Methodologies for the Possible Integral Generation of Geopolymers Based on Copper Tailings
, Humberto Collado 1,2, Thomas Droguett 3,4, Sebastián Sánchez 3,5, Mario Vesely 1, Pamela Garrido 3 and Sergio Palma 2Round 1
Reviewer 1 Report
Review of the manuscript under the title: “Methodologies for the integral generation of geopolymers based on copper tailings.” for the Journal Minerals (ISSN 2075-163X).
General thoughts:
- The article has no scientific value. This is rather a case study.
- What is the novelty?
- The introduction must be expanded - please add information about similar studies (already conducted in this field).
- You should check results from other studies and compare them to confirm your findings (there is no discussion of the results in this manuscript).
In addition to the general comments above, there are specific items that should be addressed in any follow on version of the manuscript:
- The authors should clarify all the images contain a reference in their caption whether they have permission to use those images or not.
- Add more information on where the raw materials used for research came from.
- Correct the formatting of photo titles and tables according to the journal guidelines.
- For values in tables, commas should be replaced with dots.
- Provide more detailed information about the equipment used for testing.
- Figure 2 it is not necessary to indicate as many decimal places for the chart axis values; correct units from “um” to “µm”
- Line 99 - add abbreviation extensions where they were first entered in the text.
- If possible, the formatting of charts should be unified.
- Line 114 – correct phrase “The Stell molds” to “The stell molds”
- Line 124-125 – word repetition.
- Line 126 - what exactly the authors meant to write “better mechanical resistance”?
- Figure 6 – very bad quality, please replace it;
- Figure 17 - UCS - add abbreviation extensions in the photo title
- Figure 21 - you cannot compare these photos with each other, please take a photo on a scanning microscope and then make a comparison.
- Correct the formatting of the references according to the journal guidelines.
- Line 394 – replace “vii” to “VII”.
- There is no information about the authors' contribution.
Author Response
Dear reviewer,
Thank you very much for your comments.
The article is designed to generate copper flotation tailings geopolymers, knowing that in Chile, our country, is one of the main copper producers and in turn the one with the most tailings deposits, the need to produce environmentally friendly solutions environment and a circular economy. Copper flotation tailings geopolymers are being considered for use for filling underground tunnels in mining.
The introduction has been expanded.
Comparative studies have been indicated, however, studies on the generation of geopolymers from copper flotation tailings are academically few, studies that abound are based on metakaolin and fly ash, but not on copper flotation tailings that the base of our research.
All images and photographs are the property of the authors of this article.
The comments on the lines, figures and tables that you have indicated have been modified as indicated.
Due to the fact that other reviewers have requested to highlight the modifications with respect to the previous version, in this revision the changes introduced have been marked with yellow color.
Thank you very much for your comments, we will continue working to improve this article.
Reviewer 2 Report
Nothing is said about the petrology and mineralogy of the tailings, only the chemical composition is referred to. The formation of geopolymers and their characteristics depend heavily on these two parameters and not only on chemical composition. The type of deposit and the characteristics of the ore and, consequently, of the tailings should be mentioned.
Some other comments that need to be clarified:
Solid samples need to be prepared before they are submitted to ICP – pulverization, fusion, digestion by acid(s) and dilution. It is known that the preparation affects the analytical results. The article should mention, even briefly, the procedures that were used to prepare the samples for chemical analysis in the ICP.
Table 1 refer the chemical composition of the liquid that was analysed. Is it an average value? Or only one sample was analysed? In the last case, how was it obtained? The variability of the composition is irrelevant?
In relation to the chemical composition of the industrial water, the values pointed out in Table 2 are mean values? Or they refer to an occasional sample?
The results show that:
- The most important variable in the procedure for the addition of NaOH; (concentration, L/S ratio and temperature and method);
- Curing time and temperature are also essential to produce an acceptable final product.
These conclusions are not a surprise and they were expected from previous knowledge (production of geopolymers from other sources). What conclusion do you enhance as a novelty?
Consistency and hardness are only quantified by visual inspection. Some relevant properties for industrial applications cannot be appraised by visual inspection: soundness, compactness, water absorption, compressive strength, excess of soluble salts, in addition to some other properties.
The study should be considered as a preliminary approach to the possibility of using copper tailings for producing geopolymers and this fact should also be stressed in the title.
Author Response
Dear reviewer,
Thank you very much for your comments.
The results of petrography and mineralogy tests, respectively, have been reported.
The information regarding the source of the copper flotation tailings that we have used for this investigation has been supplemented.
The information from the ICP trial has been supplemented.
The industrial water used is the industrial water from the process of obtaining copper and the copper flotation tailings, and they are reported values are average values.
The results are novel for obtaining geopolymers based on copper flotation tailings. The bibliographic review carried out has shown us that it is easy to reproduce results of geopolymers based on metakaolin and fly ash, but not for copper flotation tailings, that is why the methods, tests and trial / error trials, until achieve a Method VII that achieves a quantitatively measurable resistance.
The objective of the research is to be able to achieve a mixture that can harden, and that its uniaxial resistance to compression can be measured. The mixtures that did not harden were discarded, since when they were removed from the mold, they deformed, liquefied, and did not maintain their shape, and the compression test could not be carried out. See for example figure 7.
Due to the fact that other reviewers have requested to highlight the modifications with respect to the previous version, in this revision the changes introduced have been marked with yellow color.
Thank you very much for your comments, we will continue working to improve this article.
Reviewer 3 Report
The manuscript is defiantly shown a great effort of experiments and it is worth to be published. However, I would like to address the following questions or comments to be taking in consideration when revising the manuscript:
1- The “introduction” part needs to be strengthened.
2- Authors should improve the quality of all figures.
3- I do not see any characterization tests for mixtures (for example: shaking table tests?) It is important to watch how the mixture behaves.
4- Why the curing time is 7d and it should be cured in the oven?
5- Explain how you choose the water/solid ratio.
6- Are the dimensions of the molds or the compression tests associated with standards?
7- The conclusion must be reinforced.
8- It is better to have this paper extensively edited to improve the language.
9- Authors must be correct references according to the journal guide.
10- The introduction part is not fully cited, and a lot of cements research has been carried out, for example: (1) Huang Z, Yilmaz E, Cao S. Analysis of Strength and Microstructural Characteristics of Mine Backfills Containing Fly Ash and Desulfurized Gypsum[J]. Minerals, 2021. (2) Li J, Yilmaz E, Cao S. Influence of Solid Content, Cement/Tailings Ratio, and Curing Time on Rheology and Strength of Cemented Tailings Backfill[J]. Minerals, 2020, 10(922). It is recommended to add the above papers. (3) Huang Z, Yilmaz E, Cao S. Investigation on the flexural strength, failure pattern and microstructural characteristics of combined fibers reinforced cemented tailings backfill[J]. Construction and Building Materials, 300 (2021) 124005.
In summary, the reviewer believes that this manuscript is strongly recommended for the publication through the abovementioned revisions.
Author Response
Dear reviewer,
Thank you very much for your comments.
The introduction has been strengthened.
The quality of the images and figures have been improved, which are all of the authors of this article.
Greater test results have been incorporated with which the mixtures that failed to harden were discarded in order to perform a simple compression test, as shown in Figure 7.
When you inquire about the curing time and the days, this is what we have wanted to show with the different methods that we have carried out, a clear and precise guide on how to achieve a geopolymer based on copper flotation tailings achieves resistance to simple compression. With less temperature and fewer days of setting - curing, a specimen that was capable of being tested in simple compression was not achieved.
The choice of the water-solids ratio has been based on the percentage of concentration of original solids of the tailings, and from there several mixtures were made that are shown in Table 4. Then it was optimized and tested by trial - error until the Method was achieved. VII with their respective results. Procedure that took us approximately 10 months of intense work.
The molds are in accordance with the regulations indicated in the article.
The conclusion has been reinforced.
References have been indicated as requested.
In the scientific community there are many studies of geopolymers, but not so in geopolymers generated from copper flotation tailings. The generation of geopolymers with metakaolin or fly ash is simple and its method is known, but for copper flotation tailings there is no information about it, until now, with our article.
Due to the fact that other reviewers have requested to highlight the modifications with respect to the previous version, in this revision the changes introduced have been marked with yellow color.
Thank you very much for your comments, and recommend the publication of our article, your words are very valuable to the entire team of this investigation, we will continue working to improve this article.
Round 2
Reviewer 1 Report
The manuscript under the title: “Methodologies for the possible integral generation of geopolymers based on copper tailings.” still needs some corrections:
- the authors still have not demonstrated the novelty of the work/conclusions
- Line 178-180 - in the sentence the authors write about previously carried out research - please add references to this sentence
- Figure 17 – as above, please add references
- Line 458 - in the received version of the article, the text "Error! Reference source not found" appears on this line
- Correct the formatting of the references according to the journal guidelines. References should be described as follows, depending on the type of work:
Journal Articles:
1. Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.
Books and Book Chapters:
2. Author 1, A.; Author 2, B. Book Title, 3rd ed.; Publisher: Publisher Location, Country, Year; pp. 154–196.
3. Author 1, A.; Author 2, B. Title of the chapter. In Book Title, 2nd ed.; Editor 1, A., Editor 2, B., Eds.; Publisher: Publisher Location, Country, Year; Volume 3, pp. 154–196.
Unpublished materials intended for publication:
4. Author 1, A.B.; Author 2, C. Title of Unpublished Work (optional). Correspondence Affiliation, City, State, Country. year, status (manuscript in preparation; to be submitted).
5. Author 1, A.B.; Author 2, C. Title of Unpublished Work. Abbreviated Journal Name year, phrase indicating stage of publication (submitted; accepted; in press).
Unpublished materials not intended for publication:
6. Author 1, A.B. (Affiliation, City, State, Country); Author 2, C. (Affiliation, City, State, Country). Phase describing the material, year. (phase: Personal communication; Private communication; Unpublished work; etc.)
Conference Proceedings:
7. Author 1, A.B.; Author 2, C.D.; Author 3, E.F. Title of Presentation. In Title of the Collected Work (if available), Proceedings of the Name of the Conference, Location of Conference, Country, Date of Conference; Editor 1, Editor 2, Eds. (if available); Publisher: City, Country, Year (if available); Abstract Number (optional), Pagination (optional).
Thesis:
8. Author 1, A.B. Title of Thesis. Level of Thesis, Degree-Granting University, Location of University, Date of Completion.
Websites:
9. Title of Site. Available online: URL (accessed on Day Month Year).
Unlike published works, websites may change over time or disappear, so we encourage you create an archive of the cited website using a service such as WebCite. Archived websites should be cited using the link provided as follows:
10. Title of Site. URL (archived on Day Month Year).
Author Response
Dear Reviewer,
Thank you very much for your comments.
The research team believes that the scientific article presented is novel for the reality of our country, Chile, to seek solutions for the large environmental liabilities that copper flotation tailings have generated, making it possible to generate geopolymers with them.
Line 178-180: references were added and marked with green for better identification. See on Line 181.
In Figure 17 the references were added and marked with green for better identification. See on Line 372.
Line 458 has been corrected, however, it may be a problem in your text editor, since the research team does not see this error. Please check it on another PC.
References have been updated.
Thank you very much for allowing us to improve our article.
Reviewer 2 Report
The authors took into consideration all the suggested remarks. The article in its present form is clear and more accurate by detailing and amplifying the information that was previously supplied.
Author Response
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