Alumina

Aluminum oxide rikaitika chaiwo ezvinhu muchimiro kwakajairika alumina, ayo makemikari payakavakirwa - AL2O3. In kwezvinhu crystals mhando iyi vasina mavara kuti vari tembiricha kuti 2044 ° C dzinotanga zvinonyauka uye kana pachiyero 3530 ° C mota.

Dzinongoitika zvinokukanganisa kugadzikana chete nadzurudzo fuma iri aruminiyamu oxide tine arambe achirema pamusoro 3,99 g / cm3. Iyi yakasimba chaizvo mharidzo kuva rechipfumbamwe padanho Mohs tafura. The kukosha refractive indekisi iri sezvinotevera nekuti vanhuwo Ray - 1,765 uye 1.759 kuti zvinoshamisa. Dzinongoitika zvinokukanganisa alumina kazhinji ine siyana simbi oxides Zvisinei, zvicherwa corundum anogona rinoreva zvakasiyana kwayo ruvara. Somuenzaniso, muri nesafiro avo, anovaima uye mamwe matombo anokosha. Zvazvakadaro, ari alumina anogona kugadzirira uye rabhoritari-makemikari nzira. Nokuti chinangwa ichi, A12O3 metastable chimiro dzavo yaora thermally. Uyewo, sezvo anokonzera murabhoritari nzira inoshandiswa aruminiyamu oxide , aruminiyamu hydroxide.

Standard nadzurudzo remubatanidzwa ndiyo tetragonicheskuyu yekamuri ine ayo sezvamunoita vanenge 1-2% mvura. Kunogona kuwanikwa amorphous mu mamiriro alumina - alumina gel, izvo gelevidny mhinduro pamusoro AL (OH) 3 dewatered kuwana porous zvinhu segirazi guru.

Aluminum oxide iri insoluble zvachose mumvura asi zvinogona zvakanaka zvazvichanyungudutswa cryolite, huru kune mukuru tembiricha. Amphoteric fuma. Characteristically imwe pfuma yacho synthesized alumina sezvo Ivan Kuchin kutsamira waro inotungamirwa tembiricha uye nemakemikari basa rakadaro. Sezvo chakagadzirwa (i.e., vakawana mumwe tembiricha anopfuura 1200 ° C) uye dzinongoitika corundum mu zvake ezvinhu zviratidzwa rakada zana muzana kwakakwana zvemakemikari inertness uye kushaya hygroscopicity.

Oxide aruminiyamu kwemakemikari ehupfumi anotanga nokushingaira kushandisa dzimwe kutonhora kumativi 1000 ° C, kana rwunotanga nokukurumidza kushamwaridzana zvinhu zvakadai siyana alkali carbonates ose alkali simbi. Kana ichi kukurukurirana aluminates vari aumba. The nomumugwagwa kwaitora nguva remubatanidzwa ikasakendenga pamwe SiO2, uyewo nekuve acidic slags. Somugumisiro mukukurukurirana aya vakawana aluminosilicates.

Alumina gel uye alumina ayo vakazvigadzirirwa calcination kuti aruminiyamu hydroxides chero zvinenge 550 ° C, vane yakakwirira zvikuru hygroscopicity, chakanakisisa kupinda nemakemikari uye kushingaira kushamwaridzana acidic uye alkaline mhinduro.

Kazhinji, somunhu mbishi zvinhu hwokubereka aruminiyamu oxide anoshandiswa bauxite, alunite uye nepheline. Kana zviri muvanhu mubvunzo mavari anopfuura 6-7% Kugadzirwa Nde nzira - ne Bayer, uye pane yakaderera zviri pafuma kushandiswa esimbi sintering nzira nesuko kana pasoda. Bayer muitiro iri kubudiswa yakapwanyika dombo iri bhora zvigayo, akatevera bauxite ikarapwa pamwe alkaline mhinduro ari kudziya 225-250 ° C. The sezvamunoita Saka atorwe yakanga rakasanganiswa aqueous yavaibvisa aluminate mhinduro uye yakasvinwa zvakanaka. Mukuita rokuchenesa munhu slurry ine alumina, vane ehupfumi dzinoenderana mureza, iri yaora mu centrifuges. Michina kwakadaro kunoita kuti vawane 50% zvibereko fuma. Uyezve, kushandisa nzira iyi kunoita kuti tikwanise kuchengeta mai nezvinobata dzokushandisa nekutambira kushanda kubudikidza leaching pamusoro bauxite.

Kazhinji, kwaizoita chakaita zvokugadzirwa nzira aruminiyamu oxide rinoshandiswa sezvo zvenguva zvinhu achigadzirira yakaisvonaka aruminiyamu. In indasitiri, rinoshandiswa sechiratidzo mbishi zvinhu hwokubereka refractory zvinhu, zvedongo hasha uye vakatema zvokushandisa. Yazvino nokushingaira kushandisa crystals kuroorwa aruminiyamu oxide pakuburitswa maawa, pcb, zvishongo.