Gasification of iron coke and cogasification behavior of iron coke and coke under simulated hydrogen-rich blast furnace condition

To explore the iron coke application in hydrogen-rich blast furnace,which is an effective method to achieve the purpose of low carbon emissions,the initial gasification temperature of iron coke in CO_(2) and H_(2)O atmosphere and its cogasification reaction mechanism with coke were systematically studied.Iron coke was prepared under laboratory conditions,with a 0-7wt%iron ore powder addition.The properties of iron cokes were tested by coke reactivity index(CRI)and coke strength after reaction(CSR),and their phases and morphology were evolution discussed by scanning electron microscopy and X-ray diffraction analysis.The results indicated that the initial gasification temperature of iron coke decreased with the increase in the iron ore powder content under the CO_(2) and H_(2)O_((g))atmosphere.In the 40vol%H_(2)O+60vol%CO_(2) atmosphere,CRI of iron coke with the addition of 3wt%iron ore powder reached 58.7%,and its CSR reached 56.5%.Because of the catalytic action of iron,the reaction capacity of iron coke was greater than that of coke.As iron coke was preferentially gasified,the CRI and CSR of coke were reduced and increased,respectively,when iron coke and coke were cogasified.The results showed that the skeleton function of the coke can be protected by iron coke.

Effect of Coke Reaction Index on Reduction and Permeability of Ore Layer in Blast Furnace Lumpy Zone Under Non-Isothermal Condition

Reasonable control on CRI（coke reaction index）is one of the key factors for BF（blast furnace）low-carbon smelting.However,there are contrary opinions.One is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in furnace.Different methods are adopted to realize effective catalysis（increasing CRI）and passivation（decreasing CRI）of coke.Simulation tests of coke in BF lumpy zone under gradual temperature rising have been done.Effect of CRI on gas composition,ore reduction,burden column permeability and heat reserve zone′s temperature under non-isothermal condition are studied.Then combined with iron making calculations,a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.

Effect of Ca-Fe oxides additives on NOx reduction in iron ore sintering

As the emission control regulations get stricter,the NO;reduction in the sintering process becomes an important environmental concern owing to its role in the formation of photochemical smog and acid rain.The NOxemissions from the sintering machine account for 48% of total amount from the iron and steel industry.Thus,it is essential to reduce NO;emissions from the sintering machine,for the achievement of clean production of sinter.Ca-Fe oxides,serving as the main binding phase in the sinter,are therefore used as additives into the sintering mixture to reduce NOxemissions.The results show that the NO;reduction ratio achieves 27.76% with 8% Ca-Fe oxides additives since the Ca-Fe oxides can advance the ignition and inhibit the nitrogen oxidation compared with the conventional condition.Meanwhile,the existence of Ca-Fe oxides was beneficial to the sinter quality since they were typical low melting point compounds.The optimal mass fraction of Ca-Fe oxides additives should be less than 8%since the permeability of sintering bed was significantly decreased with a further increase of the Ca-Fe oxides fines,inhibiting the mineralization reaction of sintering mixture.Additionally,the appropriate particle size can be obtained when mixing an equal amount of Ca-Fe oxides additives of-0.5 mm and 0.5-3.0 mm in size.