Optimization of Magnetization Roasting and Magnetic Separation for the Recovery of Iron from Low-Grade Iron Plant Tailings
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript provides a systematic study on the recovery of iron from low-grade iron ore tailings. The response surface methodology used to optimize the process parameters is scientific and innovative. The experimental design is reasonable and the result analysis is more comprehensive. It provides a feasible method and valuable reference for the research in this field. However, the article needs to be further improved in terms of format standards, consistency of some data, and discussion of practical application value.
- For the reducing agent (macadamia shell) used in the process of magnetization roasting, although its basic physical and chemical properties are given, there is a lack of detailed explanation of the reasons for its selection. It is recommended to explain why this reducing agent is selected and its advantages and characteristics compared with other common reducing agents (such as coal, charcoal, etc.).
- Some format problems in the article need to be carefully modified. For example, the 119 line '2.2. . Beneficiation of magnetite' on page 3 should be '2.2. Beneficiation of magnetite'; formula 7 has format problem; 'conclusion' should be the fourth part of the full text, not the fifth part.
- Please carefully check the consistency of the data in Table 4 with Figure 3. The content of Fe element in point A of the surface distribution map of Fe element is significantly higher than that in other places, while the content of Fe element in point C and D is significantly lower than that in other places, which is inconsistent with the data in Table 4.
- It is suggested that the final prediction results should be experimentally demonstrated to verify the accuracy of the model.
- The experiment in this manuscript uses Macadamia nut shell as a reducing agent. Although it has achieved certain success in the experiment, Macadamia nut shell is not a bulk reducing agent. In practical industrial applications, it may face problems such as insufficient supply and high cost, which limits the applicability of the model in a wider range of scenarios. Therefore, the author needs to further discuss the applicability of the model, such as whether other more common reducing agents (such as coal, coke, charcoal, etc.) can be used to replace Macadamia nut shells to verify the stability and feasibility of the model under different reducing agent conditions. At the same time, for different types of low-grade iron ore tailings, there may be differences in mineral composition and chemical properties. Whether the model can adapt to these changes is also worth exploring.
Author Response
Comment 1: For the reducing agent (macadamia shell) used in the process of magnetization roasting, although its basic physical and chemical properties are given, there is a lack of detailed explanation of the reasons for its selection. It is recommended to explain why this reducing agent is selected and its advantages and characteristics compared with other common reducing agents (such as coal, charcoal, etc.).
Response 1: Thank you for pointing this out. The selection of biomass - macadamia nutshell was not substantiated. We have made revisions which are found on pages 2-3, lines 83 - 93.
Comment 2: Some format problems in the article need to be carefully modified. For example, the 119 line '2.2. . Beneficiation of magnetite' on page 3 should be '2.2. Beneficiation of magnetite'; formula 7 has format problem; 'conclusion' should be the fourth part of the full text, not the fifth part.
Response 2: Thank you for pointing out these typo mistakes. We have made corrections accordingly in the document.
Comment 3: Please carefully check the consistency of the data in Table 4 with Figure 3. The content of Fe element in point A of the surface distribution map of Fe element is significantly higher than that in other places, while the content of Fe element in point C and D is significantly lower than that in other places, which is inconsistent with the data in Table 4.
Response 3: Thank you for pointing this out. It is correct. The pointed spots on the backscatter image do not correspond to the table EDS data. The corrections were revised and are now fixed.
Comment 4: It is suggested that the final prediction results should be experimentally demonstrated to verify the accuracy of the model.
Response 4: Thank you for mentioning this point. I think it is a good suggestion to verify the model outcome. Additional experiments were conducted using the model-predicted operational conditions. The results are now presented in the paper.
Comment 5: The experiment in this manuscript uses Macadamia nut shell as a reducing agent. Although it has achieved certain success in the experiment, Macadamia nut shell is not a bulk reducing agent. In practical industrial applications, it may face problems such as insufficient supply and high cost, which limits the applicability of the model in a wider range of scenarios. Therefore, the author needs to further discuss the applicability of the model, such as whether other more common reducing agents (such as coal, coke, charcoal, etc.) can be used to replace Macadamia nut shells to verify the stability and feasibility of the model under different reducing agent conditions. At the same time, for different types of low-grade iron ore tailings, there may be differences in mineral composition and chemical properties. Whether the model can adapt to these changes is also worth exploring.
Response: This is a good remark. And it is necessary to conduct more studies on the use of other biomass, either in combination or individually, to increase the supply, as pointed out in the comment. A statement was added on page 22, line 549 - 555.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper “Optimization of the magnetization roasting and magnetic separation for the recovery of iron from low-grade iron plant tailing” is interesting and the subject relevant to the journal and hence is worthy of publication. There is quite a lot of information contained within the paper and some of the ways that I believe would improve the presentation are mentioned below.
1. Which devices were used for Proximate and ultimate analysis?
2. I suggest the authors rename Section 2.2. Beneficiation of magnetite to 2.2. Methods, so that 2.2.1. Beneficiation of magnetite, then 2.2.2. Magnetic susceptibility test, etc.
3. In the paper and tables, use the unit Tesla T for magnetic field strength.
I would also like to thank the authors of the article for the comprehensive numerical analysis. I believe that this paper can be accepted for publication with minor revisions.
Author Response
Comment 1: Which devices were used for Proximate and ultimate analysis?
Response 1: Thank you for pointing this out. The device are mentioned on the manuscript. The devices are: for the moisture, volatile matter, and ash content a muffle furnace, model AAF 11/3, manufactured by Carbolite Gero Ltd, Sheffield, United Kingdom was used. For the calorific value the combustion calorimeter, model CAL3K-F, manufactured by DDS CALORIMETERS, Randburg, South Africa was used. For the ultimate analyses a CHNS analyser, model flash 2000, manufactured by Thermofisher scientific, Sunnyvale, CA USA was used.
Comment 2: I suggest the authors rename Section 2.2. Beneficiation of magnetite to 2.2. Methods, so that:
2.2.1. Beneficiation of magnetite, then 2.2.2. Magnetic susceptibility test, etc.
Response 2: Thank you for pointing out the mistake made; the corrections were applied as advised.
Comment 3: In the paper and tables, use the unit Tesla T for magnetic field strength.
Response 3: All the units in gauss were changed to Tesla (T)
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors, I thank you for the effort invested in writing this article. Please correct what is indicated in the attachment, such as elaborating the summary, research methodology (experimental plan) and conclusion a little better. Literature was not cited according to the instructions.
Comments for author File: Comments.pdf
I'm not the kind of person who can do that with certainty.
Author Response
I would like to thank the reviewer for taking the time to review our article. The revisions were done as advised. The attached document has revisions.
Author Response File: 
Author Response.docx
