Kev npaj thiab kev siv ntawm high purity alumina

Crystallization pyrolysis txoj kev

Aluminium ammonium sulfate crystallization pyrolysis txoj kev

Ammonium aluminium sulfate txoj kev yog dav siv, thiab nws cov khoom muaj kev ua haujlwm zoo thiab cov khoom me me. Lub refined txhuas sulfate yog crystallized nyob rau hauv ammonium sulfate system, thiab ammonium txhuas sulfate yog purified thaum lub sij hawm ntau recrystallization. Thaum kawg, purified ammonium aluminium sulfate yog pyrolyzed los tsim alumina hmoov. Wang Shouping et al. [1] npaj high-purity alumina los ntawm segmented pyrolysis ntawm ammonium aluminium sulfate, thiab cov khoom tau txais yog high-purity kheej kheej alumina nrog zoo dispersion thiab particle loj ntawm 200-300nm, uas yog conducive rau tom ntej ntau lawm thiab siv. Cov txheej txheem yog yooj yim, tsis tshua muaj nqi, zoo hmoov thiab yooj yim rau loj-scale industrial ntau lawm, tab sis cov txheej txheem yog prone rau thermal dissolution, rau kev tshem tawm ntawm poov tshuaj, calcium, halogen thiab lwm yam impurities nyuaj.

Tsis tas li ntawd, ammonia thiab sulfur oxides tsim nyob rau hauv cov txheej txheem ntawm thermal decomposition ua rau ib puag ncig muaj kuab paug, uas yog lub ntsiab tseem ceeb txwv nws txoj kev loj hlob. Hauv qhov no, Yin Yongquan et al. [2] absorbed, neutralized thiab concentrated cov pa khib nyiab tsim los ntawm pyrolysis ntawm ammonium sulfate los tsim ammonium sulfate, uas tuaj yeem paub txog kev lag luam thiab kev tiv thaiv ib puag ncig ntawm alumina ntau lawm.

Crystallization pyrolysis ntawm ammonium aluminium carbonate

Kev tshawb fawb txog kev ua tiav thiab kev txhim kho ntawm txhuas ammonium sulfate txoj kev tau ua kom pom tseeb ntawm tib neeg tau ntau xyoo. Txoj kev txhim kho crystallization pyrolysis ntawm ammonium aluminium carbonate raws li ammonium aluminium sulfate txoj kev tau tswj cov pa phem rau qee yam thiab tau siv dav hauv kev lag luam tam sim no. Cov purified ammonium aluminium sulfate reacts nrog ammonium bicarbonate los hloov nws mus rau hauv ammonium aluminium carbonate, tsis txhob sulfur oxide gas tsim thaum lub sij hawm tom ntej pyrolysis. Piv nrog rau ammonium aluminium sulfate txoj kev, cov khoom hmoov loj faib ntawm ammonium aluminium carbonate txoj kev tsis zoo li qub, agglomeration tshwm sim tshwm sim, thiab cov nqi ntau dua. Lin Yuanhua et al. [3] pom tias reactant concentration, kua pH, additives thiab lwm yam yuav cuam tshuam cov khoom purity thiab hmoov zoo. Txhua yam tsis muaj thiab cov tshuaj tiv thaiv yuav tsum tau tswj nruj me ntsis hauv cov txheej txheem tsim khoom.

hydrolysis

Aluminium cawv hydrolysis txoj kev

Aluminium cawv hydrolysis txoj kev hauv cov catalyst system, organic cawv thiab hlau txhuas cov tshuaj tiv thaiv los tsim cov kua dej cawv txhuas, thiab tom qab ntawd hydrolysis, siab purity aluminium hydroxide tau tom qab sintering kom tau siab purity aluminium oxide. Nyob rau hauv qhov kev pom ntawm txoj kev no, cov yuam sij kev ua kom zoo ntawm alumina yog raws li hauv qab no: 1. Ob, ntxiv distillation ntawm aluminium cawv purification, tshem tawm siab melting point impurities; Peb, aluminium cawv kom qhuav, sintering tej yam kev mob thiab hmoov npaj khoom los tswj cov particle loj ntawm cov hmoov. Fu Gaofeng [4] thiab al npaj ultrafine high-purity alumina los ntawm kev siv cov ntawv txhuas nrog cov ntsiab lus txhuas ntau dua 99.9 feem pua ​​thiab cov tshuaj ntsuam xyuas cov ntshiab propanol. Lawv xav tau qhov kub thiab txias dej da dej kub, ntxiv isopropanol thiab mercury chloride ua catalysts, thiab thaum kawg npaj cov khoom los ntawm distillation, hydrolysis, laus, ziab thiab calcination ntawm generated aluminium isopropanol. Cov txheej txheem yog ib puag ncig tus phooj ywg thiab muaj siab purity rau cov tau txais alumina. Txawm li cas los xij, lub siab purity ntawm cov organic cawv precursors ua rau cov nqi tsim khoom siab, cov txheej txheem nyuaj thiab kev tswj xyuas tsis yooj yim.

Direct activation hydrolysis txoj kev

Mercury chloride activation hydrolysis txoj kev, siv mercury chloride txhuas ntawv los yog txhuas chips qhib, thiab ces muab tso rau hauv 1 feem pua ​​concentration ntawm txhuas sulfate hydrolyzed, lub alumina hydroxide sol tau tom qab kub ziab gel, ntxiv kub ua los npaj alumina hmoov. . Lub ntsiab lus tseem ceeb ntawm cov txheej txheem no yog kev ua kom hydrolysis ntawm txhuas. Nws yog ib qho tsim nyog los xyuas kom meej tias cov khoom siv raw yog aluminium flakes ntawm purity siab. Yog tias hydrolysis tsis txaus, yuav muaj cov khoom siv txhuas sab laug hauv cov khoom. Lub voj voog ntau lawm ntawm high purity aluminium activation hydrolysis txoj kev yog luv luv, thiab cov hmoov alumina tau tuaj yeem txhim kho kev xa tawm thiab kev tiv thaiv corrosion ntawm pob tshab ceramics. Txawm li cas los xij, purity ntawm raw aluminium hlau yog siab, thiab kev tswj cov txheej txheem nruj yuav tsum tau ua kom ntseeg tau tias cov khoom purity. Qhov hnyav hydrolysis tej yam kev mob thiab ib puag ncig teeb meem txwv tsis pub siv cov qauv no hauv kev sim.

2.3 Txhim kho txoj kev bayer

Txoj kev txhim kho Bayer tuaj yeem ua rau alumina hydroxide los ntawm sodium metaluminate tov tom qab ob peb desilication thiab hlau tshem tawm, thiab ces calcinate ntawm qhov kub thiab txias kom tau siab purity alumina nrog lub siab xav siv lead ua. Cov tshuaj purification, impurity tshem tawm thiab crystallization txheej txheem yuav cuam tshuam rau purity thiab hmoov zoo ntawm cov khoom kawg, uas yog tus yuam sij ntawm txoj kev no. Tang Haihong et al. [5] tshawb nrhiav kev siv barium aluminate rau kev ua kom huv si sib sib zog nqus ntawm sodium aluminate tov kom tsis txhob muaj txhuas poob hauv cov txheej txheem purification.

Tsis tas li ntawd, kev saib xyuas yuav tsum tau them nyiaj rau kev tshem tawm sodium, ntxiv cov mineralizer thaum lub sij hawm ci los yog ntxiv sodium tshem tawm thaum lub sij hawm hydrothermal hloov pauv ntawm aluminium hydroxide yog qhov zoo ntawm kev tshem tawm sodium. Nyob rau hauv tus txheej txheem ntawm crystallization, susaturation ntawm kev daws, crystallization kub, noob loj thiab lwm yam tsis ncaj qha cuam tshuam rau purity thiab hmoov zoo ntawm alumina. Los ntawm kev tswj cov tshuaj tiv thaiv kom raug, cov txheej txheem crystallization tuaj yeem ua haujlwm maj mam, zam kev tsim cov crystal nuclei txawv txav, thiab pab txo qis kev suav nrog Na, Si thiab lwm yam impurities. Cov txheej txheem muaj tus nqi qis thiab cov khoom siv dav dav, tab sis cov txheej txheem nyuaj, roasting kub yog siab, cov khoom tawm los yog qis, purity tsawg.

2.4 Sol-gel txoj kev

Sol-gel txoj kev yog ib txoj hauv kev tseem ceeb los npaj siab purity alumina ntawm qhov kub thiab txias. Lub siab purity txhuas ntsev yog hydrolyzed nyob rau hauv siab purity inorganic ntsev los yog organic acid los tsim hydrate precursor hyalosol, thiab ces cov gel yog polymerized thiab gelated kom tau pob tshab gel, uas yog ntxiv rhuab mus rau siab purity alumina. Xu Sankui et al. [6] npaj sol los ntawm kev siv high-purity txhuas nitrate los tsim hydrate precursor system nyob rau hauv ammonia dej system. Nyob rau hauv lub gelation theem, high-purity alumina siv lead ua noob tau ntxiv, thiab txhuas trifluoride tau siv los ua additive los npaj high-purity nano-alumina ntawm qhov kub thiab txias.

2.5 Hydrothermal synthesis txoj kev

Lub purity thiab granularity ntawm hydrothermal synthesis txoj kev rau cov khoom tswj yog ib qho yooj yim, siv aqueous tov raws li cov tshuaj tiv thaiv kab mob, los ntawm cov cua kub siab nce lub solubility ntawm precursor, siab purity aluminium thiab dej vapor ncaj qha hydrolysis ntawm txhuas hydroxide, nyob rau hauv kub thiab nag lossis daus nyob rau hauv. cov txheej txheem ntawm alumina, zam aluminium hydroxide calcined los ua ib qho nyuaj ua ke, tom qab ntawd los ntawm kev ua haujlwm xws li ziab, calcination tuaj yeem tsim cov hmoov alumina.

thawj zaug yaj NaOH hauv dej ammonia ntawm chav tsev kub, tom qab ntawd maj mam ntxiv aluminium chloride los npaj cov mis nyuj dawb flocculent precursor, thiab tom qab ntawd npaj diaspore nano-hmoov los ntawm hydrothermal synthesis txoj kev los ntawm kev kho tus nqi pH ntawm cov tshuaj. Qhov tsis zoo ntawm txoj kev no yog tias cov cuab yeej siv peev yog loj, qhov kub thiab txias siab muaj qee yam kev phom sij, kev ua haujlwm ntawm alumina hydroxide hloov dua siab tshiab yog tsawg, feem ntau yuav tsum tau ntxiv cov noob kom txo tau cov theem hloov pauv kub.

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