Al_(2)O_(3)-SiC castables,for the relining of BF hearths in mid-campaign repair,were sampled and investigated after two years’service.The chemical and mineralogical characteristics of the residual castables were anal...Al_(2)O_(3)-SiC castables,for the relining of BF hearths in mid-campaign repair,were sampled and investigated after two years’service.The chemical and mineralogical characteristics of the residual castables were analyzed by X-ray diffraction,scanning electron microscopy,and energy dispersive X-ray spectrometry to study the erosion mechanism.The results show that as gaseous K diffuses in the castables,leucite(KAlSi_(2)O_(8))and multiple cracks are formed.Molten iron and slag penetrate through the cracks to form anorthite([Ca,Na][Al,Si]_(4)O_(8))and iron,which will not form an embrittlement layer similar to carbon bricks.The entire repair of the hearth with Al_(2)O_(3)-SiC castables combined with the design of thin-wall lining hearth eliminates“elephant foot shaped”erosion,greatly prolonging the service life of the hearth lining.展开更多
Cooling water provides the best protection for refractory in the blast furnace hearth. Stable and suitable water quality and abundant cooling water are the basis for long service life of the hearth. Some phenomena abo...Cooling water provides the best protection for refractory in the blast furnace hearth. Stable and suitable water quality and abundant cooling water are the basis for long service life of the hearth. Some phenomena about cooling system in the commercial blast furnaces were described, and reasonable explanations of these phenomena were analyzed. The results show that increasing the amount of cooling water and reducing the inlet temperature of cooling water can increase the cooling effect significantly in the case of water scaling. Heat flux in the blast furnace hearth is the average heat flux of cooling stave, and the erosion of carbon brick is uneven. There is no direct connection between the actual erosion condition and the heat flux in the hearth. The change trend of thermocouple temperature and heat flux in the hearth can reflect whether the gaps exist among the bricks or not, providing an effective guidance for industrial production and the evaluation of safety state in the hearth. And, the film boiling will not occur in the normal cooling system in the blast furnace hearth.展开更多
The cooling water flow rate for hearth of large blast furnaces was calculated by simulation. The results show that the cooling water flow rate shall be above 4 200m3/ h for hearth of large blast furnaces; to meet requ...The cooling water flow rate for hearth of large blast furnaces was calculated by simulation. The results show that the cooling water flow rate shall be above 4 200m3/ h for hearth of large blast furnaces; to meet requirements of the increasing smelting intensity and to ensure the safety at the end of the first campaign,the designed maximum cooling water flow rate should be 5 900m3/ h; according to the flow distribution stability and the calculated resistance loss,hearth cooling stave pipes with the specification of 76 mm × 6 mm shall be adopted to assure the flow velocity in pipes of hearth cooling stave in the range of 1. 9- 2. 3 m / s.展开更多
The article introduces the composition and working principle of the batching and weighing system underneath the blast furnace hearth.Besides,the shortcomings of the batching and weighing system during installation,deb...The article introduces the composition and working principle of the batching and weighing system underneath the blast furnace hearth.Besides,the shortcomings of the batching and weighing system during installation,debugging,and calibration,as well as the dynamic errors in the batching process are also analyzed.Corresponding solutions are then provided.展开更多
文摘Al_(2)O_(3)-SiC castables,for the relining of BF hearths in mid-campaign repair,were sampled and investigated after two years’service.The chemical and mineralogical characteristics of the residual castables were analyzed by X-ray diffraction,scanning electron microscopy,and energy dispersive X-ray spectrometry to study the erosion mechanism.The results show that as gaseous K diffuses in the castables,leucite(KAlSi_(2)O_(8))and multiple cracks are formed.Molten iron and slag penetrate through the cracks to form anorthite([Ca,Na][Al,Si]_(4)O_(8))and iron,which will not form an embrittlement layer similar to carbon bricks.The entire repair of the hearth with Al_(2)O_(3)-SiC castables combined with the design of thin-wall lining hearth eliminates“elephant foot shaped”erosion,greatly prolonging the service life of the hearth lining.
基金This work National Science Foundation （51704019）. was financially supported by the for Young Scientists of China
文摘Cooling water provides the best protection for refractory in the blast furnace hearth. Stable and suitable water quality and abundant cooling water are the basis for long service life of the hearth. Some phenomena about cooling system in the commercial blast furnaces were described, and reasonable explanations of these phenomena were analyzed. The results show that increasing the amount of cooling water and reducing the inlet temperature of cooling water can increase the cooling effect significantly in the case of water scaling. Heat flux in the blast furnace hearth is the average heat flux of cooling stave, and the erosion of carbon brick is uneven. There is no direct connection between the actual erosion condition and the heat flux in the hearth. The change trend of thermocouple temperature and heat flux in the hearth can reflect whether the gaps exist among the bricks or not, providing an effective guidance for industrial production and the evaluation of safety state in the hearth. And, the film boiling will not occur in the normal cooling system in the blast furnace hearth.
文摘The cooling water flow rate for hearth of large blast furnaces was calculated by simulation. The results show that the cooling water flow rate shall be above 4 200m3/ h for hearth of large blast furnaces; to meet requirements of the increasing smelting intensity and to ensure the safety at the end of the first campaign,the designed maximum cooling water flow rate should be 5 900m3/ h; according to the flow distribution stability and the calculated resistance loss,hearth cooling stave pipes with the specification of 76 mm × 6 mm shall be adopted to assure the flow velocity in pipes of hearth cooling stave in the range of 1. 9- 2. 3 m / s.
文摘The article introduces the composition and working principle of the batching and weighing system underneath the blast furnace hearth.Besides,the shortcomings of the batching and weighing system during installation,debugging,and calibration,as well as the dynamic errors in the batching process are also analyzed.Corresponding solutions are then provided.
