Sodium metasilicate pentahydrate Txheej txheem ntau lawm
Cov txheej txheem synthesis ntawm sodium metasilicate muaj xws li tshuaj tsuag kom qhuav txoj kev, yaj solidification crystallization txoj kev, ib-lub sij hawm granulation txoj kev thiab tshuaj crystallization txoj kev.
Cov txheej txheem crystallization muaj cov yam ntxwv ntawm cov cuab yeej siv tsawg dua, cov nqi tsim khoom qis thiab ruaj khov zoo. Cov txheej txheem khiav yog qhia raws li nram no
2.1 Cov nyhuv ntawm crystal concentration
Sodium metasilicate pentahydrate yog npaj los ntawm kev daws cov txheej txheem crystallization. Raws li daim duab qhia theem [3], qhov concentration ntawm nws cov tshuaj crystallization (Na2O + SiO2) yuav tsum tau tswj kom ntev li ntev tau.
Sodium metasilicate pentahydrate tuaj yeem tsim nyob rau hauv thaj tsam ntawm 25% ~ 28% (feem ntau). Txawm li cas los xij, muaj txaus N a2O thiab SiO 2 hauv cov tshuaj
Tus naj npawb raug cuam tshuam. Qhov loj feem ntawm 8i02 yog siab, lub sij hawm crystallization yog ntev, thiab cov saw piv ntawm n (Na2O) / n (SiO2) ncaj qha siv yog 1,
Cov tshuaj muaj 58% pawg pawg yog crystallized, thiab cov noob siv lead ua ntxiv. Lub voj voog crystallization yuav siv sij hawm 72 ~ 120h; Cov ntsiab lus siab ntawm Na2O
Qhov ceev nrawm dua, tab sis qhov ceev ceev crystallization yog ib qho yooj yim ua rau cov khoom siv lead ua zoo, ntau Na2O nkag los ntawm kev loj hlob siv lead ua, thiab cov khoom lag luam modulus yog qhov nyuaj rau ncav cuag.
Rau qhov xav tau, saib Table 1.
2.2 Noob nyhuv
Hauv cov txheej txheem crystallization ntawm sodium metasilicate, txhawm rau tswj cov khoom siv lead ua kom zoo thiab tau txais cov khoom lag luam nrog cov khoom me me.
Ntxiv cov noob siv lead ua uas tsim nyog qhov loj me thiab kom muaj nuj nqis, thiab maj mam do tag nrho cov txheej txheem los ua kom cov noob siv lead ua ntau sib npaug rau hauv tag nrho cov tshuaj.
Txo tus nqi ntawm cov nucleation theem nrab, kom cov khoom siv crystallized tsuas yog loj hlob ntawm cov noob siv lead ua
Tus nqi ntawm cov noob siv lead ua ntxiv nyob ntawm qhov zoo, ntau yam thiab qhov loj me ntawm cov khoom uas tuaj yeem crystallized thaum lub sij hawm tag nrho cov txheej txheem crystallization thiab cov khoom xav tau.
Lub granularity ntawm. Piv txwv tias tsis muaj thawj nucleating noob yog tsim nyob rau hauv tus txheej txheem, tus naj npawb ntawm hais nyob rau hauv cov khoom tiav yog sib npaug zos rau tus naj npawb ntawm cov tshiab tshiab additive noob hais.
Mp/KvpLp3=Ms/KvLs3P, then Ms=Mp (Ls/Lp) 3
Qhov twg: M s, M p —— zoo ntawm cov noob siv lead ua thiab cov khoom tiav; Ls, Lp —- nruab nrab particle loj ntawm siv lead ua noob thiab cov khoom tiav; K v, P metasilicic acid
Lub cev muaj zog tas li ntawm sodium.
Rau cov txheej txheem crystallization ntawm sodium metasilicate aqueous tov, raws li kev tsom xam ntawm kev hloov pauv siv lead ua, vim qhov nqaim dav ntawm nws thaj tsam metastable, nws yooj yim rau nkag mus.
Hauv thaj chaw tsis ruaj khov, cov noob uas muaj qhov loj me ntawm 0.1-0.2mm feem ntau ntxiv. Yog hais tias qhov nruab nrab particle loj ntawm cov khoom tiav lawm yuav tsum yog 1mm Xav txog qhov tsis tuaj yeem
Cov nucleation kom muaj nuj nqis ntawm cov tshuaj dawb nws tus kheej yog 40% ~ 60% ntawm cov feem loj thaum 0.1 m siv lead ua noob tau ntxiv.
2.3 Kev tswj qhov kub thiab txias
Cov txheej txheem crystallization ntawm sodium metasilicate pentahydrate yog rhiab rau qhov kub thiab txias, thiab nws cov siv lead ua kev loj hlob yuav tsum tau mus los ntawm cov txheej txheem induction, uas tau txais los ntawm 50-60 ℃
Tag nrho cov siv lead ua nuclei yog tswj los ntawm kev ntxiv cov noob siv lead ua rau kev daws, thiab tom qab ntawd cov siv lead ua loj hlob ntawm tus nqi sib xws hauv qhov kub thiab txias thiab supersaturation. Nyob rau theem tom ntej ntawm crystallization, txias ntawm tus nqi ntawm 1 ℃ ib feeb kom cov siv lead ua loj hlob sai, thiab cais cov khoom thaum nws nce mus txog 38-48 ℃
2.4 Kev cuam tshuam ntawm lwm cov tshuaj ntxiv
Txhawm rau pab txhawb kev sib cais ntawm cov dej dawb thiab siv lead ua thaum lub sijhawm ua haujlwm sib cais, qhov piv ntawm 0.005% ~ 0.015% ntawm tag nrho cov nyiaj yuav tsum tau noj 0.5h ua ntej qhov kawg ntawm qhov txias.
Qhov nro ntawm cov siv lead ua thiab dej tuaj yeem raug txo los ntawm kev ntxiv dodecyl sulfonic acid surfactant ib zaug, uas tuaj yeem tso cov qauv ntub dej.
Dej poob qis dua 4% rau ziab thiab khaws cia
Post lub sij hawm: Oct-13-2022