Alabaster yog cov ntxhia thiab cov khoom siv hauv tsev niaj hnub no. Tab sis cov khoom no yog dab tsi? Dab tsi yog cov tshuaj formula rau alabaster? Nws tsim nyog hais tam sim ntawd tias ob yam khoom tuaj yeem nkag siab zoo li alabaster ib zaug: calcium carbonate thiab calcium sulfate. Wb sim ua kom tawm ob qho ntawm cov subspecies ntawm alabaster.
Calcium carbonate
Cov mis ntawm alabaster nyob rau hauv cov ntaub ntawv no yog calcium carbonate (CaCO3), uas yog cov khoom ntawm chalk thiab marble. Qhov no yog dab tsi cov neeg Iyiv thaum ub hu ua cov pob zeb no thiab nquag mined nws. Luxurious sarcophagi thiab lwm yam cult khoom tau ua los ntawm nws. Muaj txawm hais txog nws hauv phau Vajlugkub, lawv hu nws tias "oriental alabaster".
Nyias txheej ntawm cov pob zeb no yog pob tshab txaus rau glaze qhov rais. Qhov no tau siv nyob rau hauv Medieval Ltalis, thiab tseem siv niaj hnub no. Muaj tseeb tiag, thaum rhuab, nws poob nws pob tshab.
Hnub no, calcite alabaster yog mined hauv limestone qhov tsua, zoo li marble. Nws yog siv los ua vases, figurines, qab nthab teeb thiab lwm yam khoom dai.
YCalcium sulfate
Hnub no, lo lus "alabaster" los ntawm lub neej ntawd txhais tau tias gypsum, lossis cov khoom siv raw rau nws cov khoom siv. Formulaalabaster nyob rau hauv cov ntaub ntawv no yuav yog calcium sulfate dihydrate (CaSO4 × 2H2O). Cov pob zeb zoo li no yog mined yuav luag thoob plaws ntiaj teb: hauv Ltalis, Fabkis, Tebchaws Asmeskas, Lub Tebchaws Yelemees, Askiv, Russia.
Thaum alabaster yog calcined nyob rau hauv ib lub kiln, nws poob yuav luag tag nrho cov dej thiab ua gypsum. Nyob rau hauv lem, qhov no kuj yog heev pab tau cov ntaub ntawv. Ib qho ntawm nws cov khoom sib txawv yog hluav taws kub, yog li nws yog siv los tiv thaiv cov nplaim taws thiab kub kub. Nws kuj yog siv rau soundproofing.
Gypsum, crushed rau hauv cov hmoov zoo, thaum dej ntxiv rau nws, ua ob-dej dua thiab sai sai solidifies rau hauv pob zeb. Cov cuab yeej ntawm gypsum no paub ntau yam. Vim qhov no, nws yog siv rau sealing seams thiab tawg, kho kom zoo nkauj phab ntsa. Muaj tseeb, feem ntau rau kev yooj yim ntawm kev siv nws yog tov nrog cement mix. Qhov no tso cai rau koj los kho cov yam ntxwv ntawm cov khoom siv tawv.
Qhov txawv yog dab tsi?
Txawm hais tias lawv qhov sib txawv ntawm cov qauv, alabasters zoo sib xws. Tab sis lawv cov khoom sib txawv heev. Cia peb txheeb xyuas qhov sib txawv no kom ntxaws ntxiv. Cov mis ntawm carbonate alabaster tsis muaj noo noo. Qhov no ua rau nws cov qauv ntau ntom, thiab yog li ntawd, cov pob zeb hauv av nws tus kheej ua tau zoo dua piv rau gypsum alabaster. Kev kho cua sov tso cai rau gypsum alabaster kom nws lub zog, nrog rau qee yam ntawm lwm yam. Carbonate alabaster yog qhov ruaj khov nrog qhov kub thiab txias.
Tseem muaj qhov sib txawv ntawm qhov ceev. Calcium sulfate alabaster yog me ntsis ntom: 2.3 g / cm3 3 vs. 2.6 g / cm 3 ycarbonate. Nws yog tsim nyog hais txog kev tiv thaiv noo noo. Gypsum, raws li kev sib cuag nrog dej ntev, pib tawg, tab sis nws cov counterpart marble tuaj yeem tiv taus ya raws tau ntev yam tsis hloov nws cov yam ntxwv.
