The corundum-spinel castable was prepared by using tabular alumina, white fused alumina,sintered magnesia-alumina spinel,active α-Al2O3 micropowder and calcium aluminate cement as main raw materials.The effects of different firing temperature on the physical properties and microstructure of corundum-spinel castable were studied.The results show that part of CA6 crystals begin to form after firing at 1 400  ℃.With the increase of firing temperature,a large number of CA6 crystals form and grow up,interspersing in the pores to form a continuous network structure.The continuous network structure makes the sample become dense and strengthens the combination of the matrix,and makes the fracture mode of the sample gradually change from intergranular fracture to transgranular fracture,so that CMOR ,HMOR and the thermal shock stability of the sample become continuously improved.After firing at 1 550  ℃,the HMOR of the sample is the highest and the thermal shock stability is the best.After firing at 1 400  ℃ to 1 450  ℃,the formation of CA6 crystal is dominant,and the sample shows expansion after firing; after firing at 1 500  ℃ to 1 550  ℃,the sintering is dominant,and the sample shows shrinkage after firing.After firing at 1 550  ℃,the shrinkage of the sample reached 0.25%.

Castables were prepared with high-quality bauxite,fused white corundum,tabular corundum,magnesium aluminate spinel,fused magnesia and alumina micro powder as main raw materials,and pure CAC, ρ-Al2O3 micro powder and magnesium gel as binders respectively.Effects of binder types,grain grading and addition amount of burst resistance agent on strength of ladle bottom after demolding,burst resistance performance and apparent porosity were compared.The results showed that the magnesium gel was the best binder for burst resistance,while silica micro powder was the secondary.Appropriate increase the amount grain and burst resistance agent was better for improving the burst resistance performance.

The combustion process in a lime kiln is the process of oxidation and reduction of fuel in the reburning zone.The process parameters not only affect the product quality,but also directly affect the NOx emission.The effects of temperature and air excess coefficient on fuel nitrogen oxide reduction are analysed.The results show that adjusting combustion parameters is an effective way to reduce NOx emission.

With fused magnesia as aggregate,fused magnesia powder,sintered magnesia powder and carbonaceous material as matrix material,some anti oxidants,promoters,wetting agents and composite binders are added,and proper particle gradation is selected,a large surface mending material for converter with dense and long life is developed,which can meet the requirements of the site.In this paper,the particle size distribution,the type and particle size of carbonaceous materials and the amount of their addition,as well as the type and amount of the promoters and wetting agents were studied.The results show that the particle size distribution is better when the ratio of coarse,medium and fine is 20∶40∶40.The composite use of carbonaceous materials is conducive to the improvement of various properties of the mending materials.The combustion promoter can promote the carbonization of carbonaceous materials such as asphalt and shorten the sintering time.The wetting agent can reduce the dust during production,which is beneficial to environmental protection.In addition,it can enhance the combination of magnesia and asphalt,which is conducive to the improvement of the high temperature performance of the mending materials.

Thermal insulation measures should be taken during the winter construction of refractory castable for heating furnace.This paper proposes a series of practical thermal insulation measures on site,which can be applied to heating furnace construction in winter such as new construction,minor repair,medium repair and overhaul according to actual conditions.

Ladle shroud is an important part of the sliding nozzle system.In this paper,the causes of the problems such as transverse fracture,perforation, steel entrainment and steel sticking of the ladle shroud in service are analyzed,and some improvement measures are summarized.

In order to meet the demand of alkaline pellet production line and flue gas desulfurization for lime,it is necessary to build a line kiln with output of 630 000 tons  per year.Based on the basic design conditions,three central burner kilns with output of 600 tons per day using blast furnace gas were built.After ten months of construction,three kilns were delivered for use.According to production situation,the output,quality,consumption,pollutant discharge and other indicators can meet the design requirements and the demands of lime for the production line.

In this paper,the recycling status of carbon-containing refractories after use is summarized,and some research achievements of recycling of magnesia-carbon refractories,alumina-magnesia-carbon refractories,alumina-carbon refractories and alumina-silicon carbide-carbon refractories after use are mainly introduced.The recycling of carbon-containing refractories after use can not only effectively reduce the production cost,but also protect the environment and bring some economic benefits.

In order to understand the causes of cracking and damage of magnesium slag dam in tundish，the physical properties，phase composition，thermal shock resistance and slag resistance of castable preforms for slag dam at room temperature were detected and analyzed by X-ray diffraction，scanning electron microscope and other detection methods.The results show that molten steel and slag infiltrate along the pores and cracks of the slag dam of the tundish，and forsterite and slag react in the erosion and infiltration layer to form low melting point monticellite or magnesium rhodonite，etc.At the same time，the molten slag infiltrating in the refractory material causes the composition of the infiltration layer and the original layer to be different，and the thermal expansion and cold contraction are inconsistent，resulting in separation and cracking，which generates a large number of cracks and intensifies the cracking damage of the slag dam.

The content of amorphous phase in refractories was quantitatively analyzed by X-ray diffraction.The fireclay brick was analyzed by internal standard,and the silica brick was quantitatively analyzed by external standard.Through the comparison of the test results from Sinosteel Luoyang Institute of Refractories Research Co.,Ltd., Bruker (Beijing) and our laboratory,it is found that the amorphous phase content in fireclay brick and silica brick were satisfactory and achieve the expected goal.

This paper introduces the operational principle of hoisting and feeding trolley,and puts forward solutions to the existing problems,optimizes the trolley control system,and ensures the stable operation and no failure.