Ceramics
Alumina ceramic yog ib hom hnav-tiv taus, corrosion-resistant thiab high-strength ceramic khoom. Txhawm rau tsim cov khoom loj thiab ua tau raws li qhov yuav tsum tau ua ntawm cov khoom tsis tu ncua, kev sib tsoo me me thiab kev sib tsoo yooj yim, nws yog ib qho tsim nyog yuav tsum xaiv txoj kev ua kom qhuav pressing.Compression molding yuav tsum tau cov hmoov dawb nrog ib qho kev gradation, nrog tsawg noo noo thiab binder.Yog li ntawd, cov slurry ntawm cov batch tom qab pob milling thiab nplua crushing yuav tsum tau qhuav kom zoo dua cov hmoov thiab granulated. ceev. Txau ziab granulation tau dhau los ua txoj hauv kev rau kev tsim cov khoom siv hauv tsev thiab cov ceramics tshiab.Cov hmoov npaj los ntawm cov txheej txheem no muaj qhov zoo fluidity, ib qho kev faib ua feem ntawm cov loj thiab me me, thiab zoo bulk ntom.Yog li ntawd, tshuaj tsuag kom qhuav yog txoj kev zoo tshaj plaws los npaj cov hmoov qhuav qhuav.
Txau kom qhuav yog txheej txheem uas cov ntaub ntawv ua kua (xws li slurry) yog atomized thiab tom qab ntawd hloov mus rau cov khoom siv hmoov qhuav hauv qhov kub kom qhuav. Cov ntaub ntawv yog atomized rau hauv zoo heev spherical fogdrops, vim cov fogdrops yog zoo heev thiab qhov piv ntawm thaj tsam ntawm lub ntim yog loj heev, cov ya raws sai evaporates, thiab ziab thiab granulation txheej txheem tiav nyob rau hauv ib qho instant. Qhov loj me me, cov ntsiab lus noo noo thiab qhov ntom ntom ntawm cov ntaub ntawv tuaj yeem tswj tau los ntawm kev kho cov kev ua haujlwm kom qhuav. Spherical hmoov nrog cov khoom zoo thiab rov ua tau zoo tuaj yeem tsim los ntawm kev siv tshuab ziab khaub ncaws, yog li txo cov txheej txheem ntawm cov hmoov, ua kom tsis siv neeg thiab tsis tu ncua ntau lawm, thiab yog ib txoj hauv kev zoo rau kev npaj loj ntawm cov khoom zoo alumina ceramic qhuav hmoov.
2.1.1 Kev npaj ntawm Slurry
Thawj chav kawm muaj alumina nrog purity ntawm 99% yog ntxiv nrog li 5% ntawm cov khoom ntxiv los npaj 95% cov khoom siv plooj (porcelain), thiab pob milling yog ua raws li qhov piv ntawm cov khoom: pob: dej = 1: 2: 1, thiab binder, deflocculant thiab tsim nyog tus nqi ntawm cov dej ntxiv los npaj qhov kev ncua kev ncua kev ntsuas qhov yooj yim nrog kev ntsuas qhov tsim nyog. av nkos cov ntsiab lus, hom thiab ntau npaum li cas ntawm deflocculant.
2.1.2 Txau kom qhuav txheej txheem
Cov txheej txheem tswj xyuas tseem ceeb hauv cov txheej txheem tshuaj tsuag qhuav yog: a). Lub qhov hluav taws xob kub ntawm lub tshuab ziab khaub ncaws.Tseem tswj ntawm 110 ℃ .b). Sab hauv txoj kab uas hla ntawm lub nozzle.Siv 0.16mm los yog 0.8mm orifice phaj. c), Cyclone separator siab sib txawv, tswj ntawm 220Pa.
2.1.3 Kev soj ntsuam kev ua tau zoo ntawm cov hmoov tom qab ziab kom qhuav
Kev txiav txim siab noo noo yuav tsum tau ua raws li kev txiav txim siab ntawm cov khoom siv ceramic.The particleCov morphology thiab particle loj tau soj ntsuam los ntawm lub tshuab tsom iav.Qhov fluidity thiab bulk ntom ntawm cov hmoov yog kuaj raws li ASTM cov qauv kev sim rau fluidity thiab bulk ntom ntawm hlau hmoov. Cov txheej txheem yog: nyob rau hauv cov xwm txheej tsis muaj kev vibration, 50g hmoov (muab rau 0. 01g) dhau los ntawm lub khob funnel caj dab nrog ib txoj kab uas hla ntawm 6 hli thiab ntev ntawm 3 hli rau nws cov fluidity; Nyob rau hauv qhov xwm txheej tsis muaj kev vibration, cov hmoov hla dhau ntawm tib lub iav funnel thiab ntog rau hauv ib lub thawv 25 hli siab los ntawm tib lub iav funnel. Qhov tsis-vibrating ntom yog qhov xoob ntim ntom ntom.
3.1.1 Kev npaj ntawm slurry
Siv cov txheej txheem ziab kom qhuav granulation, kev npaj cov slurry yog ib qho tseem ceeb heev. Khoom cov ntsiab lus, fineness thiab fluidity ntawm av nkos yuav ncaj qha rau cov zis thiab particle loj ntawm qhuav hmoov.
Vim hais tias cov hmoov ntawm no alumina porcelain yog barren, nws yog ib qhov tsim nyog yuav tsum tau ntxiv ib tug npaum li cas ntawm binder los txhim kho txoj kev ua tau zoo ntawm cov dawb paug.Feem ntau siv organic tshuaj xws li dextrin, polyvinyl cawv, carboxymethylcellulose, polystyrene, thiab lwm yam.Polyvinyl cawv (PVA), ib tug dej-soluble binder ntawm no rhiab heev binder. ambient humidity yuav cuam tshuam rau cov khoom ntawm cov hmoov qhuav.
Polyvinyl cawv muaj ntau yam sib txawv, qib sib txawv ntawm hydrolysis thiab degree ntawm polymerization, uas yuav cuam tshuam rau cov txheej txheem ziab qhuav. Nws cov degree hydrolysis dav dav thiab polymerization degree yuav cuam tshuam rau cov txheej txheem ziab qhuav. Nws qhov ntau npaum li cas feem ntau yog 014 - 015wt%.Qhov sib ntxiv ntawm ntau dhau yuav ua rau cov tshuaj tsuag granulation hmoov los ua cov hmoov qhuav qhuav kom tsis txhob muaj cov khoom deforming thaum nias.Yog hais tias cov yam ntxwv tsis tuaj yeem tshem tawm thaum nias, cov kev tsis zoo no yuav khaws cia rau hauv lub cev ntsuab thiab tsis tuaj yeem tshem tawm tom qab tua hluav taws, uas yuav cuam tshuam rau cov khoom zoo. Binder ntxiv me ntsis ntsuab lub zog yuav ua rau kom lub lag luam poob. Qhov kev sim qhia tau hais tias thaum muab cov khoom sib txuas ntxiv, ntu ntawm daim ntawv ntsuab ntsuab tau pom nyob rau hauv lub tshuab tsom. Nws tuaj yeem pom tau tias thaum lub siab nce ntawm 3Mpa mus rau 6Mpa, ntu tau nce siab, thiab muaj qee qhov sib txawv me me. Thaum lub siab yog 9Mpa, cov seem yog du, thiab muaj cov hauv paus tsis muaj spherical hais, tab sis lub siab siab yuav ua rau lub stratification ntawm ntsuab billet.PVA yog qhib ntawm txog 200 ℃.
Pib hlawv, thiab ntws ntawm txog 360 ℃ .in xaj kom yaj tawm ntawm cov khoom siv thiab cov khoom sib txhuam ntawm cov khoom siv hluav taws xob, txhawb nqa cov roj hluav taws xob tsim nyog, siv tau yog siv glycerin, ethyl oxalic acid, thiab lwm yam.
Vim hais tias cov ntaub ntawv yog cov organic macromolecular polymer, txoj kev ntxiv cov binder rau hauv slurry kuj tseem ceeb heev.Nws yog qhov zoo tshaj plaws los ntxiv cov ntaub ntawv npaj rau hauv cov av nkos nrog cov ntsiab lus uas yuav tsum tau ua. Nyob rau hauv no txoj kev, cov undissolved thiab undispersed organic teeb meem yuav raug zam kom coj mus rau hauv lub slurry, thiab qhov ua tau tsis xws luag. los ntawm pob milling los yog nplawm. Cov cua qhwv rau hauv cov tee dej yog nyob rau hauv cov hmoov qhuav, uas ua rau cov khoom qhuav hollow thiab txo qhov ntim ceev. Txhawm rau daws qhov teeb meem no, defoamers tuaj yeem ntxiv.
Vim yog kev lag luam thiab kev xav tau, cov ntsiab lus siab yog yuav tsum tau.Raws li lub peev xwm ntawm lub tshuab ziab khaub ncaws hais txog cov dej evaporation ib teev, cov slurry nrog cov ntsiab lus siab yuav ua rau kom cov hmoov qhuav qhuav. Thaum cov ntsiab lus khoom nce ntawm 50% mus rau 75%, cov zis ntawm lub tshuab ziab khaub ncaws yuav nce ob zaug.
Cov ntsiab lus tsis tshua muaj siab yog qhov laj thawj tseem ceeb rau kev tsim cov hollow particles.In the process of drying, water migrates to the deg ntawm cov tee dej thiab nqa cov khoom, uas ua rau lub puab ib feem ntawm lub droplet hollow; Yog hais tias ib tug tsis tshua muaj permeability elastic zaj duab xis yog tsim nyob ib ncig ntawm lub tee dej, vim qhov tsawg evaporation ceev, qhov kub ntawm lub tee dej nce, thiab cov dej evaporates los ntawm lub puab sab, uas ua rau lub droplet bulge. Nyob rau hauv ob qho tib si, lub pob zoo ntawm cov khoom yuav raug puas tsuaj, thiab hollow annular los yog apples los yog pear zoo li hais tias cov hmoov qhuav yuav ua kom qhuav. Ntxiv rau, slurry nrog cov ntsiab lus siab tuaj yeem txo
Hauv cov txheej txheem ziab luv luv, qhov txo qis ntawm cov txheej txheem ziab tuaj yeem txo tus nqi ntawm cov nplaum xa mus rau cov khoom seem nrog rau cov dej, kom tsis txhob muaj cov binder concentration ntawm cov khoom seem ntawm qhov chaw siab tshaj qhov nruab nrab, kom cov khoom muaj ib qho nyuaj, thiab cov khoom tsis deform thiab crushing nyob rau hauv tus txheej txheem ntawm nias thiab sib sau, thiaj li yuav txo tau lub cev loj ntawm daim nqi. Yog li ntawd, txhawm rau kom tau txais cov hmoov qhuav zoo, cov ntsiab lus ntawm cov slurry yuav tsum tau nce ntxiv.
Cov slurry siv rau cov tshuaj tsuag kom qhuav yuav tsum muaj txaus fluidity thiab me ntsis ya raws li sai tau.Yog hais tias lub viscosity ntawm slurry yog txo los ntawm kev qhia ntau dej, tsis yog tsuas yog lub zog noj ntawm qhuav yog nce, tab sis kuj lub bulk ntom ntawm cov khoom yog txo. Yog li ntawd, nws yog ib qhov tsim nyog los txo cov viscosity ntawm slurry nrog kev pab los ntawm ob peb coagulants. uas tuaj yeem suav tau tias yog ib qho colloidal dispersion system.Qhov kev xav ntawm colloidal stability qhia tau hais tias muaj ob lub zog ua haujlwm ntawm cov khoom raug tshem tawm: van der Waals force (Coulomb force) thiab electrostatic repulsion force. Yog hais tias lub zog yog lub ntiajteb txawj nqus, agglomeration thiab flocculation yuav tshwm sim.Qhov tag nrho lub zog muaj peev xwm (VT) ntawm kev sib cuam tshuam ntawm cov khoom muaj feem xyuam rau lawv qhov kev ncua deb, thaum lub sij hawm uas VT ntawm qee qhov taw tes yog qhov sib npaug ntawm lub zog gravitational VA thiab lub zog repulsive VR.When VT ntawm cov khoom nthuav tawm qhov siab tshaj plaws lub zog muaj peev xwm, nws yog qhov system ntawm depolyization. Lub kaw lus yog cov haujlwm uas tswj VR: tus nqi ntawm cov khoom thiab cov thickness ntawm ob chav hluav taws xob txheej.Lub thickness ntawm lub bilayer yog inversely proportional rau lub square cag ntawm valence daim ntawv cog lus thiab concentration ntawm equilibrium ion.Ob txheej compression yuav txo tau lub peev xwm barrier ntawm flocculation, yog li lub valence daim ntawv cog lus thiab cov concentration ntawm ions nyob rau hauv equilibrium yuav tsum tau. yog HCI, HNO3, NaOH, (CH) 3noh (quaternary amine), GA, thiab lwm yam.
Vim tias cov dej-raws li slurry ntawm 95 alumina ceramic hmoov yog nruab nrab thiab alkalescent, ntau cov coagulants uas muaj cov nyhuv diluting zoo rau lwm cov ceramic slurry poob lawv txoj haujlwm.Yog li ntawd, nws yog ib qho nyuaj heev los npaj cov slurry nrog cov ntsiab lus siab thiab zoo fluidity.The barren alumina slurry, uas belongs rau amphoteric oxides, muaj cov txheej txheem sib txawv ntawm cov kua qaub los yog cov kua qaub. dissociation xwm txheej ntawm txawv micelle muaj pes tsawg leeg thiab qauv. Tus nqi pH ntawm slurry yuav cuam tshuam ncaj qha rau cov degree ntawm dissociation thiab adsorption, uas ua rau qhov kev hloov ntawm ζ muaj peev xwm thiab sib raug flocculation lossis dissociation.
Alumina slurry muaj tus nqi siab tshaj plaws ntawm qhov zoo thiab qhov tsis zoo ζ muaj peev xwm hauv cov kua qaub lossis alkaline nruab nrab.Lub sijhawm no, lub viscosity ntawm slurry yog nyob rau hauv tus nqi qis tshaj ntawm lub xeev de coagulation, thaum lub slurry nyob rau hauv nruab nrab, nws viscosity nce, thiab flocculation tshwm sim. slurry raug txo los ntawm kev ntxiv cov demulsifier kom zoo, kom nws cov nqi viscosity nyob ze ntawm cov dej. Lub fluidity ntawm cov dej ntsuas los ntawm ib qho yooj yim viscometer yog 3 vib nas this / 100 ml, thiab fluidity ntawm slurry yog 4 vib nas this / 100 ml. Lub viscosity ntawm slurry yog txo, yog li cov khoom ntawm cov slurry tuaj yeem nce mus rau 60%, thiab cov khoom ntim ruaj khov tuaj yeem tsim tau.Raws li lub peev xwm ntau lawm ntawm lub tshuab ziab khaub ncaws yog hais txog evaporation ntawm dej ib teev, yog li qhov kev ncua.
3.1.2 Kev tswj hwm qhov tseem ceeb hauv cov txheej txheem tshuaj tsuag kom qhuav
Cov qauv huab cua nyob rau hauv lub tshuab ziab khaub ncaws muaj feem xyuam rau lub sij hawm ziab, lub sij hawm tuav, cov dej seem thiab cov phab ntsa ntawm cov tee dej. Hauv qhov kev sim no, cov txheej txheem ntawm cov tee dej yog sib xyaw, uas yog, cov roj kub nkag mus rau hauv lub tshuab ziab khaub ncaws los ntawm sab saum toj, thiab lub atomizing nozzle yog nruab rau hauv qab ntawm lub tshuab ziab khaub ncaws, tsim cov dej phwj tuaj, thiab cov tee dej yog cov khoom siv hluav taws xob sib xyaw ua ke, thiab cov roj kub kub nkag mus rau hauv lub tshuab ziab khaub ncaws los ntawm sab saum toj, thiab lub atomizing nozzle yog nruab rau hauv qab ntawm lub tshuab ziab khaub ncaws, tsim cov dej phwj tuaj, thiab cov tee dej yog ib qho kev sib xyaw ua ke, uas yog cov roj kub kub nkag mus rau hauv lub tshuab ziab khaub ncaws los ntawm sab saum toj, thiab cov atomizing nozzle yog nruab rau hauv qab ntawm lub tshuab ziab khaub ncaws, tsim cov dej phwj tuaj, thiab cov tee dej yog ib qho kev sib tov sib xyaw. mus txog rau sab saum toj ntawm cov hlab ntsha tawg, nws dhau los ua cov dej ntws qis thiab cov tshuaj tsuag mus rau hauv cov duab conical.Raws li cov tee dej nkag mus rau hauv lub tshuab ziab khaub ncaws, nws yuav sai sai mus txog qhov siab tshaj plaws kom qhuav thiab nkag mus rau qhov ceev kom qhuav theem. Qhov ntev ntawm qhov ceev ceev kom qhuav theem yog nyob ntawm cov dej noo ntawm cov tee dej, viscosity ntawm cov av nkos, qhov kub thiab av noo ntawm huab cua qhuav. Lub ciam teb point C los ntawm qhov ceev ceev kom qhuav mus rau lub sij hawm ziab sai yog hu ua qhov tseem ceeb. Lub sijhawm no, qhov chaw ntawm cov tee dej tsis tuaj yeem tswj hwm lub xeev saturated los ntawm kev tsiv teb tsaws ntawm cov dej, Nrog rau qhov txo qis ntawm cov evaporation, qhov kub ntawm cov tee dej nce, thiab cov tee dej ntawm point D yog saturated, tsim ib txheej ntawm lub plhaub tawv. evaporation txav mus rau sab hauv, thiab qhov ziab kom qhuav tseem poob qis. Kev tshem tawm cov dej ntxiv yog cuam tshuam nrog cov dej noo permeability ntawm lub plhaub tawv.Yog li ntawd, nws yog ib qho tsim nyog los tswj cov kev ua haujlwm tsim nyog.
Cov ntsiab lus noo noo ntawm cov hmoov nplej qhuav yog feem ntau txiav txim siab los ntawm cov dej ntov thiab kev txiav txim siab cov khoom siv noo noo, thiab txiav txim siab cov nias kom qhuav.pva yog rhiab rau cov av noo. Raws li cov ntsiab lus sib txawv ntawm cov dej noo, tib tus nqi ntawm PVA tuaj yeem ua rau qhov sib txawv ntawm qhov sib txawv ntawm cov txheej txheem ntawm cov hmoov qhuav qhuav, uas ua rau kev txiav txim siab ntawm lub siab hloov pauv thiab cov khoom lag luam tsis ruaj khov thaum lub sijhawm nias. Yog li ntawd, qhov hluav taws kub qhov hluav taws xob yuav tsum tau tswj nruj me ntsis kom ntseeg tau tias cov dej noo ntawm cov hmoov qhuav. Feem ntau, qhov hluav taws xob qhov hluav taws xob yuav tsum tau tswj ntawm 110 ℃, thiab qhov kub ntawm qhov hluav taws xob yuav tsum tau hloov kho raws li qhov kub ntawm qhov hluav taws xob tsis ntau tshaj 400 ℃, feem ntau tswj tau ntawm li 380 ℃ .Yog qhov kub ntawm inlet siab dhau lawm, cov cua kub kub nyob rau sab saum toj ntawm tus pej thuam yuav overheat. Thaum cov pos huab nce mus rau qhov siab tshaj plaws thiab ntsib cov cua kub dhau, rau cov hmoov ceramic uas muaj cov ntawv khi, cov nyhuv ntawm cov ntawv khi yuav raug txo, thiab thaum kawg qhov kev ua haujlwm ntawm cov hmoov qhuav yuav raug cuam tshuam. Thib ob, yog tias qhov kub ntawm inlet siab dhau lawm, qhov kev pab cuam lub neej ntawm lub rhaub yuav raug cuam tshuam, thiab cov cua sov ntawm daim tawv nqaij yuav poob tawm thiab nkag mus rau lub tshuab ziab khaub ncaws nrog cov huab cua qhuav. Qhov hluav taws xob qhov hluav taws xob yog qhov pib txiav txim siab, qhov hluav taws xob qhov hluav taws xob kuj tuaj yeem hloov kho los ntawm lub siab ntawm lub twj tso kua mis pub, lub siab sib txawv ntawm lub tshuab hluav taws xob sib cais, cov ntsiab lus ntawm cov slurry thiab lwm yam.
Lub siab sib txawv ntawm cyclone separator.Lub siab sib txawv ntawm lub cyclone separator yog loj, uas yuav ua rau kom lub qhov hluav taws xob kub, ua kom cov khoom ntawm cov khoom zoo thiab txo cov txiaj ntsig ntawm lub tshuab ziab khaub ncaws.
3.1.3 Cov khoom ntawm cov tshuaj tsuag qhuav hmoov
Lub fluidity thiab packing ceev ntawm alumina ceramic hmoov npaj los ntawm cov tshuaj tsuag kom qhuav txoj kev yog feem ntau zoo dua cov uas npaj los ntawm ib txwm txheej txheem. Cov hmoov ntawm phau ntawv granulation tsis tuaj yeem ntws los ntawm cov cuab yeej kuaj xyuas yam tsis muaj kev vibration, thiab cov hmoov ntawm cov tshuaj tsuag granulation tuaj yeem ua qhov no tag nrho. Xa mus rau ASTM tus qauv rau kev ntsuas cov hmoov hlau hmoov fluidity thiab bulk ntom, bulk ntom thiab fluidity ntawm cov khoom tau los ntawm cov tshuaj tsuag kom qhuav hauv cov dej sib txawv tau ntsuas. Saib Table 1.
Table 1 xoob ntom ntom thiab fluidity ntawm cov tshuaj tsuag qhuav hmoov
Table 1 Powder ntom thiab ntws tus nqi
| Cov dej noo (%) | 1.0 | 1.6 | 2.0 | 2.2 | 4.0 |
| Qhov ceev ceev (g / cm3) | 1.15 | 1.14 | 1.16 | 1.18 | 1.15 |
| Liquidity (s) | 5.3 | 4.7 | 4.6 | 4.9 | 4.5 |
Cov dej noo ntawm cov tshuaj tsuag qhuav hmoov yog feem ntau tswj ntawm 1 - 3%. Lub sijhawm no, cov hmoov av fluidity yog qhov zoo, uas tuaj yeem ua tau raws li qhov xav tau ntawm kev nias molding.
DG1 yog qhov ceev ntawm tes ua granulation hmoov, thiab DG2 yog qhov ntom ntawm cov hmoov rau tshuaj tsuag granulation.
Lub tes granulated hmoov yog npaj los ntawm pob milling, ziab, sieving thiab granulation.
Table 2 ceev ntawm nias hmoov tsim los ntawm phau ntawv granulation thiab tshuaj tsuag granulation
Table 2 Green Lub cev qhov ntom
| Siab (MPA) | 4 | 6 | 8 | 10 | 12 | 14 |
| DG1 (g/cm3) | 2.32 ib | 2.32 ib | 2.32 ib | 2.33 ib | 2.36 ib | 2.4 |
| DG2 (g / cm2)3) | 2.36 ib | 2.46 ib | 2.53 ib | 2.56 ib | 2.59 ib | 2.59 ib |
Cov particle loj thiab morphology ntawm cov hmoov raug soj ntsuam los ntawm lub tshuab tsom iav.Nws tuaj yeem pom tau tias cov khoom yog cov khoom siv kheej kheej kheej kheej, nrog kev sib txuam meej thiab du nto. Qee cov khoom yog cov txiv apples, pear zoo li tus lossis txuas nrog, suav txog 3% ntawm tag nrho. Cov particle loj faib yog raws li nram no: qhov siab tshaj particle loj yog 200 μ m (< 1%), qhov tsawg kawg yog particle loj yog 20 μ m (ib tus neeg), feem ntau hais yog hais txog 100 μ m (50%), thiab feem ntau hais yog hais txog 50 μ m (20%). Cov hmoov ua los ntawm cov tshuaj tsuag kom qhuav yog 160 degree sintered thiab 16 cm.3.
(1) 95 alumina slurry nrog 60% cov ntsiab lus khoom tuaj yeem tau txais los ntawm kev siv PVA ua cov ntawv khi, ntxiv cov coagulant thiab roj nplua nyeem.
(2) tsim nyog tswj cov tshuaj tsuag kom qhuav kev ua haujlwm tsis tuaj yeem tau txais cov hmoov qhuav zoo tagnrho.
(3) los ntawm kev siv cov txheej txheem ziab kom qhuav, 95 alumina hmoov, uas yog tsim rau cov txheej txheem ziab qhuav, tuaj yeem tsim. Nws qhov ntom ntom yog li 1.1g / cm33thiab sintering ceev yog 3170g / cm33.
