A New Study on the Eastern Flank of the Loma Blanca Deposit (Cuba) to Establish the Mineralogical, Chemical, and Pozzolanic Properties of Zeolitised Tuffs

Round 1

Reviewer 1 Report

This paper provides the results of a study carried out in an unexplored area that is located approximately 1.2 km east of the Loma Blanca deposit, outside the mining operations limits. In this study, four samples were taken from the study area and another four were taken from the Loma Blanca deposit, and chemical and mineral characterization analyses of these samples were performed.

The methodological approach seems solid and appropriate. The paper was well organized and the results are important for environmental and analytical chemistry. Basically, there is no problem regarding English. Therefore, I feel this paper should be acceptable after some revisions in view of the following specific comments.

 

(1) The research significance and innovation of the article should be elaborated in more detail.

 

(2) How many replicates do the experimental data represent? There are no errors for data presented in Tables and Figures (e.g., Tables 3 and 4, Figures 4 and 5).

 

(3) It would be interesting if the authors could mention the study implications, applications or recommendations for now and the future.

 

Author Response

Dear Reviewer 1:

Please find attached a file with the replies to your appreciated comments.

Kind regards;

Dr. Jorge L. Costafreda.

Author Response File: Author Response.pdf

Reviewer 2 Report

 

This article shows the results of a study carried out in an unexplored area that is located in Loma Blanca  deposit, outside the mining operations limits.

The characterization of the samples was done by XRD, SEM and XRF. The pozzolan quality was determined by pozzolanicity test (PT) and quality chemical analysis (QCA), and mechanical strength (MST) was done at 7, 23 28, and 90 days, using mortar specimens made with PC/ZT:75 ‒ 25% and PC/ZT:70 ‒ 30%, respectively.

The pozzolanicity test showed that both samples from the study area and those from the Loma Blanca deposit behave like typical pozzolans, which is a trend that can be seen in the high values of mechanical strength to compression up to 72 MPa for the PC/ZT:75 ‒ 25% formulation 30 and 66 MPa for the PC/ZT:70 ‒ 30%.

The results obtained establish that the zeolite varieties detected  in the study area are similar to those of the Loma Blanca deposit, which could have a positive impact on the increase in current reserves, especially for the manufacture of pozzolanic cements with properties that contribute to preservation of the environment.

The chemical and mineral characterization analyses of the samples establish a clear similarity between the samples taken from the Loma Blanca deposit and those from the study area, these characterizations are similar to the technical tests, such as chemical quality analysis, pozzolanicity and mechanical strength, which is the object of this research.

According to the results discussed, all the samples studied have a marked pozzolanic nature, a property that varies comparatively within very narrow limits.

The mineral and chemical composition of the samples seems to establish a link with the same formations that lie beyond the limits of the Loma Blanca deposit, which is in agreement with the comparison made with the previous work done by other researchers.

In relation to the results of the mechanical strength to compression, especially highlighted is the fact that partial replacement of portland cement by zeolitised tuff in mortars is effective, in both substitutions of 25% and 30%,.

I consider the subject matter and research included in the article to be very interesting and of great cognitive value. Recommends publishing the article in its current form,

Author Response

Dear Reviewer 2:

Please find attached a file with the replies to your appreciated comments.

Kind regards;

Dr. Jorge L. Costafreda.

Author Response File: Author Response.pdf

Reviewer 3 Report

 

 

1-       XRD- In the XRD pattern, the amorphous phase [volcanic glass] has a hump at 20-26 degrees.. it is not detectable here.. if the age of the deposit is Paleogene or older, it is possible that volcanic glass has disappeared , eventhough there exist shapes that resemble glass. Zeolites can replace it by a solid-solid inversion.. Quartz has its major peak at 26.60 degrees.. it is not visible here.. At around 22 degrees, there is cristobalite which is a common accessory mineral in zeolite tuffs.. it is not clear if it exists or not.. in addition, the opal-CT phases are between 20.80 and 21.80 degrees.. in the XRD patterns provided it is not possible to detect this opal.. The most common minerals in zeolitized tuffs are the feldspars and it is not clear if there is any of them in the deposit studied.. I suggest to run again the samples and to define each mineral phase present..

 

2-       SEM- the SEM images are poor in quality, as it is not possible to define the characteristic shape of both, mordenite [needle-like crystals] and clinoptilolite [tabular crystals]. In addition, the characterization of a spot as amorphous is actually a volcanogenic particle, possibly feldspar.. If all the tuffaceous material has only anhedral or subhedral authigenic crystals and not euhedral ones, an explanation has to be given. For mordenite needle-like crystals, see the deposits of Cavo de Gata.. What is the difference in chemistry of clinoptilolite and mordenite? Is mordenite the K-rich variety which judges for high temperature alterations? I recommend to add some EDS analysis to define the differences between clinoptilolite and mordenite.

 

3-       XRF- one column with the TOTAL% has to be added

 

4-       Literature- It is necessary to add some more papers on the behavior of zeolite tuffs as cement additives.. i.e. Stamatakis M.G., Regueiro M., Calvo J.P., Fragoulis D., Stamatakis G. A study of zeolitic tuffs associated with bentonite deposits from Almeria, Spain and Kimolos Island, Greece and their industrial potential as pozzolanas in the cement industry. Hell J. Geosci. 2010;45:283–292. [Google Scholar]

 

Dimitrios Fragoulis, Emmanuel Chaniotakis and Michael G. Stamatakis, 1997, Zeolitic tuffs of Kimolos Island, Aegean Sea, Greece and their industrial potential. Cement and Concrete Research, Volume 27, Issue 6, Pages 889-905

 

S.Özen, M.C.Göncüoğlu, B.Liguori, B.de Gennaro, P.Cappelletti, G.D.Gatta, F.Iucolano, C.Colella^c, 2016, A comprehensive evaluation of sedimentary zeolites from Turkey as pozzolanic addition of cement- and lime-based binders. Construction and Building Materials, Volume 105, Pages 46-61

 

5-       Finally, what is the new data comparing this research with the recent one of yours:  https://mdpi-res.com/d_attachment/molecules/molecules-26-04676/article_deploy/molecules-26-04676.pdf?version=1627903778

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Author Response

Dear Reviewer 3:

Please find attached a file with the replies to your appreciated comments.

Kind regards;

Dr. Jorge L. Costafreda.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Dear Authors, the problem in the SEM analysis persists.. how do you idnetify thar anhedral cryatals are either clinoptilolite or mordenite? You did not provided any EDS microanalysis to prove that.

n addition, you have to measure the % percentage of each zeolite type in each sample.

You have to compare the pozzolanic behavior of the Cuban mordnite-clinoptilolite-rich samples with similar deposits which are located in other regions.. are the results similar or different? It has been, already, detected difference in compressive strength of cements produced with mordenite or clinoptilolite-rich tuffs.. This comparison is important.. You may seach for some papers describing pozzolanic tuffs from Romania and Hungary, besides Spain, Greece and Turkey..

Author Response

Dear Reviewer 3: 

Please find attached the answers to your questions.

Kind regards.

Dr. Jorge L. Costafreda.

Author Response File: Author Response.pdf