Research On The Preparation And Properties Of High Reactivity And High Strength Ferro-coke

Ferro-coke,also known as high ferro-coke reactivity,refers to the use of coal and iron material preparation of coke by continues heat coke oven.Compare with conventional coke,ferro-coke has high reactivity,high reducibility,good adaptability and other advantages of raw materials.In the blast furnace,ferro-coke could be used to take the place of conventional coke.CO2 is produced when iron ore react with CO.Cause ferro contains ultrafine iron,ultrafine become catalyst,and it increase the reactity of coke substantially,and promote carbon solution reaction at low temperatures,which reduce the initial reaction temperature.With the loss of the blast furnace thermal deposits temperature,thereby to control the movement of FeO-Fe restore balance,make it has the characteristics of reducing coke rate,reduce CO2 emissions.In addition,iron coke can greatly improve the utilization ratio of weak bond coal and low grade iron ore,and improve the ability to cope with the shortage of resources.But low strength after reaction is severely restricting the use of coke in the blast furnace iron making.Therefore,Japanese researchers first proposed the concept of "double high"ferro-coke.Ferro-coke with high CRI and high CSR has become the focus and difficulty of industry research.In order to develop "double high" iron coke and meet the demand of blast furnace production,this study produced ferro-coke using iron ore and several blending coal based on Shagang iron making paint by 40kg test coke oven.The influence of iron ore composition,addition ratio,coking process conditions and additives on the performance of iron coke was analyzed.The carbon loss reaction of different iron coke was studied by thermogravimetric analyzer,and the initial reaction temperature was measured.The optical microstructure of the iron coke was observed with a polarizing microscope.The SEM and XRD analysis of the iron coke were also carried out.The micromorphology and microstructure of the iron coke were observed.The optimized substitution of coal blending structure with different varieties and different proportions was studied to improve the strength of iron coke,and the optimization principle was analyzed.By systematically studying the influence of various factors on the performance of Ferro-coke,the best raw material and technological conditions were obtained finally.This study provides a theoretical basis for developing "double high" iron coke.The results show that:(1)The addition of iron ore increased the ash content of ferro-coke,decreased the cold strength,increased the reactive CRI,and decreased the CSR after reaction.The iron ore powder aggravates the carbon dissolving reaction of ferro-coke,reduces the starting temperature of the reaction,and causes the increase of CRI and the decrease of CSR.(2)By scanning electron microscopy(SEM)analysis,it was found that iron ore powder was reduced to metal iron or iron oxide after carbonization,and distributed in the pores and carbon matrix of iron coke in irregular size.With the increase of iron,the iron or iron oxides reduced in iron coke increased,and gathered in local area.More metal iron,A1 and Si formed Al-Si-Fe or Si-Fe complex,which made the composition of iron coke become more complex.The optical structure analysis shows that active component relative content decreased,the relative content of inert component increased,resulting in ferro-coke coarse mosaic tissue decreased and isotropic,and silk fragments increased,thereby improving the reaction of ferro-coke.(3)As increasing the density of the reactor,the final temperature of coking progress and adding tar slag could improve the strength of ferro-coke.The cold strength and post reaction strength of iron coke are better,and the reactivity remains high,as the bulk density is 0.95kg/m3,the tar slag content is 3%,and the final temperature is controlled at 1100?.(4)By HK coking coal taking the place of SX coking coal,LX fat coking coal taking the palce of WH fat coking coal,and ZZ 1/3 coking coal taking the palce of DT 1/3 coking coal,ferro-coke with high CRI and CSR was obtained.Among these testing group,the ferro-coke reached the "double high" ferro-coke index standard,which 10%HK coking taking the palce of SX coking coal.