Magnesium refractory materials have high refractory performance and are alkaline (MgO melting point 2805 ℃), thus having good resistance to alkaline slag. However, due to their high coefficient of linear expansion ((14-15) X 10-6 ℃ -1, 0~1500 ℃), their thermal conductivity is low at high temperatures (λ Mg0100 ℃=34.33 W/(m · K), λ Mg01000 ℃=6.70 W/(m · K)), and their resistance to thermal spalling is poor. Graphite is difficult to wet by slag, has good melting resistance (graphite melting point>3000 degree), thiab muaj me me coefficient ntawm linear expansion (3.34 × 10-6℃-1, 25-1600 degree). Nws kuj muaj cov thermal conductivity zoo heev (λ graphite, 1000℃=229W/(m · K)), ua rau nws tiv taus thermal tev, tab sis nquag oxidation. Qhov tseem ceeb oxidation pib kub TA ntawm flake graphite feem ntau yog siab tshaj 580 degree. Qhia graphite rau hauv magnesium refractory cov ntaub ntawv txhim kho lawv cov slag kuj thiab tev tsis kam.
Thaum magnesia thiab graphite sib xyaw ua ke los ua magnesium carbon cib, magnesia carbon refractory cib pom zoo slag kuj, hlau corrosion kuj, permeability, thiab thermal shock kuj. Qhov laj thawj tseem ceeb yog:
Hom refractory cib
(1) Lub matrix ntawm magnesia carbon cib yog tsim los ntawm graphite thiab magnesia hmoov. Cov graphite thiab magnesia hais, nrog rau cov magnesia hais, nyob ib puag ncig los ntawm cov pa roj carbon monoxide muaj zog, uas tsis yooj yim rau plam. Tsis muaj eutectic kev sib raug zoo ntawm C thiab MgO, thiab tsis muaj cov theem ua kua. Tsuas yog ib qho me me ntawm cov kua theem yog tsim los ntawm impurities qhia los ntawm graphite thiab magnesia raw cov ntaub ntawv. Yog li ntawd, thaum siv, thaum lub siab permeable * * * nyob rau hauv lub slag ntsib carbon, nws yuav raug txo mus rau hlau hlau. Vim qhov txo cov nyhuv, lub melting point thiab viscosity ntawm slag nce, thiab cov permeability yog heev txo.
(2) Tsis ntub dej ntawm slag thiab molten hlau nrog graphite. Vim tias lub kaum sab xis ntawm slag thiab molten hlau thiab graphite yog siab dua 90 degree, magnesium carbon cib ua tau zoo heev tiv thaiv slag yaig.
(3) Cov nyhuv tiv thaiv ntawm kev tsim cov square magnesium txheej hauv cov khoom siv magnesia carbon cib; Thaum kub siab tshaj 400 degree, MgO hauv magnesia reacts nrog carbon los tsim Mg vapor. Mg vapor ntws tawm los ntawm qhov pores thiab reacts nrog FeO nyob rau hauv lub slag ntawm lub interface nyob rau hauv kev sib cuag nrog lub slag, ua magnesium oxide dua thiab tsim ib tug ntom txheej ntawm magnesia, yog li tiv thaiv infiltration ntawm lub slag.
(4) Kev cuam tshuam ntawm CO gas siab. Lub infiltrated slag reacts nrog cov pa roj carbon monoxide nyob rau hauv magnesia carbon cib los tsim CO gas, thiab lub siab nyob rau hauv lub pore channel yuav ncav cuag tshaj 0.2 MPa (2 atm), uas yuav tiv thaiv los yog ncua lub infiltration ntawm slag rau hauv lub pores.
Hu rau kuv:
Email:wp@cnjingganrefractory.com/sdwenping@163.com
Tus xov tooj: 86-0533-4188518 / FAX: 86-0533-4188518
Rose: +86-13275332819(wechat/whatsapp tus xov tooj)
