Qhov sib txawv tseem ceeb ntawm gypsum thiab plaster ntawm Paris yog tias Gypsum muaj calcium sulfate dihydrate whereas plaster ntawm Paris muaj calcium sulfate hemihydrates.
Gypsum yog ib qho ntxhia tshwm sim. Plaster ntawm Paris thiab gypsum ob leeg muaj calcium sulfate's hydrate daim ntawv, tab sis lawv cov dej ntsiab lus nyob rau hauv ib tug molecule txawv ntawm ib leeg. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm gypsum thiab plaster ntawm Paris.
Gypsum yog dab tsi?
Gypsum yog hydrated calcium sulfate ntxhia nrog cov mis molecular CaSO 4·2H2O. Qhov no yog cov ntxhia sulfate tshaj plaws. Nws yog pob zeb-forming ntxhia, uas tuaj yeem loj hlob mus txog qhov loj heev. Feem ntau, cov xim ntawm cov siv lead ua yog dawb lossis tsis muaj xim, tab sis tuaj yeem muaj lwm cov xim xws li grey, liab lossis daj. Crystals kuj tuaj yeem tshwm sim ua pob tshab lossis pob tshab. Gypsum yog siv lead ua mos, uas peb tuaj yeem khawb nws los ntawm tus ntiv tes. Tsis tas li ntawd, nws yog cov khoom siv tau yooj yim, thiab nws cov thermal conductivity tsawg. Gypsum yog me ntsis soluble hauv dej, thiab thaum peb sov nws, dej yuav evaporate thiab tuaj yeem ua tiav lub xeev anhydride dua. Gypsum muaj nyob hauv ntau qhov chaw thoob plaws ntiaj teb (hauv UK, Russia, Canada, Africa, Asia, Tebchaws Asmeskas thiab Europe). Txawm li cas los xij, Gypsum muaj ntau nyob hauv Colorado thiab Mexico hauv Asmeskas.
Daim duab 01: Tshav pob gypsum
Tsim thiab Hom
Txoj kev loj ntawm kev tsim cov khoom siv no yog los ntawm nag lossis daus ntawm dej hiav txwv. Thaum tsim cov minerals, dej los yog cov khoom tsis xav tau tuaj yeem ntxiab hauv cov khoom siv lead ua uas yog ua rau cov xim sib txawv. Tsis tas li ntawd, muaj peb hom gypsum. Lawv yog cov hauv qab no:
- Selenite
- Alabaster
Selenite yog crystalline nyob rau hauv cov xwm thiab zoo li pob tshab los yog translucent. Alabaster hlob mus rau hauv cov pob zeb hauv av loj heev. Nws muaj lub teeb xim lossis xim me ntsis tinted (vim impurities). Ntawm qhov tod tes, satin spar yog fibrous lossis silky hauv qhov xwm txheej. Peb tuaj yeem siv cov khoom no los ua plaster ntawm Paris, qee cov cement, chiv (ammonium sulfate fertilizer) thiab ua pob zeb ornamental. Tsis tas li ntawd, gypsum muaj txiaj ntsig zoo li cov quav, thiab nws yog qhov zoo ntawm leej faj. Ntxiv mus, nws muaj peev xwm los ua yas zoo li thaum peb sov nws mus txog 175 o C. Qhov xwm ntawm Gypsum yog qhov tseem ceeb hauv kev tsim cov plaster ntawm Paris. Yog hais tias cov ntsiab lus ntawm CaSO4·2H2O hauv gypsum siab, nws yog qhov zoo heev hauv kev tsim cov chiv, plaster ntawm Paris thiab cement. Yog li ntawd, muaj kev thov siab rau cov ntshiab gypsum, uas muaj tsawg kawg yog 80% CaSO4·2H2O cov ntsiab lus.
Plaster of Paris yog dab tsi?
Peb tuaj yeem tsim plaster ntawm Paris los ntawm gypsum. Tib neeg siv cov khoom no los ntawm lub sijhawm qub. Plaster ntawm Paris tau txais nws lub npe vim hais tias yav dhau los cov neeg nyob hauv cov cheeb tsam ze Paris siv cov khoom no dav, ua plaster thiab cement. Lawv kuj tau siv nws los ua haujlwm ornamental ntawm qab nthab thiab cornices. Plaster ntawm Paris muaj cov calcium sulfate hemihydrates (CaSO4·0.5H2O).
Daim duab 02: Kev Siv Plaster ntawm Paris rau Kev Kho Kom Zoo Nkauj
Peb tuaj yeem npaj cov tshuaj no los ntawm cua sov cov gypsum uas muaj calcium sulfate dihydrate (CaSO4·2H2O) kom kub ntawm kwv yees li 150 o C (120-180 o C). peb yuav tsum tau ntxiv tej yam additives thaum cua sov. Plaster ntawm Paris yog ib qho zoo, dawb hmoov. Thaum nws dhau los ua dej, peb tuaj yeem siv nws los pwm cov khoom, thiab yog tias peb cia nws qhuav, nws hardens thiab khaws txhua yam zoo li nws tau teem ua ntej ziab.
Qhov txawv ntawm Gypsum thiab Plaster ntawm Paris yog dab tsi?
Gypsum yog ib txwm tshwm sim mos sulfate ntxhia thaum plaster ntawm Paris yog cov khoom siv hauv tsev uas peb siv los tiv thaiv lossis kho kom zoo nkauj txheej. Ob qho khoom siv no muaj calcium sulfate ua cov khoom tseem ceeb. Txawm hais tias ob qho tib si gypsum thiab plaster ntawm Paris muaj calcium sulfate ua cov khoom tseem ceeb, lawv muaj qhov sib txawv hydrated calcium sulfate. Yog li ntawd, ob qho khoom siv sib txawv ntawm ib leeg. Yog li, qhov sib txawv tseem ceeb ntawm gypsum thiab plaster ntawm Paris yog tias Gypsum muaj calcium sulfate dihydrate thaum plaster ntawm Paris muaj calcium sulfate hemihydrates. Ntxiv mus, lwm qhov sib txawv ntawm gypsum thiab plaster ntawm Paris yog tias peb tuaj yeem pwm plaster ntawm Paris rau hauv cov duab sib txawv thaum peb moisten nws thaum peb tsis tuaj yeem ua qhov no rau gypsum.
Summary – Gypsum vs Plaster of Paris
Kev tsim cov plaster ntawm Paris feem ntau yog los ntawm gypsum. Txawm li cas los xij, muaj qee qhov sib txawv ntawm gypsum thiab plaster ntawm Paris. Ntawm lawv, qhov sib txawv tseem ceeb ntawm gypsum thiab plaster ntawm Paris yog tias gypsum muaj calcium sulfate dihydrate thaum lub plaster ntawm Paris muaj calcium sulfate hemihydrates.
