Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The description of the experiments for gamma spectrometry and neutron activation analysis in the "Materials and Methods" section is not sufficient. It is suggested that the author at least supplement the basic test parameters such as the energy range, calibration method, and background subtraction to improve the transparency of the experimental process and the repeatability of the results.
2. The correlation analysis between rare earth elements and natural radioactive nuclides is limited to the linear correlation coefficient (r), without further exploration of control factors or multivariate statistical results. It is suggested that the author add multiple regression or principal component analysis to enhance the persuasiveness of the conclusion.
3. In Figures 3, 4, and 5, the correlation coefficients (r = 0.63–0.80) between ΣLREE and U, Th may be overestimated. From the scatter plots, the data points are relatively scattered, the sample size is limited, and there are outliers. It is suggested that the author supplement the significance test of the correlation and residual analysis, and try to use multivariate statistical methods (such as principal component analysis or multiple regression) to improve the statistical reliability and interpretability of the results.
4. The use of the term "concentration factor" in the text is ambiguous in meaning. In Table 3, this factor represents the ratio of the average content of elements in coal samples to the Clarke value, while in the charts of the radioactive nuclide section, its meaning is closer to the ash/coal ratio. It is suggested that the author clearly provide the calculation formula of the concentration factor in the method section and clearly define its usage in different research objects.
5. The expression of the charts is slightly simple. Some tables only list the concentration range and average value of elements, lacking comparability and intuitiveness.
6. There are some problems such as misused vocabulary and inconsistent professional terms in the manuscript. The overall English needs professional editing to improve the fluency of the manuscript.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Reviewer`s remarks concerning the paper:

 

STUDYING NATURAL RADIOACTIVITY OF COALS AND ASH AND SLAG WASTE AS POTENTIAL RAW MATERIALS FOR QUALITY ASSESSMENT AND EXTRACTION OF RARE EARTH METALS

 

The subject matter brought up in the article is interesting. The article contains interesting results but reviewer has some comments.

 

-Lines 232-238 – “An assessment was made of the relationship between the total content of light rare earth elements (ΣLREE) and the concentration of radionuclides (U and Th), as well as their  sum in Ekibastuz coal samples. In coal samples, a moderate positive correlation is ob- served between ΣLREE and the uranium content (r = 0.68), as well as between ΣLREE and thorium (r = 0.63). The correlation is higher between ΣLREE and U + Th (r = 0.75) (Figure 3). This can indicate the joint presence of these elements in common mineralogical inclu- sions or is due to geochemical affinity and similar migration properties under coal formation conditions.”

 

-Lines 249-250 – “The correlation coefficient between (ΣLREE) and Th is r = 0.89, which is a very high value. The correlation coefficient between (ΣLREE) and U is (r = 0.45), ΣLREE and U+Th (r = 0.80), (Figure 4).”

 

Are all of the discussed correlations significant? Authors should only discuss results for significant correlations. In addition to the correlation coefficient, the significance level (p) should also be shown.

 

-Line 240 - Figure 3

Please show the correlation coefficient and significance level on the graph.

 

-Line 247 – “Table 2. ASW analysis results.”

What units are used to express the ASW analysis results?

 

-Lines 256 -258 – “The data obtained are in good agreement with these conclusions, indicating the possibility of using ERN as indicators of REE in coals and ash and slag waste.”

 

Please explain the abbreviation ERN.

 

-Line 259 - Figure 4

Please show the correlation coefficient and significance level on the graph.

 

-Lines 280-283 and figure 5 – “A significant positive correlation was established between ΣLREE and the Th content (r = 0.63), which can indi- cate joint migration or coaccumulation of these elements in the organo-mineral phase of coal (Figure 5).”

 

In addition to presenting the correlation coefficient, the significance level (p) should also be shown.

 

-Lines 352-353 – “One of such benchmarks is the value of the Th/U ratio significantly related to the coal ash content (Figure 6).”

 

The relationship described in lines 352–353 is shown in Figure 7. However, there is no reference to this figure in the article. Please show the correlation coefficient and significance level on the graph.

 

-Please standardise the units used to express REE content throughout the article. For example, in lines 75–78, the REE content is expressed in % and ppm, whereas in the tables it is expressed in mg/kg.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

File 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Please note that all comments have been taken into account.

Author Response

We are sending you a corrected and supplemented version of the article «STUDYING NATURAL RADIOACTIVITY OF COALS AND ASH AND SLAG WASTE AS POTENTIAL RAW MATERIALS FOR QUALITY ASSESSMENT AND EXTRACTION OF RARE EARTH ELEMENTS»

 Based on the editor's recommendations and questions, some adjustments were made to the article. Changes and additions to the text of the article are marked in yellow.

Based on the editor's recommendations, some adjustments have been made to this article. Changes and additions to the text are highlighted in yellow.

 

Added figure 1 - Geological and tectonic map of coal deposits in Central and Eastern Kazakhstan.

The overall workflow of the study is shown schematically in figure 2.

(figure 2 - The research workflow, including the main analytical and interpretative stages)

 

 

The authors thank the editor for valuable suggestions and comments.