Study On The On-line Replacing Porous Bricks And Long-term Blowing Technology In Combined Blowing Converter

The safety and economy of bottom blowing porous bricks is the key for the combined blowing.Metallurgical effects of combined converter increased with further research of bottom blowing elements,but the life desynchrony of porous bricks and converter lining become increasingly obvious.At present,on-line heat replacing of porous bricks is used to solve the problem of the porous brickone-time lifeand convert lining life getting out of synchronization.In the case of field investigation,the damage mechanism was revealed throughdetection analysis of used porous bricks.The effects of materials,antioxidants and preparation technology on the properties were studied.The on-line replacing of porous brickswas studied,through making up programs and processes,and forecasting the safety of operation.The effect factors on the permeability of porous bricks were investigated.And the protective measures were presented to prolong the service life of converter.The results are as follows:(1)The analysis results of used porous bricks showed that the damage was not the high temperature corrosion,but the mechanical damage and thermal shock.With increasing of fused magnesia critical particle size,the thermal expansion rate increased,the proper critical particle size of fused magnesia wasabout 2mm.It was found that the bottom blowing elements with good properties,such as the best oxidation resistance,more dense structure,high strength at room temperature,high bending strength at high temperature,high power blowing,and mixing well were obtained,when theporous brick specimens were added with Mg/Al alloy and B4C powders,whichled metal plastic phase transition principle and selfpropagating combustion reaction principle.(2)The programs and processes were made by studying on-line replacing the bottom blowing porous bricks.After applied the on-line replacing porous bricks,the significant metallurgical effectsandeconomic benefits were achieved.The metallurgical indexes,such as carbon-oxygen equilibrium,total iron,phosphorusand oxygen content in end point slag,oxygen supply time and capacity,were improved.Moreover,the cost per ton of steel was cut down more than 2.89 yuan,considering the consumptions of gas,deoxidation alloy and steel materials.(3)The combined blowing and converter lining life can be kept in step with each other by optimizing the layout of bottom blowing porous bricks,making reasonable operating procedures and strengthening the maintenance of bottom blowing porous bricks.