Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

There is insufficient data to show the novelty of the authors’ work.

Where is the leaching method?

Eq. 1 The compositional analysis, in atomic percentages: what does it mean? From where did it represent?

Some references (those by names) should be cited in the correct form of the journal format.

The conclusion should be revised.

How did the author make a connection between leaching efficiency and pre-treatment?

What is the concentration of copper in the leachate?

Show the process of the methods as a flow diagram.

Author Response

There is insufficient data to show the novelty of the authors’ work.

Where is the leaching method?

It’s leached with 0.34 M sodium hypochlorite, pH 12.5 and at room temperature

Eq. 1 The compositional analysis, in atomic percentages: what does it mean? From where did it represent?

It’s how the concentration of different oxidation states are calculated, from the XPS spectra (figure 3 (a), as an example) that give de atomic % of each oxidation states of one element using EQ 1, this it is represented on figure 3 (b)

Some references (those by names) should be cited in the correct form of the journal format.

I don´t understand?

The conclusion should be revised. ok

How did the author make a connection between leaching efficiency and pre-treatment? The work is based on the chalcopyrite reaction on an alkaline media, in order to remove the arsenic from a copper concentrate (chalcopyrite/enargite) prior the smelter, due to the reaction of enargite with hypochlorite is faster allowing to be uses as al concentrate cleaning stage,

What is the concentration of copper in the leachate?

Nil, because the copper remains in the solid phase

Show the process of the methods as a flow diagram.

The methods are contact the chalcopyrite surface with a solution 0.34 M sodium hypochlorite, pH 12.5 and room temperature for 2 different times.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, I find this paper to be quite good.  The methodology is well-planned and well-executed, and the results are interesting and enlightening.

Generally, the English in this paper needs work.  The are many grammatical and spelling errors.

Lines 42-46: The authors should also cite the paper by Ren et al., “The Overlooked Mechanism of Chalcopyrite Passivation” in Acta Materialia.

Lines 47-52: The authors should also cite the Jetti catalyzed leaching process, which is transforming the treatment of low-grade chalcopyrite ores.

Figure 2a: The same symbols are used for Fe and C.

Line 108 and 114: The word “pickling” is used, but in Line 119, the word “peeling” is used.  I believe that “peeling” is the correct word here.  There was no pickling involved in these tests.

Again Line 163 uses the word “pickling” which I believe is incorrect.

Line 348: There is a mistake in the repeat of equation (3) — the subscript on S should be n, not 0.

Comments on the Quality of English Language

Someone who speaks English as a first language should proofread this paper before it is published.

Author Response

Overall, I find this paper to be quite good.  The methodology is well-planned and well-executed, and the results are interesting and enlightening.

Thank a lot I really needed some words like yours

 

Generally, the English in this paper needs work.  The are many grammatical and spelling errors.

Lines 42-46: The authors should also cite the paper by Ren et al., “The Overlooked Mechanism of Chalcopyrite Passivation” in Acta Materialia.

Done .

Lines 47-52: The authors should also cite the Jetti catalyzed leaching process, which is transforming the treatment of low-grade chalcopyrite ores.

It’s included by the reference

Figure 2a: The same symbols are used for Fe and C.

 Done

Line 108 and 114: The word “pickling” is used, but in Line 119, the word “peeling” is used.  I believe that “peeling” is the correct word here.  There was no pickling involved in these tests.

Changed

Again Line 163 uses the word “pickling” which I believe is incorrect.

Ok changed

Line 348: There is a mistake in the repeat of equation (3) — the subscript on S should be n, not 0.

 OK Changed

 

Reviewer 3 Report

Comments and Suggestions for Authors

Abstract:

1. “The unattached chalcopyrite on its surface…”. This statement needs to be clarified. What does unattached mean?
2. “in the internal zones.” Internal zones of what, can the authors clarify, please? Does it mean the Cu/S ratio differs externally and internally? XPS penetration is limited to few um, how did the authors measure internal and external Cu/S ratio?
3. “displacement of the oxidation states of the surface sulfur”. Can the authors clarify this further?
4. Lines 23-24: Are the authors stipulating that the Fe hydroxide and sulphate phases are non-passivating? Per experience, this depends on a number of factors such as phase density, porosity, gangue element mobilization among other factors. I think the authors did not show these properties of the various phases identified.
5. Lines 21-22: Is this to say that Fe hydroxide, copper oxide and sulphates become the dominant secondary phases? Within what time frame do these phase transformations occur?

Introduction:

1. The key gap and contributions of this study are lacking. Can the authors rewrite the introduction to make this clear?

Methods and Results

1. “A depth composition profile…” What is the depth level? Fig 2b shows cycle but not depth in um or mm? Does this mean a surface reaction-controlled phenomenon , with no major changes beyond the surface? How about fluid penetration between in-situ micropores of the chalcopyrite mineral?
2. The atomic ratios Cu/Fe and Cu/S, Figure 6 (b), show that the surface is even more enriched in copper and depleted in iron than the surface of the original or unleached sample, sulfur decreases its fraction due to the passage to solution as SO42” Can the authors provide references for this statement and many others in the manuscript? Such observations have been reported in literature.
3. 2.1 Behavior of chalcopyrite sulfur when leached with hypochlorite - this is confusing. Do the authors mean sulfur contained in chalcopyrite?
4. Since the authors detected Na2SO4 and iron hydroxide , did they also detect jarosite formation because the reaction of these two sodium sulphate and oxidized iron can lead to NaFeSO4 phase.
5. “…100% of the chlorine is in the state of sodium chloride, NaCl”. Did the authors detect any CuCl or CuCl2 or FeCl2 or FeCl3 or FeCl- etc?
6. “desapears”…please correct all typographical errors in the manuscript
7. “environmental chalcopyrite,..” What do the authors mean by this?
8. Lines 356 – 358 “Authors should discuss the results and how they can be interpreted from the perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible. Future research directions may also be highlighted.” Why this, please? Was this a note to the authors?

Author Response

Abstract:

1. “The unattached chalcopyrite on its surface…”. This statement needs to be clarified. What does unattached mean?

Unleached and was changed

1. “in the internal zones.” Internal zones of what, can the authors clarify, please?

The chalcopyrite internal zone it’s the Chalcopyrite not exposed to ambient or reagent the analysis done after each peeling cycle until it’s reached the stoichiometric chalcopyrite composition

Does it mean the Cu/S ratio differs externally and internally?

For the unleached CPY No, However the composition changes in the surface due to the O and C incorporation the ratio kept constant (fig 2) but for leached CPY de Cu/S ratio change increasing with time due to the sulfur diminution (became sulfate) 

XPS penetration is limited to few um, how did the authors measure internal and external Cu/S ratio?

From the unleached chalcopyrite XPS spectra after each peeling cycle Because the ratio Cu/S=0.5 reach is the stoichiometric ratio of the chalcopyrite

1. “displacement of the oxidation states of the surface sulfur”. Can the authors clarify this further?

 

1. Lines 23-24: Are the authors stipulating that the Fe hydroxide and sulphate phases are non-passivating? Per experience, this depends on a number of factors such as phase density, porosity, gangue element mobilization among other factors. I think the authors did not show these properties of the various phases identified.

Yes we have done an alkaline leach a high arsenic concentrate ( CPy +Enargite) and the reaction continue, but faster for the enargite allowing a selective process .

1. Lines 21-22: Is this to say that Fe hydroxide, copper oxide and sulphates become the dominant secondary phases?  Yes, Within what time frame do these phase transformations occur? Less than 5minutes

Introduction:

1. The key gap and contributions of this study are lacking. Can the authors rewrite the introduction to make this clear?

Methods and Results

1. “A depth composition profile…” What is the depth level? Between 5 to 40 (Å) by cycle Fig 2b shows cycle but not depth in um or mm? yes because I can’t have a precise depth measurement. Does this mean a surface reaction-controlled phenomenon, with no major changes beyond the surface? It’s change with time is possible to see how the reaction penetrate from 5 seg to 5 minutes releasing Fe3+ and sulfate. How about fluid penetration between in-situ micropores of the chalcopyrite mineral? I use pure crystalline chalcopyrite and maybe for these time reactions it’s not affects but for further time must be done 
2. The atomic ratios Cu/Fe and Cu/S, Figure 6 (b), show that the surface is even more enriched in copper and depleted in iron than the surface of the original or unleached sample , sulfur decreases its fraction due to the passage to solution as SO42” Can the authors provide references for this statement and many others in the manuscript? Such observations have been reported in literature. the ratio increases due to the releasing Fe3+ and SO42-
3. 2.1 Behavior of chalcopyrite sulfur when leached with hypochlorite - this is confusing. Do the authors mean sulfur contained in chalcopyrite?

Yes, the sulphur it’s oxidized to SO4

1. Since the authors detected Na2SO4 and iron hydroxide , did they also detect jarosite formation because the reaction of these two sodium sulphate and oxidized iron can lead to NaFeSO4 phase.

NO, only Ferric Hydroxide was detected, but due to the constituents and conditions, jarosite could precipitate.

5. “…100% of the chlorine is in the state of sodium chloride, NaCl”. Did the authors detect any CuCl or CuCl2 or FeCl2 or FeCl3 or FeCl- etc?

No the reaction product were in the solid phase were CuSn, CuFe_1-xS₂ , Feric hydroxide and CuO 

1. “desapears”…please correct all typographical errors in the manuscript

Done

1. “environmental chalcopyrite,..” What do the authors mean by this?

Natural Chalcopyrite

1. Lines 356 – 358 “Authors should discuss the results and how they can be interpreted from the perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible. Future research directions may also be highlighted.” Why this, please? Was this a note to the authors?

Paragraph eliminated

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript presents interesting work; however, several revisions are required to improve clarity, structure, and scientific rigor. My detailed comments are as follows:

1. Language and Grammar:
   The manuscript requires careful editing by a native English speaker. There are numerous spelling and grammatical errors throughout. A few examples include:
   • Line 17: unattached should be untreated.
   • Line 57: de form should be the form.
   • Line 58: The sentence “anlyses was developed to apllied/utilize/employed” is unclear and should be rewritten for clarity.
   • Line 68: equip should be equipment.
   • Line 71: cuantification should be quantification.
     Additionally, the manuscript incorrectly describes samples as “attacked/attached”; they are treated with the solution.
2. Clarity of Study Objectives:
   The primary aim of the study is not clearly defined. The authors should explicitly state whether the work focuses solely on surface characterization or if it is part of a broader investigation into leaching mechanisms, bulk material behavior, and industrial applications.
3. Materials and Methods Section:
   The structure of this section should be improved. It would be more logical to describe the samples and leaching process first, followed by the XPS characterization, reflecting the actual workflow of the investigation.
4. Figures and Captions:
   • Figure 1: The peak notations are too small and difficult to read. The caption should be revised to: “XPS spectrum of the chalcopyrite surface.”
   • Figures 2a, 6a, and 7a: Carbon and Fe are represented with identical symbols; this should be corrected.
   • Figure 12: The caption refers to oxygen content in leached samples (“Oxygen in the leached samples for five seconds and five minutes”), but no oxygen data are shown in this figure. This discrepancy should be addressed.
5. Experimental Details:
   The rationale for using different numbers of cycles for various measurements should be explained. The authors are encouraged to provide:
   • An estimation of the material thickness removed per cycle.
   • An estimation of the depth represented by cycles 1–6, including the depth at which pure chalcopyrite is reached.
6. Discussion Section:
   The final paragraph of the Discussion should be removed. The discussion should instead:
   • Interpret the results in the context of previous studies and the stated working hypotheses.
   • Discuss the implications of the findings in a broader context.
   • Highlight potential directions for future research.
7. Methodological Considerations:
   XPS is primarily a surface and thin-film characterization technique and may not be ideal for investigating large-scale leaching processes or industrial applications. The limitations of this approach should be explicitly acknowledged.

Author Response

The manuscript presents interesting work; however, several revisions are required to improve clarity, structure, and scientific rigor. My detailed comments are as follows:

1. Language and Grammar:
   The manuscript requires careful editing by a native English speaker. There are numerous spelling and grammatical errors throughout. A few examples include:

1. Line 17: unattachedshould be untreated.

Done

2. Line 57: de formshould be the form.

Done

3. Line 58: The sentence “analyses was developed to applied/utilize/employed” is unclear and should be rewritten for clarity.

Done

4. Line 68: equipshould be equipment.

Done

5. Line 71: cuantificationshould be quantification.

Done
Additionally, the manuscript incorrectly describes samples as “attacked/attached”; they are treated with the solution.

Done

1. Clarity of Study Objectives:
   The primary aim of the study is not clearly defined. The authors should explicitly state whether the work focuses solely on surface characterization or if it is part of a broader investigation into leaching mechanisms, bulk material behavior, and industrial applications.

As a high arsenic concentrate pretreatment (chalcopyrite/enargite) prior smelting

1. Materials and Methods Section:
   The structure of this section should be improved. It would be more logical to describe the samples and leaching process first, followed by the XPS characterization, reflecting the actual workflow of the investigation.

Done

1. Figures and Captions:

1. Figure 1:The peak notations are too small and difficult to read. The caption should be revised to: “XPS spectrum of the chalcopyrite surface.”

Done

2. Figures 2a, 6a, and 7a:Carbon and Fe are represented with identical symbols; this should be corrected.

Done

3. Figure 12:The caption refers to oxygen content in leached samples (“Oxygen in the leached samples for five seconds and five minutes”), but no oxygen data are shown in this figure. This discrepancy should be addressed.

DONE

1. Experimental Details:
   The rationale for using different numbers of cycles for various measurements should be explained. The authors are encouraged to provide:

1. An estimation of the material thickness removed per cycle.

Each peeling cycle reaches a depth in the range of 5 to 40 (Å),

2. An estimation of the depth represented by cycles 1–6, including the depth at which pure chalcopyrite is reached.

1. Discussion Section:
   The final paragraph of the Discussion should be removed. DONE The discussion should instead:

1. Interpret the results in the context of previous studies and the stated working hypotheses.
2. Discuss the implications of the findings in a broader context.
3. Highlight potential directions for future research.

Thanks, and was incorporated

1. Methodological Considerations:
   XPS is primarily a surface and thin-film characterization technique and may not be ideal for investigating large-scale leaching processes or industrial applications. The limitations of this approach should be explicitly acknowledged.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Apparently, the authors did not like to answer the comments. The novelty of the paper is not answered. So, it can be rejected. 

Author Response

 Dear Reviewer 1, Round 2

• Comment 1: Apparently, the authors did not like to answer the comments. The novelty of the paper is not answered. So, it can be rejected.

Reviewer 1: We deeply regret the misunderstanding (it was my fault due to my lack of experience), but we'd be happy to answer any questions or comments you may have to improve the article. The novelty is now better explained by integrating this work with previous work done by the authors.

With the improvement of the problem statement, we allow ourselves to send you the corrected answers from the review of round 1

Comment 1-1 There is insufficient data to show the novelty of the authors’ work.

The text has been improved to better explain the novelty and purpose of the research, and a reference has been added to previous work conducted by the authors on the selective leaching of arsenic from copper concentrates, where selectivity of the enargite reaction over chalcopyrite was observed under the conditions studied

 

Comment 1-2 Where is the leaching method?

For the XPS surface study, a polished solid sample of chalcopyrite was contacted with 0.34 M sodium hypochlorite, pH 12.5 and at room temperature (condition defined in the previous work) for 5 seconds and 5 minutes. The leached sample was evaluated in the first surface layers to determine the changes in the oxidation states of Cu, Fe and S to determine the reaction products, and if this forms a passivating layer that explains the selectivity.

Comment 1-3 Eq. 1 The compositional analysis, in atomic percentages: what does it mean? From where did it represent?

The compositional analysis is determined from the XPS spectra obtained for each pickling cycle for Cu, Fe, S, C and O, which show the distribution of the oxidation states of these elements (figure 3, 4, 5, (a). Figure 8 shows as an example the S spectra (160 eV) in the pickling cycles for the samples leached at 5 seconds and 5 minutes. Based on this interpretation, the atomic % of each oxidation state of an element is determined using EQ 1.

Comment 1-4 Some references (those by names) should be cited in the correct form of the journal format.

I don´t understand?

Comment 1-5 The conclusion should be revised.

Conclusions were improved and aligned to determine the reason for the selectivity between enargite and chalcopyrite when leached with hypochlorite.

Comment 1-6 How did the author make a connection between leaching efficiency and pre-treatment?

This paper attempts to explain the selectivity observed in previous work on arsenic removal from copper concentrates (chalcopyrite/enargite) with high arsenic content, using alkaline leaching, which allows the cleaning of non-commercial concentrates (high arsenic) into low arsenic concentrates, and proposes a pretreatment to clean the concentrate before smelting.

Comment 1-7 What is the concentration of copper in the leachate?

Nil, because the copper remains in the solid phase as CuO

Comment 1-8 Show the process of the methods as a flow diagram.

A flow diagram for the concentrate cleaning process is described in the publication "Selective Leaching of Arsenic from Copper Concentrates in a Hypochlorite Medium."

In the present XPS study of chalcopyrite surface, the leaching conditions employed correspond to those with the highest selectivity of the enargite/chalcopyrite reaction: 0.34 M sodium hypochlorite solution, pH 12.5, and room temperature.

 

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Please correct all typographical errors – example lines 51 to 61

The authors should respond to all the previous comments raised by the reviewer's appropriately and in detail.

Author Response

 

Dear Reviewer 3, Round 2

 

Comment 1: Please correct all typographical errors – example lines 51 to 61

Thank you for your correction. We've improved the paragraph, corrected the typos, and included a reference to the authors' previous work, which raises the need to understand the reactivity of chalcopyrite in this medium.

 

Comment 2: The authors should respond to all the previous comments raised by the reviewer's appropriately and in detail.

Thanks to your corrections and those of the other reviewers, the manuscript was improved. Thanks to these improvements, we can send you the corrected responses from the first round of review.

 

Comment 1-1: “The unattached chalcopyrite on its surface…”. This statement needs to be clarified. What does unattached mean?

 

Thank you for this valuable question. For clarity, the unattached chalcopyrite was changed in the text to unleached and represents the original mineral sample, that is, pure chalcopyrite prior to contact with the leaching solution.

 

 

 

Comment 1-2: “in the internal zones.” Internal zones of what, can the authors clarify, please?

 

 

Thank you for this valuable question. The inner zone of chalcopyrite is the mineral that is not exposed to the environment or reagents; an XPS analysis is performed in each peeling cycle until the stoichiometric composition of chalcopyrite is reached. This corresponds to the internal zone.

 

 

Comment 1-3: Does it mean the Cu/S ratio differs externally and internally?

 

Thank you for this valuable question. In the case of the unleached chalcopyrite surface, the Cu/S ratio remains constant; however, the composition at the surface changes due to the incorporation of ambient O and C, which disappear upon entering the sample (Fig. 2).

In the case of leached chalcopyrite, the Cu/S ratio changes between the surface and the internal zones, the Cu/S ratio increases at the surface due to the decrease in sulfur at the surface, the sulfur passes into solution as sulfate (Figs. 6 and 7).

 

Comment 1-4: XPS penetration is limited to few um, how did the authors measure internal and external Cu/S ratio?

 

Yes, you are absolutely right, the analysis is of the surface, but leaching at 5 seconds and 5 minutes allows the progress of the reaction to be characterized. From the XPS spectra performed at each chalcopyrite peeling cycle, the elemental atomic percentage is obtained, and therefore the ratio.

 

Comment 1-5: “displacement of the oxidation states of the surface sulfur”. Can the authors clarify this further?

 

What is intended to be explained is the relationship between mono, bi and polysulfides which changes from the surface to the internal region due to the change from monosulfides to disulfides and polysulfides, which was changed in the manuscript in lines 21-23.

 

Comment 1-6: Lines 23-24: Are the authors stipulating that the Fe hydroxide and sulphate phases are non-passivating? Per experience, this depends on a number of factors such as phase density, porosity, gangue element mobilization among other factors. I think the authors did not show these properties of the various phases identified.

 

Yes, you are absolutely right, the research team has carried out the alkaline leaching of a concentrate with high arsenic content chalcopyrite/enargite where 80% of enargite and 17% of chalcopyrite are leached, so the difference in reaction rates allows a process of selective elimination of arsenic in this medium, a reference was incorporated. The XPS study allows to determine that the reaction products are not passivating (elemental sulfur is not obtained but sulfates).

 

Comment 1-7: Lines 21-22: Is this to say that Fe hydroxide, copper oxide and sulphates become the dominant secondary phases? 

 

Yes, you are correct. The reaction progress over time is shown in Figure 14, where it can be seen that the chalcopyrite composition is reached in cycle 4 for the 5-second leached sample, and intermediate products are determined. The 5-minute profile shows the progress of the reaction, as no chalcopyrite is observed, and the generation of reaction products such as Fe hydroxide, copper oxide, and sulfates is determined.

 

Comment 1-8 Within what time frame do these phase transformations occur?

 

Because it is a surface analysis involving only a few um, this reaction occurs rapidly, in less than 5 minutes. For the selective arsenic removal process, where chalcopyrite reacts 17%, this reaction is achieved in less than 30 minutes.

 

Comment 1-9: Introduction:

1. The key gap and contributions of this study are lacking. Can the authors rewrite the introduction to make this clear?

Yes, you are right, the purpose of the work is not well stated. The instructions have been improved. The authors add a reference to previous work on selective leaching of arsenic from chalcopyrite/enargite concentrates, which showed a high degree of selectivity. The purpose of analyzing chalcopyrite is to determine whether the selectivity is due to a reaction difference or the formation of a passivating layer.

Comment 1-10: Methods and Results

“A depth composition profile…” What is the depth level?

 

According to the literature and the specification of the XPS equipment, the depth reached by each peeling cycle is in the range of 5 to 40 (Å)

 

Fig 2b shows cycle but not depth in um or mm?

 

It is presented in cycles to make them comparable for the three conditions analyzed and because there is no precise measurement of depth, but the maximum depth should be between 25 to 200 A° for five cycles.

 

Does this mean a surface reaction-controlled phenomenon, with no major changes beyond the surface?

 

Yes, from what we have investigated the reaction is controlled by the chemical reaction, the result of this determines that there is an advance in the reaction front, you can see in Fig 14 how the reaction penetrates with time.

 

How about fluid penetration between in-situ micropores of the chalcopyrite mineral?

 

Thank you for the question. In the present study, a sample of pure crystalline chalcopyrite was leached for 5 seconds and 5 minutes, reaching a limited depth of attack. Therefore, an analysis of the reaction product characteristics at longer times would be advisable to determine the solution penetration into the product layer.

 

The atomic ratios Cu/Fe and Cu/S, Figure 6 (b), show that the surface is even more enriched in copper and depleted in iron than the surface of the original or unleached sample, sulfur decreases its fraction due to the passage to solution as SO42” Can the authors provide references for this statement and many others in the manuscript? Such observations have been reported in literature.

 

Yes, the reviewer is correct. A decrease in sulfur and iron was observed on the surface of both the unleached chalcopyrite and the samples leached for 5 seconds and 5 minutes. The decrease in sulfur is due to the conversion of sulfur to sulfate. Regarding iron in the solid, Fe3+ is observed, and this decrease may be due to the oxidizing conditions of the leaching process, which converts iron to ferrate, which is soluble at pH 12 (FeO42-). This transformation could be studied in future research.

 

2.1 Behavior of chalcopyrite sulfur when leached with hypochlorite - this is confusing. Do the authors mean sulfur contained in chalcopyrite?

 

Yes, the sulfur in chalcopyrite is oxidized to SO4 as shown in Fig. 9b, where sulfate appears and the leaching solution is sulfur-free

 

Since the authors detected Na2SO4 and iron hydroxide, did they also detect jarosite formation because the reaction of these two sodium sulphate and oxidized iron can lead to NaFeSO4 phase.

No, only ferric hydroxide was detected, but due to the components and conditions, jarosite could precipitate.

 

“…100% of the chlorine is in the state of sodium chloride, NaCl”. Did the authors detect any CuCl or CuCl2 or FeCl2 or FeCl3 or FeCl- etc?

 

No, the compounds mentioned were not detected in the analysis. The solid-phase reaction products were CuSn, CuFe₁-xS₂, ferric hydroxide, and CuO.

 

“desapears”…please correct all typographical errors in the manuscript

 

Thank for the correction and is done

 

“environmental chalcopyrite,..” What do the authors mean by this?

 

 

Thank you for this valuable question. For clarity, the environmental chalcopyrite was changed in the text to unleached and represents the original mineral sample

 

Lines 356 – 358 “Authors should discuss the results and how they can be interpreted from the perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible. Future research directions may also be highlighted.” Why this, please? Was this a note to the authors?

 

The paragraph was modified to incorporate a reference to previous work carried out by the authors on the removal of arsenic from copper concentrates.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The discussion is insufficiently developed and requires substantial improvement, particularly through the inclusion of additional references. At line 463, the authors claim that “The results are consistent with previous work conducted by the authors on arsenic removal from chalcopyrite/enargite concentrates”; however, no citation is provided to substantiate this statement, which undermines its credibility. Furthermore, the results are presented in isolation, without adequate comparison to relevant literature. A rigorous discussion should include a comparison with other studies on chalcopyrite dissolution in different leaching agents to properly contextualize the findings and demonstrate their broader significance.

Author Response

 

Dear Reviewer 4, Round 2

 

Comment 1: The discussion is insufficiently developed and requires substantial improvement, particularly through the inclusion of additional references. At line 463, the authors claim that “The results are consistent with previous work conducted by the authors on arsenic removal from chalcopyrite/enargite concentrates”; however, no citation is provided to substantiate this statement, which undermines its credibility. Furthermore, the results are presented in isolation, without adequate comparison to relevant literature. A rigorous discussion should include a comparison with other studies on chalcopyrite dissolution in different leaching agents to properly contextualize the findings and demonstrate their broader significance.

Dear reviewer, I am very sorry for the mistake, (it was my fault due to my lack of experience),but I am now including the reference.

 

Hernández M, Benavente O, Roca A, Melo E, Quezada V, Selective Leaching of Arsenic from Copper Concentrates in Hypochlorite Medium, Minerals, 2023 13, 1372. https://doi.org/10.3390/min13111372

 

Furthermore, the results are presented in isolation, without adequate comparison to relevant literature. A rigorous discussion should include a comparison with other studies on chalcopyrite dissolution in different leaching agents to properly contextualize the findings and demonstrate their broader significance

 

Dear reviewer the purpose of this work is to analyze the reaction of chalcopyrite in an alkaline oxidizing medium, in order to determine the mechanism of the selectivity of the reaction of enargite over chalcopyrite in this medium, found in the previous work of arsenic removal from copper concentrate, which keeps copper in solid phase as CuO, the present work defines that chalcopyrite does not form a passive layer in an alkaline oxidizing medium as it happens in sulfuric acid leaching, but the reaction is slower than the enargite reaction, allowing the removal of arsenic from chalcopyrite/enargite concentrates as a pretreatment prior to smelting.

 

 

Author Response File: Author Response.docx

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

There is insufficient data to show the novelty of the authors’ work.

Some references (those cited in the text by name, year) should be cited in the correct journal format.

Show the process of the methods as a flow diagram.

Author Response

 

Dear Reviewer 1, Round 3

 

Comment 1: There is insufficient data to show the novelty of the authors’ work.

Dear reviewer, the introduction has been modified to connect this manuscript with previous work by our team on arsenic removal from copper concentrates. This study, based on the selectivity that occurs when treating a concentrate in an oxidizing alkaline medium, found that the reaction rate of enargite is six times greater than that of chalcopyrite.

This phenomenon has not been identified in the existing literature, and the reasons for this selectivity remain to be clarified. To determine the reasons for this selectivity, the chalcopyrite surface was analyzed under these conditions of maximum selectivity at different times to identify the reaction products formed.

 

Commet 2: Some references (those cited in the text by name, year) should be cited in the correct journal format.

 

Thanks for the advice and the reference was corrected on line 52, 56 and 363.

 

Commet 3:  Show the process of the methods as a flow diagram.

A flowchart of the evaluation process was added to the manuscript, as figure 1 on line 82.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors,

Thank you for the clarification in your answer. I suggest you include the given explanation in the discussion itself. Additionally, for easier understanding and reading, consider breaking down long sentences into several shorter ones.

Comments on the Quality of English Language

The English should be improved; the sentences are too long and difficult to understand at first reading.

Author Response

Dear Reviewer 4, Round 3

 

Commente 1: Thank you for the clarification in your answer. I suggest you include the given explanation in the discussion itself.

Dear reviewer, thank you for your comment, and we're glad we were able to clarify the topic of our work. The discussion was improved following your advice on lines 333 to 336.

Commente 2 : Additionally, for easier understanding and reading, consider breaking down long sentences into several shorter ones.

Thank you very much for the suggestion and some changes were made to the manuscript. I hope that this time our work can be better understood.