refinery slag begins by means of tilting a special ladle in such a way that the slag stream would hit the metal stream. A~ter the discharge of the first 15~ by weight of the whole of the metal, that is, after about 20 tons of the metal are discharged, the discharge of the slag is discontinued. At this time about 4.5 tons o~ the slag are ladled out.
Duriny the discharge of subsequent 130 tons of the metal the slag is not ladled out. At this time the refining process proceeds due to developing an interface, as a result of the collision of t-he metal and slag streams. During this .
perlod the height of the ~all of the metal stream changes from 5 - ~7 m to 3 - 4 m, i.e., the kinetic energy of the metal stream remains high.
During the discharge o E the rest 150 tons of the metal, that is, o~ 50% by weight o~ the whole melt, the discharge of the slag is again resumed in a stream so that the stream of the slag hits the metal stream~
~ At this stage 4.5 tons of the slag are likewise ladled out~during the entire remaining period of discharge.
~ Refining result~ in reducing the content o:E sulphur by 50 - ~0~ The concelltration of sulphur in finishecl me tal is : :
.:
within the limits of 0.010 - 0.017%, as against 0.020 - 0.040%
initially. If refining had been carried out according to a usual method 12 -tons of slag would have been required to achieve the same results, that is, the consumption of slag dwindled by 1.3 - fold; and outlays on steel refining wil.l, correspondingly, go down.
~ 6 -
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for refining metals selected from the group consisting of carbon killed and alloy steels with a predetermined quantity of fluid slag, comprising: discharging slag on a discharged stream of metal, wherein half the predetermined quantity of slag is poured off before the discharge of the first 20% of the metal is over, then the metal alone is poured off onto the already discharged slag and metal until 50% of the metal has been poured off while the remaining amount of the slag is poured off during the entire period of the discharge of the remaining 50% of the metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA217,974A CA1053908A (en) | 1975-01-15 | 1975-01-15 | Method for refining of metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA217,974A CA1053908A (en) | 1975-01-15 | 1975-01-15 | Method for refining of metal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1053908A true CA1053908A (en) | 1979-05-08 |
Family
ID=4102055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA217,974A Expired CA1053908A (en) | 1975-01-15 | 1975-01-15 | Method for refining of metal |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1053908A (en) |
-
1975
- 1975-01-15 CA CA217,974A patent/CA1053908A/en not_active Expired
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