US2605180A - Method and apparatus for the production of iron - Google Patents

Description

'July 29, 1952 F. TOTZEK METHOD AND APPARATUS FOR THE PRODUCTION OF IRON Filed Jan. 15, 1949 '2 SHEETS-SHEET 1 t O a Q) 77 75 v 1 o oulgcgo OLE 75 14 w. G vao gg 16 I I" .f? ma 1 A t 2 0 t 7 a7 Jnvm/or:

July 29, 1952 TOTZEK 2,605,180

METHOD AND-APPARATUS FOR THE PRODUCTION CF IRON Filed Jan. 15, 1949 I 2 SHEETS-SHEET 2 I f A h T TORNE Y Patented July 29, 1952 METHOD AND APPARATUS FOR THE PRODUCTION OF IRON Friedrich Totzck, Essen-Ruhr, Germany, assignor to Koppers Company, Inc., Pittsburgh, Pa., a

corporation of Delaware Application January 15, 1949, SerialNo.71,i85

In Switzerland December '7, 1948' The present invention relates generally to the production of iron in the blast furnace and more particularly to the production of iron in a blast furnace being operated with a blast containing more than 30% oxygen.

In the following iron is understood to be pig iron or any ferro-alloy.

It has already'been tried to produce iron in a blast furnace with the use of a blast containing more oxygen than is contained in air. The earlier tests have been made with a blast furnace of sucha design as'is generally being used when air is being applied as blast, and it has been ascertained that a moderate increase of the content of oxygen, say up to about 30% of oxygen, may have the effect of decreasing the temperature of the blast furnace gas at the outlet of the blast furnace as compared with the temperature 7 which will result while using air as blast. Simultaneously, there wasfound a light decrease in the consumption of solid fuel. The tests showed, however, that a further increase of the oxygen content in the blast led regularly to serious disturbances in the operation of the blast furnace which became the more serious the more the oxygen content was increased and which finally put the furnace completely out of operation be cause it was no longer possible to melt the slag and the iron in the bosh of the blast furnace in order to tap them from the furnace.

An' important object of the present invention is to provide for simple and effective improvementsin the process and the means for the production'of iron in blast furnaces with a blast containing more than 30% oxygen.

A further object of the invention is ,to improve processes and means in order to produce iron in a blast furnace while using a solid lump fuel of a comparatively low crushing strength.

A still further object of the invention is to provide for new and improved methods and means for producing in a blast furnace a gas of high calorific value which may advantageously be used for lighting and heating purposes, and for chemical reactions and other purposes.

The difficulties arising in the operation of a blast furnace with a blast of a comparatively high content of oxygen (morethan 30% 02) are known to those skilled in the art. The most serious difiiculty is the tendency of the furnace to hanging or bridging. In order to eliminate these difficulties-it has been proposed 1) to decrease the angle of the bosh 23 and (2) to decrease the height of the stack above the bosh.

The opinion was held that the reactions in the hearth of the blast furnace would not be altered 13 Claims.

qualitatively, when the oxygen content of the blast was increased, but rather intensified and thus increase the temperature in the hearth l of the blast furnace. It was assumed, however, that the operating conditions and reactions would be considerably altered in the stack above the bosh 23 on account of the decrease of the quantity of the hot gases rising from the hearth due to the decreased quantity of nitrogen in the oxygen-enriched blast.

On the basis of these considerations it has been proposed to introduce carbon monoxide or blast furnace gas into the hearth of the blast furnace through special nozzles or tuyere's arranged in the spaces between the usual nozzles introducing the blast. It has also been proposed to introduce blast furnace gas into the stack above the bosh.

The opinion was held that it would be possible in this way so to increase the so-called indirect reduction (FeO+CO:Fe+COz) in the charge of the stack above the bosh of the blast furnace that the direct reduction (FeO-i-C:Fe|-CO) to be effected in the hearth would be facilitated and the temperature in the hearth of the blast furnace would rise again to the point necessary for drawing on" the iron and the slag in a molten state. It was therefore assumed that the observed decrease of temperature of the iron and of the slag in the hearth occurring when the content of oxygen of theblast was increased and which led to conditions making it impossible to tap off iron and slag in the molten state, was a consequence of the inferior preparation and the diminished indirect reduction in the stack above the bosh and of the overloading of the hearth with the so-called reduction effected thereby. But all these earlier considerations and proposals have proved to be unsuccessful.

Now, the inventor has found that the increase of the oxygen content of the blast has a direct influence on the process in the hearth of the blast furnace, quite independent of the reactions and of the method of operation of the blast furnace in the stack above the bosh and that it is therefore necessary to design the hearth of a blast furnace which is to be operated with a blast of increased oxygen content (more than 30% Oz) in another way than the hearth of a blast furnace operated with normal air as blast would be designed.

As has already been mentioned a common blast furnace designed for the use of normal air as blast tends to freeze up when oxygen content of the blast is increased considerably. This phenomenon is the more surprising as on increasing the oxygen content much higher temperatures in the tuyeres zone of the hearth will be found on observation through the tuyeres than in the normal blast furnace operated with air. However, it has been overlooked that these higher temperatures'occur only in a very limited area near the tuyeres and that at the same time in a comparatively short distance from the tuyeres the temperature drops to a point considerably below the fusion point of the slag. Therefore, there is no continuous fusion and oxidation zone being formed in the hearth; but on considerably increasing the oxygen content there occurs between the tuyeres of the blast furnace of the usual design the formation of zones in which the slag freezes up and these zones extend into the bosh of the furnace. Because of these pillar-likewalls the charge in the bosh is prevented from sliding downwards. This is the reason for the occurrence which in the earlier tests was spoken of as the formation of bridges or as hanging of the charge.

Further/on a considerable increase of the oxygen content in theblast (that is with 30% O2 and more) there o'ccur near the tuyeres such temperatures that part of the slag, especially SiOz, is evaporated and therefore the melting point of the slag israised whereby the danger of the blast furnace freezing up, ashas been mentioned before, is considerably increased,

According to one important feature of the invention these diificulties in the operation of a blast furnace with blast of increased oxygen content are overcome by introducing a gaseous medium capable of reacting exothermically with oxygen, such as carbon monoxide, besides the oxygen into thetuyres in such a Way as to enable the oxygenand carbon monoxide to mix with each other at the outlet of the tuyeres and, if possible, to react with each other.

According to the invention the tuyre is advantageously designed in such a way that the blast, highly enriched with oxygen, is introduced through a pipe provided inside the tuyere and reaching almostto its inner mouth where it discharges the oxygen in the inner mouth of the tuyere and that the gaseous medium capable of reacting exothermically with oxygen, such as carbon-monoxide, is introducedthrough an annular space insideof the vtuyre which surrounds, and is limited by, the pipe introducing the oxygen blast, orvice versa, and which mixes the so introduced oxygen and carbon monoxide with each other in the tuyre, at the inside mouth thereof before discharging the mixture into the j operated according .to .the present invention,

oxygen and carbon monoxide react primarily with the formation of carbon dioxide and that secondarily the carbon dioxide so formed reacts with the solid carbon of the charge in the hearth forming carbon monoxide. On the other hand it is possible that part of the oxygen escapes the primary. reaction with'carbon monoxide because of the very high temperatures in the hearth.

The carbon monoxide introduced with the oxygen is heated by the at least partial reaction with oxygen to such high temperatures that the dissociation of the carbon dioxide must be taken into consideration. One-can,'therefore, assume that part of the oxygen reacts directly with solid carbon in the hearth when the furnace is operated according to the invention.

Be this as it may, the introduction of carbon monoxide into the tuyres of the blast furnace as provided by the invention leads to a temperature drop in front of the tuyeres and besides, but as an important elfect, leads to a considerable extension of the fusingor oxidation-zone in front of the tuyeres as compared with the extent of the fusion zone which is formed when blast highly enriched with oxygen is introduced through the tuyres into the hearth of the blast furnace without the addition of carbon monoxide gas.

According to another important feature of the present invention a considerable progress is further achieved by arranging the tuyeres or nozzles, through which the blast of increased oxygen content (30% O2 and more) is introduced into the hearth of the blast furnace, at a distance from each other considerably less than they are usually arranged in blast furnaces operated with normal air as blast. The distance of the tuyeres in the previously common blast furnaces is usually 1.2-1.5 m. or more. In comparison, this invention provides to arrange the mouths of the tuyeres preferably about 0.3-0.6 m. from each other. This means that according to the present invention the number of tuyres or nozzles through which the blast 'is introduced into the hearth of the blast furnace is being increased far above the numberwhich had been previously provided for a blast furnace operated with normal air as blast. In the sense of this invention, the rule maybe applied that the number of tuyres provided in the hearth, when blast considerably enriched with oxygen is used, must be chosen in such a way that the comparatively small fusion zones which are formed in front of the tuyeres in the hearth touch each other and that there is a continuous annular zone of fusion in the hearth round the so-called dead man 2|.

This zone of fusion is here understood to be the annular space in the hearth at the level of the tuyeres or nozzles where the solid carbon is most uniformly used by oxidizing substances with the formation of gaseous carbon monoxide so that the charge in the stack sinks evenly into the annular space just mentioned.

According to what has been said, it is evident that the extension of the fusion zone in front of the tuyeres, effected by introducing carbon monoxide through the tuyeres, is of considerable advantage for the operation of a blast furnace when being operated with a blast highly enriched with oxygen. On the one hand, it follows from the extension of the fusion zone that the tuyres do not need to be arranged very close one to the other in order to form a coherent annular fusion zone in the hearth. On the other hand, the zone of high temperature in front of the tuyeres is extended in the direction of the dead man. Generally speaking, it may be said that the addition of carbon monoxide gas to the oxygen in the tuyre or rather at the inside mouth thereof leads to a very effective extension of the annular fusion zone in the hearth and results in essentially the same favourable operating conditions as are found in the hearth of a blast furnace being operated with normal air'as blast.

In the sense of this invention, it is off-no fundamental importance, with a blast furnace whose hearth is designed according to the invention, how the blast furnace is formed above the hearth i. e. at the bosh and the shaft. Any suitable design of these parts of the blast furnace may be used, if it assures a regular downward movement of the charge. According to the present invention, the upper portion above the hearth may be formed accordingly as required for certain contemplated operating conditions of the blast 'furnace, i. e., a relatively tall stack may be provided above the bosh, so that a relatively low temperature of the blast furnace gas at the upper outlet of the furnace may be attained, or the stack may be en d. a hi e em ature O t blast furnace gas at the upper end of the blast furnace thus being allowed.

The design above the hearth, possible with the use of 30%, and more, 02, in accordance with the present invention, depends essentially on the kind of solid fuel available, which possibility should be chosen. If there is a solid fuel of high crushing strength available, as for instance coke, and i if one desires a possibly low consumption of the valuable fuel per ton of iron produced in the blast furnace, a blast furnace with a tall stack would advantageously be used. On the other hand, if the fuel has a low crushing strength it is appropriate to prefer a furnace with a low stack. In this case, the temperature of the blast furnace gas leaving the upper end of the shaft is raised accordingly.

Whether a blast furnace with a tall or with a low stack is to be used also depends on the composition of the blast furnace gas required. If a blast furnace with a tall stack is used the indirect reduction mentioned before attains a considerable extent and the blast furnace gas produced contains comparatively much carbon dioxide, whilst on the other hand the consumption of solid fuel diminishes. If, however, a blast furnace with a low stack is to be, 'or is, being employed the carbon dioxide content of the gas leaving the blast furnace is comparatively low and the gas may be used for chemical reactions, e. g. for the synthesis of hydrocarbons from carbon monoxide and hydrogen. If much carbon dioxide is contained in the gas it must be more or less removed before the synthesis of the hydrocarbons, e. g. by scrubbing the blast furnace gas with water under increased pressure. It is obvious that such difficult operation may be eliminated if a low stack blast furnace is used and consequently a gas poor in carbon dioxide is produced.

In this description and the attached claims carbon monoxide gas which according to the invention is introduced into the tuyres of a blast furnace together with oxygen or with air of an increased oxygen content (more than about O2) is understood to include pure carbon monoxide gas as well as gases containing besides carbon monoxide other compounds, as for instance carbon dioxide. It is therefore possible to return a part of the gases leaving the top of the blast furnace to the tuyeres to use it as carbon dioxide gas as well as e. g. producer gas which has been produced in a special gas producer, possibly using finely divided fuel.

It is known that besides carbon monoxide also hydrogen shows high reducing power and at certain temperatures ore may be more easily reduced. by hydrogen than by carbon monoxide. Thereby the consumptionof solid fuel per ton of iron can be decreased advantageously.

The invention, therefore, provides for introducing a mixture of carbon'monoxide and hydrogen as a gaseous medium capable of reacting exothermically with oxygen into the tuyeres of a blast furnace which is being operated with blast of increased oxygen content (more than 30% oxygen) in such a way, that carbon monoxide as well as hydrogen can mix and react with oxygen at the inner mouth of the tuyere.

It cannot be foreseen with certainty which reactions hydrogen carries out inside the blast furnace. It is possible that hydrogen reacts primarily with oxygen with the formation of stearn'which has a very high temperature and which steam then reacts secondarily with solid carbon forming carbon monoxide and reforming hydrogen. But it may also "be that hydrogen reacts primarily with iron oxide and reduces the oxides or that both reactions occur simultaneously. But in either case, as can be easily seen, the added hydrogen facilitates the operation in both the hearth and the bosh of the furnace.

It should be observed that the amount of hydrogen introduced into the hearth with carbon monoxide should in no case be so high as to disturb the reactions in the hearth.

According to another feature of the present invention hydrocarbons in a gaseous or vapour state or in a finelyjdivide'd or dispersed state may under certain circumstances be introduced together with the oxygen into the hearth, instead of carbon monoxide or mixtures of carbon monoxide, as it is also possible to introduce hydrocarbons together with carbon monoxide or possibly hydrogen into the oxygen tuyeres. The hydrocarbons may react with oxygen in the hearth forming carbon dioxide and steam which CO2 and H20 then react secondarily with solid carbon with formationof carbon monoxide and hydrogen, if this explanation for the proceedings in the hearth-as has already been mentionedis being accepted.

' In any case, the addition of hydrocarbons, similar to the addition of carbon monoxide and hydrogen, results in a dilution of the oxygen in the hearth causing the extremely high temperatures near the tuyeres to decrease and a more uniform distribution of heat in the hearth while extending the zone of fusion. and oxidation correspondingly.

Of course, the quantity of the added hydrocarbons has an influence on the composition of the gas leaving the upper part of the blast furnace. By choosing appropriate hydrocarbons and their suitable quantity it has thus become possible, by means of the present invention, to produce a blast furnace gas of a certain useful, or predetermined, composition which may contain carbon monoxide and hydrogen in such a proportion as is then being preferred for the synthesis of hydrocarbons when practicing the pres ent invention.

By altering the quantity of the gasous medium, as for instance carbon monoxide gas, which ac cording to the invention is to be introduced into the tuyeres of a blast furnace operated with oxygen-enriched blast (more than 30% 02) it becomes possible to influence (1) the temperature of the charge in the various zones of the blast furnace and (2) the composition of the gas leaving the upper part of the blast furnace.

If besides oxygen, carbon monoxide gas is introduced into the tuyeres in such a quantity as corresponds to a mixture of 21% O2 and 79% CO there are practically the same operating conditions as with air being used as blast as far as conveyance of heat and the distribution of heat in the upper part of the blast furnace is concerned.

If, however, the addition of carbon monoxide is decreased the fusion zone in front of the tuyres is reduced and on a further decrease of the amount of carbon monoxide, or another gaseous medium, added solid walls of slag are finally'built up between the tuyeres in the hearth unless the tuyres are arranged in the most favourable distance from one another. It is, therefore, advantageous to provide the blast furnace from the start with so many tuyeres for the introduction of oxygen and carbon monoxide or oxygen respectively that a coherent zone of fusion remains existent even with the lowest possible addition of carbon monoxide gas to'the oXygen-enriched blast.

The invention may also advantageously be used for a blast furnace which is operated under increased pressure.

The accompanying drawing forms a part of this specification and shows for the purpose of exemplification the preferred operations and methods in which the invention may be embodied and practised butthe claimed invention is not limited to such illustrative instance or instances.

Figure 1 of the attached drawing shows a vertical section through a part of the blast furnace according to the invention while Figure 2 is a section taken on the line II--II of Figure 1.

Figure 3 represents a section on a larger scale, taken through one of the tuyres of a blast furnace according to Figures 1 and 2.

In Figure 1 only the lower part of a blast furnace designed and operated according to the invention is shown. The upper part of the blast furnace may be constructed in any desired way I known to those skilled in the art and which corresponds to the operating data pointed out.

The part of the blast furnace shown comprises the hearth and the bosh and part of the stack. The hearth is constructed of refractory brick work I which is surrounded by a usual steel shell 2 or the like. Near floor 3 there is a tap hole 4 for drawing off the molten liquid iron and a little higher another opening 5 is provided for drawing off the molten slag. Above the slag opening 5 the tuyeres or nozzles 6 are arranged on one level. As can be seen from Figure 3 eachtuyre or nozzle 6 is provided with a cooling jacket I to which cooling water or the like is supplied through pipe 8 and which the cooling water may leave through pipe 9.

Inside the tuyre and co-axial therewith a pipe 10 is arranged which at its inner end bears a number of ribs II by which it keeps its spaced distance from the inside of the tuyre pipe 6. Before the mouth of pipe ID the tuyere channel is tapered a little decreasing toward its outlet end, as shown at I2. Pipe ID is arranged preferably adjustably in tuyre B so that the distance of the mouth of pipe III from the mouth of tuyere 6 can be varied. In this way the velocity of mixing the media introduced through pipe II], with those media which are introduced through the annular space between pipe I0 and the inside wall of tuyre 6, may be controlled.

The body of tuyre 6 is arranged in a tapered housing I3 which is tightened against the shell 2 of the refractory brick work I.

desired, as is above Carbon monoxide gas or a mixture of carbo monoxide and hydrogen or hydrocarbons, as has been mentioned before, is introduced through pipe I4 which opens into the annular space between pipe ID and tuyere 6.

Oxygen is introduced through pipe I5 which is connected with the interior of pipe IIl. Pipes I4 and l 5 are governed by regulating valves which I are marked I6 and IT in Figure 1 of the drawing. They are connected with the annular main I 8 for leading oxygen and with the annular main [9 for feeding carbon monoxide or a mixture of carbon monoxide and hydrogen respectively. The reaction causes the formation of a high temperature zone-indicated in Figure 2 by the dotted line 20in front of each tuyere inside the blast furnace, a zone where a temperature above the fusion points of slag and iron is obtained.

As can be seen from Figure 2 the mouths of the tuyeres 6 are arranged at such a distance from each other that the high temperature or fusion zones 20 touch or overlap each other. Thereby a continuous annular zone where the slag and iron are being maintained molten is formed in the hearth of the blast furnace around the so-called dead man signified as at 2!.

According to the quantity of carbon monoxide gas that is added to the blast, the fusion zone 2!] around the mouths of the tuyeres 8 may be extended, and will finally reach the extent indicated by the dotted lines 22, if sufficient carbon monoxide is added, and operating conditions Will then essentially correspond to the conditions ex isting in the hearth when the blast furnace is operated with normal air as blast.

The charge of the blast furnace has, as conventional, such a composition as is necessary according to the composition and the properties of the ore to be treated. Therefore, the charge also contains a sufficient amount of lump coke in order to secure the passage through the charge in the stack of the gases developed in the hearth. The angle of the bosh 23 of the blast furnace depends on the total height of the blast furnace.

As is shown in Figure 2 the number of the tuyeres 6 to be provided according to the invention is considerably higher as compared with a blast furnace which is operated with normal air as blast.

The distance of the mouths of the tuyres from each other is preferably 025-08 In. and it is of advantage to keep the distance of mouths of the neighbouring tuyeres in each case below about 1.2 m.

The invention as hereinabove set forth is embodied in particular form and manner but may be variously embodied within the scope of the claims hereinafter made. I a

I claim:

1. A blast furnace for the production of iron from ore by using a blast containing more than 30% of oxygen comprising, the combination of a stack; a hearth at the base of the stack; a series of nozzles or tuyeres arranged in the wall of the hearth for introducing such blast into the hearth; a source of carbon monoxide connected with the outer ends of said nozzles or tuyeres; and a source of a blast containing more than 30 of' oxygen connected with the outer end of said nozzles or tuyeres; each of said nozzles or tuyeres comprising, a pipe-like member open at its inner end, and arranged in the wall of the hearth so that its open inner end projects into the interior of the hearth, and having means on its outer end for effecting the aforesaid'connection of said source of carbon monoxide with the outer ends of the nozzles or tuyeres,anda sieoondpipe inset within said pipe-like member and having means on its outer end' for effecting the aforesaid connection of said s ource of ablast containing more than 30% oxygen with the outer ends of said nozzles or tuyeres, saidsecond pipe being inset within said pipe-like member so as to be in spaced relation thereto and having itsinner end opening into the interior of the pipe-like member at a point near but short of the open innerend of the same, whereby the carbon monoxide from thesource thereof connected to the tuyieres' flows" inwardly theretlirough in. the. space between the second pipe and the pipe-like. member separately from the flow of the blast containing more than 30% 02 through the inset pipe,.unti'l' they both nearly reach the region of the open inner ends of the tuyeres, whereupon theym'ix in tlie outlet end of the pipe-like member before they discharge from the nozzles or tuyeres into the hearth where the open inner end of thepipe-likefmember projects into the hearth, and each of said nozzles or tuyeres having their mouths spaced from the mouth of each next adjacent tuyere such a distance between 0.25 and 0.8' m that inside the hearth at the tuyere level a continuous-and essentially annular zone is formed around the outer circumference of the hearth bed of a temperature above the fusion point of slag and iron by the blasts issuing from the mouths of the tuyeres.

2. A blast furnace as claimed in claim 1, and in which the mouths of the adjacent tuyeres are arranged at distances from each other of about 0.3 to 0.6 meter.

3. In the method of producing iron from ore with, a blast containing more than 30 oxygen, in a blast furnace having a stack, a hearth at the base of the stack, and a series of nozzles or tuyres arranged in the Wall of the hearth for introducing such blast into the hearth, conveying carbon monoxide from a source thereof remote from the hearth to the tuyeres and delivering it into the outer ends of said tuyeres, concurrently conveying a blast containing more than 30% of oxygen from a source thereof to the tuyeres and delivering it into the outer ends of the tuyeres separately from the aforesaid delivery thereto of the carbon monoxide, passing the so delivered carbon monoxide through each of the tuyeres through a pipe-like member of each tuyere extending from the outer end thereof into projecting relation in the interior of the hearth and having its inner end open for discharge into the hearth beyond the inner wall surface of the hearth, while concurrently passing the so delivered blast vcontaining more than 30% of oxygen separately through the tuyeres from the outer end of the pipe-like member to a point near but short of the inner open end thereof through a second pipe inset in spaced relation within said pipe-like member of each tuyere and opening into the interior of the pipe-like member of each tuyere at a point near but short of the inner open end thereof, for mixing of the separately delivered blast containing more than 30% of oxygen and the carbon monoxide after they have nearly reached the outlet end of the tuyere but immediately before they discharge from the tuyeres into the hearth, and effecting the aforesaid tuyere discharge through the tuyeres while they have their mouths spaced from the mouth of each next adjacent tuyere such a distance between 0.25 and 0.8 m., that inside the hearth at the tuyere level a continuous and essentially annular zone is formed around the outer circumference of the hearth bed of a temperature above the fusion point of slag andiron by the blasts issuingfrom the mouths of the tuyeres.

u 4. blastfurna ce method as claimed in claim 8', and in which thetuyere discharge is effected through mouths of. adjacent tuyeres while they are arranged at a distance from-each other of about 0.3 to 0.6 meter.

5. A blast furnace method as claimed in claim 3, and in which hydrogen is also introduced along with the carb'on'monoxi'de asamixture of carbon monoxide and hydrogen through the pipe-like members of each of the tuyeres. ;f

6. A blast furnace method as claimed in claim 5, and in which the hydrogen is introduced in the form of a compound containing hydrogen.

7. A blast furnace method as claimed in claim 6; and in which the hydrogen, which is introduced in the form of a compound containing hydrogen, is introduced in the form of a hydrocarbon compound. V V V a 8; In" the method of producing iron from ore with an oxygen blast of gas containing more than 30% of oxygen, in a blast furnace having a stack, a hearth at thebase ofythe stack, and a series of nozzles or tuyeres arranged in the wall of the hearth for introducing such blast into the hearth, the step of effecting the tuyere discharge of the oxygen blast of gas containing more than 30% of oxygen in the form of a composite of that gas and a gas comprising principally carbon monoxide through tuyeres having their mouths spaced from the mouth of each next adjacent tuyere such a distance between 0.25 and 0.8 m. that inside the hearth at the tuyere level a continuous and essentially annular zone is formed around the outer circumference of the hearth bed of a temperature above the fusion point of slag and iron by the blasts issuing from the mouths of the tuyeres.

9. A blast furnace method as claimed in claim 8, and in which the tuyere discharge is effected through mouths of adjacent tuyeres which are arranged at a distance from each other of about 0.3 to 0.6 meter.

10. In a method of producing iron from ore with an oxygen blast of a gas containing more than 30% of oxygen, in a blast furnace having a stack, a hearth at the base of the stack, and a series of nozzles or tuyeres arranged in the wall of the hearth for introducing such blast into the hearth, the steps of introducing into the hearth through said nozzles or tuyeres, a gas comprising principally carbon monoxide in the form of a separate stream concurrently with the passage of the oxygen blast of gas containing more than 30% of oxygen through the tuyeres, and initially mingling the oxygen blast gas and the carbon monoxide with each other near the immediate vicinity of the outlet ends of the tuyeres, and discharging the mixture into the charge in the hearth in mixture together from each of the tuyeres in streams which are at a distance from each other of between 0.25 and 0.8 m. with the formation of a continuous zone, of a temperature above the fusion point of slag and iron, around the outer circumference of the hearth at the level of the tuyeres.

11. A blast furnace method as claimed in claim 10, and in which hydrogen is also introduced along with the separate stream of carbon monoxide as a mixture of carbon monoxide and hydrogen prior to initial mixing of the separate stream of carbon monoxide with the blast in 11 the immediate vicinity of the outlet ends of the tuyeres. r 7 V V r 12. A blast furnace method as claimed in claim 11, and in which the hydrogen is introduced in the form of a compound containing hydrogen.

13. A blast furnace method as claimed in claim 12, and in which the hydrogen, which is introduced in the form of a compound containing hydrogen, is introduced in the form of a hydrocarbon compound.

FRIEDRICH TOTZEK.

REFERENCES. CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name A Date 2,010,073 Frank1' Aug. 6,1935 2,052,928 Harris -Sept. 1, 1936 2,124,437 Steinbacher .;July 19, 1938 2,261,559 Osborn Q Nov. 4, 1941 2,337,551 Hansgirg Dec. 28, 1943 2,394,497 Stuedel Feb. 5, 1946 FOREIGN PATENTS Number Country Date 1,730 Great Britain of 1855 1,478 Great Britain of 1873 343,055 Great Britain Feb. 9, 1931 369,393 Great Britain Mar. 24, 1932 359,778 Germany Sept. 26, 1922 457,645 France Sept. 22, 1913 737,728 France Dec. 15, 1932 OTHER REFERENCES Ser No. 297,370, Bartscherer (A. P. 0.), published May 25, 1943.

Blast Furnace Practice, vol. 1, pages 449 to 452, and 456, edited by Clements, published in 1929 by Ernest Benn, Limited, London, England.

Blast Furnace Reactions, edited by Kinney et 0 211., published in 1927 as Bureau of Mines Technical Paper 391.

Claims (1)

1. A BLAST FURNACE FOR THE PRODUCTION OF IRON FROM ORE BY USING A BLAST CONTAINING MORE THAN 30% OF OXYGEN COMPRISING, THE COMBINATION OF A STACK; A HEARTH AT THE BASE OF THE STACK; A SERIES OF NOZZLES OR TUYERES ARRANGED IN THE WALL OF THE HEARTH FOR INTRODUCING SUCH BLAST INTO THE HEARTH; A SOURCE OF CARBON MONOXIDE CONNECTED WITH THE OUTER ENDS OF SAID NOZZLES OR TUYERES; AND A SOURCE OF A BLAST CONTAINING MORE THAN 30% OF OXYGEN CONNECTED WITH THE OUTER END OF SAID NOZZLES OR TUYERES; EACH OF SAID NOZZLES OR TUYERES COMPRISING, A PIPE-LIKE MEMBER OPEN AT ITS INNER END, AND ARRANGED IN THE WALL OF THE HEARTH SO THAT ITS OPEN INNER END PROJECTS INTO THE INTERIOR OF THE HEARTH, AND HAVING MEANS ON ITS OUTER END FOR EFFECTING THE AFORESAID CONNECTION OF SAID SOURCE OF CARBON MONOXIDE WITH THE CUTER ENDS OF THE NOZZLES OR TUYERES, AND A SECOND PIPE INSET WITHIN SAID PIPE-LIKE MEMBER AND HAVING MEANS ON ITS OUTER END FOR EFFECTING THE AFORESAID CONNECTION OF SAID SOURCE OF A BLAST CONTAINING MORE THAN 30% OXYGEN WITH THE OUTER ENDS OF SAID NOZZLES OR TUYERES, SAID SECOND PIPE BEING INSET WITHIN SAID PIPE-LIKE MEMBER SO AS TO BE IN SPACED RELATION THERETO AND HAVING ITS INNER END OPENING INTO THE INTERIOR OF THE PIPE-LIKE MEMBER AT A POINT NEAR BUT SHORT OF THE OPEN INNER END OF THE SAME, WHEREBY THE CARBON MONOXIDE FROM THE SOURCE THEREOF CONNECTED TO THE TUYERES FLOWS INWARDLY THERETHROUGH IN THE SPACE BETWEEN THE SECOND PIPE AND THE PIPE-LIKE MEMBER SEPARATELY FROM THE FLOW OF THE BLAST CONTAINING MORE THAN 30% O2 THROUGH THE INSET PIPE, UNTIL THEY BOTH NEARLY REACH THE REGION OF THE OPEN INNER ENDS OF THE TUYERES, WHEREUPON THEY MIX IN THE OUTLET END OF THE PIPE-LIKE MEMBER BEFORE THEY DISCHARGE FROM THE NOZZLES OR TUYERES INTO THE HEARTH WHERE THE OPEN INNER END OF THE PIPE-LIKE MEMBER PROJECTS INTO THE HEARTH, AND EACH OF SAID NOZZLES OR TUYERES HAVING THEIR MOUTHS SPACED FROM THE MOUTH OF EACH NEXT ADJACENT TUYERE SUCH A DISTANCE BETWEEN 0.25 AND 0.8 M., THAT INSIDE THE HEARTH AT THE TUYERE LEVEL A CONTINUOUS AND ESSENTIALLY ANNULAR ZONE IS FORMED AROUND THE OUTER CIRCUMFERENCE OF THE HEARTH BED OF A TEMPERATURE ABOVE THE FUSION POINT OF SLAG AND IRON BY THE BLASTS ISSUING FROM THE MOUTHS OF THE TUYERES.

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