AN IMPROVED PROCESS FOR MAKING STEEL

Abstract: This invention relates to an improved process for making steel in an electric arc furnace (EAF) using molten high carbon ferrous metal as a part of the EAF charge mix, which comprises preparing in/or introducing a molten high carbon ferrous metal (hot metal) into an EAF, said molten high carbon ferrous metal having a carbon content of less than 3 % and a silicon and manganese content of less than 0.2 % each, and a temperature of 1375 DEG C or higher in the furnace; adding a solid metallic charge selected from Scrap, HBI, DRI (Sponge, Pellet, etc. or Iron Ore) present singularly or in any combination together with lime into the hot metal inside the EAF; melting-cum-refining of the entire EAF charge mix in the absence of gaseous oxygen for carrying out said step of melting-cum-refining; superheating, finishing and tapping the molten steel into the ladle, for its subsequent casting.

Description: AN IMPROVED PROCESS FOR MA. tNC-i STEEL IELD OF THE INVENTION " I he present invention relfϊtes- to an improved rocess for rue. inq steel in the Electric Arc Furnace <EAF), which uses molten high t srhon f-rrouE metal as a pari of ihe EAF Charge Mix. The .nven- tion particularly relates to an improved process for steel making in the EAF and for making molten high carbon ferrous metal, either in a Cupola or in a Blast Furnace or in other units which are used for ma. mu high carbon ferrous metal. PRIOR ART One can classify th EAF steel ma- mg processes- used in the prior into two types Ϊ referred to hereinafter as Type I and Type II. In the Ty 1 EAF steel mal m process, only EUIK! charge is uu.ed such as : Steel Scrap (Scrap) a Hot B iquetted Iron <HBI > ; Direct Reduced Iron (DR1 ) which could be Sponge, Pellets, etc. and in some instances, solid Pig I on or Pig I on Jam - as the E-AF'r metallic raw material. Such an EAF process and operation, incorporate bhe usual com lements of bhe currently known development' n the FΛF process technology, including the foamy slag practice. Type 1 is the traditional EAF steel making process. The Type 1J EAF rl el mal i rj process s a relatively new development. This process is replacing the Type I process. The Type II process uses the li uid charge - which is s either molten hot- metal obtained from a Blast Furnace or a COREX Furnace : or moli r. car. I i on metal from a Cupola (a l the molten high carbon ■ fcrrnuL met alt- obtained from these three 01 other similar sources, are hereinafter referred to as 'hot metal' - as one part <.f the raw material. Whereat, the othe^r part of the raw material consists of sol it! charge, such as ; Scrap : DF.I; HBϊ ; etc.. In the Type II EAF process, £ foamy slag is produced and maintained by the addition of oxycjen and carbuπser, like it is done n the " I y 1 r ocess . When compared to the steel ma- ιng process of Type I, the use of the Type II EAF steel ma. mg process results m increased produc- iivity ι-,ncl decreased power consumption in the EAF " . However, the steel ma. mg process of Type II also has following five- majo. limitations when assessed all by itself. First, it uses considerable amount of gaseous oxygen : to remove carbon, silicon and manganese from the molten hot metal and also to maintain high oxygen potential to achieve phosphorous removal. The addition of large quantity of gaseous oxygen, in turn, requires large amount of carbuπser so that a foamy slag can then e μr oduc ed . Second, the process uses a hot metal of conventional chemistry, that s ; with carbon higher than 3%, with silicon usually higher than 0.4*/. and with manganese, usually higher than 0.3*4. Such a hot metal usually p r<sp 5rGU in a Cupola, or in a BF or m a similar urn I. Hut th< removal of higher levels, of carbon, silicon and manganese requires additional oxygen, energy, t me, fluxes and other c ns mables-, during the sieel ma,, i no in the EAF. Ihis* i sr not only a wastage of the m talloids and alloying elements such as carbon, c ιl .cπn and manganese, but results i needless waste generation and corresponding loss-s of iron into the slag as iron o-irlf. Bu even more significant is thr fact that the presence of higher levels o1 silicon and manganese dissolved in the molten ferrous metal, delays the onset of carbon boil. This results in slower heat transfer from the electric arc to the metal to be melted. This delays, melting and consumes additional energy. This in this process, at first, the solid charge, such as ; Scrap, HB1 , RJ, etc. is melted after which ihe hot metal is poured into the EAF. This requires that an arc be produced to generate the heat required to melt the- s-olid charge. This, in turn, results not only in higher electrode consumption but it als-o prevents- ac e 1 e rated heat transfer from ihe art to the solid charge, as required for melting. Because, a major part of bhe heat transfer to meta llic a ge in such instances occurs by radiation and conduction, at first from the art to the slsq layer , and subsequent 1 y only by conduction from the slag to the metallic charge, after the charge is partly melted and the slag forms . The slag is a poor conduictor of heat and so is the solid metallic charge when it is added inside the EAF hearth since the charge geis automa ical y piled up with considerable amount of void space in it. Therefore, the heat transfer, both through the slag and through the piled up metallic charge ir relatively slow, res-tiJ ii.g in a poor u ilisa ion of the electrical energy used, to generate the heat for 1 melting the solid charge. Fourth, DPI if used, has. to be of a high quality, that is: high in metallic iron; and low in the oxygen which is present in the DRI as iron oxide. Such a DRI i more highly pric d. Finally bhe large quantity of silicon and manganese in bhe hot metal and higher oxygen potential used, produces larger volumes of the oxides of silicon, manganese and iron : this in turn producer large? s g volume requiring larger quantity of flux to maintain a given level of basicity and a correspondingly larger los-i- of iron as oxi e into the slag. OBJECTS OF THE INVENTION The am object of the present invention is to propose an improved process for bhe EAF εbeel mal mg without the use of gaseous oxygen and under an oxygen potential which is relatively low, so thai the losses of iron and alloying elements are minimal. Yet another object of the present invention is to propose an improved process for the EAF steel mal g which uses; resistive heat i nc o1 the slag phtse, c nsequently the har nics and Γ G ^O- nance generated in the electrical circuit during arcing are signi icantly reduced, the sophi tic ted electrical circuitry currently used to maintain stable arc is avoided, the power factor improves and electrical energy consumption decreases, the electrode consumption is less, electrode brea age is less, the heat ir genera ed mainly in the slag phase, and the heat transfer- is more effective producing an accelerated hea bing- el t mcj-ref 1- nmg and consequently, α ciprreascd power consumpti n. A further- object of the present mveniion is to propose an improved process for the EAF steel malmg with s icmi i i cant ly riecreased consumpi i on of power, fluxes and other consumables. Btill a further- object of the present invention is to propsoe an improved μroces<- of the EAF sϊbeel mal ing with the sequence of charging and the proportion of the Charςje Mi-; (which consists of: mo ten high carbon lerrou metal, Scrap, HBI and DRI ) in the EAF, so arranged and s-elecl<>d and also the rhenπstiv of hot metal so adjusted, that th< j carbon boil starts as soon as the solid charge starts: melting εnri the carbon boil continues: ust as long as the meltin -refining con inues, and that the carbon boil occurs and produces turbulence i n the entire volume of molten metal bath, instead of being localized only at the slag/metal interface, and thereby producing very efficient heat transfer between the source of heat in the EAF " and the entire molten metal bath, and r.lEo accelerates ca o removal. Yet a further object of the present invention is to propose improved process- of FAF ~ steel mal mg with the slag basicity at a level, higher ihan thai conventionally u^e in most EAF steel mαling but, without significant increase in the consump ion of flux. Y another object of the presrn. invention is to produce 1 r-om the Cupola, the molten high carbon ferrous metal of a chemistry which not only facilitates s eel making in the EAF but also facilitates the production of this metal from a Cupola (or even from ; Blasi Furnace or any other furnace which produce such metal) and requires, less expensive raw material, no ferroalloy addition and r lower- cons-.ump t ion of coke. DESCRIPTION OF THE INVENTION According to 1-hiE invention, there i s provided an improved process for mal mg steel m an electric arc furnace (EAF) using molten high carbon ferrous metal as a part of the EAF charge mix, which comprises ; ) preparing in/or introducing a molten high carbon ferrous, metal (hot metal) into an EAF, said molten high carbon ferrous mebεt having a carbon content of less than "XA and a silicon and manganese content of less than 0.2 each, and a temperature of 1375 C or higher in the furnace; b) adding a solid metallic charge selected from Scrap, HB1 , DRI (Sponge, Pellet, etc. or Iron Ore) present singularly or in any combination together with lime into the hot metal m&ide the EAF; c ) mel ti ng-cum-ref inmg of the entire EAF charge mix m the absence of gaseous oxygen for carrying ou t said step of meltmg- cum-ref m ing ; d) supe heating, inis ing and tapping the molten steel into the ladle, for its subsequent casting. In accordance with the process of the present invention, the steel is made in the EAF " which comprise pouring into the EAF bhe liquid charge consisting of the molten high c rbon metal of a given chemistry, obtained from a Cupola (or a Blast Furnace or a similar unit), and adding thereafter into the EAF the solid charge consisting of Scrap, HBI, DRI, etc.. The proportion of the liquid and the sol id charcje in the EAF charge mix i s adjus-ted so that the oxygen available as iron oxide in the entire charge mix and c-fc available by ingress of ai into ihe furnace is suf icient to oxidise carbon, silicon and manganese, a<= required. Since the silicon and manganese level dirrolvcd m the liquid charcje, that is the molten ron is l ep t deliberately very low in the present- invention, the carbon boi I tiarts. soon ;ftcr the DRI or- HBI is added and occurs., throughout the bath of bhe molten metal. This rapidly transfers heai from the source to ihe molten bath right at the start of melting and also produces turbulence in it, which mixes and also the solid charcje submerged into the molten bath, at a highly accelerated rate, in addition, the carbon boil can automati a ly promote the continued formation of a foamy r 1 acj (without having to add any oxygen or carbuπser ) , provided the sϊlag composi ion i adjus-ted through an appr-opriate addition of flux . The molten high carbon ferrous, metal of given chemistry is preferably obtained from a Cupola. However, the molten carbon fι?r- rous-. metal may also be obtained from, for example, a BF r εimi- l,.r un i I or prepared m the EAF itself. Λ di'- nct advantage ensuing by the process- of this- investigation is that HB [ or DRI of inferior quality such as with low metalli- vaticri or n an xidise or burnt condition or n a fine form may be added in the EAF with a v e ry high resultant recovery of all Ihe iron present in the charge material. The coarser fraction of such material c an be mixed with bhe raw material of Cupola or BF" with t i c.ru f carii cdvr-ntage in some instances. In I his process--, the Cupola mainly use<- meta lic raw materials, such as. jciap end/or HBI and /or- DRI; end no or only a smal quanti y o ferroalloy i; added,. Al o, the Cupola is run w t th a ow coke Tf-ie, in order to produc a molten high carbon ferrous- metal which has carbon, silicon and manganese, lower than carbon, silicon arid manc / aneee , tower than those in the molten casi iron which is conventionally produced in Cupola. The BF or other similar units , i used, can be run to produce a low carbon, low s con, low manganese hot metal wi h lower cole rate and a decreased quanliiy of qu-r- rite or manganes-e ore m the charge. In accordance with the present invention, the carbon content in the moll en high carbon ferrous metal (a ) is-- less than 3 , such as between 2 to Z'Λ . Further, the levels of silicon and manganese con erit in the molten high carbon ferrous metal is each less than *-* . --. ' . » The molten high carbon ferrous metal (a) temperature is prefer- S ably εt l-f-Jh V or higher, while the metal is tapped from either a Cupola or a Blast Furnace or from any other- furnace which can produce such α molten high carbon ferrous metal. The low pihosphorouε , low ash coke used together with metallic raw materials, such as scrap and/or- HB and/or- DRI (Sponge, Pellet, etc. ) and/or Pig Iron - as the charge in Cupola. a). The present invention enviεacjes a col e rate lower than that used for making conventional mo ten cast iron in a Cupolata. , so that the hot metal of desired chemistry (with carbon typically less than Z*A and silicon and manganese each less Cf.2*/» ) can be conveniently produced. The col e rate and the constituent of the metal tic charge used m the Cupola (a) sre changed whenever required, to change the carbon content of the hot metal to a pre-se 1 ected level such that, and correspondingly, the proportion of hot metal in the EAF " charge mix IF selected such - that the oxygen present as iron oxide - in the entire EAF charge mi-: and bhe ingress of air into the furnace is sufficient to oxidi e the carbon present in the charge as requi ed . The hoi metal of c modified chemistry (with carbon typically less than Z% and silicon and manganese typically l ss than 0.2*/. each) is added into the EAF(b), eiiher- through its door using a 'tundish attached with a runner' or from the top of the EAF after its? roof IE swung oui in which case, a small quantity of solid char-ge (around 5 to 10J , is placed at the bottom of the EAF to breal the fall of the liquid metal so that splashing of the liquid metal and the erosion of the EAF bottom are prevented. The charging ss-equence (aS-b) and the quantity, chemistry and con- stiiuent of the hot metal <a and solid charge (b) m the entire EAF charge mi--;, are so adjusted that carbon monoxide is generated throughout he entire volume of molten high carbon ferrous metal bath and during the entire period of melting refining, in order to promote efficient heat transfer and thereby accomplish accele- rated melting and refining,, The sol id metalli charge (b) and also ime (b> is added either from the top of the EAF with bhe help of a charging bucket which r-eleases the charge into the EAF, or a ternatively, the solid metallic charge and the lime is added through a conveyer charc / er or manually through the door. The quantity and bhe proportion of the different constituents of the solid metallic charge (b ) including DRI, HBI of low metalliation or in an oxidized or limit condition, or in a fine form, or alterna ively, the meta lic charge may contain i on ore, all these are added into the EAF are so adjusted that the oxygen pres:cnt in the form of iron oxide and the ingress of air into the furnacew is sufficient to oxidise the carbon, as required in the entire EAF charge mix. The oxygen potenti l during the me-111 ng-cum-ref mi ng (d) and l ø t-uper heat g and finishing (e), ir I ept deliberately low by not using the gaseous oxygen and yet at the same time achieving accelerated carbon removal, by generating carbon mono.ide throughout the entire volume of the molten high carbon ferrous metal bath anci during the entire period of mel 11 ng-ref i ning . The arcing is kept to a minimum while converting the electrical enercjy into heat, and the chemistry and volume of the slag during the mel t mg-cum-re f m mg (d) and superheating and finishing (e ) are EO adjusted that bulk of the heating is provided by the resistive heating of the slag. The pre.cess of the present invention is described herembelow, with reference to an example, which is illustrative only and shou d not be construed to limit the scope of the invention m any manner. EXAMPLE Metallic raw material consisting of Scrap (60%), HBI (20%), DRI Pellets (10% ) and Pig I on (10% ) , were added in a Cupola. The coke used the Cupola had 12% ash and 1 ess. than 0.05% P . The coke rate of the Cupola was in the ratio of 1:6 of the coke to the metallic raw material. The Cupola was run with a blowing rate adequate to produce molten high carbon ferrous material (hob Ki t J with carbon 2. c > > %, silicon 0.2*. and manganese 0.3%. The hot β me al was tapped at a temperature of 142.ϊ C from the Cupola into c. preheated ladle. The hoi metal tapped amounted to aboui 40% of It the entire charge mi (consisting of both hot metal and solid charge) of the EAF. The ladle containing ihe hot metal was qiucl ly transferred to the EAF site. The roof of the EAF was lifted and swung out. Thereafter , the eni i r-e quantity of the hot metal was poured from the ladle into the EAF " . Soon after this, a charging bucket containing the uolid charge and ime was discharged into the EAF. The solid charge consisted of about 15% scrap and S5% DRI Pellet which together const i i utecl 60% of the entire charge mix of the EAF. The lime amounted to 5% of the entire charge mix. The DRI had an oxygon content of Z . % in the form of iron oxide. Thereafter, the roof was swung in and seated on the EAF. Full power was switched on into F-AF . The me 111 ng-r-e f irting and superheating was accomplished within 45 minutes. No oxygen or carbon was- added but a foamy slag formed and a significant part of the slag overflowed towards the end of the heat. The opening rarbon was at the desi red level of 0.18%. The Feϋ content of the slag was <1.S%. The steel was deoxidized by adding εi 11co-manganese and aluminium. Fer -o-Manganei>e and Ferro-Chrome were added to adjust the εteel composition. Thereafter, steel prepared was tapped into the ladle for its subsequent casting. The present invention has-, the following advantages : 1. Sigruf icant inrrea∑.r in the EAF producti ity ~ ø to 30% more ! han that achieved n the hitherto I own EAF steel mat inq processes, which use hot metal as a part of the EAF charge mix. ',: . The increased production from EΞAF can be accomplished with a small investment (less than a tenth of the investment required in <-. BF of matching production level) since the invention requires" molten high carbon ferrous metal with varying carbon level and low manganese and silicon levels, which is more conveniently delivered by a highly flexible unit such as Cupola. The fact that Cupola is semi -continuous , like EAF and therefore conveniently matches its operator-maintenance sequence and is also inexpensive and les"s- complicated to run are i s added advantages. 3. Significant decreases in the consumption of power (about 20%) ferroalloys flu-'es and other consumables- (which range from 10 to 100%) and considerabl decrease the loss of iron (about 1%) and other elements- and significant increase in yield (aboui > when compared to those achieved in the hitherto I nown EAF " steel rnaling processes , which use hot metal as a part of the EAF charge 4. DRI or HBI of inferior quality ( highly oxidized, burnt or fine form ) can be used as metallic charge in the EAF with very high resultant recovery of almost all the iron ( 98%) present (including that in bhe form of oxide) in the charge material, producing very high yield. Also, such DPI or HB are inexpensive and are avoided in the EAF steel mal g. "ι . The gar. such as hydrogen, nitrogen and oxygen in the finished steel are generally lower, since the carbon boil is prolonged and also it occurs ihroughout the entire volume of molten bath; the o-'ygei. potential ε which the steel is. made is lower; and since the electrical resistive heating of the slag rather than e-rcing, converts the electrical energy into heat to accomplish the mel t ing-r f inmg of the steel. 6. The levels"- of 1 ramps and r-es.idualr in the steel made using this process could be 20 to 9ø% lower than the steel made using s rap, lower since bhe process permits use of 100% HBI and DRI - about half of it in Cupola and the other- half in the EAF " . The process of the present invention is similar to Type II steel mal mg process of the I nown art only in as much as that the present invention use<= high carbon molten iron as a liquid charge - as a part of the EAF " charge mi-:. But the present invention differs both from the Type 1 and Type II in the following six respects s a In the process of the present invention, no cjaεeoue oxygen and, therefore no carburiser is used in the steel making process, unl tis one has to correct the erro in achieving a given carbon level in a steel as revealed in the opening sample - that ιs~ towards, the' final stage of making the steel. b) In the present invention, the hot metal used has a special rherniEiry with levels of carbon, manganese and silicon, which are maintained deliberately lower than those in the hot metal that is conventional ly produced from a Cupola F<P " , etc.. c ) Unlike m the Type II process, in the process of the present invention, the molten high carbon ferrous metal is first added into the FAF and only thereafter the major part of the Scrap, HBI, DRI, etc. are added into the molten bath. cH DRI of low e. t -- 1 J zation and higher oxycjen level and also of finer si e can be advantageously used in bhe process of the pres-ent invention, not merely becaus.e DRI of such ε quality is 1 ess * expensive but because the higher level of oxygen present as l ron oxide improves the efficiency of the process and results in a higher recov e ry of iron present as iron oxide and in a faster carbon boi 1-aεs i εt er heating, melt me; and refining. e) The slag basicity can be maintained at a higher- level in the process- of the present invention, wi hout a correspond] nq increase in the flux addition, since the quantity of ox idess- of i on, manganese and silicon, generated during the process is, loss. A higher slag basicity achieves better- phosphorous removal. f ) The Cupola IF run with a low col e r-ate and wi 1 h l ss expensive metallic raw materials, such as HBI, DRI and Scrap, instead of a more expensive metallic raw material, such as Pig iron, which is otherwise conventionally used as the mam or- ihe only metallic raw material in a cupola. This is done, not merely because such raw materials are less expensive, but more important, the use of such raw materials enables one to conveni nt y produce the molten high carbon ferrous metal with levels f carbon, silicon and manganese which are lower- than the conventional metal tapped from a Cupola. Also thκ> production of a hot metal with this modified chemistry, res.ults in α lower col consumption and in a higher 1'=. p rod cti i y o tho Cu ola. The above d J r cu s-icm brings out the operational differences between the process of the present invention and the other- similar- proces s es hitherto 1 own before. However, the operational diffrrences apart, tho ocess of the present invention is based on an approach used in the previously I nown processes on three different counts-. These differences in the approach are discussed he1 t.ι*ι : Firs:! , in the EAF steel dial ing of the Types 1 and 11 which have been used thus f ^r , the melting and refining is accelerated by generously blowing gaseous oxygen into the steel bath. As a result, the steel is made under a high oxygen potential. On the other hand, the process of the present invention, the steel s made under low oxygen potential, and accordingly, no gaseous oxygen is blown into the bath during melting and refining. This decreases the loss of iron and other- expensive alloying elements (whenever- present the- steel scrap ) as- oxides into the slag. Second, to produce and maintain a foamy slag, both in Type I and Type II processes, the carbon monoxide has- to be generated conti- nuously and in large enough quantity. The formation of carbon monoxide ir accomplished by the addition of ihe carbuπser and the blowing of oxygen. The carburiser floats alongwith bhe slag phase on the top of the molten metal. Since the gaseous oxycjen is. blown n & the slag/me bal interface, the formation of carbon monoxide i ~ " localised mainly at the slag/metal interface, ϋn the other hand, Ihe process of the present invention, the carbon monoxide forma ion is not localised at the slag/metal interface but occurs , throughoui the volume of the molten ferrous metal bath producing v ^ y large turbulence in the bath. Also, the carbon boil begin 1 " , soon . fter the power- is switched on. This promotes rapid carbon removal and accelerated heat transfer- between the molie-n metal bath and slag and also inside the molten metal bath -due to forced convection, in addition to the usual conduction. Finally, in both Type I anci Type It proceε.s.rs , extensive arc mg i ss- requi ed bo convert the lectrical energy into heat for eltincj and refining the steel. On the* other- hand, in the present invention, arcing is avoided. Instead, the process of the present invention uses the resistive heating mainly of the slag and partly of the metallic phase to convert the electrical energy into heat. The- heat 3 s ther-efor-e, cjener-ated mainly and directly in the stag phase. The slag phase is m intimate and direct- contact with molten metal because of the extensive- carbon boil which occurs throughout the volume of mo ten metal bath an also during the entire period of mel ing anci refining. As α result, the heal generated in the sslag phase is rapidly transferred to the meta 3L charge in the EAF. The process of the present invention is charac erised by the features fhat the FAF process., the FAF opera ion and the chemistry of the molten high carbon ferrous metal used in the EAF - all are modified. The invention is also characterised by bhe feature that the raw materials- used to produce this high carbon ferrous metal with i- modified chemistry from the metallurgical units, such as a Cupola (or r Blast Furnace or the. other simila units which produce the high carbon ferrous metal ) has to be modified so that <~>uch a unit consumes , less Col and has a higher productivity. In some instance, such as in a Cupola, the production of high carbon ferrous- metal with the modified che is.try would require : very little of an expensive material such as ferroalloys, and 1 eε<-- expensive metallic raw materials, such as. : Scrap and/or DRI and/or HBI, instead of the more expensive metallic raw material < ~ .uckι as Picj 1 r on , which is conventionally and extensively used, to produce the standard cast i on in a Cupola. More distinctive feature of the process of the present invention is that the addition o f gaseous oxygen and correspondingly, the addition of c αrhur ιs".er and also the arcing - all of thern are avoided during the EAF " steel mal mg. Alss-o, in the process of the presπnl -invention, the c rbon boi occurs during the entire period of melting and refining and also throughout the entire volume of molten metal bath, instead of occurring towards , the end of melting and instead of being localised only at the slag/metal inter f ac e .

Claims: [ CLA I M : 1. An improved process for mal mg steel jr. an electric arc furnace (EAF ) using molten high carbon ferrous metal as a part of the t AF " charge mi which comprises- 5 a) preparing in/or introducing a molten high carbon ferrous metal (hot metal ) into an EAF- " , said molten high carbon ferrous metal having a carbon content of less than 3% and a silicon and manga- 0 ne-sc content of less , than 0.2% each, and α tempeature of 137b C or- higher in the furnace, [, ) adding a sol id metallic charge selected 1 rom Scrap, HBI, DRI (Sponge, Pellet, etc. or Iron Ore ) present singularly or in any trombinction together with lime into the hot metal inside the EAF " , c ) mel ing— um— efining of the entire EAF charge mix in the absence of gaseous oxygen for ccrrying out said step of melt g- cum-ref ining , cl ) supe rhec t ing , finis-hiπg and tapping the molten steel into the ladle, for its subsequent casting. 2. A process as claimed in claim i wherein the molten high carbon ferrous mebal (hot metal 1 is prepared in a Cupola. -'■■ A process as claimed in claiml wherein the molten high carbon ferrous metal (a ) temperature is preferably at a temperature of atleast 1*125 C while the metal is tapped from cither a Cupol or a Blast Furnace or from any other furnace which can produce such molten high carbon ferrous metal. ■.. A process as. claimed in claim 1 wherein the molten high carbon ferrou'- metal is heated in the EAF to a temperature of atleaεt I' . A process as claimed in clαiml wherein the molten hicjh carbon ferrous metal is heated in the EAF to a temperature of 1 5 to 150« β C. 6. A process as claimed in claim 1 wherein said DRI and HBI is of an inferior quality such as low metallisation, or in an oxidised burn condition, or in a fine form. 7. A process as claimed in claim 2 wherein low phosphorous, low sh col e is added to said solid metallic charge in the Cupola. S. A process as claimed in claim 2 wherein coke rate is lower than that as I nown hitherto used for mal incj conventional molten cast iron a Cupola. 9. A process as. claimed in claim 1 wherein the total carbon present in the charge is oxidised as required by oxygen present- in iron oxide and ingress , of air into the furnace. 10. A process as claimed in claim 1 wherein gaseous oxygen is injected into the EAF only if required ai the step of super heating or finishing the heat for correction of accidental deviation of the composition of the steel made. It. A process as claimed in claim 1 wherein the carbon monoxide LS generated throughout the entire volume of mol en high carbon ferrous metal bath and during the enbire per-iod of melting-refining in orde to promote heat transfer and bhereby accomplish accelerated melting and refining. 12. A process as claimed in claim 1 wherein slag during the mel ing-cum-refining and superheating and finishing the heat said steps is provided by the resistive heating of the slag. .13. A process as claimed in claims 1 and 2 wherein the molten high carbon ferrous metal has a carbon content- of 1.5 to 3% and preferably 2 to 3%. 14. An improved process for the electric arc furnace steel making which uses molten high carbon ferrous metal as substantially described I ier-e mabove with refer-ence to the example.

Inventors: BANERJEE SHILOWBHADRA, BANERJEE, SHILOWBHADRA
Applicants: BANERJEE SHILOWBHADRA, NAT RES DEV INDIA, BANERJEE, SHILOWBHADRA, NATIONAL RESEARCH DEVELOPMENT CORPORATION OF INDIA(A GOVT. OF INDIA ENTERPRISE)
Application year: 1999
Main classification: C21C5
IPC codes: C21C5