Commercial high purity corundum brick,corundum-mullite brick,mullite brick,calcium hexaaluminate brick and calcium hexaaluminate-corundum brick were studied to investigate their reaction state and alkali vapor corrosi...Commercial high purity corundum brick,corundum-mullite brick,mullite brick,calcium hexaaluminate brick and calcium hexaaluminate-corundum brick were studied to investigate their reaction state and alkali vapor corrosion mechanism at 1370 and 1500℃.The results show that:(1)served in hot alkali vapor,the high-purity corundum brick has no obvious slag layer but expands dramatically;(2)the corundum-mullite brick shows obvious reactive expansion at 1370℃and melting corrosion happens at 1500℃;(3)at 1370℃alkali vapor and mullite brick react and form a slag layer without volume effect;when the temperature increases to 1500℃,the reaction melting corrosion intensifies;(4)the calcium hexaaluminate brick and the calcium hexaaluminate-corundum brick form a thin slag layer in alkali vapor,and the sample surface absorbs Na+to form a dense layer with small volume effect.展开更多
A SiC assembled large block for blast furnace tuyeres was prepared using silicon carbide particles(3-1 and 1-0.088 mm)and fine powder(<0.088 mm),silicon powder(<0.088 mm),industrial carbon black(N990),microsili...A SiC assembled large block for blast furnace tuyeres was prepared using silicon carbide particles(3-1 and 1-0.088 mm)and fine powder(<0.088 mm),silicon powder(<0.088 mm),industrial carbon black(N990),microsilica,ρ-Al_(2)O_(3) powder,etc.as raw materials.The developed block was compared with a silicon nitride bonded silicon carbide brick,a self-bonded silicon carbide brick and an imported self-bonded silicon carbide block to analyze and evaluate their service performance.The results show that:(1)in the 0-100 mm zone,the SiC large block mainly consists ofβ-SiC and nitrides such as O'-SiAlON,β-SiAlON,α-Si_(3)N_(4),and Si_(2)N_(2)O,the bulk density is 2.68-2.70 g·cm^(-3),the apparent porosity is 14%-15%,and the material structure is uniform;(2)in the 0-100 mm zone,β-SiC nano-whiskers intercalate with nitrides;with the depth increasing,the number of flocculentβ-SiC nano-whiskers increases,while the number of nitrides decreases;when the depth reaches 150 mm or more,the main bonding phases areβ-SiC and mullite;(3)compared with the reference products,the developed SiC large block has a good basic performance,and after alkali corrosion,the mass change rate is-0.1%,which is obviously superior to the imported self-bonded silicon carbide and the homemade silicon nitride bonded silicon carbide materials.展开更多
文摘Commercial high purity corundum brick,corundum-mullite brick,mullite brick,calcium hexaaluminate brick and calcium hexaaluminate-corundum brick were studied to investigate their reaction state and alkali vapor corrosion mechanism at 1370 and 1500℃.The results show that:(1)served in hot alkali vapor,the high-purity corundum brick has no obvious slag layer but expands dramatically;(2)the corundum-mullite brick shows obvious reactive expansion at 1370℃and melting corrosion happens at 1500℃;(3)at 1370℃alkali vapor and mullite brick react and form a slag layer without volume effect;when the temperature increases to 1500℃,the reaction melting corrosion intensifies;(4)the calcium hexaaluminate brick and the calcium hexaaluminate-corundum brick form a thin slag layer in alkali vapor,and the sample surface absorbs Na+to form a dense layer with small volume effect.
文摘A SiC assembled large block for blast furnace tuyeres was prepared using silicon carbide particles(3-1 and 1-0.088 mm)and fine powder(<0.088 mm),silicon powder(<0.088 mm),industrial carbon black(N990),microsilica,ρ-Al_(2)O_(3) powder,etc.as raw materials.The developed block was compared with a silicon nitride bonded silicon carbide brick,a self-bonded silicon carbide brick and an imported self-bonded silicon carbide block to analyze and evaluate their service performance.The results show that:(1)in the 0-100 mm zone,the SiC large block mainly consists ofβ-SiC and nitrides such as O'-SiAlON,β-SiAlON,α-Si_(3)N_(4),and Si_(2)N_(2)O,the bulk density is 2.68-2.70 g·cm^(-3),the apparent porosity is 14%-15%,and the material structure is uniform;(2)in the 0-100 mm zone,β-SiC nano-whiskers intercalate with nitrides;with the depth increasing,the number of flocculentβ-SiC nano-whiskers increases,while the number of nitrides decreases;when the depth reaches 150 mm or more,the main bonding phases areβ-SiC and mullite;(3)compared with the reference products,the developed SiC large block has a good basic performance,and after alkali corrosion,the mass change rate is-0.1%,which is obviously superior to the imported self-bonded silicon carbide and the homemade silicon nitride bonded silicon carbide materials.
