Magnesia chrome bricks were prepared with fiLsed MgO- Cr2 O3 synthesized material, fused magnesite and ：hrome ore as main starting materials. Nano-Al2O3 was tdded into refractories （ 2% , 4% and 6% in mass ） ;ubst...Magnesia chrome bricks were prepared with fiLsed MgO- Cr2 O3 synthesized material, fused magnesite and ：hrome ore as main starting materials. Nano-Al2O3 was tdded into refractories （ 2% , 4% and 6% in mass ） ;ubstit,ting for Al203 micropowder. After m＆ing and ;haping, the bricks were fired at 1 550 ℃, 1 600 91℃, t 650 ℃ and 1 750℃, respectively. The microstruc-ure , sintering property, mechanical properties, thermal ;kock resistance and shtg resistance of the specimens with he addition of nano-Al2O3 were investigated. The results indicate that the performance of brick with 4 mass% of nano-Al2O3 is greatly improred afier firing at 1 650 ℃.展开更多
Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,th...Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,the bricks tend to have reaction with water or moisture and result in cracks and loss on their structural strength. Those bricks cannot be used anymore and cause substantial loss for the related parties. In 2013,the Siam Refractory Industry Co.,Ltd.,Thailand,successfully developed and applied a special nano-technology to create ＂Anti-Hydration Magnesia-Spinel Bricks ＂ for cement industry which can have the storage time more than two years even in high humidity areas. The cement producers can ensure that all bricks still have good properties as the new ones.展开更多
The precursor for nano-sized magnesia was prepared by using Mg(NO3)2·6H2O as raw material, the hydrolysis product of hexamethylene tetramine as precipitating reagent and water as reaction media, and with the poly...The precursor for nano-sized magnesia was prepared by using Mg(NO3)2·6H2O as raw material, the hydrolysis product of hexamethylene tetramine as precipitating reagent and water as reaction media, and with the polymer (PEG) and DMF as protection reagents for particles. Nano-sized magnesia was prepared by calcining the precursor at 873 K after being dehydrated by freeze centrifugation and vacuum drying at a constant temperature. The formation process and structure of MgO nanocrystallites were investigated by means of TG-DTA, FTIR, TEM, XRD and BET. The results showed that the crystal belonged to cubic system and the average size was 3.1 nm and the specific surface area was 229 m2·g-1.展开更多
文摘Magnesia chrome bricks were prepared with fiLsed MgO- Cr2 O3 synthesized material, fused magnesite and ：hrome ore as main starting materials. Nano-Al2O3 was tdded into refractories （ 2% , 4% and 6% in mass ） ;ubstit,ting for Al203 micropowder. After m＆ing and ;haping, the bricks were fired at 1 550 ℃, 1 600 91℃, t 650 ℃ and 1 750℃, respectively. The microstruc-ure , sintering property, mechanical properties, thermal ;kock resistance and shtg resistance of the specimens with he addition of nano-Al2O3 were investigated. The results indicate that the performance of brick with 4 mass% of nano-Al2O3 is greatly improred afier firing at 1 650 ℃.
文摘Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,the bricks tend to have reaction with water or moisture and result in cracks and loss on their structural strength. Those bricks cannot be used anymore and cause substantial loss for the related parties. In 2013,the Siam Refractory Industry Co.,Ltd.,Thailand,successfully developed and applied a special nano-technology to create ＂Anti-Hydration Magnesia-Spinel Bricks ＂ for cement industry which can have the storage time more than two years even in high humidity areas. The cement producers can ensure that all bricks still have good properties as the new ones.
文摘The precursor for nano-sized magnesia was prepared by using Mg(NO3)2·6H2O as raw material, the hydrolysis product of hexamethylene tetramine as precipitating reagent and water as reaction media, and with the polymer (PEG) and DMF as protection reagents for particles. Nano-sized magnesia was prepared by calcining the precursor at 873 K after being dehydrated by freeze centrifugation and vacuum drying at a constant temperature. The formation process and structure of MgO nanocrystallites were investigated by means of TG-DTA, FTIR, TEM, XRD and BET. The results showed that the crystal belonged to cubic system and the average size was 3.1 nm and the specific surface area was 229 m2·g-1.
