To advance green ironmaking and expand the utilization of magnetite with complex gangues,the hydrogen reduction behavior and mechanisms of barite-containing magnetite pellets were investigated.The findings revealed th...To advance green ironmaking and expand the utilization of magnetite with complex gangues,the hydrogen reduction behavior and mechanisms of barite-containing magnetite pellets were investigated.The findings revealed that increasing barite led to the increased amount of Ba_(x)Fe_(3−x)O_(4)and Ba-containing silicates in oxidized pellets,which hindered the continuous crystallization of Fe_(2)O_(3).During the reduction process,the reduction of Ba_(x)Fe_(3−x)O_(4)to Ba and Fe by H_(2)was challenging,resulting in the formation of BaFeO_(2.64).Furthermore,Ba_(x)Fe_(3−x)O_(4)impeded the reaction between Fe_(2)O_(3)and H_(2),decreasing the reduction degree and metallization ratio of the pellets.Ba^(2+)diffused into the Fe_(2)O_(3)lattice during oxidation,stabilizing the crystal structure during the initial reduction stage(Fe_(2)O_(3)to Fe_(3)O_(4)).In the third reduction stage(Fe_(x)O to Fe),BaFeO_(2.64)inhibited the rapid precipitation of metallic iron,thus preventing the abnormal growth of iron whiskers.Consequently,BaSO_(4)reduced the reduction swelling index of barite-containing magnetite pellets in hydrogen.These findings offer a theoretical basis for the future implementation of barite-containing pellets in the hydrogen-based shaft furnace direct reduction process.展开更多
基金Science and Technology Innovation Program of Hunan Province(Nos.2023RC1025,and 2024RC3022)the Basic Science Center Project(72088101)Major Scientific Research Projects(HKF202300356).
文摘To advance green ironmaking and expand the utilization of magnetite with complex gangues,the hydrogen reduction behavior and mechanisms of barite-containing magnetite pellets were investigated.The findings revealed that increasing barite led to the increased amount of Ba_(x)Fe_(3−x)O_(4)and Ba-containing silicates in oxidized pellets,which hindered the continuous crystallization of Fe_(2)O_(3).During the reduction process,the reduction of Ba_(x)Fe_(3−x)O_(4)to Ba and Fe by H_(2)was challenging,resulting in the formation of BaFeO_(2.64).Furthermore,Ba_(x)Fe_(3−x)O_(4)impeded the reaction between Fe_(2)O_(3)and H_(2),decreasing the reduction degree and metallization ratio of the pellets.Ba^(2+)diffused into the Fe_(2)O_(3)lattice during oxidation,stabilizing the crystal structure during the initial reduction stage(Fe_(2)O_(3)to Fe_(3)O_(4)).In the third reduction stage(Fe_(x)O to Fe),BaFeO_(2.64)inhibited the rapid precipitation of metallic iron,thus preventing the abnormal growth of iron whiskers.Consequently,BaSO_(4)reduced the reduction swelling index of barite-containing magnetite pellets in hydrogen.These findings offer a theoretical basis for the future implementation of barite-containing pellets in the hydrogen-based shaft furnace direct reduction process.
