Hlau silicon feem ntau yog cais raws li cov ntsiab lus ntawm nws peb lub ntsiab impurities: hlau, txhuas, thiab calcium. Raws li cov ntsiab lus ntawm peb lub ntsiab lus, nws yog xim hlau silicon tuaj yeem muab faib ua ntau qib xws li 553, 441, 411, 421, 3303, 3305, 2202, 2502, 1501, thiab 1101.
Industrially, nws yog xim hlau silicon feem ntau yog tsim los ntawm kev txo cov silicon dioxide nrog cov pa roj carbon nyob rau hauv lub cub hluav taws xob. Cov tshuaj tiv thaiv kab mob sib npaug yog: SiO2 + 2C → Si + 2CO. Cov silicon tau txais nyob rau hauv txoj kev no muaj purity ntawm 97-98% thiab hu ua metallic silicon. Tom qab melting thiab recrystallizing, impurities raug tshem tawm nrog cov kua qaub kom tau nws cov hlau silicon nrog purity ntawm 99.7-99.8%.
Hlau silicon feem ntau yog tsim los ntawm silicon, thiab yog li ntawd muaj cov khoom zoo sib xws rau silicon. Silicon muaj nyob rau hauv ob allotropes: amorphous silicon thiab crystalline silicon. Amorphous silicon yog greyish - cov hmoov dub, uas yog ib hom microcrystal. Crystalline silicon muaj cov qauv siv lead ua thiab cov khoom siv semiconductor ntawm pob zeb diamond, nrog lub melting point ntawm 1410 degree, boiling point ntawm 2355 degree, Mohs hardness ntawm 7, thiab yog nkig. Amorphous silicon yog tshuaj reactive thiab kub hnyiab hauv oxygen. Nws reacts nrog nonmetals xws li halogens, nitrogen, thiab carbon ntawm kub kub, thiab kuj nrog hlau xws li magnesium, calcium, thiab hlau los tsim silicides. Amorphous silicon yuav luag insoluble nyob rau hauv tag nrho cov inorganic thiab organic acids, nrog rau hydrofluoric acid, tab sis nws yog soluble nyob rau hauv ib tug sib tov ntawm nitric acid thiab hydrofluoric acid. Concentrated sodium hydroxide kua tuaj yeem yaj amorphous silicon, tso cov pa roj hydrogen. Crystalline silicon yog inert; txawm nyob rau qhov kub thiab txias, nws tsis ua ke nrog oxygen. Nws kuj yog insoluble nyob rau hauv tej inorganic los yog organic acid, tab sis nws yog soluble nyob rau hauv ib tug sib tov ntawm nitric acid thiab hydrofluoric acid, raws li zoo raws li nyob rau hauv concentrated sodium hydroxide tov.
