US874391A - Process of making steel. - Google Patents

Description

W mw H 0 CHUTE PRGESS 0F MAKING STEEL.

APPLICATION FILED JAN.14,1907.

Witnesses 4U y oflfuel as -compared with the ordinary smelt- UNITED STATES HARRY O. CHUTE, OF CLEVELAND, OHIO.

Pnocnss 0F MAKING STEEL.

Specification of Letters Patent.

Patented Dec. e4, 1907.

Application filed January 14. 197. Serial No. 352,269.

To all whom it may concern.

Be it known that I, HARRY O. CHUTE, a

4citizen of the United States, residing in Cleve* land, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Processes of Making Steel; and I do hereby declare the following to be a full, clear, and exact description of thc saine, such as will enable others skilled in the art to which it appei'tains to make and usc the same. Y y

This invention relates to processes of making steel and consists 4in a method ofsinclting low-grade and impure ores to. produce a special iron and in systematically reiining such iron; all as more fully hereinafter set forth and as claimed.

-Many non-besseiner oresl are highly sili- 4 cious and do not make good basic pig iron,

and these ores are frequently high in sulfur, or, in some cases, the only fuels available for smeltingthem are high in sulfur. VV ith such ores and such fuels, 'in ordinary practice if the furnace is run hot a silicious pig iron isv saturated with carbon. The pro produced Which cannot be easily handled in a basic furnace. If the furnace is run cold, a sulfurousl pig iron is produced which cannot be easily freed of impurities in the basic open hearth. This is especially true in the absence of manganese in the ores,- a very frequent condition.

It is the purpose of the present invention to treat these. ores by a'sim le, cheap and ready method, making ava' able large deposits noW considered-unavailable certain of these ores best adapted to the resent. proc ess being generally considered t for nothing because too impure or too-deficient in Inanganese. y' y I have discovered that by using an excess ing operation to produce basic pig ironin the blast furnace and thereby running such furnace very hot, I can charge it With'an ore' mixture. containing man anese and phosphorus, both preferably ad ed as by-products resulting from a later operation, and with enough ime to fnake a basic slag, and thereby almost completely eliminate sulfur in the slag as manganese sulid, producing a veryl hot and iiuid pig iron, rich'in silicon and phosphorus, all the phosphorus in the charge,

substantially, appearing in the iron.

half the manganese in the charge also appears in the iron and suchl iron is ractical y dliict of this About' operation is a hi hly silicious, very hot pig iron, Which may eV termed superheated as compared with the ordinary temperature at which iron is tapped from furnaces producing basic pig iron, While the sulfur is mostl -eliminated in the basic slag as sulfid of ca cium or manganese. While other pio iron containing much silicon and phosphorus, produced in other methods of operating the furnace, may be employed for my purposes, as hereinafter setforth, such other pig iron must be heated to a temperature analo ous to that of the pig iron produced in the a ove. operation; inust be superheated as compared with the ordinary 'tapping temperature of basic pig. A superheated iron of this character, I have discovered, can be readily desiliconized 'by causing it to fioW into contact `with oxid of iron. The oXid may be dusted on the hot, very fluid iron by any suitable mechanism or the container may have the bottom lined with iron ore or mill scale. c In pig iron of the described character made in the described vmanner there is enou h sensible heat to inaugurate the reaction Whi e' its comosition insures that the reaction With the iron oxid shall be sufficiently exothermic to maintain itself. `The iron does not become chilled and is preserved in the melted condi- I tion While the larger part of the silicon is removed and the carbon begins to be attacked. The presence of the phosphorus is useful in maintaining the fluidity during the reaction. It remains in the iron While the siliconis being removed. The manganese in the iron is jlargely attackedand removed during the oxidation of the silicon, going into the slag use in the furnace. In this operation ad vantage is taken of the fact that with a high temperature and a silicious iron, the silicon and manganese are referentially attacked.

It is important t at the uantity of iron ore orother iron oxid -broug t into contact With the ironshould be limited to that necessary to-remove the silicon, withoutotherwise changing materially thel composition 'or fluidity of the pig iron. This may be readily effected by control of the amount dusted in orlengtheningor shortening the time of contact of the .molten metal With ironoxid.

The product of the reaction on the molten metal, or slag, may be skimmed off by any suitable means. Asstated, it is to be reserved ior re-use in the blast furnace. One appropriate Way of separating it is by the nant mass of molten metal, in which the ref tions.

' slag from the desiliconizing, which is silicate shown more or less diagrammatically, one

`manganese, forming-a floating slag of siliideal material for treatment in a basic open 'manganese be absent in the ore, some must employed in the auxiliary i In this showing, 1 is the usual type of blast use of an auxiliary furnace connected With the container in which the Ytreatment with oxid is performed and serving at once as slag-separating means, re-heating means and means for forming a reservoir or domiaction can be equalized, continued orregulated, to be drawn on for the later opera- The purified, skimmed iron is still essentially pig iron but is now largelyfreed from silicon, sulfur and manganese but contains large amounts of carbon and phosphorus, rendering it fusible, fluid and an hearth furnace in which it may be treated in the usual way to eliminate the carbon and phosphorus, with formation of the well known phosphoric basic slag. lThis phosl phoric slag, being highly4 basic and containing a considerable amount of iron as well as thephosphorus, is Well suited as, an mgredient of the charge in the blast furnace to ,f

produce the high-phosphorus pig iron. It may he used for this purpose, wholly or in part. Or it may be utilized: for other purposes. 'There will always be an excess oi' phosphoric slags. A considerable economy 1n the process is effected by returningr the of iron and man anese, to the furnace together with the s ag from the basic hearth, whereby the iron may be recovered andthe manganese and phosphorus re-utilized. If

be supplied from any convenient. source. Running the furnace hot with suflicient fuel to produce the describedpig iron, a rich gas containing phosphoric and 1s obtained which may he advantageously furnace an( in the basic open hearth furnace.`

In the accompanying illust-ramon, I have assemblage of apparatus of the many combine-tions adapted to perform my process.

furnace, shown fragment arily, provided with cinder notch 2 and iron notch 3, The latter' leads into trough 4, provided With the usual skimming .a para-tus 5 and slag outlet. 6. The trough 1s lined, as usual, Wlth irebrlck or other refractory material, and as shown, it is also lined in use for a portion of its length With iron oxid or mill scale 7. As an alternative means of using the iron oxid, feeder spout 8 from the hopper 9 may be employed.

It may also be used in conjunction with the stated lining. The amount of iron oXi used in either or both Waysis of course adjustedl to the tenor in silicon of'l the pig iron.` A portion of the trough may be covered, as shown at 10., During transit' throu h the trough in contact with the iron oXid, t e iron ls deprived of its silicon and partly of its Cates. vThis is skimmed ott by an ordinary i skimmer 11 and passes out throu h the side trough 12, Where it cools and is roken u for return to the blast furnace. The desilicorized iron, still fluid because of its carbon an skimmer and into and through a movable trough 13l into the auxiliary furnace and reservoir 14'. From able trough 16 into the basic open hearth. furnace 1,7. This latter should be of the usual or standard basic open hearth construction, With the usual regenerative chambers 18, the gaseous fuel being admitted through the valve 20 and conduit22 to the regenerative chambers and thence to the furnace in the usual manner. The air similarly reaches the furnace through valve 19. The hot rich gas produced by the blast furnace While Working in this process is Well adapted to heat the basic open hearth furnace.

1. The process-of making steel which consists in smelting iron from a basic charge containing phosphorus and manganese under properthermal conditions to roduce a superheated pig iron rich in si icon and phosphorus and a sulfurous slag, contacting the superheated pig iron with suiicient oxid of iron to remove silicon and then treating the desiliconized iron to remove phosphorus and carbon.

making steel rwhich coniron from a basic charge m-anganic slag from a later operation under pro er thermal conditions to produce a super eated ig iron rich `in silicon'and phosphorus andD a sulfurous slag, contacting the superheated pig iron with sufficientoxid of iron to remove silicon and removing and reserving the produced slag for subsequent use in the smelting, and then treating the desiliconized iron to remove phosphorus and carbon and -2. The process of sists'in smelting l produce a basic slag.

3. The process of making steel Which consists in smelting silicious non-bessemer ores under proper thermal and fluxing conditions to produce a su erheated pig iron rich in silicon and phosp orus and asulfurous slag,

contacting the superheated lpig iron With phosphorus content, passes under the this it is tapped from l time to time through the spout 15 and mov-l suflicient oxid of iron to remove silicon, and

' 5. The process of making steel which consists in smelting silicious non-bessemer ores in the presence of basic slag containing phosphorus and a silicate slag containing manganese under proper thermal conditions to produce a superheated pig iron'rich in silicon and phosphorus and a sulfurous slag, producing a flowing current of such molten superheated pig iron and contacting it in transit with sufiicient oXid of iron tov remove `,silicon and form a silicate slag containing manganese, and then treating the desiliconizfed iron to remove phosphorus and carbon and form a basic slag containing hosphorus.

6. rlh'e process of making steeFWhich consists in smelting silicious non-bessemer ores under proper thermal and fluxing conditions to forma superheated pig iron rich in silicon and phosphorus and a sulurous slag, roducing a iioWing current of such mo ten superheated pig iron and contacting it 'in transit with sufficient oXid-of iron to remove silicon and then treating the desiliconized iron by the basic open'hearth process to remove phosphorus and carbon. Y

7. The process of making steel Which lconsists in producing molten pig iron containin silicon and phosphorus and in a superheate st ate, contacting it While in said superheated state with sufficient oxid of iron to remove silicon and form a silicate slag, and then treating the desiliconized iron by the basic open hearth process to remove phosphorus and carbon.

8.' The process of makmg steel Which conslsts in smeltmg s1l1c1ous nonebessemer ores under proper thermal and luXing conditionsl HARRY o'. oHU'rE. Witnesses B. L. CHADWLL, K. P. McELRoY.

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