ZHOU Ningsheng,HU Shuhe and ZHANG Sanhua (2) 3
Abstract
Recent developments in terms of binding system, new material system, installation method and pre-cast shapes of refractory castables are introduced and discussed. In authors’ view, binding system is advancing on the one hand towards “purification” to minimize impurity components from binder materials, and on the other hand “stabilization” to minimize the structure destroy by volatility and decomposition of binder materials. Challenges of higher service temperature, slag resistance, clean steel production and better thermal shock resistance have promoted the booming of new varieties of castables including MgO based, natural flake graphite containing and non-oxides like Si3N4, AlON and SiAlON containing castables. Installation technique is developing towards convenience, simplification and high efficiency. Advancement in installation and dry-out is of an incentive to the boost of self-flow castables, shotcreting castables, infiltration casting, quick dry-out castables and pre-cast shapes. Along with the increased adoption of pre-cast shapes of castables, the boundary between “shaped” and “unshaped” is becoming vague.
 

B.Hashemi,Z.Ali Nemati and S.K.Sadrnezhaad (2) 13
Abstract
An investigation on the oxidation mechanism of the graphite in the MgO-C refractory materials is helpful to improving both the quality of these materials and to preventing and/or lowering of the adverse effects of the high-temperature oxidation. In this research, the oxidation behavior of the MgO-C refractories containing 5–20 wt% graphite was studied via weight-loss method. Atmospheric air was used for oxidation at temperatures ranging from 900°C to 1300°C and the experimental data were compared with those obtained from the dimensionless kinetic equations of the shrinking core model, in order to determine the oxidation mechanisms of the refractories. The best fit was achieved with the porous layer diffusion control regime. Oxidation mechanism tends, however, to slightly deviate from pure pore diffusion control to pore diffusion-external gas transfer regime in the samples having more graphite contents (e.g. 20%).

YANG Daoyuan,GUO Xinrong and ZHONG Xiangchong(2)21
Abstract
MgO·Al2O3 spinel fibers may be obtained by thermal treatment of pressed specimens composed of Mg-Al-O materials with appropriate oxide-metal ratio at high temperature under controlled atmosphere. Their phase composition and microstructure have been examined.
 

QI Xiaoqing and CHEN Renpin (2) 24
Abstract
The microstructure and phase composition of high chrome brick (LIRR-HK90) used in coal slurry gasifier has been analyzed by means of SEM and Energy Spectrum. The results indicate that the used brick can be divided into different zones as slag-adhered zone, reaction zone, penetration zone and unaltered zone. The phase composition and microstructure are different and cracks around in different degree at these zones. A dense ring belt was formed with complex spinel (Mg、Fe)（Cr、Al、Fe）2O4 in the reaction zone near the hot face. The wear mechanism of the brick during its employment has been discussed. It is considered that the reaction and penetration of coal slag and strong reductant bring about the composition change of the brick and destroys its original network inlayed structure and consequently result in its structure spalling and weakening strength, which is the main wear mechanism of the brick and followed by temperature fluctuation and high mechanical impact of flowing fluid with high-speed. 
 

LIU Huilin,REN Xiangyang,YUAN Cuiju,LI Yong and SHEN Weiping (2) 29
Abstract
Special grade bauxite and roll scale was used as raw materials to investigate, the influences of reducing atmosphere and firing temperature on sintering clinker. The results showed that: 1) The maxture of the materials could be sintered enough to synthesise hercynite under reducing atmosphere by adding reducing reagent; 2) The hercynite clinker could be sintered to high density and the content of FeAl2O4 may attain 80~90% under the firing temperature of 1550℃.
 

WU Xingrong and CAO Feng(2)33
Abstract
Silicon fines, boron acid solid powders and microfine SiO2 as sintering agents were incorporated into Al2O3-SiC-C ramming mix in order to investigated their effects on the microstructure, mechanical properties and sintering behavior of the ramming masses. Results show that all the three agents could improved both densification and mechanical properties markedly, compared to that of non-agent specimens and the effect of the composite of boron acid solid powders and microfine SiO2 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.