The Surface Structure Change of Columbite-(Fe) Dissolution in H2SO4
Round 1
Reviewer 1 Report
This paper is concerned with the study of ferrocolumbite mineral surface structure and structural control reaction and dissolution in sulfuric acid leaching, and to improve the knowledge of governing columbite/fluid interface leaching. The topic of the study is relevant.
The introduction section is well structured. The basic methods of extraction of the studied rare earth elements are presented, the problem is shown and the purpose of the study is set. Literature sources cited in the introduction section are 16, of which a rather small number of sources published in the last five years. Perhaps the authors could expand this section and pay more attention to contemporary developments in the field.
In the section Materials and methods of research the parameters for the preparation of samples for the study are given. It would be worthwhile for the authors to explain the chosen acid concentrations for the leaching, namely 8 mol/l and 12 mol/l. Why were the two concentrations chosen?
With application of complex analysis the dependences of Fe2+/Fe3+ ratio on ferrocombite and residues surface on concentration of sulphuric acid during leaching were determined by the authors, Niobium to Iron stoichiometry was determined by ICP test results of leaching solution. The novelty and practical importance of the results obtained are beyond doubt.
As a recommendation perhaps the authors should add the conclusions about possibility of practical application of the obtained data, including recommendations on the leaching parameters of REE.
Author Response
Dear reviewer,
Thank you for your comments and sugesstions.The following changes have been made to the article according to your suggestions and to answer your questions.
1. The references have been extended.
2. According to the limit of sulfuric acid concentration, 8M dilute sulfuric acid concentration and 12M concentrated sulfuric acid concentration were selected as comparison.
Sincerely,
Qiuju Li
Reviewer 2 Report
After a careful reading, I found some major comments that the authors must performed before being accepted in the Minerals journal, they are listed as follow:
1. Please define the chemical equation in another subsection in the Materials and Methods.
2. Please, separate the units from values, e.g., 175℃ or 175 °C, 3h or 3 h?
3. The introduction must be re-written with updated references, research gaps of the study and the novelty of the research must be clear in this section. They must defend the importance of their work and compare it to previously published updated publications. They should contain benefits and applications over other known systems. The introduction should be expanded upon.
4. The abstract should have more technical details about your findings.
5. Figure 8 has a black background, is this part of the Figure? Please, revise it.
6. Plz. uniformize units through the manuscript, e.g., mol/L or M?
7. In line 161, please add % to 54.6.
8. Moderate English and typos are suggested to be revised in the whole ms.
9. Authors must increase their discussion and compared with the current literature of parent leaching procedures. No references are cited in this section. This section must be definitetly improved. A Table would be really useful for easy read.
10. In lines 77, authors mentioned “The leaching experiment conducted at 350℃ for 3h in atmosphere”, which atmosphere, inert or air?
11. What was the total Nb % in the residue by this method? Can authors give more information about ICP results?
Authors must address these points for a second round revision process.
Author Response
Dear reviewer,
Thanks for your comments and suggestions. Below, I will respond to your comments and suggestions.
Point 1: Please define the chemical equation in another subsection in the Materials and Methods.
Response 1: Corrections have been made.
Point 2: Please, separate the units from values, e.g., 175℃ or 175 °C, 3h or 3 h?
Response 2: Corrections have been made.
Point 3: The introduction must be re-written with updated references, research gaps of the study and the novelty of the research must be clear in this section. They must defend the importance of their work and compare it to previously published updated publications. They should contain benefits and applications over other known systems. The introduction should be expanded upon.
Response 3: Corrections have been made.
Point 4: The abstract should have more technical details about your findings.
Response 4: Corrections have been made.
Point 5: Figure 8 has a black background, is this part of the Figure? Please, revise it.
Response 5: Corrections have been made.
Point 6: Plz. uniformize units through the manuscript, e.g., mol/L or M?
Response 6:The units have been unified.
Point 7: In line 161, please add % to 54.6.
Response 7: Corrections have been made.
Point 8: Moderate English and typos are suggested to be revised in the whole ms.
Response 8: Corrections have been made.
Point 9: Authors must increase their discussion and compared with the current literature of parent leaching procedures. No references are cited in this section. This section must be definitetly improved. A Table would be really useful for easy read.
Response 9: The references ha been expanded
Point 10: In lines 77, authors mentioned “The leaching experiment conducted at 350℃ for 3h in atmosphere”, which atmosphere, inert or air?
Response 10: Air atmosphere
Point 11: What was the total Nb % in the residue by this method? Can authors give more information about ICP results?
Response 11: More information about ICP results has updated given in the Tble 1.
Sincerely,
Qiuju Li
Reviewer 3 Report
The present manuscript presents an interesting and original study on the acid leaching of columbite. In my opinion, this manuscript deserves to be published but several minor corrections must first be made: 1) Line 65: The chemical reaction is not balanced; 2) Line 77: Specify how the leaching conditions were selected; 3) What was the solids concentration during the leaching tests?; 4) Line 78: What “atmosphere”?; 5) Line 163: Replace “Spetra” with “Spectra”; Line 165: Replace “Resudues” by “Residues”. This change needs to be made in several other places in the text; Figure 2: It is difficult to understand why the sum of Fe2+ and Fe3+ does not equal 100% for the results of 8M residual and 12 M residual?; Title of figure 2 and 5: Replace “ferrocomubite” by “ferrocolumbite”; Line 204: 10M or 12M?; What were the solubilization yields of Fe and Nb during the leaching tests?; The manuscript should also be reviewed by an English-native speaker.
Author Response
Point 1: Line 65: The chemical reaction is not balanced.
Response 1: The chemical reaction has been changed to FeC2O4•2H2O + Nb2O5→FeNb2O6+ CO↑ +CO2↑ + H2O↑
Point 2: Line 77: Specify how the leaching conditions were selected;
Response 2: According to the limit of sulfuric acid concentration, the dilute sulfuric acid concentration of 8M and concentrated sulfuric acid concentration of 12M were selected.
Point 3: What was the solids concentration during the leaching tests?
Response 3: The solid concentration was 0.25g/ml.
Point 4: Line 78: What “atmosphere”?
Response 4: Air atmosphere.
Point 5: Line 163: Replace “Spetra” with “Spectra”; Line 165: Replace “Resudues” by “Residues”. This change needs to be made in several other places in the text;
Response 5: A correction has been made for Line 163 and Line 165 replacement issues.
Figure 2: It is difficult to understand why the sum of Fe2+ and Fe3+ does not equal 100% for the results of 8M residual and 12 M residual?;
Because not all of the Fe elements are fully leached after leaching. The content is also relative to the mineral.
Title of figure 2 and 5: Replace “ferrocomubite” by “ferrocolumbite”;
Replacement has been completed.
Line 204: 10M or 12M?;
12M.
What were the solubilization yields of Fe and Nb during the leaching tests?;
The solubilization yields of Fe and Nb in the leaching test have been reflected by modifying the table in the paper.
Round 2
Reviewer 2 Report
Dear authors,
Some minor points before the acceptance of your work. Please, carefully revised them:
1) HF what is the meaning? It is important for readers!
2) In lines 27-28, "Nb and Ta were often labeled as critical or strategic raw materials which were considered critical materials utilized widely in the steel, electronic, high-tech industries". Critical materials is repeated, please use another synonym.
3) Please, separate units from numbers. E.g. 8 M, 12 M. See Lines 83 and 84, 175 °C, 235 °C.
4) 15 h and not 15 hours
5) References have not an order. Above reference 11 follows reference 1? It makes not sense.
6) Line 236, 、or comma symbol.
Author Response
Dear reviewer,
Thanks for your comments and suggestions. I will response to your comments.
Point 1: HF what is the meaning? It is important for readers!
Response 1: Hydrofluoric acid has been labeled HF in the paper.
Point 2: In lines 27-28, "Nb and Ta were often labeled as critical or strategic raw materials which were considered critical materials utilized widely in the steel, electronic, high-tech industries". Critical materials is repeated, please use another synonym.
Response 2: Changes have been made in the article.
Point 3: Please, separate units from numbers. E.g. 8 M, 12 M. See Lines 83 and 84, 175 °C, 235 °C.
Response 3: Changes have been made in the article.
Point 4: 15 h and not 15 hours
Response 4: Changes have been made in the article.
Point 5: References have not an order. Above reference 11 follows reference 1? It makes not sense.
Response 5: The references appear in the correct order. There may be some problems in the format conversion when submitting, which has been corrected now.
Point 6: Line 236, 、or comma symbol.
Response 6: Changes have been made in the article.
Sincerely,
Qiuju Li
