Alumina

Aluminium oxide kwenzeka kwindalo ngohlobo alumina eqhelekileyo, ifomula layo kwemichiza - AL2O3. Xa olu hlobo ziikristale ngebengabanga imibala ukuba kubushushu ka-2044 ° C aqale ukunyibilika, yaye xa inqanaba ka 3530 ° C kwethumba.

Kwindawo zendalo kuphela loguqulelo iziyobisi ezinzileyo aluminiyam oxide ukuba ukuxinana 3,99 g / cm3. Le isampuli okuqinileyo kakhulu besive kwinqanaba lesithoba yetafile Mohs. Ixabiso isalathiso zokunganyangeki limi ngolu hlobo: ngokuba ray eziqhelekileyo - 1.765 no 1.759 ngokumiselwa, abagqithiseleyo kubo. Kwindawo yendalo alumina badla iqulethe oxides ezahlukeneyo zesinyithi, nakuba kunjalo, le corundum izimbiwa sinokuzuza lineentsingiselo ezahlukeneyo umbala wayo. Ngokomzekelo, abo ngesafire, neerubhi, ngeempahla zakho kunye nezinye namatye anqabileyo. Ngenxa yoko, le alumina nibe senilungile nendlela elebhu-chemical. Ukulungiselela le njongo, fomu A12O3 metastable kwaye ibolile zabo thermally. Kwakhona, njengomthombo indlela laboratory esetyenzisiweyo aluminiyam oxide , aluminium hayidroksayidi.

Standard ukuguqulwa ephindeneyo tetragonicheskuyu emkhusaneni equlethe kumafa yayo malunga 1-2% yamanzi. Ngaba ingafumaneka amorphous kubume alumina - gel alumina, isicombululo gelevidny of AL (OH) 3 dewatered ukufumana izinto aneentunja mass ngaphaya.

Aluminium oxide ezingenakunyibilika ngokupheleleyo emanzini kodwa songanyibilikisswa kakuhle cryolite, ndinobushushu kwiqondo eliphezulu. into Amphoteric. Akumangalisi ukuba propati le alumina kuhlelwe njengoko ukuxhomekeka uguqulo kwithempritsha yayo ukubunjwa kunye nomsebenzi imichiza. Njengoko lokwenziwa (ngamanye amazwi, efunyenwe kwiqondo lobushushu kwama 1200 ° C) kunye corundum zendalo kwindawo umboniso oqhelekileyo phantse ikhulu ekhulwini epheleleyo iikhemikhali inertness kunye nokunqongophala hygroscopicity.

Oksayidi Iipropati aluminium imichiza uqalisa ukusebenzisa elibonakalayo kwiqondo lobushushu 1000 ° C, xa uqala ukuba basebenzisane ngokukhawuleza kunye izinto ezifana carbonates ezahlukeneyo kwealkali zesinyithi kwealkali. Xa oku ukusebenzisana aluminates kwakheka. Umchiza benomkhuhlane idityaniswe SiO2, kwakunye iintlobo ezahlukeneyo slags emuncu. Ngenxa yezi iintsebenziswano ifunyenwe aluminosilicates.

gel Alumina kunye alumina leyo lungiselela calcination of hydroxides aluminiyam ngalo naliphi na ubuncinane 550 ° C, abe hygroscopicity eliphezulu kakhulu, elihle ukungena ekudibaneni kwemichiza kwaye bazibandakanye ngokubonakalayo kunye nezisombululo emuncu kunye obrak.

Ngokuqhelekileyo, njenge ekrwada izinto ku tswala aluminiyam oxide ziyasetyenziswa webauxite, alunite kunye nepheline. Xa umxholo nomongo ekuthethwa ngazo ngaphezulu kwe 6-7 imveliso% yeyona ndlela iphambili - ngu Bayer, yaye ezinomthamo ophantsi ukusetyenziswa kweziyobisi indlela ekrwada sintering ngekalika okanye soda. inkqubo Bayer i processing oxhwalekileyo ingxondorha ematyeni ibhola, bamlandela webauxite iphathwa kunye nezisombululo obrak kubushushu ka 225-250 ° C. Ukubunjwa oko ndiwazuze exutywe kunye nesisombululo sodium aluminate zolwelo kunye yahluzwa. Xa inkqubo lokucoca a oluludaka equlathe alumina, ogama iipropati bahambelana umgangatho, leyo ibolile ngo centrifuges. buchwepheshe ikuvumela ukuba bepasa nge-50% isivuno kweziyobisi. Ngaphezu koko, ukusetyenziswa kwale ndlela yenza kube lula ukugcina utywala kunina ukuze zisetyenziswe imisebenzi ekugqibeleni ukuhluzeka kuloko of webauxite.

Ngokubanzi, kubangela indlela zokwenziwa aluminiyam oxide lisetyenziswa esiphakathi lokulungisa aluminiyam ecocekileyo eziphathekayo. Kushishino, lisetyenziswa njenge ekrwada ukwenzela ukuvelisa izinto elinjubaqa, yodongwe esirhabaxa ilifinyeze izixhobo eziphathekayo. zobugcisa zale mihla asebenza ngenkuthalo ziikristale enye aluminiyam oxide kwiiyure zemveliso, PCB, izacholo.