US1646728A - Refining of iron - Google Patents

Description

2 192 Oct 7 e. s. EVANS I REFINING OF IRON Filed June '7. 1926 5 m Wm Trw R N VTO V T me M Wk m a Patented 0a. 25, 1927.

GEORGE S.

oF IcE.

EVANS, OF OAK PARK, ILLINOIS, ASSIGNOR TO THE MATHIESON ALKALI WORKS, 013' NEW YORK, N. Y.,' A CORPORATION OF VIRGINIA.

REFINING OF IRON.

Application filed. June 7,

This inventionrelates to improvements in the refining of iron, and relates more particularly to improvements in the utilization of soda ash refining'agents for this purpose. Hitherto, in the utilization of soda ash in the refining of iron it has been considered impractical to use this refining agent except in an aggregated state, fused or briquetted or aggregated with other materials, due to the loss and danger involvedin dusting of the material where it was employed in the granular or pulverulent condition. This inven tion provides a method ofhandling refining agents such as soda ash and soda ash mixtures which makes it possible to employ these or similar materials in a granular or pulverulent condition without loss or danger.

Incarrying out the process of the present invention, the refining operation proper is effected primarily in a receptacle such asa bull ladle or mixing furnace'in which a pool of the molten iron is subjected to the action of a fused refining slag containing the refining agent. This operation may, for example, be'c'arried out as described in my prior application filed April 10, 1925, SerialNo.

22,047, a pool of iron being continuously maintained in the refining receptacle in contact with a slag bath continuously maintained thereon, iron being supplied to and withdrawn from the pool during the operation without exhausting it' and spent slag discharged and fresh refining agent added to the slag during the operation as required. The present invention is also useful in connection with refining operations in which successive'batches of iron are subjected to the action of a refining slag in such a bull ladle or mixingfurnace or other refining recep-' tacle. The present invention relates more particularly'to the operation by which the refining sla on the pool of iron in the refining reoeptac e is supplied thereto or by which fresh additions ,ofrefining agent are made.

to such a slag on a pool of iron in the refining receptacle. 7

According to the present invention, the iron to be refined is passed as a moltenstream through an elongated. passage way on its way to the refining receptacle and the granular or pulverulent refining agent is introduced into this passage way in contact with the stream of molten iron passing there- "through. The soda ash refining agent or other'refining material fusible at the tem- 1926. Serial No. 114,157.

perature of the molten iron is thereby sintered or melted to form an agglomerated mass or a fused slag which is permitted to pass with the stream of molten iron to the r'efining receptacle, and at the same time the pul verulent or granular refining material is confined'to the passage way in which it is brought into contact with the molten iron until it is sintered or fused and it is not permitted to escape to the refining receptacle until it has been agglomerated or melted and escape of the re ing material into the surrounding atmosphere is thereby prev vented.

' The invention will be further described in connection with the accompanying drawings which illustrate, ina diagrammatic and conventional manner, apparatus for carrying Fig. 2 shows in a similar manner a modi fied arrangement of the cupola or melting furnace spout, and

Fig. 3 is a view similar to Fig. 2 showing a further modification.

The cupola or melting furnace illustrated is in general of the usual construction and operation and comprises a refractorylined shell 1 supported on legs 2, the furnace bottom 3, also refractory lined, being supported on doors 4 held closed by support 5. A

number of tuyeres 6 are arranged opening into the furnace at some distance above the bottom and are connected to a common blast pipe 7. A slag spout 8 is'also provided opening from the furnace a short distance belowthe tuyeres. The cupola or melting furnace may be operated either with continuous tapping of the molten iron orwith removal of the molten iron from the cupola periodi- .cally' with separation of the cupola slag in the cupola proper. In the first type of opera-' tion the cupola slag is caused. to overflow through spout 9 being trapped from passing further bythe dam 10. In' the second ty e of operation the cupola slag is periodic y removed through spout 8. These types of furnace operation are well known and need not be described here.

' In operation, the molten iron flows, either intermittently or continuously according the scheme ofroperation employed, from the.

cupola or melting furnace beneath the dam through the passage way 20 formed bythe cupola spout 11, the dams 10 and 12 and 'the refractory roof. 13 to the refinin r'ecep-' tacle 14, in this case a bull ladle wit a botveyer 18 of the usual type, the rate of suptom pourin spout 15 and a slag discharge spout 16. ranged above the cupola spout is a bin 17 from which refining materia is fed into the passage way20 by helical conplyof refining material to the passage way 20 being controlled by regulation of: the

speed-of the conveyer. The bin 17 is kept: supplied with the refining material from; some suitable source through chute 19.

Granular or pulverulent soda ash or other refining. material is supplied from the bin 17 to the passage way 20 while a stream of 'molten iron 1s flowing therethrou h and is .sintered or fused by'heat from t e-molten 'ironto form an agglomerated mass or a fused slag which then passes with the stream of molten iron into the ladle 14. The-dam 10 extending below the surfaceof themolten iron'flowing through the cupola spout 11'.-

is arranged" to permit only a stream of sintered refining material or refinin slag to escape'with the molten iron into t e refining receptacle. The refining material introduced into the passage way 20 is thus prevented from escaping until it is sintered.

or fused, and when it is sintered or fused itis permitted to discharge with the molten iron into the refining receptacle.

In the modified type of cupola spout illustrated in Fig. 2, instead of providing a dam,

as shown at 12 in Fig. 1, to prevent the escape of unfused refining material at the i molten iron and fused refining material are end of the passage way from which the discharged, the passage way 21 is prolon ed M sufficiently to insurethat all of the refimng f 22 Man intermedi te material mtroduced at, the endof the passage wayat which the molten iron enters is .sintered -or fused before-it can reach the other. end of the passage way where the V sintered or. fused refining material is dis charged with the molten iron.-. y

In the modified type. of cupola spout illus-' trated in Fig. 2, the passage way 22 is pro; longed onboth sides of the point of addition of refining-material. This type of spout is more particularly adapted for'use inconnec 7 -tion with operations where the cupola ,slag j. I is removed within the cigpola. The mplten.

- firon,.freefrom on la ,ag h zp 4 mt of which'the' reflows as a stream ro m material' is i111 the cupela terial being sintered fusedbefore it can escape from the passage way, thus passing in smtered or Lfusedgcondition with the m'olten iron to the refining receptacle.

If soda. ash "susedas a refining agent the amount employed per ton of;iron may 'ap proximate 2 to 10 pounds per ton or maybe more than this. The batch type of operation usually requires a somewhat greater pro portion ofrefining agent than the continuous type of operation if similar results are to be secured. In the batch type of operation, the refining material is added untila slag bath sufiicient to treat the batch of iron is 6 I 8 ,fining receptacle and after suficient time has pasfsed tdpermit the refining operationformed on the pool of molten iron in the reto take'place the spent slag is removed and the iron poured. Inthe continuous type of operation, where a pool of molten iron is maintained in the refining receptacle, it is advantageous to add fresh increments of refining material as additional molten iron is added to the receptacle if the cupola or melting furnace is tapped intermittently; Or if the cupola or-.melting furnace is tapped continuously, it is advantageous to supply refining'mate'rial more or less con- "tinuously to maintain the refining slag on the pool of iron inthe refining receptacle in a sufficientstate of activity.

vides an improved. method of operation is employed in a granular or pulverulent :It will be apparent that this invention prov condition in the refining, of iron. Loss and danger due to escape of the refining agent into the atmosphere, are thus both avoided. Manual handling of the refining agent is also made unnecessary. While theinvention has heen desdribed partlcularly in connection j with the utilization of soda ash refining agents for this purpose, it will be apparent that it is also useful in ,connection'with the utilization of other refining agents havin similar properties. .Another advanta'ge'p I the present invention; which is particularly important in connection with ger s f n. whichthe continuous type-o'f-re g operation is employed in conjunction with'continuous tapgimg of the cupola or melting furnace, is t stantially continuously so that t e refining slag can be maintained/at a more uniform activity and sothat ..the-.refihing operation can bemore closely controlled.

anothenas t in that itprovides -fot ;the

With

The invention has further advantages in" atit makes it possible to supply the refining materialprogressivel and sub-' addition 9 the" refiningagent in compare; 2,

'tively small increments to a likewisecomparativel stream of the molten ileum contain baabsgrb addition of 1. z

large batches of the refining agent to large batches of the molten iron may involve a danger of explosion due to flash vaporization of such moisture. In carrying out the present invention, the refining agent is added progressively to a flowing stream of the molten metal so that at no time is there any large amount either of the metal or of the refining agent present at the point of addi tion. Any danger of explosion is thus mine mized, and any explosions that may result are of such minor magnitude that they can. readily be confined, for-example in the confined passage Way in which the addition of refining agent is carried out. The progressive addition of the refining agent in carrying out this invention is also of advantage in making possible an improved pro ortioning between the refining agent and t e molten iron.

I claim 1. A process of refining iron which comprises flowing a stream of the ir'on in a molten state through an elongated passage way to a receptacle adapted to contain a pool of the ,molten iron, introducing into the-passage way in contact with the stream of molten iron a pulverulent refining agent fusible.

to the said receptacle to form a refining slag on. the pool of iron therein.

2. A process of refining iron which comprises flowing a stream of the iron' in a molten state through an elongated passage Way to a receptacle adapted to contain a pool of r the molten iron, introducing into the passage way in contact with the stream .of molten iron a pulverulent soda ash refining agent, confining the pulverulent refining agent so introduced to the passageway until sintered, and thereafter permitting the refining agent. to flow with the stream of molten iron to the said receptacle to form a refining slag on the pool of iron therein.

In testimony whereof I aflix my signature.

. v 4 GEORGE S. EVANS.

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