Aluminium sulfate (Al2(SO4)3), feem ntau hu ua alum, yog tsim los ua cov siv lead dawb uas tsis kub hnyiab thiab yaj tau hauv dej. Cov hydrate qhuav no (Al2(SO4)3.14H2O) yog 17% Al2O3 thiab kuj muag ua 47% w/w aluminium sulfate kua uas yog 8% Al2O3. Nws kuj muag ua cov khoom khov ua kibbled, av lossis hmoov av.
Aluminium sulfate, Al2(SO4)3, yog siv dav los ntawm kev lag luam. Nws cov ntawv thov feem ntau yog nyob rau hauv kev lag luam pulp thiab ntawv thiab hauv kev ntxuav dej. Aluminium sulfate tau siv los ntawm tib neeg txij li xyoo 2000 BC, thaum cov neeg Iyiv siv cov pob zeb alum ua cov mordant hauv kev zas xim. Nws tau siv ntev hauv kev ntsuas ntawv kom txhim kho kev ruaj khov thiab kev lees txais number case thiab hauv kev kho dej kom ua kom dej ntshiab. Lwm yam kev siv rau alum suav nrog kev kho dej khib nyiab, ua tus neeg sawv cev tiv thaiv dej thiab ua kom nrawm hauv cov pob zeb ua vaj tse, ua tus neeg sawv cev rau cov rog thiab roj thiab ua tus neeg sawv cev ua npuas dej hauv cov npuas hluav taws.
Alum (raws li txhuas sulfate feem ntau hu ua) yog tsim los ntawm ob kauj ruam yooj yim los ntawm txhuas trihydrate thiab sulfuric acid raws li cov tshuaj tiv thaiv hauv qab no:
2Al(OH)3 + 3H2SO4 + 8H2O → Al2(SO4)3 .14H2O ∆fH = -156 kJ mol-1
Kauj ruam thawj zaug suav nrog kev sib tov cov khoom xyaw hauv lub reactor, thiab qhov thib ob yog cov txheej txheem ntawm kev tsoo cov khoom siv los ua ntau qib ntawm cov khoom alum khov uas muag.
Cov khoom siv raw
Aluminium trihydrate yog purified los ntawm bauxite. Cov bauxite lag luam (30-75% Al2O3) deposits tshwm sim nyob rau hauv Australia, Jamaica, Fabkis, Guyana, Guinea, Tebchaws Meskas thiab Brazil. Bauxite ore yog yaj nyob rau hauv muaj zog caustic soda los ua sodium aluminate. Lub txhuas trihydrate ces yog precipitated los ntawm neutralization (feem ntau nrog carbon dioxide) lossis los ntawm autoprecipitation (Bayer txheej txheem). Lwm yam raw khoom, sulfuric acid, yog tsim rau superphosphate ntau lawm ntawm Farmers Fertiliser Ltd. Acid tuaj txog los ntawm txoj kev tanker thiab yog pumped rau hauv cov thoob dej cia khoom.
Lub sijhawm tshaj tawm: Lub Ob Hlis-18-2022