Investigation of Mineral Phase Transformation Technology Followed by Magnetic Separation for Recovery of Iron Values from Red Mud
Round 1
Reviewer 1 Report
In this work, the mineral phase transformation and magnetic separation for iron recovery from high-iron red mud (RM) is studied to attend a huge environmental problematic. Authors demonstrated that iron minerals in the raw ore mainly could have different crystal structures such as hematite, limonite, and goethite. They obtained a phase transformation to magnetite during the roasting process. They studied the compositional elemental distribution being able to get information about the surface and affinity among different relevant species. From my perspective, this manuscript has scientific value and represents an extensive study of a physical treatment for RM, a using multiple characterization techniques to demonstrate it feasabilty. I recommend it to be published after major revisons. I would like to ask the authors to address the following points before continuing forward:
Line 36: Cite studies where red mud morphologies and particle sizes been have studied
Section 2.1: You are presenting results (XRD and composition analysis. What technique did you use here?) and no materials and methods. Please move and rename (something like structural and compositinal characterization) this section to results and discussion (probably as the first one of section 2). In 2.1 ”Materials” you should talk about the RM in general, you could show a figure of your RM.
Line 83: “characterized with different characterization techniques” looks redundant. Fix it.
Line 84: Replace just XRD by X-ray diffraction (XRD)
Line 85: After mention each crystal phase identified in your XRD pattern, please indicate the corresponding PDF card or your source where that you used to assign the peaks.
Figure 2: Please rescale your y-axis. There is no information between 3000 cps and 5000 cps, so it would be more clear to identify the peaks
Table 1. TFe?. T is a typoI think so. Also, What is LOI?
Table 2. It is ambiguous “Oxide Fe” do you mean FeO? Because magnetite (Fe3O4) is also an iron oxide/ Please clarify.
Line 115: Add acquisition mode for the XRD measurement. Was grazing angle mode?
Line 117: Add respectively at the end of the sentence. Could you please indicate for the EDS characterization the cover area and the accelerating voltage?
Line 118: Replace just VSM by Vibrating Sample Magnetometer (VSM)
Line 128: Typo, N2, 2 should be a subscript.
Figure 4. Right y-axis of left figure overlap with right graph. Please do it clear.
Line 171: This section has same name that previous and next section.
Section 3.3: This section does not have the proper name. I can not read it until you rebuil it. Figure here doesn’t correspond to the main text. There was a mistake.
Figure 6: It is the same figure 5. Please fix it to be able to read section 3.3
Section 3.4: Again, this section has same name of the 2 previous sections.
Line 214: Typo. Replace was by were.
Line 253: Eliminate obviously.
Line 287: Typo. Change assays by essay.
Line 359: Typo. Eliminate “that”
Line 367: Fig. 16 letters appears in blue color
Author Response
The authors greatly appreciate the time and energy the reviewers invested in reviewing our manuscript. The reviewer’s insightful comments are not only valuable for us to revise our manuscript to meet the journal’s quality standard, but are also beneficial for our current and future research. The authors carefully studied the reviewer’s comments subsequently revised our manuscript and additional work was conducted and included in the current version. The main revisions and responses to the reviewer’s comments are provided below.
We have carefully studied the comments on the email and made revisions, which have clearly highlighted. Revisions according to the comments are highlighted in red.
For a point-by-point response to the reviewers' comments and a revised manuscript, please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article is well written and deserves publication. However, I feel the paper is too long. I suggest reviewing that instead of three separate "Effects of roasting time" titles, there should be a single title. Discussions should be made with clearer and clearer sentences rather than long hard-to-understand sentences and should be revised accordingly. Also, improve the Figure's quality for the better eminence of your research work. In some figures, the inscriptions are not fully readable.
Author Response
The authors greatly appreciate the time and energy the reviewers invested in reviewing our manuscript. The reviewer’s insightful comments are not only valuable for us to revise our manuscript to meet the journal’s quality standard, but are also beneficial for our current and future research. The authors carefully studied the reviewer’s comments subsequently revised our manuscript and additional work was conducted and included in the current version. The main revisions and responses to the reviewer’s comments are provided below.
We have carefully studied the comments on the email and made revisions, which have clearly highlighted. Revisions according to the comments are highlighted in red.
For a point-by-point response to the reviewers' comments and a revised manuscript, please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
I really appreciate that all my comments and suggestion were thoroughly considered to improve the quality of this work. I agree with how the authors made the corrections and I think it is ready to be published.
Author Response
The authors greatly appreciate the time and energy the reviewers invested in reviewing our manuscript. The reviewer’s insightful comments are not only valuable for us to revise our manuscript to meet the journal’s quality standard, but are also beneficial for our current and future research.Once again, we are grateful for your work.
