The Contribution of Long-Terms Static Interactions Between Minerals and Flotation Reagents for the Separation of Fluorite and Calcite
Round 1
Reviewer 1 Report
Dear Authors,
Many thanks for your contribution to the journal. I have carefully read and examined your article and found that there are few important corrections which I highlighted and inserted my comments on the manuscript.
Please consider those in order to develop the quality of the article. Regards,
Comments for author File: 
Comments.pdf
Author Response
Point 1: The title seems to me too large and somehow not reflecting the importance of the subject. It should be compacted by removing some words, such as two times flotation, minerals and the specific names, etc.

Response 1: Thanks for the reviewer’s valuable comments and thoughtful suggestion on our manuscript and the title has been revised, as seen in the text from line 2-3.
Point 2: What is a zero day? Does it mean the beginning of the tests or some minutes?
Response 2: A zero day refers to “the pulp was not placed from the beginning to the end of the tests”. And the time required to complete the whole test is 18 min, as seen in the text from line 105.
Point 3: Can only the FTIR data explain whether the adsorption mechanism is chemisorption, physisorption, electrostatic or etc.?
Response 3: The XPS data can also suggest the adsorption between minerals and collector is chemisorption, as seen in the text from line 325-327, 335-337 and 340-342.
Point 4: Why tailings? not ore itself?
Response 4: Because there is a large amount of fluorite and calcite in the tailings of Jianfengpo tin-zinc mine in Jiangxi province, China. In order to make full use of resources and solve the environmental problems caused by tailings accumulation, tailings were then selected.
Point 5: There are some other mineral separation methods especially dry optical processing and some other rather than flotation depending on the liberation particle size.
Response 5: Fluorite with large particle size and high grade is limited in nature, and fluorite is often co-existed with other minerals. Furthermore, most fluorite particles in tailings are small. Therefore, to meet market’s demand, fluorite must be liberated from other gangue minerals and collected by flotation before entering the fluorite commercial market.
Point 6: What does the sites mean?
Response 6: The sites mean the points at which the reagents interacts with the mineral surface, ie Ca2+ active sites, as seen in the text from line 48.
Point 7: The past tense?
Response 7: Thank you for your reminder. It has been revised, as seen in the text from line 50.
Point 8: It is recommended that Fuerstenau, Laskowski, Yarar and some other wellknown previous researchers' work should be read on the subject to compare the present data.
Response 8: Thank you for your advice. Fuerstenau, Laskowski, Yarar and other wellknow previous researchers’ work have been added, as seen in the text from line 50-53 and 57-62.
Point 9: Where are the reference numbers?
Response 9: The reference number is 21, as seen in the text from line 443.
Point 10: Why do you use tailings here? Why not real feed raw ore?
Response 10: Because tailings itself is also a kind of resource, the utilization of tailings can not only realize the secondary resource utilization, but also solve the environmental problems caused by tailings accumulation.
Point 11: What is the XRD equipment brand and measurement parameters?
Response 11: The XRD equipment brand and measurement parameters have been inserted, as seen in the text from line 84-86.
Point 12: Please define? water glass or sodium metasilicate?
Response 12: Sodium silicate is a kind of water-soluble silicate. Its aqueous solution is commonly called as water glass.
Point 13: What does it stand for?
Response 13: XFGC is a flotation machine model manufactured by Jilin exploration machinery plant in China, as seen in the text from line 96-97.
Point 14: Is it really that precise to measure rpm? if the value is over than 2000 rpm, the pulp might be mixed vigorously and the medium can be chaotic?
Response 14: This speed is the default speed when the equipment is delivered from the factory and can be adjusted. The speed is displayed on the instrument panel and is not manually measured. When the value is over than 2000 rpm, the pulp can be mixed vigorously, but too high speed is not conducive to flotation.
Point 15: It is difficult to understand the 0 value from the abstract.
Response 15: A 0 day refers to “the pulp was not placed from the beginning to the end of the tests”. And the 0 value represents the time of pulp placed. The time required to complete the whole test is 18 min.
Point 16: Where did you get it? any reference?
Response 16: The reference has been inserted. The reference number is 14, as seen in the text from line 120.
Point 17: Why didn’t you use the real ore rather than the tailings? is there a specific reason for that?
Response 17: Since tailings accumulation will cause a series of environmental problems, the utilization of tailings can not only realize the full utilization of resources, but also solve environmental problems. In fact to recover fluorite from tailing is more difficult than real ore.
Point 18: I think it is better to show all three separate graphs side by side or one by one from up to bottom as large images.
Response 18: Thank you for your advice. It has been revised, as seen in the text from line 308-310.
Point 19: The recoveries of below 50% show that the mechanism is somehow reverse flotation occurred. For single minerals, the data seem OK to me, however the flotation data of the tailings are not parallel with the single minerals data.
Response 19: Tailings flotation experiment is carried out to verify its feasibility, not as a parallel control.
Point 20: Between pH 9 and 10, the flotation mechanism seems to me electrostatic interaction rather than chemisorption.
Response 20: It has been reported in the literature [1] that between pH 9 and 10, the collector and fluorite surface are chemisorbed.
Zhao, W.; Liu, D.; Li, H.; Feng, Q.; Xu, G.; Yuan, J.; Jia, X. Influence of pulp pH on flotation of fluorite and calcite. Mater. Res. 2013, 616-618, 614-618. http://doi.org/10.4028/www.scientific.net/AMR.616-618.614.
Point 21: Why is environmental friendly? The readers should find some more clue.
Response 21: Because tailing accumulation can cause a series of environmental problems, such as soil and groundwater contaminations. Making full use of tailings can not only realize resource reuse, but also avoid environmental pollution, which is beneficial to environmental protection.
Point 22: There is need for some more international literature.
Response 22: Thank you for your advice. Some international literatures have been added, as seen in the text from line 409, 416-430, 434-440 and 461-443.
Reviewer 2 Report
The manuscript entitled "Long-term static interaction between minerals and flotation reagents significantly promoted the
selective separation of fluorite from calcite by flotation" investigated the responses of flotation reagents on
mineral surfaces by performing different tests such as adsorption, FTIR, XPS and contact angle tests.
The organization of paper and the usage of English language is good but in my opinion the quality of discussion and the novelty
of paper should be better emphasized throughout introduction and conclusion sections. Before acceptance to publication, there are some
few points that needs to be corrected and explained;
-In Line 76, please correct "Water grass" to "Water glass"
-I think the title should be revised to "The contribution of long-terms static interactions between minerals with flotation reagents"
-What is the main criteria for selecting 8 days? And is there any additional data for other days? I think, it would be
better to show the variations of at least one test procedure as a function of day.
-In addition, is it possible to show flotation recoveries, contact angle values and adsorption capacities in the same graph?
Author Response
Point 1: In Line 76, please correct "Water grass" to "Water glass"
Response 1: Thanks for the reviewer’s valuable comments and thoughtful suggestion on our manuscript. It has been revised, as seen in the text from line 88.
Point 2: I think the title should be revised to "The contribution of long-terms static interactions between minerals with flotation reagents"
Response 2: Thank you and the title has been revised, as seen in the text from line 1-2.
Point 3: What is the main criteria for selecting 8 days? And is there any additional data for other days? I think, it would be better to show the variations of at least one test procedure as a function of day.
Response 3: As shown in Figure 3 of the manuscript, the recovery of fluorite at 8 days was not significantly different from that at 0 day, while the recovery of calcite at 8 days was significantly lower than that at 0 day, which was conducive to the separation of two minerals. Therefore, the time was selected. And there were some additional data for other days and the trend is the same.
Point 4: In addition, is it possible to show flotation recoveries, contact angle values and adsorption capacities in the same graph?
Response 4: Sorry, I think it’s difficult.
Author Response File: Author Response.pdf
Reviewer 3 Report
Line 48: Many researches "have" and not "had"
Literature review lacks depth. I expected a review
of the different mechanisms for mineral-collector
interactions. This should then justify why the author
focused solely on static interactions.
The authors should define what static interactions are
and not assume that the reader knows them.
The authors state that a ball mill was used for comminution? Why ball mill? What grinding media was used and why? And how would the type of grinding media affect flotation performance?
Was your XRD based on the Rietveld method? Is
so, please specify?
Why did the authors investigate the mentioned
reagents in particular? Please justify?
What is XFGC?
2 g of mineral sample was added "to" and not "and".
Section 2.2 should be clear of the flotation times in
terms of the time intervals at which the concentrates
were collected.
Section 2.7 Schematic of the flow-sheet used must be added to the manuscript.
Line 198: Plays and not played.
Line 204: not clear what is being compared to what?
Author Response
Response to Reviewer 3 Comments
Point 1: Line 48: Many researches "have" and not "had"
Response 1: Thanks for the reviewer’s valuable comments and thoughtful suggestion on our manuscript. It has been revised, as seen in the text from line 50.
Point 2: Literature review lacks depth. I expected a review of the different mechanisms for mineral-collector interactions. This should then justify why the author focused solely on static interactions.
Response 2: It has been revised according to the suggestion, as seen in the text from line 50-53 and 57-62.
Point 3: The authors should define what static interactions are and not assume that the reader knows them.
Response 3: It has been revised. Static interaction refers to a state without agitation under natural conditions, as seen in the text from line 105.
Point 4: The authors state that a ball mill was used for comminution? Why ball mill? What grinding media was used and why? And how would the type of grinding media affect flotation performance?
Response 4: The particle size required for flotation tests is -74+38 μm, so the comminution is extremely necessary. In order to avoid contamination, the ceramic ball mill and ceramic balls were used in this work. The ceramic ball is a common grinding media for flotation of pure minerals. Other grinding medium, such as steel ball, will be consumed in the grinding process due to repeated collision between media or between media and minerals, thereby affecting the flotation effect.
Point 5: Was your XRD based on the Rietveld method? Is so, please specify?
Response 5: XRD patterns were not refined, and all XRD results were analysed by Jade 6.0, as seen in the text from line 84-86.
Point 6: Why did the authors investigate the mentioned reagents in particular? Please justify?
Response 6: These reagents were commonly used in fluorite flotation. And many literatures [1-4] have reported these reagents have a good effect on these minerals.
Marinakis, K.I.and Shergold, H.L. The mechanism of fatty acid adsorption in the presence of fluorite, calcite and barite. J. Miner. Process. 1985, 14, 161–176. http://doi.org/10.1016/0301-7516(85)90001-8. De Leeuw, N.H.; Parker, S.C.; Rao, K.H. Modeling the Competitive Adsorption of Water and Methanoic Acid on Calcite and Fluorite Surfaces. Langmuir 1998, 14, 5900–5906. http://doi.org/10.1021/la980269k. Fa, K.; Jiang, T.; Nalaskowski, J.; Miller, J.D. Interaction Forces between a Calcium Dioleate Sphere and Calcite/Fluorite Surfaces and Their Significance in Flotation. Langmuir 2003, 19, 10523–10530. http://doi.org/10.1021/la035335j. Gao, Z.; Gao, Y.; Zhu, Y.; Hu, Y.; Sun, W. Selective Flotation of Calcite from Fluorite: A Novel Reagent Schedule. Minerals 2016, 6 (4), 114. https://doi.org/10.3390/min6040114.
Point 7: What is XFGC?
Response 7: XFGC is a flotation machine model manufactured by Jilin exploration machinery plant in China, as seen in the text from line 96-97.
Point 8: 2 g of mineral sample was added "to" and not "and"
Response 8: It has been revised, as seen in the text from line 98.
Point 9: Section 2.2 should be clear of the flotation times in terms of the time intervals at which the concentrates were collected.
Response 9: The whole flotation time was 18 min. And we have explained the time intervals in detail in my manuscript, as seen in the text from line 97-104.
Point 10: Section 2.7 Schematic of the flow-sheet used must be added to the manuscript.
Response 10: The flow-sheet used has been added to the manuscript, as seen in the text from line 167-168.
Point 11: Line 198: Plays and not played.
Response 11: It has been revised, as seen in the text from line 214.
Point 12: Line 204: not clear what is being compared to what?
Response 12: It has been revised, as seen in the text from line 220.
