Determination of Total Mercury and Mercury Thermospecies in Cement and Cement Raw Materials

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for your submission entitled “Determination of Total Mercury and Mercury Thermospecies in Cement and Cement Raw Materials.” This is a timely and well-executed study that addresses a significant gap in the understanding of mercury behavior during cement production. The combination of total Hg quantification with thermospecies analysis is a valuable contribution to environmental analytical chemistry and industrial process control. I commend the effort taken to validate the methodology and the comprehensive data collected across multiple cement plants.

Below are my specific comments and suggestions for improvement:

Major comments

1. Clarify Figures and Tables:

   - Some figures (e.g., Figure 1 and Figure 2) would benefit from improved formatting. Ensure that all axis titles include proper units (e.g., ng g⁻¹, °C).

   - Table 3 could be improved by standardizing how values and uncertainties are presented (e.g., use of ± and consistent decimal places).

2. English Language and Style:

   - While the manuscript is generally clear, there are several instances of awkward phrasing and grammatical issues. For example:

   • • "Hg concentrations in cement lied between..." should be "ranged between."

     • "Hg analyzer was calibrated using..." Consider: "The Hg analyzer was calibrated using..."

     • I recommend a light language edit to enhance fluency and clarity throughout the manuscript.

    

3. Discussion Depth:

   - The discussion of the implications of thermospecies is informative. However, it would be valuable to further emphasize how this data might support improvements in emissions mitigation or process control in cement kilns.

   - Consider comparing your results more directly with the Hg speciation profiles reported in similar industrial processes (if available).

    

Minor Comments

- Line 13–14: Consider briefly explaining why different heating rates were used for total Hg vs. thermospecies determinations.

- Line 237–243: It would help readers if you included a brief explanation of what a "thermospecies" implies in the context of environmental risk or volatility.

- Line 326–337 (Conclusions): The summary is well-written. However, you might want to rephrase “with higher degree of certainty at 95% confidence level” to avoid implying a formal statistical inference unless such tests were actually performed on that point.

 

Thank you again for your contribution.

Sincerely,
Reviewer

Author Response

Comments 1: Figures and tables can be improved

Response: Figures and tables were improved

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a detailed and methodologically rigorous study on the determination of total mercury and its thermospecies in cement and the raw materials. The study is original, well-designed and supported by analytical validation. However, a few areas require refinement before the manuscript can be recommended for publication.

In the Introduction, the novelty of the work should be more explicitly highlighted, particularly in terms of how thermal desorption overcomes the limitations of traditional wet chemical digestion methods.

In Sections 2.2 “Calibration Standards” and 2.3 “Reagents and Solutions”, information regarding certified reference materials appears to be repeated. Consider combining or reorganizing these sections.

The manuscript does not clearly explain how the temperature stages were selected, nor whether these stages correspond to the known volatilization profiles of specific mercury compounds. This should be clarified, ideally with reference to the literature.

The Discussion section would benefit from a more policy-oriented perspective. Consider integrating references to regulatory frameworks such as the Minamata Convention or the EU BREF documents, to enhance the environmental relevance of the findings.

In the Conclusion section, it would be valuable to outline possible future research directions, such as the use of complementary techniques for speciation (e.g., thermal desorption–GC–MS), or broader applications of the methodology.

Despite these issues, the manuscript demonstrates strong scientific merit and addresses a relevant and underexplored topic in industrial mercury speciation. With minor revisions related to language, structure, and contextual discussion, this work would make a valuable contribution to the field.

Comments on the Quality of English Language

The manuscript would benefit from a thorough language revision. For example, in Line 17, the phrase “And in cement lied between…” is grammatically incorrect and should be revised. A general proofreading by a native English speaker or professional editor is recommended, as grammar and syntax issues are present throughout the manuscript.

Author Response

Comments1: English language can be improved.

Response 1: English language was improved. Improvements are highlighted in yellow.

Comments 2: Figures and tables can be improved.

Response 2: Figures and tables were improved.