Removal of Mg and MgO By-Products through Magnesiothermic Reduction of Ti Powder in Self-Propagating High-Temperature Synthesis
Round 1
Reviewer 1 Report
This is a reasonable comprehensive study.
My only comment is that the authors should compare the residual oxygen content in the final product. Is 1 at% oxygen inclusion tolerated by the end users in industry?
Overall, this work is an incremental piece from previous studies but adequate for this special issue on metal powder processing.
Author Response
Point 1: My only comment is that the authors should compare the residual oxygen content in the final product.
Response 1: The authors would like to thank the reviewer for pointing out the importance of residual oxygen content in the final product. The authors have modified accordingly.
It can be viewed at page number 9, line 249-250.
Point 2: Is 1 at% oxygen inclusion tolerated by the end users in industry?
Response 2: The authors would like to thank the reviewer for this important point. The specifications of commercial pure titanium (CP-Ti) in the American Society for Testing and Materials (ASTM) are classified as grade 1-4. In addition, each oxygen concentration that defined up to 4000 ppm maximum in ASTM Ti grade 1-4 is classified as an item that must be involved for improvement of Ti quality. However, this oxygen concentration is based on the Ti produced by commercial process including the chlorination-metallothermic reduction-distillation process. It is difficult to directly compare the oxygen concentration of produced Ti by the direct reduction of Ti oxide excluding the chlorination and the oxygen concentration of Ti produced by the commercial process.
Although Ti powder produced through this study cannot be used industrially, but the scope of this research is to mainly focus on the possible environmental aspects involved in Ti oxide reduction. Many researchers are conducting research on Ti oxide direct reduction due to environmental problems. These issues are described in the introduction and related research papers are selected as references.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper reports the findings of an experimental study performed to study different leaching approaches to remove magnesium and magnesium oxide in the preparation of the pure titanium powder from titanium oxide by a method called self-propagating high-temperature synthesis (SHS) using magnesium as a reducing agent. The authors of this paper have conducting and publishing on this research topic. The results are presented and interpreted appropriately (sections: 2 and 3). This study addresses a research topic that falls within the scope of this journal. However, there are some suggestions/revisions required before I can recommend this paper for publication in this journal, as detailed below:
Comment 1: The abstract must be profoundly improved according to the following points:
- The abstract should clearly state its aims and objectives.
Suggestions: The aim/purpose of this work/article/paper is…)
- The authors must avoid abbreviations in the abstract. But, if it is necessary, the authors should define an abbreviation/chemical symbol. In the other words, first write the term in full followed by the abbreviation in parentheses. For example, “Ti”, “TiO2”, “Cl2”, “Mg oxide”, “XRD”, “SEM”, “EDS” are not defined in the body of the text.
Suggestions: instead of “Ti” it should read “titanium”; instead of “Mg oxide” it should read “magnesium oxide”; These and other identical situations should be corrected.
- The authors must avoid abbreviations in the Keywords. The authors should remove “SHS”.
- The authors must avoid unpolished expressions.
Suggestion: Instead of “aggressively researched” it should read “extensively studied/investigated”
- See these sentences “Acid leaching was performed using two different reactants and the tests were divided into two groups. Group 1 used a single leaching process using a relatively highly concentrated acid acid (???), whereas Group 2 first used a weak acid (???) followed by a strong acid acid (???).”This part must be rewritten in a concise and clear manner for the reader understand this work. Remove the terms “Group 1” and “Group 2” in the abstract. For example, give to the reader the main leaching approaches studied (single and two-leaching processes), indicating the acids used (hydrochloric acid, acetic acid) and their concentration. The following should be clear for the reader:
Single leaching process – the effects of different concentration of hydrochloric acid on the… were studied.
Two- leaching processes were studied using combination of different acids. (i) using acetic acid (concentration???) followed by hydrochloric acid (concentration???). (ii) using less-concentrated hydrochloric acid (concentration (?) followed by HCl (concentration???)
Comment 2: The authors must avoid abbreviations in the keywords. Remove the abbreviation “SHS”.
Comment 3: The authors should check if the abbreviations are defined in the body of the text in a correct manner. First write the term in full followed by the abbreviation in parentheses. For example, “HCl (hydrochloric acid) is defined in the body of the text in the line 81 but was used before as HCl (e.g. line 79).
Comment 4: The authors must include a conclusion section that should be concise and to the point.
Author Response
Point 1: -The abstract should clearly state its aims and objectives. Suggestions: The aim/purpose of this work/article/paper is…)
- The authors must avoid abbreviations in the abstract. But, if it is necessary, the authors should define an abbreviation/chemical symbol. In the other words, first write the term in full followed by the abbreviation in parentheses. For example, “Ti”, “TiO2”, “Cl2”, “Mg oxide”, “XRD”, “SEM”, “EDS” are not defined in the body of the text.
Suggestions: instead of “Ti” it should read “titanium”; instead of “Mg oxide” it should read “magnesium oxide”; These and other identical situations should be corrected.
- The authors must avoid abbreviations in the Keywords. The authors should remove “SHS”.
- The authors must avoid unpolished expressions.
Suggestion: Instead of “aggressively researched” it should read “extensively studied/investigated”
- See these sentences “Acid leaching was performed using two different reactants and the tests were divided into two groups. Group 1 used a single leaching process using a relatively highly concentrated acid acid (???), whereas Group 2 first used a weak acid (???) followed by a strong acid acid (???).”This part must be rewritten in a concise and clear manner for the reader understand this work. Remove the terms “Group 1” and “Group 2” in the abstract. For example, give to the reader the main leaching approaches studied (single and two-leaching processes), indicating the acids used (hydrochloric acid, acetic acid) and their concentration. The following should be clear for the reader:
Single leaching process – the effects of different concentration of hydrochloric acid on the… were studied.
Two- leaching processes were studied using combination of different acids. (i) using acetic acid (concentration???) followed by hydrochloric acid (concentration???). (ii) using less-concentrated hydrochloric acid (concentration (?) followed by HCl (concentration???)
Response 1: The authors would like to thank the reviewer for raising this important point. The authors have modified the abstract to make it more clear and understandable.
It can be viewed at page number 1 and 2.
Point 2: The authors must avoid abbreviations in the keywords. Remove the abbreviation “SHS”
Response 2: The authors would like to thank the reviewer for raising this important point. The authors have modified accordingly.
It can be viewed at page number 1, line 28-29.
Point 2: The authors should check if the abbreviations are defined in the body of the text in a correct manner. First write the term in full followed by the abbreviation in parentheses. For example, “HCl (hydrochloric acid) is defined in the body of the text in the line 81 but was used before as HCl (e.g. line 79).
Response 2: The authors would like to thank the reviewer for raising this important point. The authors have modified accordingly.
It can be viewed at page number 2, line 53.
Point 2: The authors must include a conclusion section that should be concise and to the point.
The authors would like to thank the reviewer for raising this important point. Previously we did not include the conclusion following the journal’s guideline, but now we have included the conclusion following the reviewer comment.
It can be viewed at page number 10, line 251-265.
Author Response File: Author Response.pdf
Reviewer 3 Report
This is a simple study yet interesting. However, it seems like the report was not well prepared. The objective is not stated. The Materials and Methods are not detailed, i.e. the grade and purity of the reagent used, sample preparation and protocol for SEM and XRD. The results interpretation and analysis are not enough benchmarked with those found in the literature, not enough supporting reference. No conclusion.
Author Response
Point 1: This is a simple study yet interesting. However, it seems like the report was not well prepared. The objective is not stated. The Materials and Methods are not detailed, i.e. the grade and purity of the reagent used, sample preparation and protocol for SEM and XRD. The results interpretation and analysis are not enough benchmarked with those found in the literature, not enough supporting reference. No conclusion.Response 1: The authors would like to thank the reviewer for raising this important point. We have rewritten the manuscript accordingly to make it more clear and understandable.
It can be viewed at page number 2, line 74-80.
It can be viewed at page number 3, line 95-99.
It can be viewed at page number 4, line 102-106.
It can be viewed at page number 6, line 164-166 and line 169-172.
It can be viewed at page number 10, line 251-265.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors corrected what was proposed in the first revision. Thus, to my understanding the paper as is can be accepted for publication in the jornal.
Author Response
Point 1: The authors corrected what was proposed in the first revision. Thus, to my understanding the paper as is can be accepted for publication in the journal.
The authors would like to pay gratitude to the reviewer for their kind comment and acceptance.
Reviewer 3 Report
This version looks very well prepared and addresses well to the previous comments. The results interpretation and analysis are well executed and the conclusion is drawn properly. Among some minor corrections: please improve the quality of Fig. 8., we should expect a high quality image produced by a FE-SEM. Fig. 1 can be made nicer. In Table 2, the a and b can be merged, side-by-side.
Author Response
Point 1: This version looks very well prepared and addresses well to the previous comments. The results interpretation and analysis are well executed and the conclusion is drawn properly. Among some minor corrections: please improve the quality of Fig. 8., we should expect a high quality image produced by a FE-SEM. Fig. 1 can be made nicer. In Table 2, the a and b can be merged, side-by-side.
The authors would like to thank the reviewer for their kind comment. The authors have modified the manuscript accordingly.
