Study On Hearth Erosion Behavior And Mechanism Of One 1800m~3 Domestic Blast Furnace

With the development of large-scale blast furnace,it is urgent to study the longevity technology of blast furnace.The erosion rate of brick lining in hearth of blast furnace,as a limiting link of blast furnace life,has attracted close attention of researchers.The first generation of this blast furnace had only lasted for 7 years and 3 months.It belongs to one of the shorter blast furnaces in China.Through the investigation of hearth damage,the erosion behavior and mechanism of hearth was studied.In this paper,general situation of the blast furnace campaign was introduced.The rationality of blast furnace design was evaluated from the aspects of hearth structure,refractory,cooling system and hot stove system.Also,the general production situation during the campaign period of blast furnace was briefly described.Secondly,the erosion pattern and regularity of hearth and bottom of blast furnace were summarized,and the erosion morphology and characteristics in hearth were analyzed.According to the highest temperature of thermocouple in hearth inner ring and temperature of the corresponding cold end,the theoretical calculation value of residual thickness of carbon brick in hearth was obtained,which has a certain reference value for analyzing the actual erosion condition of carbon brick.At the same time,the temperature trend of thermocouples at 7.851 m,8.653 m and 9.455 m elevations where hearth erosion was serious at the end of campaign was summarized.Combined with the corresponding content changes of Mn,Ti and other elements in molten iron,the actual erosion situation of brick linings at various parts of hearth was comprehensively analyzed.Based on the samples of residual brick lining eroded at hearth and hearth bottom,representative parts of carbon brick,ceramic pad and bonding layer were selected and their elements,morphology,energy spectrum and phase were analyzed: The erosion characteristics of carbon bricks at different locations in hearth were mastered,and the mechanism of zinc participating in reaction and destroying carbon bricks in hearth was clarified through calculation.The erosion characteristics of ceramic pad and the reasons for its better preservation were analyzed.In addition,the bonding layer,and the occurrence form and enrichment degree of harmful elements on which,were totally analyzed.Also,the protective mechanism of the bonding layer in the hearth of the blast furnace was discussed.Finally,the content distribution of harmful elements and coke quality in hearth were studied:(1)The spatial distribution characteristics of harmful elements in hearth were analyzed from both vertical and transverse aspects to understand their distribution regularity in hearth and their influence on hearth erosion;(2)By means of comprehensive analysis such as industrial analysis,morphology and energy spectrum,the quality of coke reaching hearth area was mastered and the deterioration behavior of coke in hearth was studied.