RH ntxig yeeb nkab hauv ob sab phlu yog feem ntau ua nrog cov khoom zoo ncaj nraimMagnesia-chrome refractory cibnrog zoo thermal poob siab tsis kam, thiab txheej txheej yog tsim los ntawm ib tiam tshiab ntawm ultra-low cement-bonded Al2O3-MgO castable nrog kev ua tau zoo heev.
Direct-bonded magnesia-chrome bricks feem ntau xa mus rau cov khoom ua los ntawm chromium ore nrog cov ntsiab lus impurity tsawg thiab cov ntshiab magnesia xuab zeb, raug rho tawm haujlwm ntawm qhov kub siab tshaj 1700 degree, thiab cov nplej refractory feem ntau nyob rau hauv kev sib cuag ncaj qha [29 ~ 34]. Cov tshuaj muaj pes tsawg leeg ntawm ncaj qha-bonded magnesia-chrome bricks muaj ob peb impurities thiab ib tug siab ncaj kev sib raug zoo tus nqi ntawm refractory nplej, yog li ntawd lawv muaj zoo slag kuj thiab kub kev kawm. Nws cov slag tsis kam yog tshwj xeeb tshaj yog tshwm sim nyob rau hauv uas Cr2O3 muaj lub siab melting point (kwv yees 2400 degree), thiab tuaj yeem tsim cov kev daws teeb meem, siab melting point compounds lossis qis eutectic nrog kub melting kub nrog ntau oxides, uas ua rau kom cov viscosity ntawm infiltrated slag. thiab inhibits ntxiv nkag mus ntawm slag. Nyob rau tib lub sijhawm, qhov sib txuas ncaj qha magnesia-chrome cib tau zoo heev thermal poob siab, thiab tuaj yeem txias los ntawm dej ntawm 1100 degree rau 4 mus rau 10 zaug.
Txawm li cas los xij, magnesia-chrome refractory cib kuj muaj qhov tsis txaus ntseeg. Qhov teeb meem ntawm magnesia-chrome bricks feem ntau yog cov pa phem ntawm ib puag ncig los ntawm hexavalent chromium. Nyob rau hauv lub xub ntiag ntawm oxidizing cua los yog muaj zog alkaline oxides xws li Na2O, K2O thiab CaO, Cr3+ nyob rau hauv refractory cov ntaub ntawv uas muaj Cr2O3 yuav hloov mus rau hauv Cr6+. Hexavalent chromium yog cov kab mob carcinogen tshaj tawm los ntawm International Cancer Research Center thiab American Toxicology Organization, thiab muaj cov teebmeem carcinogenic. Hexavalent chromium tuaj yeem ua rau tib neeg cov tawv nqaij, ua pa, qhov muag thiab plab hnyuv. Nyob rau tib lub sijhawm, CrO3 kuj tuaj yeem muaj nyob rau hauv daim ntawv ntawm cov pa roj, ua paug rau ib puag ncig. Tsis tas li ntawd, magnesia-chrome cib yog cov khoom zoo li cov khoom, tsis muaj kev sib xyaw ua ke, thiab feem ntau yuav slag thaum siv dua li castables, ua rau muaj kuab paug rau cov hlau molten.
Qee tus neeg kuj tau siv MgO-C refractory cib ntawm RH rauv thiab ua tiav cov txiaj ntsig zoo. Nyiv siv MgO-C cib nyob rau hauv qis tank thiab sab hauv ntawm lub immersion raj ntawm RH rauv, thiab lub cub tawg lub neej tau mus txog 417 lub sij hawm thiab 94 lub sij hawm. Yog hais tias RH rauv tsis yog rau refining ultra-low carbon steel, lub RH insert tube hauv ob sab phlu siv tsawg-carbon magnesia-carbon bricks los yog tsawg-carbon magnesia-calcium-carbon bricks, uas yog tsim nyob rau hauv cov nqe lus ntawm thermal shock kuj, slag nkag. tsis kam, thiab alkaline slag yaig kuj. Qhov no feem ntau yog vim qhov tsis zoo ntawm cov dej tsis zoo ntawm cov ntaub ntawv uas muaj cov pa roj carbon refractory thiab slag, uas ua rau lawv muaj kev tiv thaiv zoo rau slag nkag mus thiab cov txheej txheem spalling. Nyob rau tib lub sijhawm, cov pa roj carbon muaj cov thermal conductivity siab thiab qis thermal expansion coefficient, thiab thermal stress tuaj yeem tso tawm rau lub sijhawm tom qab cua sov, kom cov khoom siv carbon muaj cov thermal shock stability.
Cov ntaub ntawv uas muaj cov pa roj carbon monoxide tsis haum rau kev sib xyaw ntawm cov pa roj carbon tsawg thiab cov hlau huv. Carbon muaj ib tug siab solubility nyob rau hauv hlau thiab yog yooj yim soluble nyob rau hauv molten steel, uas yuav ua rau muaj kuab paug rau cov hlau molten. Thaum lub RH rauv tshuab cua tshuab pa kom decarburize cov hlau molten, cov pa roj carbon nyob rau hauv magnesia-carbon bricks kuj yooj yim oxidized, ua rau cov refractory puas. Tib lub sijhawm, tus nqi ntawm cov ntaub ntawv uas muaj cov pa roj carbon monoxide kuj nce ntxiv. Yog li ntawd, txhim kho ib puag ncig tus phooj ywg thiab lub zog txuag cov ntaub ntawv refractory los hloov cov ntaub ntawv magnesium-chromium yog ib txoj haujlwm tseem ceeb rau kev lag luam steel thiab kev lag luam refractory.
