Sintering Behaviour of Al_2O_3-SiC-C Ramming Mix

Silicon fines, boron acid solid powders and microfine SiO 2 as sintering agents were incorporated into Al 2O 3-SiC-C ramming mix in order to investigated their effects on the microstructure, mechanical properties and sintering behavior of the ramming mix. Results show that all the three agents could improved both densification and mehanical properties markedly, compared to that of non-agent specimens and the effect of the composite of boron acid solid powders and microfine SiO 2 is the best. The oxidation resistance increased with the addition of agents, which is supported by densification. Microstructures showed that agent powders could fill pores or produce liquid phases at high temperature, therefore, improve the sintering of the ramming mix.

Rheological and Adhesive Behavior of Gunning Mix for Blast Furnace Repair

The aim of this experimental work was to investigate the Theological and adhesive performance of gunning mix suspensions. The results of rheological tests indicate that: the rheological curve of gunning mix bonded by high-alumina cement (HACG) is Bingham type ; the rheological curve of low cement gunning mix (LCG) bonded by mi-crosilica is characterized by pseudo-plasticity fluid with yielding stress ; and the rheological property of low-cement gunning mix bonded by microsilica is proved to be better than that of gunning mix bonded by cement. Meanwhile as indicated by the adhesive tests: the better the rheological properties of gunning mix suspension , the better the repair effect would be.

Mullite Precursor Gels and as Binder in Corundum-mullite Refractory

Boehmite sol is synthesized via sol-gel process using Al 2(SO 4) 3·18H 2O and (CH 2) 6N 4 as starting materials, then adding silica sol into boehmite sol to prepare mullite precursor gels. XRD studies are performed to characterize the gels. It is found that the gel can be transformed into mullite when calcined at 1100℃ and completed at 1300℃. Corundum-mullite firebricks with different additions of the mullite precursor gel are made by mixing, semi-dry pressing and then sintering at 1520℃. Apparent porosity, bulk density, flexural strength and thermal shock resistance are measured. Results show that the mullite gel can improve densification and strength of corundum-mullite firebricks, especially enhance the thermal shock resistance. SEM micrographs show that the gel added can be formed into needlelike and elongated mullite in the matrix, whose micromorphology can enhance the strength and thermal shock resistance of the samples.

Tb^(3+)/Ce^(3+)掺杂高铝高炉渣构筑硅铝酸盐发光玻璃的发光性能

采用高铝高炉渣高温水淬法制备了Tb^(3+)单掺及Tb^(3+)/Ce^(3+)共掺的硅铝酸盐发光玻璃,研究了基体结构和共掺对玻璃发光性能的影响.结果表明:经过1000℃保温4 h后,玻璃晶化为Ca_(2)(Mg_(0.5)Al_(0.5))(Si_(1.5)Al_(0.5)O_(7)),发光性能急剧下降,4%(摩尔分数)Tb^(3+)掺杂的发光玻璃发光强度最高约是晶化后的12倍.Ce^(3+)和Tb^(3+)之间通过多极相互作用传递能量,Tb^(3+)/Ce^(3+)共掺的发光玻璃发光强度最高达到Tb^(3+)单掺的约6倍.4%Tb^(3+)/1%Ce^(3+)共掺的发光玻璃在150℃时具有良好的发光热稳定性,可以作为近紫外LED激发的绿光固体发光材料.