Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory

Round 1

Reviewer 1 Report

This study aims to analyze the PSD multifractal properties of the gang using multifractal theory, including the ball-to-gang ratio and grinding time, under different ball milling conditions.

It is an interesting study that examines in detail the dependence of particle size distribution and shape change on some grinding conditions. However, it would be useful to explain why coal gangue was chosen and in which aspects and in which applications the findings related to this material are important.Some of my questions and suggestions about the entire manuscript are highlighted in the text and given as pop-up notes.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer ,

Thank you for recognizing our efforts and putting forward constructive suggestions. We appreciate your time and effort in making valuable improvements to our article. We have revised the manuscript accordingly. Reviewer’ comments are in black text, and the author responses appear in red. The revised manuscript is attached.

Point1：

This study aims to analyze the PSD multifractal properties of the gang using multifractal theory, including the ball-to-gang ratio and grinding time, under different ball milling conditions.

It is an interesting study that examines in detail the dependence of particle size distribution and shape change on some grinding conditions. However, it would be useful to explain why coal gangue was chosen and in which aspects and in which applications the findings related to this material are important. 

Response1：

Thank you so much for such a constructive comment,

Firstly, as a kind of solid waste with large reserves, gangue has good utilization prospects. Currently, it is known that crushed gangue is used for filling, making cement, making ceramics, and even chemical products. Under this background, we put gangue as the research object.

Secondly, the various ways of using gangue mentioned above have higher requirements on the particle size of gangue, and even have higher requirements on the shape of gangue in the production of cement and chemical products. The process parameters in the process play an important role in enabling the gangue to achieve the expected particle size and shape requirements.

We put the research significance of this paper as part of the last paragraph of the introduction, as follows:

Considering that gangue is a solid waste resource with large reserves, it has a good prospect of utilization in the world, and the current common utilization methods such as filling, cement making, ceramics making, and chemical products all affect the parti-cle size and shape of gangue. There are high requirements, so the research results are of great significance for controlling the process parameters of gangue in the ball mill-ing process and guiding the resource utilization of gangue

Point2：There are several reference errors in the text that need to be corrected (Error! Reference source not found).

Response2：

We also noticed this error, so we re-corrected and re-cited all "Error! Reference source not found" in the text.

Point3：There are several Statements about the procedures are both unclear and incompatible with the scientific study presentation style in 2.2. Test apparatus and procedure .

Response3：

There are two modifications here.

Firstly ,

We have replaced " Ball-to-gangue ratio and grinding time are common and easy-to-control operating factors in the grinding process. Their changes determine the movement state of the grinding media group and the energy carried by the grinding media, affecting the particle size structure changes in the ball mill. So, the ball-to-gangue ratio and grinding time are selected as the main factors to carry out the gangue ball milling test."

by

 " The ball-to-gangue ratio and grinding time affect the particle size of gangue in the ball mill by affecting the movement state of the grinding media and the energy carried by the grinding media".

Secondly,

We have replaced " Step3: The test ball mill is stopped every 10 min, the sealing plate on the end face of the cylinder is opened, the gangue particles are equally divided by a sample divider, and the PSD of the samples is tested by laser particle size analyzer (Fig. 2).

Step4: Reseal the end face of the ball mill barrel, and then start the test ball mill to run for 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min in turn, and repeat step 3.

Step5: According to the test plan in Table 2, change the ball-to-gangue ratio and repeat step 2~4."

by

 " Step3: Stop the operation of the ball mill every 10 minutes, open the seal-ing plate on the cylinder, take out the gangue sample with a sample divider, and test the particle size distribution of the sample through laser particle size analyzer (Figure 3).

Step4: Reseal the barrel of the ball mill, then start the ball mill and run for 10min, 20min, 30min, 40min, 50min, 60min in sequence, and repeat step 3"

Point4：what does "to absorb samples " mean ?

Response4：

This place is improperly expressed in language, and has been modified as follows:

We have replaced

" Finally, we used pipettes to absorb samples and measure particle size and volume percentage. "

By

" Finally, draw the sample with a straw to determine the volume percentage of the particle size. "

Point5："It should be rewritten" in 2.2. Test apparatus and procedure

Response5：

I'm sorry we didn't do a good job in sentence expression, I'm sorry that we didn't do a good job in sentence expression. We have made the following revisions to the problems you pointed out:

We have replaced

" For external morphology observation, a JSM-IT500 scanning electron microscope was used. A double-sided tape paper was pasted on the sample holder, and the bulk material was sprinkled. Then the unstuck powder was blown off with an ear-absorbing ball, and the conductive film was plated and placed in the scanning electron microscope for observation. Then, the structural and morphological parameters of gangue particles after milling were obtained by binarization of ESEM images. Fig. 2 shows the quantitative process of the structure and morphology of gangue particles after milling. "

By

" The morphology characterization tests were conducted on gangue particles as depicted in Figure 2. JSM-IT500 scanning electron microscope (SEM) was used to scan and observe the gangue samples coated with a conductive film. The microstructure and morphology parameters of gangue particles under different ball milling time were analyzed by ImageJ."

Point6： " I think it’s particle size percentages" with the title of table 3

Response6：

Thank you for your advice.

We have replaced " Table 3. PSD characteristics of gangue particles after ball milling "by " particle size percentages of gangue after ball milling ".

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Author

After detailed readings, I suggest accepting the manuscript ("Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory: Taking “ball-to-gangue ratio”and “grinding time”as example") with major corrections:

1 - I suggest revising the title, it's confusing, maybe the title could be: "Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory".

2 - The subtitle "Abstract", is with exaggerated font size.

3 - At the end of the "Abstract", I recommend deleting the following section: "The mesoscopic mechanism of multifractal parameter variation and its correlation with particle morphology parameters are analyzed by scanning electron microscopy".

4 - The "Keywords" need revision, many look like the title of the manuscript, which would not make the manuscript comprehensive.

5 - There are several reference errors in the text that need to be corrected (Error! Reference source not found).

6 - At the end of the introduction, it is necessary to highlight the importance that your study would have at a global level, this would arouse more interest from readers.

7 - The map in figure 1, it would be important to present the grid of coordinates, north, which are basic elements of a location map.

8 - The methodological procedure is written correctly and clearly.

9 - The results need to be better discussed with the literature, with the inclusion of more references.

10 - In the "Conclusions", at the end you need to make clear the possibility of future work, this would enable a relationship of continuity of your study, even at a global level.

Author Response

Dear Reviewer ,

Thank you for recognizing our efforts and putting forward constructive suggestions. We appreciate your time and effort in making valuable improvements to our article. We have revised the manuscript accordingly. Reviewer’ comments are in black text, and the author responses appear in red. The revised manuscript is attached.

Point1： I suggest revising the title, it's confusing, maybe the title could be: "Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory".

Response1：

Thank you so much for such a constructive comment

We have replaced the title " Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory: Taking “ball-to-gangue ratio”and “grinding time”as example " by  "Analysis of Influencing Factors of Gangue Ball Milling Based on Multifractal Theory".

Point2：The subtitle "Abstract", is with exaggerated font size.
Response2：

Please allow me to explain it. The font and format of the subtitle "Abstract" are determined by the editor of the journal. Therefore, please allow us to communicate further with the editor, and then revise.

Point3：At the end of the "Abstract", I recommend deleting the following section: "The mesoscopic mechanism of multifractal parameter variation and its correlation with particle morphology parameters are analyzed by scanning electron microscopy".
Response3：

Thanks for your suggestion, we have deleted the section: "The mesoscopic mechanism of multifractal parameter variation and its correlation with particle morphology parameters are analyzed by scanning electron microscopy".

Point4：The "Keywords" need revision, many look like the title of the manuscript, which would not make the manuscript comprehensive.
Response4：

Thanks for your suggestion, we have changed the " Gangue; Particle size distribution; Mass ratio of ball-to-gangue; Grinding time; Multifractal theory" to the " Gangue; Particle morphology and size; heterogeneity; Multifractal theory ".

Point5：There are several reference errors in the text that need to be corrected (Error! Reference source not found).

Response5：

We also noticed this error, so we re-corrected and re-cited all "Error! Reference source not found" in the text.

Point6：At the end of the introduction, it is necessary to highlight the importance that your study would have at a global level, this would arouse more interest from readers.
Response6：

Thanks for your suggestion, we have simplified the conclusion. We have added a section at the end of the Introduction to emphasize the importance of the research，as follows

Considering that gangue is a solid waste resource with large reserves, it has a good prospect of utilization in the world, and the current common utilization methods such as filling, cement making, ceramics making, and chemical products all affect the particle size and shape of gangue. There are high requirements, so the research results are of great significance for controlling the process parameters of gangue in the ball milling process and guiding the resource utilization of gangue

Point7：The map in figure 1, it would be important to present the grid of coordinates, north, which are basic elements of a location map.

Response7：Thank you for your advice. We have modified Figure 1 as follows:

Point8： The methodological procedure is written correctly and clearly.Introduction; give benefits of fractal analysis used in the experimental study.

Response8：

Thank you, in order to make the language more concise, we have refined some of the experimental content and process

Point9： The results need to be better discussed with the literature, with the inclusion of more references.

Response9：

Thanks, we have added some discussion and references.

Point10：In the "Conclusions", at the end you need to make clear the possibility of future work, this would enable a relationship of continuity of your study, even at a global level.

Response10：

We refine the conclusion and make clear the possibility of future work in conclusion (5) as follows:

For different types of gangue, the optimal ball-to-gangue ratio and grinding time need to be further studied, which requires consideration of the matching relationship between rock mechanics parameters and ball milling parameters in future research

Author Response File: Author Response.docx

Reviewer 3 Report

In order to reduce the size of the coal gangue, the article investigating the effect of the ball-gang ratio and grinding time on the grindability of the coal gangue in the ball mill is a research article. In the article, the effect of ball-gangue ratio and the effect of grinding time on the grindability of coal gangue in the ball mill are clearly demonstrated by experimental data. The results obtained from the experimental data are explained by discussing with the analysis methods. The present work is an interesting article presenting a different experimental approach on coal gangue grinding. I think it is appropriate for this article to be published in your journal. But there are typos in many places in the article (Error! Reference source not found). These errors need to be fixed.

Author Response

Thank you for your approval of the paper. We have revised the "Error! Reference source not found" in the article and re-polished some sentences.

Thanks again for your attention and time

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors performed the necessary revisions. The manuscript is ready to be published