Kupanga kwa aluminium sulfate - zopangira, aluminium trihydrate

Sulfate ya aluminiyamu (Al2(SO4)3), yomwe imadziwikanso kuti alum, imapangidwa ngati makhiristo oyera omwe sangatenthe ndipo amasungunuka m'madzi. Madzi ouma awa (Al2(SO4)3.14H2O) ndi 17% Al2O3 ndipo amagulitsidwanso ngati yankho la 47% w/w la aluminium sulfate lomwe ndi 8% Al2O3. Imagulitsidwanso ngati yolimba ngati yophwanyika, yophwanyika kapena fumbi.

Aluminium sulfate, Al2(SO4)3, imagwiritsidwa ntchito kwambiri ndi mafakitale. Ntchito zake zodziwika kwambiri ndi mafakitale opanga zamkati ndi mapepala komanso poyeretsa madzi. Aluminium sulfate yakhala ikugwiritsidwa ntchito ndi anthu kuyambira 2000 BC, pomwe Aigupto ankagwiritsa ntchito alum yamchere ngati chofufutira utoto. Kwa nthawi yayitali yakhala ikugwiritsidwa ntchito polemba kukula kwa mapepala kuti ikhale yolimba komanso kuti inki ilandire bwino komanso pokonza madzi kuti madzi asamawonongeke. Ntchito zina za alum ndi monga kukonza madzi otayidwa, ngati choletsa madzi kulowa ndi kufulumizitsa konkire, ngati chowunikira mafuta ndi mafuta komanso ngati chothandizira kutulutsa thovu mu thovu lamoto.

Alum (monga momwe aluminiyamu sulfate imatchulidwira nthawi zambiri) imapangidwa m'njira yosavuta ya magawo awiri kuchokera ku aluminiyamu trihydrate ndi sulfuric acid motsatira izi:

2Al(OH)3 + 3H2SO4 + 8H2O → Al2(SO4)3 .14H2O ∆fH = -156 kJ mol-1

Gawo loyamba limaphatikizapo kusakaniza zosakaniza mu reactor, ndipo lachiwiri ndi njira yophwanya zinthuzo kuti apange mitundu yosiyanasiyana ya alum yolimba yomwe imagulitsidwa.

Zida zogwiritsira ntchito

Aluminium trihydrate imayeretsedwa kuchokera ku bauxite. Ma depositi a bauxite ogulitsa (30-75% Al2O3) amapezeka ku Australia, Jamaica, France, Guyana, Guinea, USA ndi Brazil. Madontho a bauxite amasungunuka mu soda yamphamvu kuti apange sodium aluminate. Kenako ma trihydrate a aluminiyamu amasungunuka ndi kuchepetsedwa mphamvu (nthawi zambiri ndi carbon dioxide) kapena ndi autoprecipitation (njira ya Bayer). Zinthu zina zopangira, sulfuric acid, zimapangidwa kuti zipange superphosphate ku Farmers Fertiliser Ltd. Acid imafika ndi sitima yonyamula katundu ndipo imapopedwa m'matanki osungiramo zinthu.