| Thick bed sintering technology has significant advantages in reducing solid fuel consumption and increasing sintering capacity due to its characteristics of heat storage and high Thick bed.It has been widely used in the world since its development.However,in the process of continuous increase of material layer,sintering production generally appears significant increase in cost,index deterioration and other phenomena,the continuous increase of material layer into a bottleneck.Scholars at home and abroad have done a lot of research on the realization of thick bed sintering,but there is no substantial and universal help for the further increase of sintering layer and the further improvement of economic and technical indicators.Therefore,this topic carries out the analysis of the sintering technology mechanism of 1000mm ultra-thick material layer,and applies the experimental results to the practice of 230m~2 sintering machine of iron and steel enterprise,discusses and studies the theoretical system and technological measures of ultra-thick bed layer sintering from multiple angles,which has been well verified in production practice.The theoretical basis and comprehensive technology system of ultra-thick bed sintering are further improved,which makes a certain contribution to the development of thick bed sintering technology in the new era.This thesis begin with two kinds of different degrees of quick lime activity based detection,the flux through chemical composition,phase composition,microstructure,properties and the degree of activity detection,digestion ability metallurgical properties,such as contrast,to explore the different mechanism of active lime in sintering performance impact and influence,preliminarily determine the highly active lime improved sintering technology optimization direction,Based on this technology system,the sintering technology of ultra-thick material layer is proposed,and the core medium is highly active lime,which lays a foundation for the subsequent experimental study of sintering granulation and high temperature performance.The results of the granulation experiment of the sintering mixture with the addition of active lime showed that with the increase of the ratio of active lime,the depulverization rate of the mixture was improved,and the depulverization rate of the mixture decreased from 22.81%to 1.94%.In addition,the granulation experiments with different water mixtures under the condition of full active lime flux show that the increase of water mixtures can significantly improve the average particle size of the mixture and almost have no effect on the depulverization rate.Based on the experimental results,established a highly active lime flux structure across all wet with granular structure and width influence mechanism,use of sintering flue heat into superheated steam,access to design a mix tank form heating effect,and granulating ingredients water heated to 90℃,help quicklime digestion as well as to improve the mixture material temperature,It can inhibit the over-wet zone[1]Through this technical measure,the proportion of particle size>8 mm of the mixture is significantly increased,the particle size of the sintered mixture is improved,and the initial air permeability of the sintered mixture is better[2].Based on the enhanced sintering technology of fully active lime with highly active lime as the core medium,the influence of lime activity on the hightemperature properties of iron ore powder and fuel in sintering process was investigated.The minimum assimilation temperature of ore powder under the condition of high active lime is 11℃ lower than that of low active lime,and the assimilation time interval is 3℃ shorter.The comprehensive combustion index reaches the maximum when the ratio of high active lime is 1%,while the comprehensive combustion characteristic index reaches the peak when the ratio of low active lime is 2%.The influence of the ratio of active lime on the economic and technical indicators and flue gas emission of sinter was explored through the sinter cup experiment.The experimental results showed that with the increase of the ratio of active lime,the sintering utilization coefficient increased from 1.13 t/(m~2·h)to 1.66 t/(m~2·h),and the strength of finished ore drum increased from 70%to 72%.The test results of flue gas emission showed that,High activity lime can effectively reduce NOx,COx and other pollutants in flue gas content,in line with the trend of low carbon environmental protection.Furthermore,equipment and process improvement were carried out in the 230m~2 sintering machine at the sintering site of the enterprise,in order to coordinate with the enhanced sintering technology of full high active lime,the sintering production of 1000mm ultra-thick material layer was realized.In view of the"large water content and high material temperature" required by high active lime,the efficient utilization technology of sintering heat source was designed to raise the material temperature of the mixture to above the dew point temperature.At the same time,in view of the phenomenon that the trolley slide is easy to leak air,the sealing structure of the trolley slide,the new frame plate inlaid structure device,the new pin rod fastening structure of the detail air leakage part,the frame plate thread anti tilt design are designed.Based on the design and implementation of these air leakage treatment technologies,the air leakage rate of sintering machine is reduced by 34%from 55%,which realizes the reduction of solid fuel consumption,the reduction of power consumption,the improvement of sinter output,the emission reduction of gas pollutants and the increase of benefits.Finally,after the development and application of 1000mm ultra-thick bed sintering technology,the utilization coefficient of sintering machine reaches 1.87t/(m~2·h),the solid fuel consumption decreases from 53kg/t to 41.85kg/t,the air leakage rate of sintering machine decreases from 55%to 34.68%,and the sintering power consumption reaches only 27(kW·h)/t.The temperature distribution of bellows exhaust gas is good and stable,and the overall economic and technical indexes reach the excellent level of sintering production.In maintaining economic and technical indexes of excellent condition,has realized:the sinter composition is stable,the sinter temperature and reduction desintegration index was 74.60%on average,the sinter softening drop feature performance is good,the sinter mineral composition iron acid calcium content is enough,damaging mineral content rarely,qualified sinter quality as a whole,some outstanding quality indicators.Based on the production effect,the technology system of "full active lime enhanced sintering"was put forward as the key technology system to guide the sintering of ultra-thick bed layer. |
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