Coke behavior with H_(2)O in a hydrogen-enriched blast furnace:A review

Hydrogen-enriched blast furnace ironmaking has become an essential route to reduce CO_(2)emissions in the ironmaking process.However,hydrogen-enriched reduction produces large amounts of H_(2)O,which places new demands on coke quality in a blast furnace.In a hydrogen-rich blast furnace,the presence of H_(2)O promotes the solution loss reaction.This result improves the reactivity of coke,which is 20%-30%higher in a pure H_(2)O atmosphere than in a pure CO_(2)atmosphere.The activation energy range is 110-300 kJ/mol between coke and CO_(2)and 80-170 kJ/mol between coke and H_(2)O.CO_(2)and H_(2)O are shown to have different effects on coke degradation mechanisms.This review provides a comprehensive overview of the effect of H_(2)O on the structure and properties of coke.By exploring the interactions between H_(2)O and coke,several unresolved issues in the field requiring further research were identified.This review aims to provide valuable insights into coke behavior in hydrogen-rich environments and promote the further development of hydrogen-rich blast furnace ironmaking processes.

Coupling effect and characterization modeling of iron ore fines mixing and granulating at 0-1 mm

Characteristic of iron ore is the essential factor of granulating.Three ores,namely specularite,magnetite concentrate and limonite,were selected as adhesion powder to investigate granulating behavior and evolution process of agglomeration.Experiments and modeling were performed to represent granulating behavior on the basis of selectivity,ballability and adhesion rate.The mass fraction of water and particles size of adhesion and nucleation were set at(11±1)%,0-1 mm and 3-5 mm,respectively.Experimental results show that selectivity and ballability promote the evolution of granulation.The water absorption rate of specularite and the ballability of limonite are better.The coupling effects exist in two ores mixing and present positive effect when the proportion of magnetite concentrate is greater than that of specularite or specularite and limonite blend.During three ores mixing,the coupling effect presents a complex superposition state.A characterization model of adhesion rate of mixing granulation was established by random forest algorithms.Its output is adhesion rate,and its inputs include water absorption rate,balling index and mixing proportion.The model parameters are 957 trees and four branches,and the training and prediction errors of the model are 2.3%and 3.7%,respectively.Modeling indicates that the random forest model can be used to represent coupling effects of mixing granulation.

Correction to:Influence of inclusions on hydrogen-induced delayed cracking in hot stamping steels

Correction to:J.Iron Steel Res.Int.(2019)26:1199-1208 https://d0i.0rg/l 0.1007/S42243-019-00312-z The original version of this article unfortunately contained a mistake.Table 6 was incorrect.The corrected table is given below.The line 11 of page 1205 is revised as“The diffusion coefficient of hydrogen in CSPS is 2.76×10^(-7)cm^(2)/s,which is lower than that of CRS”.

Influence of inclusions on hydrogen-induced delayed cracking in hot stamping steels

The hydrogen-induced delayed cracking(HIDC)behaviors of two types of 1500 MPa grade hot stamping steels(HSSs)have been investigated by the method of slow strain rate tensile test and hydrogen permeation,where one is manufactured by compact strip production(CSP)process which is a revolution to the traditional HSS and the other by the traditional cold rolling process.The results show that the performance of HSS produced by CSP is superior to that of the traditional HSS,due to lower hydrogen embrittlement index,lower hydrogen diffusion coefficient and lower hydrogen content.It has been found that HIDC behavior is closely associated with inclusions.The inclusions of HSS produced by CSP are mainly spherical Al-Ca-O and CaS,while the inclusions in the traditional HSS are TiN+AI2O3+MnS with sharp edges and corners.Based on these results,the influence of composition,shape and distribution of inclusions in HSS on HIDC and the mechanism of HIDC from the perspective of inclusions were analyzed and discussed.