The Microstructure and Properties of Alumina—Rich Spinel and Its Products

The paper describes the effect of chemical composition on the microstructure and properties of spinel specimens synthesized from bauxite and magnesite,The alumina-rich spinel with higher ratio of Al2O3/MgO,with smaller spinel grain,contains more titaniferous mineral and silicate phase compared to the spinel with lower Al2O3/MgO ratio.In the products obtained from alumina-rich spinel and magnesite clinker,the ratio of Al2O3/MgO of spinel decreases,ti-taniferous mineral and silicate phase in the spinel aggregate are changed,and its content tends to degradation,contrasted with original alumina-rich spinel,The products have good high temperature properties.

Improvement on Thermal Conductivity Measurement Involved in ISO 8894—2

Measurements of thermal conductivity of some materials have been conducted using parallel hot wire method desribed in ISO8894-2,With improved techniques,the measuring range has been extended ,It is suggested that this method be used to determine thermal conductivity of various refractories more widely.

Study on Slag Resistance of Self—flowing Type Alumina—Spinel Castable

Four kinds of slags with different compositions have been chosen for comparing the slag resistance of the castable by crucible slag test,It is found that CaO/SiO2 ration and rerrite content have certain influence on the slag resistance of the castable.

Test Method for Determination of Thermal Shock resistance（Air Quenching）

On the basis of the theory of thermal shock resistance in the science of materials and the test method of air quenching which is generally rec-ognized internationally,especially in Europe,the present test methods for determination of thermal shock resistance in China have been analysed,Experiment study on thermal shock resis-tance of silica and basic refractory products has been conducted,and a new test method of thermal shock resistance-air quenching method has been put forward.

Study of Thermal Expansion of Al2O3—MgO—C Bricks Used in Ladles

The reason that Al2O3-MgO-C bricks and Al2O3-Spinel-C bricks excesively expand when used in ladles at high temperature has been analysed,and the effects of spinels aadding amount and their chemical constituents on ther-mal expanion have been studied ,It is pointed out that adding amount of spinels and their chemical contents are the key factors to bring the excessive expansion of above-mentioned bricks at high temperature under control.

Development of Forsterite Based Insulating Board for Alloy Steel Con—casting Tundish

To meet the operation requirement of com-casting tundish for alloy steel.a forsterite based insulating board has been developed.The effects of binder ,fiber and other additives on the properties of the properties of the products have been described;the theoretial reason of assuring containing clear steel by using inorganic binder bonded forsterite based insulating board were also discussed;the mineral composition and microstructure of the products have been analyzed by means of XRD.SEM and microscope ,The results indicate that the forsteite based insulating board with excel-lent performance and dood application results has been obtained.

Synthesis of ZrO2—Al2O3 Ultrafines Composites and Their Sintering Behavior

Four kinds of ultrafies were manufac-tured by different methods,Sintering behavior,mechanical properties,thermal shock resis-tance and microstructure were studied,ZrO2 grains and Al2O3 grains can inhibit each other's growth during sintering process,ZrO2-Al2O3 comosites have higher sintering temperatures than single Y-ZrO2 or Al2O3 materials,Proper ZrO2 addition can reinforce and densify Al2O3 ultrafines material as well as improve thermal shock resistance,20wt% Al2O3 doped to 3Y-ZrO3 material is beneficial to stability of ZrO2 materials,the bend strength can reach 817.8 MPa.

Investigation and Application of Cr2O3—Al2O3—ZrO2 Refractories for Slagging Coal Gasifiers

High-chromia grains were synthesized by sintering and fusing methods,It was difficult for their sintering body to densify by sintering proess,but high densification grains with high chromia content could be obtained by fusing process.High performance,Cr2O3-Al2O3-ZrO2 refractories needed a suitable amount of alumina powder and pigment chromia,as well as the additive form of unstabilized zirconia,80% Cr2O3 material was ined in a slagging coal gasifier and had gained the service life of 6003 h.The improved Cr2O3-Al2O3-ZrO2 refractory has been used in most of the coal gasi-fiers in China and much better performance is being proved.

Effect of CeO2 on Sintering and Hydration Resistance of Natural Dolomite

The sinteribility and hydration resistance of high pure natural dolomite doped with CeO2 addition were studied.It is found that the addition of CeO2 to dolomite can significantly improve the sintering and the resistane to hydration of dolomite.Doping 0.25% CeO2,followed by firing at 1600℃ for 4 hours,a dense doloma clinker with bulk density>3.25 g/cm^3, apparent porosity<1.0% and excellent hydration resistance has been obtained.

Application of Refractories in Chemical and Petrochemical Industries

Over the last decade,significant development of chemicl and petrochemical industries has been achieved in China,Fluid catalytic cracking,steam reforming furnace,carbon black reactor,oil gasifier and coal gasifier are common chemical reactos operated at high tem-perature,A number of the high technological refractory bricks and castables,mainly developed by LIRR,have been used in their serious working environments,The roperies and service performance of these materials are reviewed.