Magnesium oxide feem ntau hu ua hlawv magnesia lossis tsuas yog magnesium oxide. Cov tshuaj no yog lub teeb thiab zoo crystalline hmoov dawb. Magnesium oxide tshwm sim raws li cov ntxhia periclase. Hauv kev lag luam khoom noj khoom haus, cov tshuaj no yog lub npe hu ua cov khoom noj ntxiv raws li txoj cai E530.
Khoom ntawm magnesium oxide
Cov tshuaj formula ntawm cov tshuaj no yog MgO. Cov tshuaj no yog xyaum tsis muaj ntxhiab, nws dissolves zoo nyob rau hauv ammonia thiab acid, nyob rau hauv dej nws solubility ntawm 30 ° C tsuas yog 0.0086 grams / 100 ml, thiab nyob rau hauv cawv nws tsis yaj kiag li. Cov molar loj ntawm MgO yog 40.3044 g / mol. Ntawm 20 ° C, nws qhov ceev yog 3.58 g / cm³, boiling point - 3600 ° C, melting point - 2852 ° C. Fine-crystalline magnesium oxide yog tshuaj lom neeg heev. Nws muaj peev xwm nqus tau cov pa roj carbon dioxide los tsim cov carbonate sib xws:
- MgO + CO2=MgCO3;
txawm tias maj mam, tab sis tseem ua rau cov dej, ua rau lub hauv paus tsis muaj zog:
- H2O + MgO=Mg(OH)2;
reacts nrog acids:
- 2HCL + MgO=MgCl2 + H2O
Calcined magnesium oxide poob nws cov tshuaj lom neeg. Nws tseem yuav tsum tau ntxiv tias cov hmoov no yog hygroscopic.
Tau txais magnesium oxide
Hauv kev lag luam, qhov sib xyaw no feem ntau tau los ntawm roasting. Minerals xws li dolomite (MgCO3. CaCO3) los yog magnesite (MgCO3) yog siv los ua raw khoom. Tsis tas li ntawd, burnt magnesia yog tsim los ntawm calcining bischofite (MgCl 2 x 6H 2 O) hauv dej vapor, calcining Mg (OH) 2 thiab lwm yam. kub-labile Mg compounds. Raws li kev kuaj mob, MgO tuaj yeem tau txais los ntawm kev sib cuam tshuam ntawm nws cov khoom siv:
- 2Mg + O2=2MgO;
lossis los ntawm thermal decomposition ntawm qee cov ntsev lossis hydroxide:
- MgCO3=MgO + CO2.
Nyob ntawm txoj kev tau txais magnesium oxide, nws yog ib txwm ua kom paub qhov txawv ntawm ob hom kev sib xyaw no: lub teeb thiab hnyav magnesia. Thawj yog cov hmoov tsis muaj xim, uas yooj yim nkag mus rau hauv ntau yam kev cuam tshuam nrog dilute acids, uas ua rau tsim Mg ntsev. Qhov thib ob muaj cov muaju loj ntawm ntuj lossis dag periclase thiab yog dej resistant thiab ntau inert.
Daim ntawv thov ntawm magnesium oxide
Hauv kev lag luam, qhov sib xyaw no yog siv rau kev tsim cov cements, refractories, ua cov muab tub lim hauvnyob rau hauv zus tau tej cov roj hmab thiab rau refining roj av khoom. Ultralight magnesium oxide yog siv los ua abrasive zoo heev, uas yog siv los ntxuav qhov chaw. Tshwj xeeb, nws yog siv hauv kev lag luam hluav taws xob. Tsis tas li ntawd, burnt magnesia yog dav siv hauv tshuaj. Ntawm no MgO yog siv nyob rau hauv kev ua txhaum ntawm theem ntawm acidity ntawm gastric kua txiv uas tshwm sim vim ntau tshaj hydrochloric acid. Magnesium oxide kuj raug coj los ua kom tsis txhob muaj cov tshuaj nquag uas nkag mus rau hauv plab. Hauv kev lag luam khoom noj khoom haus, MgO yog siv los ua zaub mov ntxiv (code E530), uas tiv thaiv clumping thiab caking. Burnt magnesia kuj tseem siv hauv gymnastics. Ntawm no, cov neeg ncaws pob siv cov hmoov no rau lawv txhais tes txhawm rau txhawm rau tiv nrog cov cuab yeej gymnastic ntau txhim khu kev qha. Peb kuj ntxiv tias magnesium oxide yog ib qho kev pom tseeb. Lub reflection coefficient ntawm cov khoom no nyob rau hauv lub ncua spectral band yog sib npaug zos thiab yog li ntawd nws yuav siv tau raws li ib tug qauv rau cov xim dawb.
