Kev laij yog cov txheej txheem ntawm tshav kub-kho cov pa roj carbon raw khoom ntawm qhov chaw kub (1200-1500 degree) hauv ib puag ncig airtight. Kev laij tawm yog ib qib pretreatment hauv cov roj carbon ntau lawm. Ntau cov khoom muaj cov khoom siv khib nyiab ntau qhov kev hloov pauv tseem ceeb hauv lawv cov khoom lag luam theem pib thiab microstructure thaum rov ua haujlwm.
Anthracite, roj av coke, thiab ncua suab sib tsoo tag nrho cov nyiaj ntawm cov teeb meem uas tsis muaj teeb meem thiab yuav tsum tau laij. Coke Metallurgical coke, nrog nws cov coking siab coking kub, yog kwv yees sib npaug rau cov kev cais cov nroj tsuag, thiab yog li tuaj yeem faib nrog los ntawm kev ziab tawm ntawm cov dej noo. Ntuj Graphite tseem tuaj yeem muab calcined txhawm rau txhim kho nws cov wettability. Feem ntau, cov khoom calcined yog qhov nyuaj thiab ntau nkig, ua rau nws yooj yim dua los tsoo, zom, thiab tshuaj ntsuam.
Lub hom phiaj ntawm kev laij tawm yog tshem kom ya raws thiab cov khoom siv tsis sib xws, tso cai rau lawv cov khoom siv hluav taws xob nrog lub cev thiab tshuaj lom neeg. Cov ntsiab lus noo noo (huab hwm pawg feem ntawm cov khoom nkag rau cov khoom lag luam khib nyiab feem ntau ntawm 3% thiab 10%. Ntau dhau noo nyob hauv cov khoom siv raw ua rau crushing, sib tsoo, thiab kev sib tsoo, thiab tseem cuam tshuam rau cov khoom siv raw 'lub peev xwm los nqus cov nyom, ua cov khoom sib tsoo. Yog li no, cov ntsiab lus noo noo (Massion cov ntsiab lus (pawg feem ntau) ntawm cov khoom calcined) yog feem ntau yuav tsum tsis pub tshaj 0.3%.
Yog hais tias cov ntsiab lus tsis txaus ntseeg ntawm cov ntaub ntawv raw yog qhov siab dhau, cov khoom yuav yauv ntim qhov tob hauv lub sijhawm thaum tso tawm ntawm kev tawm tsam loj, ua rau muaj kev tawg. Yog li, volatiles yuav tsum tau muab tshem tawm ntawm cov khoom siv raw. Thaum xam kub kub, raws li cov neeg tsis huv, muaj cov qauv sib xyaw ua ke, yog li hloov kho cov khoom siv roj av thiab muaj zog ntxiv thiab siv zog. Feem ntau hais lus, ntawm tib qho kub, ntau dua qhov tseeb ntaug ntawm cov khoom calcined, qhov yooj yim nws yog rau graphitize.