Abstract
Herein a big Fe-C-Ca cycle, clarifying the basic element flows and energy flows in modern carbon-intensive industries including the metallurgical industry and the cement industry, was proposed for the first time in the contexts of emission reduction and iron ore degradation nowadays. This big cycle was focused on three industrial elements of Fe, C and Ca and thus it mainly comprised three interdependent loops, i.e., a C-cycle, a Fe-cycle and a Ca-path. As exemplified, we started from the integrated disposal of hot steel slags, a man-made iron resource via char gasification and the employment of hematite, a natural iron resource greatly extended the application area of this idea. Accordingly, based on this concept, the theoretical potentials for energy saving, emission reduction and Fe resource recovery achieved in modern industry are estimated up to 7.66 Mt of standard coal, 63.9 Mt of CO2 and 25.2 Mt of pig iron, respectively.
Highlights
To deal with these issues, we began with the heat recovery and material recycling of steel slags, a man-made iron resource, using char gasification reaction and a natural iron resource, hematite, was further employed to explore a promising way towards utilization of iron resources
This study started from the treatment of steel slags using coal char gasification and the initial analysis was focused on identification of the gasification process and the role of steel slags, especially on the Boudouard reaction expressed as follows: CO2 + C = 2CO, ∆rH1273θ = 166.7 kJ/mol
As the coal char/CO2 reaction occurred at high temperatures, the sample mass would continuously vary, which was simultaneously detected using a precision balance
Summary
During the char gasification integrated with steel slag disposal, the transient and final valence states of Fe and C elements are still unclear, especially under a non-equilibrium condition in a flowing gasifying agent The clarification of this could provide significant clues of Fe and C flows in the metallurgical industry. The further utilization of the solid wastes, after iron extraction and heat recovery, should be taken into account, which, offered the basic information of Ca flows in modern industry. The present study was motivated with respects to the two great issues, i.e., emission reduction and resource utilization To deal with these issues, we began with the heat recovery and material recycling of steel slags, a man-made iron resource, using char gasification reaction (coal char and biomass char) and a natural iron resource, hematite, was further employed to explore a promising way towards utilization of iron resources. A big idea of Fe-C-Ca cycle was proposed where the development of modern industry was reconsidered including the metallurgical industry and the cement industry
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