JIANG Jimu,HUANG Xinyuan,ZHOU Ningsheng and LI Zhaoxia (4) 3
Abstract
There exists a reciprocal relationship between refractories industry and high temperature industries, in particular metallurgy industry. Refractories are consumed in many metallurgical processes of nonferrous metallurgy industry and have close association with the technological progress of this sector. In the past two decades, China’s nonferrous metallurgy industry has kept fast growing, with much increased output, improved process technologies and more imported advanced equipment and technologies, which have put forward stringer requirements on refractories, not only in quantity, but in variety and performance as well. This article, based on the authors’ knowledge and information, reviews the development of China’s nonferrous metallurgy industry in recent years and the related refractories issues.
 

ZHANG Haijun,LIU Zhanjie and ZHONG Xiangchong (4) 8
Abstract
The phase composition and microstructure of Sialon prepared from Chinese bauxite have been studied. The use of Si powder is more effective than that of activated carbon for reduction-nitridation. For bauxite specimens with 40~50% Si addition, more than 90% of Sialon may be obtained when nitrided at 1450~1500°C ; the main crystalline phase is O¢-Sialon (Z=0.2).

WU Xingrong,LI Liaosha and DONG Yuanchi (4) 13
Abstract
Boehmite sol is synthesized via sol-gel process using Al2(SO4)3·18H2O and (CH2)6N4 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 resistence are measured. Results show that the mullite gel can improve densification and strength of corundum-mullite firebricks, especially enhance the thermal shock resistence. 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 resistence of the samples.
 

BU Jinglong,YU Zhidong,WANG Ruisheng and WANG Zhifa et al.(4)17
Abstract
Sintering additives to gelcasting Sialon-SiC were decided by the optimizing experiments. The results show that Sialon-SiC can be sintered under 1450°C and sintering temperature decreases by 100°C, when 2%～3% TiO2 or Guangxi clay is used as sintering additive.
 

YANG Xianfeng,WANG Jinxiang and YANG Bin(4)21
Abstract
The role of nano-SiO2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated. The study showed that the ultra-fine boron carbide added modified the microstructure of residual carbon and promoted the chemical bond between residual carbon from phenolic resin and flake graphite. The carbon white could strengthen the residual carbon from phenolic resin. These two additives improved the mechanical properties of AG refractories at both room temperature and high temperature, and thermal shock resistance was improved noticeably. When the two additives were doped together, carbon white could retard the evaporation of B2O3. Thermal shock resistance was guaranteed with a smaller amount of ultra-fine boron carbide.