Development of a Moving-Bed Ironmaking Process for Direct Gaseous Reduction of Iron Ore Concentrate
Round 1
Reviewer 1 Report
This paper described a novel horizontal moving-bed ironmaking process using iron concentrate and analyzed the hydrogen reduction kinetics. In this manuscript, authors formulated a moving bed reactor, and analyzed the hydrogen reduction between 650~1000℃ considering interparticle diffusion. The manuscript provides amounts of results of various tests and this study can be accepted after revision. Specific comments are provided as follows:
1. The data shown in line 19 need be updated to the latest one.
2. Abbreviations in Figure 1 should be given full names.
3. “Ln” in Formula (1)(2)(3)(7)(8)(9)(13) should be uniformly modified to “ln”.
4. The injection rate of the gas mixture needs to be described more specifically in line 59.
5. Formula (2) shew that the rate decreased with temperature in the range 650–800℃. Please explain this trend in terms of mechanism.
6. Line 151 mentioned that the length of the reactor should be under 50m. What is this data based on?
7. Please supplement the result of chemical composition analysis of iron concentrate before the reduction kinetics.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper proposes a horizontal moving-bed ironmaking process, which uses iron concentrate directly and reduce it 8 with hydrogen in the temperature range of 500 – 1000 oC. They researches the horizontal moving-bed furnace, hydrogen reduction kinetics of concentrate particles, incorporation of interparticle diffusion in the rate analysis,design of a horizontal moving-bed furnace. I suggest this paper a minor revision before it is published.
1. The introduction is too short to give a detailed understanding for its technological background.
2. Authors had better to make a detailed description of raw materials, methods and equipment in the experiment process instead of a process concept.
3. Both abstract and keywords should be polished.
4. I suggest the authors carry out water model or numerical simulation to elaborate the experimental research
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The application of the countercurrent reactor theory to model metallurgical processes has a long tradition. Examples include works from the 1960s, eg H. Schenk, E. Steinmetz, M. Frohberg: Ableitungen zum Ausmaß chemischer Umsetzungen zwischen flüssigen Phasen in ruhendem und bewegtem Zustand, Archiv für das Eisenhüttenwesen, 34, Sept. 1963. Therefore, the idea of using such a model for direct reduction is understandable.
Unfortunately, there are gaps in the description of the model and design of the industrial reactor, which prevent a reliable assessment of the submitted study. In particular, this applies to the following issues:
1. In equations 13-17 it is impossible to assess their correctness without the knowledge of work [12]
2. In the industrial reactor design, tables 1 and 2 show the calculation results obtained from the model used. Assuming that the calculations are correct, it should be noted that they do not entitle us to formulate the conclusion No. 2, which is the main conclusion of the work. The lack of knowledge about the approximate energy consumption in the designed furnace and the source of this energy does not allow us to conclude that energy consumption will be lower and CO2 emission will decrease. This conclusion does not follow from the information provided in the paper.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
After the introduced corrections, the test results may be published. It is a pity that the text does not explicitly state that the model calculations do not estimate the energy demand of the proposed furnace.
