At present,the refractory materials which used in the blast furnace tapping trenches in China are mainly Al2O3-SiC-C castables.This paper reviewed the current research progress of domestic scholars to prepare new Al2O3-SiC-C castables by changing Al2O3 source,replacing carbon source,silica sol binder to replace aluminate cement and adding different additives.Finally,some suggestions for the development of Al2O3-SiC-C castables are proposed.

good application results.

With 97 fused magnesia with the particle size of 5~3 mm,3~1 mm,1~0 mm as main raw materials,97 fused magnesia with the particle size of ≤0.088 mm and MA spinel as matrix,four kinds of MgO-MA samples were prepared，the effects of α-Al2O3 micro-powder (~2  μm),zirconia (~5 μm) and titania (~1 μm) on the strength,thermal shock resistance and slag resistance of specimens fired at 1 700 ℃ were studied.The results show that the specimen with titania has the highest strength,the best thermal shock resistance and slag resistance because of the excellent pore structure and binders，the titania additive can effectively improve the properties of fired MgO-MA based refractory.

In this paper,the current situation of magnesite resources in Liaoning province as well as the market position of magnesia refractory in domestic and foreign market was introduced.From different aspects of ore supplement,productive capacity,technical equipment,transformation and upgrading,environmental protection and business management,the main problems of the magnesia refractory industry were discussed.In order to speed up the industrial structure adjustment,transformation and upgrading,and achieve high-quality development,this paper puts forward some practical countermeasures and suggestions.

The ultra-light siliceous refractories were prepared by foaming method firing at 1 400 ℃ for 4 hours.The influences of the amount of water added,the amount of waste silica brick powder added and the stirring time on the porosity,bulk density,cold crushing strength and thermal conductivity of the sample were explored.The results show that as the amount of water added increases,the porosity of the sample increases while the bulk density,cold crushing strength and thermal conductivity decrease.The performance is better when the added amount is 50%,which will adversely affect the structure of the sample when too much is added.As the amount of waste silica brick powder added increases,the porosity of the sample increases while the bulk density,the cold crushing strength,and the thermal conductivity decrease,when the added amount is 30%,the porosity is the highest,the bulk density,the cold crushing strength and the thermal conductivity are the lowest.As the stirring time increases,the bulk density of the sample decreases,and the porosity increases.When the stirring time is 15 min,the bulk density of the sample is the lowest,the porosity is the largest,the cold crushing strength is the highest,the thermal conductivity is the lowest,the number of pores is large,and the pore size is uniform,and the distrbution is uniform in the sample.

The standard for quantitative analysis of α-quartz phase by X-ray diffraction has always been YB/T 172-2000.The revised standard will be adopted on April 1,2021.The comparison of the standard before and after revision shows that when the content is ≤5.2%,the absolute error before and after revision is ≤0.10；When the content is >5.2%,the absolute error before and after revision is >0.10;and the absolute error increases with the increase of the content.The revised standard has well inherited and developed the technical requirements of YB/T 172-2000.It has strong operability,high accuracy,good repeatability,and it is more convenient and fast.The diffraction intensity value of the sample can be directly substituted into the working curve to obtain the analysis results.

The performance of silicon mud directly affects the quality of coke oven masonry and its service life.The practical application of domestic silicon mud in coke oven shows that its performance is better than that of Japanese silicon mud,which reduces the cost and improves the economic benefit.

On the basis of the original experience of production and operation of Maerz kiln，the existing equipment，feeding equipment and gas system of Maerz kiln in Fangchenggang steel plant are optimized and improved，which reduces the cost of kiln construction，reduces the failure rate of Maerz kiln equipment，improves the production stability and achieves good results.

The effect of the amount of recycled material on slag erosion resistance of recycled magnesia-carbon brick was analyzed in this paper.The results show that the compressive strength,bulk density and porosity of regenerated magnesia-carbon brick decrease with the increase of the amount of recycled material.The anti-erosion performance of regenerated magnesia-carbon brick with 5% recycled material after adding antioxidant was the best.

By analyzing the characteristics of ladle nozzle mould and combining the shape and production process of the products,the nozzle mould is optimized,the stability of product use is improved and production cost is reduced,which can achieve the purpose of improving product competitiveness.