ispaat nirmaan

lauh ayask se ispaat banaane ki prakriya ka doosra charan ispaat nirmaan (Steelmaking) hai. kachche lohe se ispaat banaane ke liye kachche lohe mein upasthit atirikt kaarban tatha gandhak, fausforas aadi ashuddhiyon ko nikaala jaata hai aur maiganeej, nikil, kromiym tatha vanaadiym (vanadium) aadi tatv milaaye jaate hain taaki vaanchhit prakaar ka ispaat banaaya ja sake.

anukram

parichay tatha itihaas

ispaat utpaadan ka itihaas kareeb chaar hajaar saal puraana hai. antoliya ke utkhanan se kuchh ispaat ke saamaan mile hain. Asia mahaadveep ki baat karein to Sri Lanka mein teen sau varsh isaapoorv mein uchch-maatra vaale ispaat ka pramaan mila hai. Sri Lanka ne ispaat nirmaan ke liye hi vaayu-bhatti ka nirmaan kiya tha. Delhi ka lauh stambh bhaarateeya ispaat nirmaan ki praacheenata evam utkrushtata ka jita-jaagata pramaan hai. simeinteekaran vidhi dvaara pehli baar Italy mein balistar ispaat ka nirmaan kiya gaya.

aadhunik kaal mein ispaat ka vyavasaayik nirmaan besamer vidhi ki khoj ke baad shuru hua. besamer vidhi se ispaat ka utpaadan kaafi sasta ho gaya. baad mein Gilchrist-thomas vidhi ke aane se besamer vidhi mein aur jyaada sudhaar hua. baad mein seeman-Martin vidhi ki khoj se ispaat nirmaan aur bhi sugam ho gaya.

loha dharati ke garbh mein svatantr avastha mein naheen paaya jaata hai, balki yeh okseejan aur salfar ke saath yaugik avastha mein paaya jaata hai. mool rup se lauhe ke do ayask hote hain- hemaataait (efa2o3) aur paairaait (efaesa2). hemaataait se lauhe ko nishkarshan kiya jaata hai, jisse okseejan alag ho jaata hai. lauh ayask se lohe ko alag karna lauh nishkarshan kahalaata hai. lauhe ke nishkarshan mein kaarban ki upasthiti mein lohe ko galaaya jaata hai. is kriya ko pragalan kehte hain. shuru-shuru mein kam galanaank vaale dhaatuon ka pragalan kiya jaata tha. taanbe ka galanaank 1000 degree selsisiys hai, jabki teen 250 degree celcius par pighl jaata hai. Caste aayaran ka galanaank 1370 degree celcius hai. 800 degree celcius ke baad okseekaran dar teji se badh jaata hai. yahi kaaran hai ki pragalan ki kriya nimn-okseejan vaale vaataavaran mein karaayi jaati hai. taanbe aur teen ke vipreet, kaarban tarah lohe mein aasaani se ghul jaata hai. is tarah se lohe mein kaarban ke mishran se ispaat banaaya jaata hai.

ayask (ore) se adhik se adhik dhaatu praapt karne ke liye avakaarak vastu, kaarban, bahutaayat se milaai jaati hai. kaarban baad mein ichhit maatra tak aakseekaran ki kriya dvaara nikaal diya jaata hai. isse saath ke doosare tatvon ka bhi, jinka avakaran hua rahata hai aur jo aakseekaraneeya hote hain, aakseekaran ho jaata hai.

yahaan dhyaan dene waali baat ye hai ki lohe mein kaarban ke thod se her-fer se ispaat ki gunavatta mein bada badlaav aa jaata hai. ispaat ke gunon mein vaanchhit badlaav ke liye lauhe aur kaarban ke mishran mein doosare padaarth bhi milaae jaate hain. ispaat ki tanyata badhaane ke liye ismein nikel aur mainganeej milaaye jaate hain. kathorata badhaane ke liye kromiym aur venediym ka mishran kiya jaata hai.

dhaatukaarmik vyavahaar mein "vishuddh dhaatu" shabd ka upayog aise vyaapaarik mel ki dhaatu ke liye bhi hota hai jismein pradhaanat: ve hi gun (jaise, rang vidyuchchaalakata ityaadi) hote hain jo shuddh raasaayanik dhaatu mein hote hain. inmein shesh jo ashuddhata hoti hai ya to use door karna kathin hota hai, athva dhaatu mein koi vishesh gun praapt karne ke liye use jaan boojhakar milaaya jaata hai. is prakaar milaae jaanevaale tatvon ko 'mishradhaatukaari tatv' (alloying elements) kehte hain.

puraani vidhiyaaain

praacheen kaal mein ispaat utpaadan ki do vidhiyaaain prachalit theen.

  • (1) kaarbaadhishoshan ya seemeintakaran vidhi (Cementation Process) tatha
  • (2) ghadiya vidhi (Crucible Process)

Bhaarat ka prasiddh 'vuts' ispaat (wootz steel) inheen vidhiyon se banaaya jaata tha.

kaarbadhishoshan vidhi

kaarbaadhishoshan vidhi mein pitvaaain lohe ko kok ke sampark mein rakhakar paryaapt samay tak uchch taap par garam kiya jaata hai. jin paatron mein yeh kriya ki jaati hai unhein parivartan paatr (Conversion Pots) kehte hain aur ye patthar ki silon ke bane hote hain. in paatron ko kaarbaadhishoshan bhatthiyon kiya jaata hai. paatr ke andar vaayu ka pravesh na ho iske liye inhein achhi tarah se agnish padaarthon se band kar diya jaata hai anyatha vaayu ke prabhaav se koyala jalakar raakh ban jaaega aur lohe ka okseekaran hone lagega. paatr ko lagabhaag 48 ghante mein 1,000° sein. tak garam kiya jaata hai. is taap ko saat se lekar nau dinon tak sthir banaae rakhate hain. is kriya ke parinaam svaroop koyale ka kaarban lohe mein pravisht ho jaata hai. jab kaarban paryaapt gaharaai tak pahuainch jaata hai tab paatron ko ek saptaah ki avadhi tak dheere dheere sheetal kiya jaata hai. is prakaar jo chhadein niklati hain unki satah par fafole dikhaai dete hain. isliye inhein 'fafoledaar ispaat' (Blister Steel) kehte hain. is ispaat ko garam karke pitaai ki jaati hai jisse yeh samaras ho jaae.

ghadiya vidhi

kaarbaadhishoshan ispaat ki pitaai karne ke baad bhi ismein nyoonaadhik asamata rahati hai. is ispaat ko ghadiya mein dravit karke usak raasaayanik sanghatan ek sa kar liya jaata hai. is kriya ke dvaara kaarbaadhishoshan ispaat mein vidyamaan dhaatumal ke kanon se bhi mukti mil jaati hai. is kaarya ke liye adhiktar 50 pound dhaaritaavali graifaait ki ghadiyaaain prayukt ki jaati hain. in ghadiyon mein kaarbaadhishoshan ispaat ko rakhakar inhein kok bhatthiyon mein garam kiya jaata hai. ghadiya vidhi mein dhaatu ka parishkaar naheen hota, isliye iske liye upayukt prabhaar yathaasanbhav shuddh hona chaahiye. pehle isi vidhi ke dvaara uchch koti ka aujaari ispaat taiyaar hota tha.

aadhunik prakriyaaeain

ispaat-nirmaan mein asli kraanti 1850 ke dashak ke antim dinon mein aayi. besamar vidhi pratham safal vidhi thi jisse badi maatra mein ispaat utpaadan kiya ja sakta tha. iske baad khula chulha vidhi aayi.

aadhunik ispaatanirmaan ko do bhaagon mein baant sakte hain - praathamik tatha dviteeyak ispaatanirmaan (primary and secondary steelmaking). praathamik ispaat nirmaan use kehte hain jismein ispaat-nirmaan ke liye adhikaanshat: vaatya bhatthi se nikle naye lohe ka upayog kiya jaaya. dviteeyak ispaatanirmaan use kehte hain jismein ispaat nirmaan ke liye bhangaar ya kabaad ispaat (scrap steel) ka upayog ho. ispaatanirmaan ke samay nikleen gaison ka upayog urja ke srot ke roop mein kiya ja sakta hai.

besemar vidhi

san‌ 1856 mein henari besemar ne ispaat utpaadan ki vidhiyon mein kraantikaari parivartan kiya. is vidhi mein naashpati mein jise 'besemar parivrtiddh' (Bessemer Converter) kehte hai, dravit kachche lohe mein dhaunkani se vaayu pravaahit ki jaati hai. dravit lohe mein vidyamaan apadravyon ka okseekaran vaayu ke okseejan dvaara hota hai. ye kriyaaeain ooshmaakshepak hoti hain, isliye is vidhi mein baahya idhann ki aavashyakta naheen padti. lohe mein vidyamaan apadravya okseekrut hokar dhaatumal banaate hain aur bacha hua loha ispaat ka roop dhaaran kar leta hai.

besemar parivrtitr ka vaahya bhaag ispaat patt se bana hota hai tath andar ki or ooshmasah padaarthon ke astar diye jaate hain. besemar vidhi ke antargat do paddhatiyaaain prachalit hain : (1) amleeya (acidic) tatha (2) samaakshaareeya (basic). in paddhatiyon ka upayog kachche lohe ke gunon par nirbhar karta hai. yadi kachche lohe mein fausforas ki maatra adhik hoti hai to samaakshaareeya vidhi ka upayog kiya jaata hai. jahaaain fausforas ke niraakaran ki aavashyakta naheen hoti vahaaain amleeya paddhati vyavahrut ki jaati hai. besemar parivrtitr ke andar diye jaanevaale ooshmasah padaartho ke astar upayog mein laai jaanevaali paddhati par nirbhar karte hain. amleeya paddhati mein adhiktar silikaamaya padaarth (sileceous material) upayog mein aate hain jabki samaakshaareeya paddhati mein samaakshaareeya padaarth, jaise daulomaait (dolomite, CaCo3MgCO3), hi upayog mein laae jaate hain.

besemar parivrtitr ke nitl mein hava tontiyaaain lagi hoti hain, jinke dvaara dravit lohe mein uchch daav (25 pound prati varg inch) par vaayu dhaunkani se pravaahit ki jaati hai. uchch daab isliye aavashyak hai ki dhaman kaal mein drav loha tonti ke dvaara parivrtittr ke vaayudhaan (wind box) mein na chala jaae. amleeya paddhati mein mukhya apadravya silikn, mainganeej tatha kaarban hote hain. inke okseekaran mein lagbhag 12 minute lagte hain. pehle silikn tatha maiganeej ka okseekaran hota hai aur ve dhaatumal banaate hain. fir kaarban okseekrut hokar kaarban monoksaaid (CO) gas banaata hai, jo parivrtitr ke muainh par prajvalit hokar vishaal jvaala utpann karta hai. is kriya ke baad parivrtitr paatr ko namit karke taiyaar ispaat ko darvi (ladle) mein nikaal liya jaata hai. fir aavashyakataanusaar ismein pun: kaarburikaarak (recarburizer) tatha viokseekaran (deoxidizer) daalkar ispaat ko aichhik raasaayanik sanghatan ka banaaya jaata hai.

samaakshaareeya paddhati mein sabhi kriyaaeain amleeya paddhati ki tarah hi hoti hain, parantu usamein fausforas ke okseekaran ke liye 5-6 minute ka atirikt samay lagta hai. silikn, mainganeej, tatha kaarban ke kramik okseekaran ke pashchaat‌ hi fausforas okseekrut hota hai aur paatr mein vidyamaan choone ke saath milkar samaakshaareeya dhaatumal banaata hai. is dhaatumal ko alag karne ke pashchaat‌ hi dhaatu mein pun: kaarbureekaarak tatha viokseekaarak daale jaate hain.

L. di. vidhi (L. D. Process)

ise 'besik aakseejan vidhi' (basic oxygen steelmaking) bhi kehte hain. san‌ 1851 mein aastriya ke linj tatha donaavitj dhaatuvijnyaon ne besemar vidhi ke sanparivrtit roop ki khoj ki, jise unke naam par L. di. vidhi kaha gaya. ismein parivrtitr paatr mein dravit lohe ki satah par shuddh okseejan pravaahit kiya jaata hai. is vidhi se apadravyon ka sheegra okseekaran hokar naaitrojan rahit ispaat ki praapti hoti hai.

khuli chulli bhatthi vidhiyaaain (Open Hearth Processes)

san 1895 mein nirmit khuli choolha bhatthi

aaj vishv ka lagbhag 75 pratishat ispaat utpaadan khuli chulli bhatthi vidhi se kiya jaata hai. is kaarya ke liye khuli bhatthi ka upayog hota hai. besemar vidhi ki tarah hi ismein bhi amleeya tatha samaakshaareeya roopaantaran (modifications) hote hain. in paddhatiyon ka upayog kachche maal ke raasaayanik sanghatan par nirbhar karta hai. yahaaain yeh smaran rakhana aavashyak hai ki khuli chulli bhatthi ki ispaat utpaadan vidhi mein dhaatumal ki banaavat par hi ispaat ka gun nirbhar karta hai. isliye is vidhi mein dhaatumal ki taiyaari par hi vishesh dhyaan diya jaata hai. yadi samaakshaareeya dhaatumal taiyaar karne ki aavashyakta hoti hai, to 'samaakshaareeya khulli chulli bhatthi paddhati' ka upayog kiya jaata hai aur yadi amleeya mal ki aavashyakta hoti hai to 'amleeya vidhi' ka upayog hota hai.

khuli chulleebhatthi 25 se 300 tan dhaarita tak hi hoti hai. bade bhraashtron ka chulleetal 15 foot chauda, 40 foot lamba tatha 20 inch gahra hota hai. chulleetal ka nirmaan vibhinn ooshmasah padaarthon se hota hai. amleeya paddhati mein amleeya ooshmasah tatha samaakshaareeya paddhati mein samaakshaareeya ooshmasah padaarth prayukt hote hain. bhraashtr ki deevaar tath chhat (roof) saadhaaranat: silika iton ki bani hui hoti hain. aajkal chhat ke liye maignesaait (magnesite) iton ka bhi upayog hone laga hai. chulleetal ke neeche donon or ooshmasah iton ke rodhakon (checkers) se nirmit do do kaksh hote hain, jinhein 'punarjanitr' (Regenerator) kehte hain. bhraashtr se bahirgaami dahan-utpaad ek or ke donon punarjnitron mein se hokar gujarte hain aur is prakaar apni jnyaeya ooshma (sensible heat) rodhakon ko pradaan karte hain. kuchh samay pashchaat‌ bhatthi mein dahan yogya gas tatha vaayu in tapt rodhakon ke dvaara bheji jaati hain, jisse ye (gas tatha vaayu) rodhakon se ooshma praapt karti hain aur tab dahan-utpaad doosari or ke punarjanitron se hokar gujarata hai. yeh kriya 15-20 minute ke antar par duharaai jaati hai. is pranaali ke dvaara bhatthi mein idhann tatha dahan ke liye aavashyak vaayu chulleetal ke donon or nirmit do alag alag maargon dvaara bheji jaati hai. in maargon ko port (Port) kehte hain. badi bhatthiyon mein prabhaar ko bharne ke liye saamaanyat: paaainch prabhaar dwaar (charging doors) hote hain. dravit dhaatu tatha mal ke nikalne ke liye bhatthiyon ki pichhli deevaaron mein 'tonti chhidr (tap holes) hote hain. in bhatthiyon ko tapt karne ke liye gaiseeya athva taral idhann ka prayog kiya jaata hai.

khulli chulli bhatthi mein ispaat utpaadan ke liye kachche maal ke roop mein loha (thos tatha saral), raddi maal (scrap) athva donon ka mishran upayog mein laaya jaata hai. bhatthi ke prabhaar ke pashchaat‌ prabhaar ko dravit hone diya jaata hai. dhaatu ke parishkaar ke liye gaalakon ka upayog hota hai, jinmein patthar tatha loh ayask pramukh hain. loh ayask ke okseejan ke sampark se kramik roop se silikn, mainganeej tatha fausforas jaise apadravyon ka okseekaran hota hai aur ve dhaatumal banaate hain. tatpashchaat‌ lohe ke kaarban ka okseekaran hota hai, jo choone mein budabudaahat utpann hone ke kaal mein apni charam seema par pahuainch jaata hai. jab dhaatu ka raasaayanik sanghatan aichhik vindu par pahuainch jaata hai tab use darvi mein nikaal liya jaata hai. vahaaain par pun: kaarburikaarak tatha viakseekaarak daala ja sakta hai. is ispaat ko pind ke roop mein sanchit kar lete hain.

bahudha amleeya beinsemar vidhi ke saath samaakshaareeya khuli chulli bhatthi vidhi ka upayog kiya jaata hai. ise duple vidhi (Duplex Process) kehte hain. jab amleeya besemar tatha samaakshaareeya evam amleeya khuli chulli bhatthi vidhiyon ka upayog hota hai to use trik ya tripleks, vidhi (Triplex Process) kehte hain.

vidyut‌ vidhiyaaain

ispaat utpaadan mein mukhyat: do prakaar ki vidyut‌ bhatthiyon prayukt hoti hain :

  • (1) chaap bhatthi (Arc Furnace) tatha
  • (2) preran bhatthi (Induction Furnace).

chaap bhatthi mein graifaait vidyudagron, athva vidyudagr aur dhaatu, ke beech vidyuchchaap banta hai, jisse tej ooshma niklati hai aur dhaatu ka pragalan karti hai. preran bhatthi mein dhaatu prerit vidyuddhaara ke pravaah ko avaruddh karti hai, jisse ooshma utpann hoti hai. bade parimaan mein ispaat utpaadan ke liye chaap bhatthi hi adhik upayogi hai aur iski dhaarita ek tan se lekar 100 tan tak hi hoti hai. preran bhatthi mukhyat: aujaari athva vishesh prakaar ke ispaaton ke utpaadan mein kaam aati hai.

chaap bhatthi mein vidyudagron aur dhaatu ke beech chaap utpann karke dhaatu ka galan hota hai. galan ke pashchaat‌ parishkaar kriya aarambh hoti hai, jo bahut kuchh prabhaar ke oopar nirbhar karti hai. yadi prabhaar mein adhikaansh raddi maal hai, to keval viokseekaran ki aavashyakta padti hai aur fir kaarbaneekaran ityaadi darvi mein kiya ja sakta hai. preran bhatthi mein mukhyat: galan kriya hi ki jaati hai aur vahaaain kisi prakaar ka parishkaran sambhav naheen hai.

hlsarn ispaat nirmaan prakriya

HIsarna steelmaking process

inhein bhi dekhein

baahari kadiyaaain