I-aluminium oxide

I-aluminium oxide itholakala emvelweni wemvelo njengesimo se-alumina esivame kakhulu, i-al2O3 yayo yamakhemikhali. Ekubukeni, lawa makristalu angenawo umbala, oqala ukudilika ekushiseni kwe-2044 ° C, futhi lapho efika uphawu lwe-3530 ° C, apheka.

Endalweni yemvelo, ukuguqulwa okuzinzile kuphela kwezinto eziyimvelo ku-corundum, kunesisindo esingu 3.99 g / cm3. Lena isampuli eqinile kakhulu, eyingxenye yesishiyagalolunye etafuleni le-Mohs. Ubukhulu benkomba yokucubungula yilezi: i-ray evamile - i-1,765, ne-1,759 engavamile. Esimweni semvelo, i-aluminium oxide ngokuvamile iqukethe izinhlobo ezihlukahlukene zensimbi zensimbi, ngakho-ke, amaminerali e-corundum angathola ama-shade ahlukene wombala wawo. Isibonelo, okufana namasafire, ama-rubi kanye namanye amatshe ayigugu. Kule fomu, i-aluminium oxide ingatholakala nangendlela ye-laboratory-chemical. Kule ndlela, izinhlobo ze-A12O3 ezisetshenziselwa ukuhlaziywa zisetshenzisiwe futhi zidilizwa ngendlela yokushisa. I-aluminium hydroxide nayo isetshenziswa njengomthombo we-aluminium oxide yokukhiqizwa yi-laboratory indlela .

Ukuguqulwa okujwayelekile kwe-compound iyi-tetragonal crystal lattice equkethe cishe ama-1-2% amanzi ekubunjweni kwayo. Kungenzeka futhi ukuthola i-alumina yama-amorphous esakhiweni sayo, lapho isisombululo se-gel AL (OH) 3 siphelelwa amanzi futhi sitholakala ngesimo senqwaba ebonakalayo ebonakalayo.

I-aluminium oxide ayinakutholakali ngokuphelele emanzini, kodwa ingaqhekeka kahle nge-cryolite, igcwele ukushisa okuphezulu. Isidakamizwa si-amphoteric. Imfanelo yindawo ye-synthesized aluminium oxide, njengobudlelwane obuphambene phakathi kokushisa kokwakhiwa kwayo kanye nemisebenzi yamakhemikhali. Njengomsebenzi wokufakelwa (okungukuthi, etholakala ekushiseni okungaphezu kwe-1200 ° C), kanye ne-corundum yemvelo ngendlela ejwayelekile, babonisa cishe ukungamaphesenti angamakhulu ayisishiyagalolunye amakhemikhali kanye nokungabikho okuphelele kwe-hygroscopicity.

I-aluminium oxide yamakhemikhali izindawo ziqala ukubonakala ngokubonakalayo emazingeni okushisa azungeze i-1000 ° C, lapho iqala ukusebenzisana ngokuqinile ngezinto ezifana ne-alkalis ehlukahlukene, i- alkali metal carbonates . Kulokusebenzisana, ama-aluminates akhiwa. Ngokuhamba kancane, i-compound iphendula nge-SiO2, kanye nezinhlobo ezahlukene ze-slags eziqinile. Ngenxa yalokhu kusebenzisana, kutholakala ama-aluminosilicates.

I-Aluminogels ne-aluminium oxide, etholakala ngokugcoba noma yikuphi kwe-aluminium hydroxide ekushiseni okungenani ama-550 ° C, ine-hygroscopicity ephakeme kakhulu, ihamba phambili ekusebenziseni amakhemikhali futhi ihlangene ngokuqinile nezixazululo zamakhemikhali nama-alkali.

Njengomthetho, ama-bauxite, ama-alunites, kanye nemigqa yezintambo zisebenza njengezinto ezibonakalayo zokukhiqizwa kwe-aluminium oxide. Uma okuqukethwe kwezinto ezibuzwayo kungaphezu kuka-6-7%, ukukhiqizwa kwenziwa ngendlela eyinhloko - indlela ye-Bayer, futhi ngokuqukethwe okungezansi kwezinto ezibonakalayo, indlela yokwenza i-ore ne-lime noma i-soda isetshenziswa. Indlela ye-Bayer ukucubungula idwala elichotshoziwe emagayini amabhola, bese i-bauxite iphathwa ngezixazululo ze-alkaline ekushiseni kuka-225-250 ° C. Ukwakhiwa kwe-sodium aluminate okwenziwe ngakho kuhlanjululwe ngesisombululo se-aqueous futhi sihlungiwe. Phakathi nenqubo yokuhlunga, i-sludge equkethe i-alumina, enezindawo ezihambisana nezindinganiso ezijwayelekile, zenziwa ukubola phakathi kwama-centrifuges. Lolu buchwepheshe lwenza kube lula ukuthola isivuno se-50% salo. Ngaphezu kwalokho, ukusebenzisa le ndlela kuvumela ukuthi utshwala bomama ligcinwe ukuze lusetshenziswe emisebenzini elandelayo ye-bauxite leaching.

Njengomthetho, i-oxide etholakala yi-synthetic aluminium indlela isetshenziswe njengezinto eziphakathi kokukhiqizwa kwe-aluminium ehlanzekile. Embonini, isetshenziselwa njengento eluhlaza yokukhiqiza izinto zokwenza izinto ezikhanyelayo, amathuluzi okusika amakhemikhali. Ubuchwepheshe banamuhla benza ngokugcwele ukusebenzisa amakristalu amancane e-aluminium oxide ekukhiqizeni amawashi, amabhodi wesifunda abhalwe, amabhlocwe.