Cov txheej txheem tsim cov iav fwj muaj ob peb kauj ruam. Ua ntej, cov khoom siv raw, uas suav nrog xuab zeb, dej qab zib tshauv, limestone, thiab lwm yam khoom siv ntxiv, tau muab tso rau hauv lub cub tawg thiab ua kom sov rau qhov chaw melting. Lub iav molten yog tom qab ntawd hloov mus rau lub tshuab tsim, uas ua rau nws mus rau hauv lub raj mis uas xav tau siv pwm.
Thaum lub raj mis tau tsim, lawv raug tshuaj xyuas seb puas muaj qhov tsis zoo lossis tsis zoo. Cov teeb meem no raug kho los ntawm kev siv cov tshuab xws li lub tshuab reheat tshuab, uas hloov lub raj mis, lossis lub trimmer, uas tshem tawm cov iav ntau dhau.
Tom qab ntawd cov fwj raug ntxuav thiab qhuav kom huv si thiab tsis muaj kab mob. Qhov no yog ib kauj ruam tseem ceeb raws li tej impurities tuaj yeem cuam tshuam qhov zoo ntawm cov khoom kawg.
Thaum kawg, lub raj mis tau ntim thiab xa mus rau ntau tus neeg siv khoom. Cov txheej txheem tsim khoom rau cov iav fwj yog qhov nyuaj thiab xav tau cov neeg ua haujlwm txawj thiab cov tshuab tshwj xeeb kom ntseeg tau tias cov khoom kawg yog cov khoom zoo.
