Daim ntawv thov:Tshem tawm cov impurities thiab purify cov khoom tsis yog xim hlau, xws li silica xuab zeb, feldspar, kaolin thiab lwm yam. Nws kuj tseem siv tau rau lwm yam lag luam, xws li cuam tshuam cov dej khib nyiab hauv cov nroj tsuag steel, cov nroj tsuag tsim hluav taws xob, thiab ntxuav cov pa phem. chemical raw khoom.