Advances in Methods for Recovery of Ferrous, Alumina, and Silica Nanoparticles from Fly Ash Waste

Round 1

Reviewer 1 Report

Yadav et al presented a comprehensive review of coal fly ash recovery processes. The review is reader-friendly and informative with schemes and compiled tables. I recommend the publication of the manuscript.

Minor Comment

Table 3 does not show the properties of Indian coal fly ash

Author Response

Table 3 does not show the properties of Indian coal fly ash

Author response: Thank you for this suggestion and comment. We have added the required table [under, Table 4. The size distribution in Indian fly ash particles] in the revised manuscript.

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments on “Advances in the methods for recovery of ferrous, alumina and silica nanoparticles from fly ash waste” (ID: ceramics-780926)

This manuscript reviews recent advances in the recovery and synthesis of alumina, silica and ferrous nanoparticles from fly ash. Comments are listed below for the authors to revise and improve this manuscript.

1. The purpose and innovation of this work needs to be pointed out at the end of the Introduction.
2. The role of nanotechnology has been illustrated in lines 708-743, whereas the nanotechnology has not been described in the Introduction. The descriptions should be added in the Introduction and be updated to the manuscript.
3. In the extraction of alumina nanoparticles from fly ash, the authors mentioned that “Techniques of the aluminum extraction from coal fly ash can be classified into acidic [93][94], alkali [92][95]; and acidic-alkali method [96][97].” However, acidic-alkali method has not been described in the following paragraphs. Therefore, the acidic-alkali method should be added (please referred to Reviews in Chemical Engineering, DOI:10.1515/revce-2019-0032).
4. Latin abbreviation such as “e.”and “etc.” should be italicized. Please carefully check the format of these words and make similar modifications.
5. Some figures and tables are not described in the article. In addition, the serial number of the figure needs to be checked.
6. “Figure” and “Fig.” appear in this manuscript and they should be
7. The reaction formulas in the manuscript need to be numbered.
8. Tables 7 and 9 should be located below their corresponding captions.
9. Figures 6 and 7 need to be improved and decorated, such as using the same-size arrows.
10. The format of cited references in the reference list should be uniform.

Author Response

This manuscript reviews recent advances in the recovery and synthesis of alumina, silica and ferrous nanoparticles from fly ash. Comments are listed below for the authors to revise and improve this manuscript.

1. The purpose and innovation of this work needs to be pointed out at the end of the Introduction.

Author response: Thank you for your valuable comments and suggestion. We have incorporated the “purpose and innovation of the current review work in the introduction section” in the revised manuscript.

2. The role of nanotechnology has been illustrated in lines 708-743, whereas the nanotechnology has not been described in the Introduction. The descriptions should be added in the Introduction and be updated to the manuscript.

Author response: The description of nanotechnology in the introduction is incorporated in the revised manuscript. Thank you for your comment and suggestion.

3. In the extraction of alumina nanoparticles from fly ash, the authors mentioned that “Techniques of the aluminum extraction from coal fly ash can be classified into acidic [93][94], alkali [92][95]; and acidic-alkali method [96][97].” However, acidic-alkali method has not been described in the following paragraphs. Therefore, the acidic-alkali method should be added (please referred to Reviews in Chemical Engineering, DOI:10.1515/revce-2019-0032).

Author response:  Recovery of Al from fly ash by this method was not found, and that section was left by mistake. Still, we have added one investigation under this section in the revised manuscript as suggested. The authors are very thankful to the reviewer for this valuable input.

4. Latin abbreviation such as “e.”and “etc.” should be italicized. Please carefully check the format of these words and make similar modifications.

Author response: Thank you for this comment. The suggestion was incorporated throughout the revised manuscript.

5. Some figures and tables are not described in the article. In addition, the serial number of the figure needs to be checked.

Author response: All the missing, mismatched tables and figures are incorporated in the revised manuscript as per the suggestion of the reviewer. The serial number also corrected and incorporated properly in the revised manuscript. Thank you for this comment.

6. “Figure” and “Fig.” appear in this manuscript and they should be

Author response: Thank you for the suggestion. It was incorporated in the revised manuscript as per the suggestion. All the Figures wrote as Fig.

7. The reaction formulas in the manuscript need to be numbered.

Author response: All the reaction formulas numbered as per the suggestion of the reviewer in the revised manuscript. Thank you for this suggestion.

8. Tables 7 and 9 should be located below their corresponding captions.

Author response: Both the tables placed at proper place with their captions in the revised manuscript. Thank you for this comment.

9. Figures 6 and 7 need to be improved and decorated, such as using the same-size arrows.

Author response: Both the Figures redrawn with high quality as suggested by the reviewer and incorporated in the revised manuscript. The authors are thankful for this suggestion and comments.

10. The format of cited references in the reference list should be uniform.

Author response: Thank you for this comment and suggestion. All the cited references formats are uniform in the revised manuscript as suggested. While few journals, especially for MDPI, don’t take up to page number by using Endnote software. So, most of the MDPI journals are only up to issue no.   

Please see the attachment. 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors answered all of the comments raised by this reviewer and significantly revised the original manuscript. Therefore, I recommend its publication as it is.

Author Response

The reviewer's comment is already responded and there is no pending response. 

Thank you