Lub taphole khiav ua hauj lwm raws li ib tug tseem ceeb channel rau channeling tawm siab - kub molten hlau. Thaum lub sijhawm ua haujlwm, nws tsis yog tsuas yog ua rau muaj kev cuam tshuam loj heev, yaig, thiab infiltration los ntawm kev ntws siab - kub molten hlau thiab slag tab sis kuj rau khaus thermal shock uas tshwm sim los ntawm qhov sib cuam tshuam ntawm cov txheej txheem tapping. Kev siv hluav taws xob ntau dua rau lub qhov cub smelting tau ua rau muaj qhov kub thiab txias ntau dua, nce tus nqi ntawm cov hlau molten, qhov loj ntawm cov hlau tapping thiab slag, thiab ntev tapping ntev; Yog li ntawd, cov kev pab cuam rau cov ntaub ntawv refractory siv nyob rau hauv taphole runners tau ua ntau xav tau. Raws li hom monolithic refractory khoom tshwj xeeb tsim rau blast furnace taphole runners, tapholerefractory castablessuav rau ntau dua 70% ntawm tag nrho cov khoom siv refractory tau noj nyob rau hauv qhov chaw tawg rau lub qhov cub hearth. Tsis tas li ntawd, lub binder ua haujlwm nyob rau hauv cov castables ncaj qha txiav txim siab tapping yield, kev noj cov khoom siv refractory ib tuj ntawm cov hlau tsim, thiab tag nrho kev nyab xeeb ntawm hearth - sab haujlwm; Yog li, kev xaiv thiab kev ua kom zoo ntawm cov binders tau tshwm sim los ua qhov tseem ceeb hauv kev tshawb fawb thiab kev loj hlob ntawm siab -kev ua tau zoo taphole castables.
1.1 Ntshiab Calcium Aluminate Cement
NtshiabCalcium Aluminate Cement(CAC) yog hydraulic binder uas ua los ntawm high -kub sintering lossis hluav taws xob- cub hluav taws xob- melting ntawm siab - purity calcium oxide thiab industrial alumina. Nws cov tshuaj muaj pes tsawg leeg muaj feem ntau ntawm Al₂O₃ thiab CaO, nrog rau Al₂O₃ pawg feem ntau yog nyob nruab nrab ntawm 70% thiab 80%. Cov theem tseem ceeb ntawm cov crystalline lub luag haujlwm rau CAC cov khoom siv hydraulic yog monocalcium aluminate (CA) thiab dicalcium aluminate (CA₂)-txawm hais tias dodecacalcium hepta- aluminate (C₁₂A₇) theem kuj tseem muaj nyob rau hauv ultra-high ACriants{1. Qhov kev sib xyaw no ua rau CAC tsis yog tsuas yog muab cov khoom siv kho tshuab zoo rau cov khoom siv refractory monolithic xwb tab sis kuj pab rau lawv nrog kev ua haujlwm siab tshaj - kub; yog li ntawd, tam sim no nws yog ib qho kev siv dav hauv cov khoom siv hluav taws xob monolithic xws li taphole castables. Castables bonded nrog CAC yuav tsum muaj txheej txheem kho kom zoo los xyuas kom meej tias cov khoom hydration tau ua tiav kev teeb tsa thiab tawv. Qhov tseem ceeb, cov khoom siv dej tshwj xeeb tsim los ntawm CAC sib txawv nyob ntawm qhov kub kub ua haujlwm. Thaum kho tau ntawm qhov kub qis dua 20 degree, cov khoom hydration tshwm sim muaj koob -zoo li monocalcium aluminate decahydrate (CAH10). Nyob nruab nrab ntawm 21℃thiab 35 degree, thawj cov khoom hydration yog acicular - rau -lamellar dicalcium aluminate octahydrate (C2AH8); saum toj 36 degree, cov khoom tseem ceeb yog granular tricalcium aluminate hexahydrate (C3AH6). Cov koob no -zoo li, acicular-rau-lamellar, thiab granular hydration products overlap and interlace to form a network structure, li no endowing the cast body with high green strength after the curing process. Thaum xaiv cov ntshiab calcium aluminate cement, nws tseem yog ib qho tseem ceeb kom nkag siab txog cov yam ntxwv hydration ntawm nws cov txheej txheem ntau yam. Cov theem sib txawv muaj ntau qhov sib txawv ntawm cov cua sov ntawm hydration thiab tus nqi ntawm kev teeb tsa thiab hardening. Feem ntau, qhov qis dua qhov kub ntawm hydration ntawm ib qho calcium aluminate mineral theem, qhov ceev ntawm qhov chaw thiab hardening tus nqi ntawm nws cov khoom hydration.
1.2 Hydratable Alumina
Refractory materials for blast furnace tapholes typically utilize Al2O3-SiC-C based castables. Since the primary aluminum-bearing raw materials employed are various forms of corundum and high-grade bauxite, hydratable alumina (HA) serves as an effective binder for these refractory castables. HA is an amorphous, transitional alumina phase-specifically ρ-Al2O3-characterized by a high specific surface area (>150 m²/g). Chemically reactive, it undergoes a hydration-induced gelation reaction upon contact with water or water vapor, generating gels of pseudo-boehmite (AlOOH·nH2O, where n = 0.08–0.62) and boehmite (γ-AlOOH). This gelation process is accompanied by significant volume expansion, which helps reduce the porosity within the cast body's structure; ultimately, these gels transform into crystalline bayerite (Al(OH)3). The gelation process typically results in setting and hardening within a timeframe of less than one hour (at temperatures >25 degree), yog li sib txuas cov khoom sib xyaw ua ke thiab ua kom muaj zog ntsuab. Yog li ntawd, zoo li calcium aluminate cement (CAC), HA yog cais raws li hydraulic binder. Nws yuav tsum raug sau tseg tias kev tsim ntawm crystalline bayerite yog nyob ntawm qhov loj me, dej kub, lub sijhawm tshuaj tiv thaiv, thiab pH tus nqi.
1.3 Silica Sol Binders
Lub xub ntiag ntawm CaO hauv cement-bonded castables ua rau muaj teeb meem nyob rau hauv qhov ntim ntawm cov kua theem nce ntawm qhov kub thiab txias; yog li ntawd, ntau tus kws tshawb fawb hauv thaj chaw ntawm cov ntaub ntawv refractory tau txiav txim siab siv ntau yam CaO-cov ntaub ntawv pub dawb. Ntxiv nrog rau hydrated alumina (HA), lwm yam CaO-cov ntaub ntawv pub dawb uas ntxim nyiam muaj ntau hom colloidal binders lossis sols-xws li SiO2 sol, Al2O3 sol, colloidal spinel, thiab colloidal mullite. Tam sim no, feem ntau siv thiab thev naus laus zis paub tab calcium-free binder yog silica sol. Tsis zoo li lwm cov binders, lub hauv paus ruaj khov ntawm lub sol nws tus kheej yog qhov tsim nyog yuav tsum tau ua ua ntej rau nws txoj kev ruaj ntseg. Qhov chaw ntawm cov khoom colloidal hais nyob rau hauv ib tug silica sol tau txais ib tug nqi hluav taws xob los ntawm dissociation ntawm nto functional pawg los yog xaiv adsorption ntawm tej ions los ntawm ib puag ncig cov tshuaj. Yuav kom tswj tau tus nqi nruab nrab, qhov kev daws teeb meem tam sim ntawd nyob ib sab ntawm cov khoom them nyiaj no yuav tsum muaj qhov sib npaug ntawm cov txee- ions uas coj tus nqi rov qab rau qhov khoom ntawm qhov chaw. Qhov kev sib txuas ntawm cov khoom siv hluav taws xob thiab cov kev daws teeb meem uas nyob ib sab ua rau "hluav taws xob ob txheej": ib qho khoom siv yog txheej nyob ruaj ruaj nyob rau hauv kev sib cuag ncaj qha nrog cov khoom particle deg-paub tias "txheej txheej" lossis "Stern txheej"-thaum qhov seem seem (txuas ntxiv los ntawm lub dav hlau nplawm sab nraud ntawm qhov sib npaug) thiab qhov sib npaug ntawm qhov sib npaug hu ua "diffuse layer."
Although refractory castables bonded with silica sol exhibit significantly enhanced mechanical strength following high-temperature sintering (>1000℃) piv rau cov sib txuas nrog hydraulic cements (xws li CAC thiab HA), lub zog ntsuab ntawm unsintered (los yog qis-kub kub-kho) lub cev castable yog qhov qis dua.
1.4 Alumina Sol Binders
Nyob rau hauv sib piv rau silica sol, muaj tsawg dua kev tshawb fawb ua nyob rau hauv alumina sol thiab nws txuam coagulation thiab hardening cwj pwm. Tsis tas li ntawd, feem ntau ntawm cov kev tshawb fawb tshawb fawb tau luam tawm tsuas yog ua rau sub-micron alumina suspensions es tsis yog nanoscale alumina sols. Qhov no qhia tau tias cov txiaj ntsig uas twb muaj lawm yuav tsis tuaj yeem siv ncaj qha rau sols ntawm nanoscale. Tus nqi ntawm cov khoom nyob rau hauv ib qho alumina ncua kev kawm ntawv yog txiav txim los ntawm tus nqi pH, cov ntsiab lus ntawm cov khoom, thiab cov electrolytes tshwj xeeb ua hauj lwm los stabilize lub ncua kev kawm ntawv. Nyob rau hauv ntshiab alumina suspensions, raws li qhov concentration ntawm alumina nce, tus nqi saum npoo hloov ntawm qhov zoo mus rau qhov tsis zoo. Nrog rau kev nce ntxiv hauv kev ncua kev kawm concentration, qhov loj ntawm cov nqi tsis zoo kuj nce ntxiv. Lub "stabilization-flocculation" mechanism ntawm alumina suspensions nyob rau hauv ambient kub.
