The Impact of Ultra-Low Temperature Quenching Treatment on the Pore Structure of Natural Quartz Sand
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors!
The article devoted to the influence of low temperatures on the porosity of quartz sand is submitted for review.
The research topic is interesting for the reader in its field.
The title of the article corresponds to the content.
The abstract contains basic information about the article. The key words in the article are chosen correctly.
The introduction section contains information on the research topic from earlier, but the authors should break the text into paragraphs. The paragraph on line 57-96 is too big and difficult to read.
The authors should add the purpose of the paper to better let the readers understand what they are researching in the paper.
The “materials and methods” section needs to be improved. No equipment is specified to obtain data on the specific surface area (line 111). Similar questions to Table 1. How were the elemental content values determined?
The objects of study are not clear from Figure 1. The separation by stage is clear. However, the difference between QC-2 and QC-3 is not clear. The authors should make a table or diagram showing more clearly what kind of samples were studied in the paper.
The “results and discussion” section is well structured. It contains the description and results of the study. The pictures presented in the paper are of good quality. Comparisons of the findings with existing works are given.
The conclusion contains the main results of the paper. The sources considered in the paper correspond to the topic of the study, both recent studies and quite old works are presented.
The work is recommended for a major revision because of questions to the section “materials and methods of research”, as well as the missing purpose of the work.
Author Response
|
Comments 1: The introduction section contains information on the research topic from earlier, but the authors should break the text into paragraphs. The paragraph on line 57-96 is too big and difficult to read. |
||||||||||||||||||||||||||||||||||||||||
|
Response 1: Agree. We have, accordingly, revised line 57-96 of the paper to emphasize this point. The revised content (line 67-81 of revised paper) is as follows. Numerous studies have confirmed that the shear stress caused by water quenching promotes the fracture of quartz particles and significantly enhances the purity of quartz sand and the removal rate of impurities. Shao et al. found that the surface pits and cracks of vein quartz ore increased significantly, and the cracking degree of cracks also increased [11]. The aluminum content in purified quartz sand dropped from 738.8 ppm to 17.9 ppm, with a removal rate as high as 97.58%, according to Song et al.'s research, which also demonstrated that the temperature differential between water and quenching had a substantial impact on the removal of aluminum impurities [12]. Li et al. also found that water quenching can effectively destroy the crystal structure of muscovite (KAl2(AlSi3O10)(OH)2) in quartz sand, reduce the α-quartz phase transition temperature, and increase the purity of quartz sand from 99.938% to 99.995%[13]. In addition, water quenching can cause cracks at the junction of quartz and impurity ore, exposing impurities in fluid inclusions in quartz particles, thereby increasing its removal rate [14,15]. Some research results have proved that the formation of cracks can remove impurities such as iron and volatile compounds and enhance the dissociation of impurities [16-19]. |
||||||||||||||||||||||||||||||||||||||||
|
Comments 2: The authors should add the purpose of the paper to better let the readers understand what they are researching in the paper. |
||||||||||||||||||||||||||||||||||||||||
|
Response 2: Thank you for pointing this out. We agree with this comment. Therefore, we have revised the last paragraph of the introduction, and add the research purpose of this paper. The revised content (line 98-102 of revised paper) is as follows. By studying the pore structure of quartz sand, the structural characteristics and variation rules of micro-scale and mesoscale pores can be clarified, which lays a foundation for further study of the mass transfer process in pores. In addition, pore structure research also provides theoretical basis and support for the development of more effective quartz sand pretreatment technology and purification technology.
|
||||||||||||||||||||||||||||||||||||||||
|
Comments 3: The “materials and methods” section needs to be improved. No equipment is specified to obtain data on the specific surface area (line 111). Similar questions to Table 1. How were the elemental content values determined? |
||||||||||||||||||||||||||||||||||||||||
|
Response 3: Agree. We have, accordingly, revised section 2.1 and 2.2 to emphasize this point. Revised section 2.1 (line 105-114 of revised paper) and 2.2 (Table 2) is as follows. The samples of natural quartz sand used in this study are was obtained from Fengyang County, Anhui Province, with a grain size of 80-140 mesh. The chemical composition, specific surface area and pore volume distribution of natural quartz sand were tested and analyzed by ICP-MS and BET respectively. The specific surface area of quartz sand is 0.0728 m2/g, and the pore volume distributions of micropores, mesoporous (2-10nm), mesoporous (10-50nm) and macropores (50-200nm) are 0%, 32.84%, 26.53% and 40.63%, respectively. The chemical composition of natural quartz sand is shown in Table 1, where elements less than 0.0001% of the chemical composition are not shown. Liquid nitrogen is a commercially available product that uses deionized and distilled water throughout the work.
Table 2. The variable factors and experimental conditions of quartz sand cracking experiment.
|
||||||||||||||||||||||||||||||||||||||||
|
Comments 4: The objects of study are not clear from Figure 1. The separation by stage is clear. However, the difference between QC-2 and QC-3 is not clear. The authors should make a table or diagram showing more clearly what kind of samples were studied in the paper. |
||||||||||||||||||||||||||||||||||||||||
|
Response 4: Agree. I/We have, accordingly, revised Figure 1 to emphasize this point. We corrected the errors in Figure 1 and added Table 2 to make the details of the experiment clearer and more intuitive. |
||||||||||||||||||||||||||||||||||||||||
|
Revised Figure 1 (line 124-125 of revised paper) and Table 2 (see Response 3) is as follows. |
||||||||||||||||||||||||||||||||||||||||
|
Figure 1. Technological process of ultra-low temperature stress crushing of quartz sand. |
||||||||||||||||||||||||||||||||||||||||
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
- The article does not provide any explanation of the process flow chart of ultra-low temperature stress crushing of quartz sand in Figure 1. It is very difficult to understand the process flow just by Figure 1. It is recommended to provide a detailed explanation for Figure 1. What do the sample numbers represent? Please specify in detail in the caption or experimental steps.
- Why is Ct-3 data missing in Figure 2？
- H3 and H4 appear for the first time in the N2 adsorption desorption isotherm model, although references are cited, their full names should also be provided.
- In the Introduction, "Numerous academic works have demonstrated how water quenching may raise the hot particle quenching’s shear stress and create more stress fractures, both of which have a major positive effect on quartz sand purity.", at the end of this paragraph, some references should be cited to prove that there are a large number of academic works to prove this.
- In 2.1 Materials, the chemical compositions and pore distribution analysis of natural quartz sand are reported in Table 1. The pore distribution analysis is not shown in Table 1.
- The author did not explain the characteristics of H3 and H4 hysteresis loops in the article. It is recommended that they be explained in the article.
- There are no explanations for the labels of all the pictures in the article, which makes it difficult for readers to understand the specific meaning of the samples represented by the abbreviations. It is recommended that they be explained in the article.
- In the section “The influence of calcination temperature on the specific surface area and fracture structure of quartz sand is shown in Figure 4.”, the authors mentioned that “the fractal dimensions D1 and D2 are consistent with the variation trend of SBET, Ma, and Me10,” but according to Figure 4, the variation trends of D2 are not similar to those of SBET, Ma, and Me10.
- In the section “The influence of calcination temperature on the specific surface area and fracture structure of quartz sand is shown in Figure 4.”, the author’s explanation of the curve changes in Figure 4 is confusing and difficult for the readers to understand. It is recommended to re-explain.
- The statement in line 234 is incorrect. The trends of D1 and D2 are different.
- On page 8, line 278, the author wrote, “The specific surface area of broken quartz sand changes more quickly at temperatures above 700°C during calcination”. Based on the change in the slope in Figure 5a, it cannot be seen that during the calcination process, the specific surface area of broken quartz sand changes more quickly at temperatures above 700°C.
- The author chose 900oC as the phase transition temperature in Section 3.3. However, in the previous calcination temperature section, it was stated that the adsorption amount at 1000oC was higher than that at 900oC. Why didn’t they choose 1000oC to study the calcination time?
- In the article, there are only curves simulated by the FHH model, but no real sample pictures and scanning electron microscope photos to support them. I think the real sample photos and scanning electron microscope photos of the corresponding stages should be added for the explanation.
- Figure 11 does not show the changes in the pore structure of the quartz sand during the entire calcination process and ultra-low temperature quenching. The stages in the figure are only illustrated by the self-drawing, which is not convincing, and the state of the quartz sand cannot be seen clearly in the "Quenching stage". It is not convincing to only show the changes through a few bar graphs such as Ma, Me, and Mi. It is recommended that the author supplement it.
- After calcining at 900oC, quenching in 0oC ice water and -197oC liquid nitrogen environment produces a large temperature difference. Is there any difference between these two? Is quenching in liquid nitrogen needed to change the pore structure of the quartz sand, or does quenching in ice water also achieve similar results? In actual production, quenching in liquid nitrogen has certain cost pressures and production safety issues. In addition, the author mentioned in Section 3.5 that mechanical force and temperature difference stress cannot promote the generation of additional and larger pore structures. The main factors for cracking quartz sand are phase change effects and thermal expansion, which may significantly change the pore structure of the quartz sand, so I don’t think it is necessary to quench in liquid nitrogen.
There are many English grammar errors. It is better to find an English professional translator with a background in mineral processing to edit this article.
Author Response
|
Comments 1: The article does not provide any explanation of the process flow chart of ultra-low temperature stress crushing of quartz sand in Figure 1. It is very difficult to understand the process flow just by Figure 1. It is recommended to provide a detailed explanation for Figure 1. What do the sample numbers represent? Please specify in detail in the caption or experimental steps. |
|
Response 1: : Agree. We have, accordingly, revised section 2.1 and 2.2 to emphasize this point. Revised section 2.1 (line 105-114 of revised paper) and 2.2 (Table 2) is as follows.
|
|
Comments 2: Why is Ct-3 data missing in Figure 2. |
|
Response 2: It was a clerical error. We have, accordingly, corrected the errors. |
|
Figure 1 (line 124-125 of revised paper) is updated and shown in the revised manuscript. |
|
Comments 3: H3 and H4 appear for the first time in the N2 adsorption desorption isotherm model, although references are cited, their full names should also be provided. |
|
Response 3: Thank you very much for your comments. Unfortunately, our existing papers and other literature do not mention the relevant names of hysteresis types. Therefore, we still remain consistent with the references. |
|
Comments 4: In the Introduction, "Numerous academic works have demonstrated how water quenching may raise the hot particle quenching’s shear stress and create more stress fractures, both of which have a major positive effect on quartz sand purity.", at the end of this paragraph, some references should be cited to prove that there are a large number of academic works to prove this. |
|
Response 4: Thank you very much for your comments. In order to avoid the deficiency of poor readability caused by excessive references, we modified the original content based on the opinions of other reviewers to enhance the readability of the introduction. In addition, references 11-19 have been able to well support the views of this paper, which is typical. Other related studies only mentioned water quenching, but did not put forward the necessary analysis and explanation of the role of water quenching, or many statements are doubtful. Therefore, this paper does not cite more references as a footnote to the argument. |
|
Comments 5: In 2.1 Materials, the chemical compositions and pore distribution analysis of natural quartz sand are reported in Table 1. The pore distribution analysis is not shown in Table 1. |
|
Response 5: Agree. We have, accordingly, revised section 2.1 and 2.2 to emphasize this point. Revised section 2.1 (line 105-114 of revised paper) and 2.2 (Table 2) is updated in the revised manuscript.
|
|
Comments 6: The author did not explain the characteristics of H3 and H4 hysteresis loops in the article. It is recommended that they be explained in the article. |
|
Response 6: Thank you very much for your comments. We have, accordingly, added supplementary description of the hysteresis characteristics to emphasize this point. |
|
Revised content (line 178-180 of revised paper) is updated in the revised manuscript.
Comments 7: There are no explanations for the labels of all the pictures in the article, which makes it difficult for readers to understand the specific meaning of the samples represented by the abbreviations. It is recommended that they be explained in the article. |
|
Response 7: Agree. I/We have, accordingly, added the relevant explanation. Revised content (line 109-110 ) is updated in the revised manuscript. |
|
Comments 8: In the section “The influence of calcination temperature on the specific surface area and fracture structure of quartz sand is shown in Figure 4.”, the authors mentioned that “the fractal dimensions D1 and D2 are consistent with the variation trend of SBET, Ma, and Me10,” but according to Figure 4, the variation trends of D2 are not similar to those of SBET, Ma, and Me10. |
|
Response 8: Agree. This is an error in the manuscript. We have, accordingly, rewrote this paragraph to emphasize this point. Revised content (line 229-250) is updated in the revised manuscript.
|
|
Comments 9: [In the section “The influence of calcination temperature on the specific surface area and fracture structure of quartz sand is shown in Figure 4.”, the author’s explanation of the curve changes in Figure 4 is confusing and difficult for the readers to understand. It is recommended to re-explain.] |
|
Response 9: Agree. This is an error in the manuscript. We have, accordingly, rewrote this paragraph to emphasize this point. Revised content (line 229-250) is updated in the revised manuscript.
|
|
Comments 10: The statement in line 234 is incorrect. The trends of D1 and D2 are different. |
|
Response 10: Agree. This is an error in the manuscript. We have, accordingly, rewrote this paragraph corrected that description to emphasize this point. Revised content (line 229-250) is updated in the revised manuscript.
|
|
Comments 11: On page 8, line 278, the author wrote, “The specific surface area of broken quartz sand changes more quickly at temperatures above 700°C during calcination”. Based on the change in the slope in Figure 5a, it cannot be seen that during the calcination process, the specific surface area of broken quartz sand changes more quickly at temperatures above 700°C. |
|
Response 11: Thank you very much for your comments. Based on the change in the slope in Figure 5a, we can see a positive correlation between the increment of calcination temperature and the increment of specific surface area. To avoid ambiguity, revised content (line 272-275) is updated in the revised manuscript.
|
|
Comments 12: The author chose 900℃ as the phase transition temperature in Section 3.3. However, in the previous calcination temperature section, it was stated that the adsorption amount at 1000℃ was higher than that at 900℃. Why didn’t they choose 1000℃ to study the calcination time? |
|
Response 12: Thank you very much for your comments. The main reason for the higher adsorption capacity at 1000℃ is the shorter calcination time (1h). 1000℃ is much higher than the phase transition temperature, and it is easier to induce phase transition in the early stage of calcination. On the contrary, 900℃ is close to the phase transition temperature. The quartz sand in the early stage of calcination is still dominated by thermal expansion, and the phase transition degree is not complete. Therefore, in order to better control the phase transition process, 900℃ is more appropriate in sufficient phase transition time. |
|
Comments 13: In the article, there are only curves simulated by the FHH model, but no real sample pictures and scanning electron microscope photos to support them. I think the real sample photos and scanning electron microscope photos of the corresponding stages should be added for the explanation. |
|
Response 13: Thank you very much for your comments. In the submitted manuscript, we did not add photos of physical samples and SEM photos for the following reasons. First, the quartz sand at different stages in appearance is not recognizable, which has no practical significance to support the thesis. Second, this paper mainly studies the pore structure of quartz sand, including the visualization of the particle surface and the internal pore structure. Neither TEM nor SEM photos can directly observe the pore structure and its changes inside the particles, so they cannot provide valuable evidence for the viewpoint of this paper. Based on the above two points, we did not choose to add physical sample photos and SEM photos for illustration. |
|
Comments 14: Figure 11 does not show the changes in the pore structure of the quartz sand during the entire calcination process and ultra-low temperature quenching. The stages in the figure are only illustrated by the self-drawing, which is not convincing, and the state of the quartz sand cannot be seen clearly in the "Quenching stage". It is not convincing to only show the changes through a few bar graphs such as Ma, Me, and Mi. It is recommended that the author supplement it. |
|
Response 14: Thank you very much for your comments, and I have the following three comments to reply to your comments: 1) The main purpose of the process analysis in Figure 11 is to re-examine from the perspective of the entire cracking process and get some common conclusions, rather than just repeating the research conclusions of a single factor. a) The calcination process is the result of the joint action of phase transformation expansion and expansion closure on the change of pore distribution. The quartz sand is closed by thermal expansion in the three stages of non-phase change calcination, early stage of calcination and after phase change, while the phase change process shows phase change cracking. b) The main function of quenching is not only to instantly solidify the high-temperature pore structure of quartz sand, but also to adjust the relative proportion of mesoporous pores. Repeated quenching and the combined effect of mechanical force and thermal stress do not increase the specific surface area of quartz sand, but the quenching process can increase the proportion of Me50 pores. c) In the pretreatment process, the pore structure of quartz sand has significant fractal characteristics, and there is a strong correlation with the influencing factors. The above analysis can not only be applied to single-factor experiments, but more importantly, the overall cognition of the pretreatment process of quartz sand is clearer. This indicates the direction of how to control the pretreatment process to achieve the regulation of the microscopic and mesoscopic structure of quartz sand. (2) The change relationship between Ma, Me and Mi is not only the most direct and reliable evidence to support process analysis, but also the main purpose of this paper is to obtain structural characteristics and their change rules. Clarifying the relationship between process and structure is the core of this study. (3) The quenching conditions are constant, and the quenching state of quartz sand is difficult to be determined, and only the pore structure after quenching is obtained. Therefore, the quenching process can be regarded as a transient cooling process of the calcination process. We have no better solution to study this problem. Based on the above reasons, we believe that the research content of this paper is matched with the research purpose, and the structure of the paper is relatively complete. Here we also realize that there are still some shortcomings in the research work, which puts forward a new direction for our further research and improvement. Thank you again for your valuable suggestions on our paper. |
|
Comments 15: After calcining at 900℃, quenching in 0℃ ice water and -197℃ liquid nitrogen environment produces a large temperature difference. Is there any difference between these two? Is quenching in liquid nitrogen needed to change the pore structure of the quartz sand, or does quenching in ice water also achieve similar results? In actual production, quenching in liquid nitrogen has certain cost pressures and production safety issues. In addition, the author mentioned in Section 3.5 that mechanical force and temperature difference stress cannot promote the generation of additional and larger pore structures. The main factors for cracking quartz sand are phase change effects and thermal expansion, which may significantly change the pore structure of the quartz sand, so I don’t think it is necessary to quench in liquid nitrogen. |
|
Response 15: Thank you for pointing this out. (1) Water is the most economical and widely used quenching medium for the purification of quartz sand. Due to the low temperature and volatile characteristics of liquid nitrogen, the instantaneous thermal stress between liquid nitrogen and quartz sand reaches the maximum. Moreover, the heat transfer between the two can also be completed in a very short time, and the pore structure at high temperature can be preserved as much as possible, so as to obtain more effective pore cracking characteristics. In the process of water quenching, the heat transfer between water and quartz sand is a gradual process, and the temperature difference is small. The cracking effect will be affected by more factors, so it is difficult to obtain accurate information of pore cracking effectively. (2) Compared with liquid nitrogen, ultra-low temperature media such as liquid oxygen and liquid ammonia are easy to form volatile toxic gases or high concentration accelerants, which has potential risks. Moreover, the liquid temperature of liquid nitrogen is lower than that of other ultra-low temperature media, which can form greater temperature difference stress，and is more suitable as a quenching medium. |
|
|
|
4. Response to Comments on the Quality of English Language |
|
Point 1: There are many English grammar errors. It is better to find an English professional translator with a background in mineral processing to edit this article. |
|
Response 1: According to your suggestions, we have carefully checked the grammar, paragraph and writing for proofreading and correction. |
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis article investigates the effects of calcination temperature, time, quenching, and grinding frequency on the formation of micro cracks in natural quartz sand. Research has found that the fracture structure of quartz sand has fractal characteristics, which are significantly affected by thermal expansion and phase transformation. Non phase change thermal expansion leads to a decrease in specific surface area, while phase change expansion increases specific surface area. Thermal stress and mechanical force play an important role in the formation of specific mesoporous cracks, especially Me50 mesoporous cracks. By establishing a linear regression model between fractal dimension and pore volume distribution, the correlation coefficient is high, providing a foundation for understanding the relationship between quartz sand purification effect and structure and improving its purification technology. Overall, this manuscript is well organized and written. I would like to recommend it to be published in Minerals after addressing the following issues:
1. The current research status in the introduction section is somewhat cumbersome, and it is suggested to simplify and condense it.
2. The citation of references in the title is unreasonable. If there are supporting references in the narrative, they can be cited in the corresponding content. So, like 2.4 Fractal characteristics analysis of microfractures [22-24] needs to be modified.
3.It would be more appropriate to replace the 'leach' in line 46 on page 2 with 'leaching'
4. The format of SBET on line 233 of page 7 should remain consistent throughout the text and should be replaced with SBET.
5. What is the reason for choosing liquid nitrogen as the quenching medium? Have you considered other possible quenching media?
6. Have the effects of calcination temperature, calcination time, quenching frequency, and grinding frequency on the cracks in quartz sand been considered in terms of their interactions?
7. The summary is very similar to the abstract, it is best to describe the conclusion in sections.
Author Response
|
Comments 1: The current research status in the introduction section is somewhat cumbersome, and it is suggested to simplify and condense it. |
|
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have revised the introduction and redivided the paragraphs. |
|
The revised introduction is detailed in line 35-102 of revised paper.
Comments 2: The citation of references in the title is unreasonable. If there are supporting references in the narrative, they can be cited in the corresponding content. So, like 2.4 Fractal characteristics analysis of microfractures [22-24] needs to be modified. |
|
Response 2: Thank you for pointing this out. We agree with this comment. Therefore, we have revised citation format of references. |
|
The revised citation of references is detailed in line 143 of revised paper.
Comments 3: It would be more appropriate to replace the 'leach' in line 46 on page 2 with 'leaching'. |
|
Response 3: Thank you for pointing this out. We agree with this comment. Therefore, we have have amended the word "leach" in line 46 on page 2 to "leaching". |
|
Comments 4: The format of SBET on line 233 of page 7 should remain consistent throughout the text and should be replaced with SBET. |
|
Response 4: Agree. We have, accordingly, corrected the clerical errors. |
|
Comments 5: What is the reason for choosing liquid nitrogen as the quenching medium? Have you considered other possible quenching media? |
|
Response 5: Thank you for pointing this out. |
|
(1) Water is the most economical and widely used quenching medium for the purification of quartz sand. Due to the low temperature and volatile characteristics of liquid nitrogen, the instantaneous thermal stress between liquid nitrogen and quartz sand reaches the maximum. Moreover, the heat transfer between the two can also be completed in a very short time, and the pore structure at high temperature can be preserved as much as possible, so as to obtain more effective pore cracking characteristics. In the process of water quenching, the heat transfer between water and quartz sand is a gradual process, and the temperature difference is small. The cracking effect will be affected by more factors, so it is difficult to obtain accurate information of pore cracking effectively. (2) Compared with liquid nitrogen, ultra-low temperature media such as liquid oxygen and liquid ammonia are easy to form volatile toxic gases or high concentration accelerants, which has potential risks. Moreover, the liquid temperature of liquid nitrogen is lower than that of other ultra-low temperature media, which can form greater temperature difference stress.
Comments 6: Have the effects of calcination temperature, calcination time, quenching frequency, and grinding frequency on the cracks in quartz sand been considered in terms of their interactions? |
|
Response 6: Thank you for pointing this out. We have taken note of the research question you mentioned. In this paper, the cracking process of quartz sand involves two different stages: (1) the calcination stage is phase change cracking process; (2) The quenching stage is temperature difference stress cracking, or the collaborative cracking of temperature difference stress and mechanical force. The experiments of calcination temperature, calcination time and quenching frequency mainly study the interaction between phase transformation and quenching, while the experiments of grinding frequency mainly study the interaction between temperature difference stress and mechanical force. |
|
Comments 7: The summary is very similar to the abstract, it is best to describe the conclusion in sections. |
|
Response 7: Agree. We have, accordingly, revised the conclusions of the paper to emphasize this point. The revised introduction is detailed in line 531-556 of revised paper. The cracking of quartz sand at ultra-low temperature was studied by using liquid nitrogen as quenching medium. The relationship between pore structure and specific surface area was determined by BET analysis, and the cracking effect of quartz sand under the limit temperature difference was evaluated. (1) Pore distribution studies show that calcination temperature and calcination time have significant effects on SBET and pore volume distribution of cracked quartz sand. The reason is that thermal expansion leads to pore shrinkage, a large number of pores form wedge pores, and SBET of cracked sand is significantly reduced. The corresponding Me50 and Mi are formed by pore shrinkage of Ma and Me10, resulting in an increase in the ratio of Me50 to Mi. (2) Phase transition is the key factor to determine the pore structure of quartz, and the ratio of SBET and Me10 of phase-change cracking sand is significantly higher than that of non-phase-change cracking sand. Quenching can change the relative proportion of mesoporous pores of different scales. Cracking of Me10 pores leads to a significant increase in the proportion of Me50. However, quenching and grinding have no significant strengthening effect on the pore structure and SBET of quartz sand. Therefore, reasonable regulation of phase transformation process and quenching process, increasing specific surface area, Me10 ratio and total pore volume will be more conducive to subsequent purification. (3) The pore structure of raw sand and cracked sand has fractal characteristics. Fractal dimension D1 is positively correlated with the pore distribution of SBET, Ma and Me10, and fractal dimension D2 and D3 are positively correlated with the pore distribution of Mi and Me50. The pore structure characteristics and fractal quantification of quartz sand can provide key material structure information for predicting and evaluating the purification effect of quartz sand.
|
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors!
Thank you for your work on the paper.
Author Response
Thank you again for your constructive suggestions and contributions to improving this paper.
Reviewer 2 Report
Comments and Suggestions for Authors1. H3 and H4 first appeared in the N2 adsorption desorption isotherm model. Although the literature was cited, their full names were still missing.
2. The author still did not explain the characteristics of H3 and H4 hysteresis in the article.
3. Please provide a detailed explanation of Figure 1. The author's arbitrary deletion and modification of numbering greatly reduces the credibility of the article, and the curve drawn in Figure 1 is quite arbitrary. Please be sure to carefully check it.
4. The same situation also occurs in Figure 2. The author must check it carefully again.
5. In the section “Effect of Calcination Temperature on Specific Surface Area and Fracture Structure of Quartz Sand”, as shown in Figure 4, the author is still unclear about the interpretation of the curve variation in Figure 4. In lines 232-234, the variation trend of fractal dimensions D2 and D3 is not consistent with Mi and Me50.
6. In Section 3.3, the authors chose 900 °C as the phase transition temperature. However, in the previous calcination temperature section, it was pointed out that the adsorption at 1000 °C was higher than that at 900 °C. They still did not explain why 1000 °C was chosen to study the calcination time.
7. The article only shows the curves simulated by the FHH model and still does not include real sample pictures and SEM photos as support. I think photos of real samples and SEM photos of the corresponding stages should be added for explanation.
8. Figure 11 does not show the changes in the pore structure of quartz sand during the entire calcination process and ultra-low temperature quenching process. The stages in the figure are only illustrated by self-drawing, which is not convincing. The state of quartz sand in the "quenching stage" is not clear. It is not convincing to show the changes only through a few bar graphs such as Ma, Me, Mi, etc., and the author is advised to supplement it.
9. After calcining at 900°C, it is quenched in an environment of 0°C ice water and -197°C liquid nitrogen, resulting in a large temperature difference. Is there any difference between the two? Does quenching in liquid nitrogen require changing the pore structure of quartz sand, or can quenching in ice water achieve similar results? In actual production, liquid nitrogen quenching has certain cost pressures and production safety issues. In addition, the author mentioned in Section 3.5 that mechanical force and temperature difference stress cannot promote the generation of additional and larger pore structures. The main factors for quartz sand cracking are phase change effects and thermal expansion, which may significantly change the pore structure of quartz sand, so I think quenching in liquid nitrogen is not necessary.
10. The main reason for the significant reduction of aluminum mentioned by Song et al in Ref. 12 is not water quenching, but microwave chlorination roasting combined with acid leaching and purification. Authors are advised to read Ref. 12 carefully.
11. Ref. 13 also states that there are similar problems as Ref. 12, water quenching cannot reduce the temperature of the phase transition of α-quartz, and can not improve the purity of quartz sand too much, water quenching is only a means to assist the purification process.
12. In lines 92-94 of page 2, “Based on the BET test results, the effects of calcination temperature, calcination time, quenching frequency… were studied.”, quartz sand is generally in the micrometer level and the micrometer particle size is generally tested and analyzed by mercury injection method, and the sample with nanometer particle size is tested by BET.
13. In Figure 2, the interval time in the third row is 2 h, and the interval time in the fourth row is 4 h. There is no relevant explanation and experimental proof in the experimental conditions. An interval of several hours is optimal for experimental results.
Comments on the Quality of English LanguageThere are many English grammatical errors. It would be best to find an English professional translator with a mineral processing background to edit this article.
Author Response
Comments 1:. H3 and H4 first appeared in the N2 adsorption desorption isotherm model. Although the literature was cited, their full names were still missing.
Response 1: Thank you very much for your comments. We reviewed the relevant literature and consulted the technical staff of the instrument supplier. They do not have a corresponding name, but are simply short for hysteresis classification. We would appreciate it if you have relevant literature to provide.
Comments 2: The author still did not explain the characteristics of H3 and H4 hysteresis in the article. Response 2: Thank you very much for your comments. We have further revised and supplemented the questions you mentioned. Revised content (line 200-216) is updated in the revised manuscript.
Comments 3: Please provide a detailed explanation of Figure 1. The author's arbitrary deletion and modification of numbering greatly reduces the credibility of the article, and the curve drawn in Figure 1 is quite arbitrary. Please be sure to carefully check it.
Comments 4: The same situation also occurs in Figure 2. The author must check it carefully again.
Response 3 and 4: Thank you very much for your comments. In order to explain the whole experiment process more clearly, easy for readers to understand. According to your modification suggestions, we have described and modified the experimental process in Figure 1 in detail, and unified and standardized the name format in the original draft. Revised content (line 117-144) is updated in the revised manuscript.
Comments 5: In the section “Effect of Calcination Temperature on Specific Surface Area and Fracture Structure of Quartz Sand”, as shown in Figure 4, the author is still unclear about the interpretation of the curve variation in Figure 4. In lines 232-234, the variation trend of fractal dimensions D2 and D3 is not consistent with Mi and Me50.
Response 5: Thank you very much for your comments. According to your modification comments, we have made further modifications to the relevant content. Revised content (line 254-286) is updated in the revised manuscript.
Comments 6: In Section 3.3, the authors chose 900 °C as the phase transition temperature. However, in the previous calcination temperature section, it was pointed out that the adsorption at 1000 °C was higher than that at 900 °C. They still did not explain why 1000 °C was chosen to study the calcination time.
Response 6: Thank you very much for your comments. The most important reason is that the degree of phase transition is not complete due to the short time calcination of quartz sand at the phase change temperature. The experimental results also show that the calcined quartz sand for 4h has the best effect. Therefore, after calcination at 900℃ for 1h, quartz sand is still dominated by thermal expansion process. On the contrary, the phase transition degree of the sample calcined at 1000℃ will be greater. However, the higher the calcination temperature also means the greater the energy consumption and the higher the equipment requirements. For practical consideration, 900℃ was chosen as the phase transition temperature in our experiment.
Comments 7: The article only shows the curves simulated by the FHH model and still does not include real sample pictures and SEM photos as support. I think photos of real samples and SEM photos of the corresponding stages should be added for explanation.
Response 7: Thank you for raising the question again. First of all, the appearance of quartz sand does not change during the experiment, which does not support the views of this paper. Secondly, the nanoscale pore structure inside quartz sand cannot be directly observed through TEM and SEM photos, and the evidence of surface structure cannot support the change of internal structure. Based on the above two points, we still did not add physical sample photos and SEM photos to supplement.
Comments 8: Figure 11 does not show the changes in the pore structure of quartz sand during the entire calcination process and ultra-low temperature quenching process. The stages in the figure are only illustrated by self-drawing, which is not convincing. The state of quartz sand in the "quenching stage" is not clear. It is not convincing to show the changes only through a few bar graphs such as Ma, Me, Mi, etc., and the author is advised to supplement it.
Response 8: Thank you very much for your comments. According to your modification comments, we have further modified and supplemented the relevant content. Revised content (line 528-553) is updated in the revised manuscript.
Comments 9: After calcining at 900°C, it is quenched in an environment of 0°C ice water and -197°C liquid nitrogen, resulting in a large temperature difference. Is there any difference between the two? Does quenching in liquid nitrogen require changing the pore structure of quartz sand, or can quenching in ice water achieve similar results? In actual production, liquid nitrogen quenching has certain cost pressures and production safety issues. In addition, the author mentioned in Section 3.5 that mechanical force and temperature difference stress cannot promote the generation of additional and larger pore structures. The main factors for quartz sand cracking are phase change effects and thermal expansion, which may significantly change the pore structure of quartz sand, so I think quenching in liquid nitrogen is not necessary.
Response 9: Thank you very much for your comments. We will explain from the following three points. (1) First of all, water and liquid nitrogen are used as quenching agents, and the cooling effect of the two is different, and the quenching effect of liquid nitrogen cannot be achieved by ice-water quenching. Due to the low temperature and volatilization characteristics of liquid nitrogen, the surface can be chilled immediately after contact with quartz sand, so as to obtain the maximum transient temperature difference stress. Moreover, the transient heat transfer between the two can also preserve the pore structure at high temperature as much as possible. If water or ice water is used as the quenching agent, the heat transfer between water and quartz sand will increase the water temperature, and the temperature difference inside the surface is higher, resulting in less temperature difference stress. In addition, the heat transfer process between the particle interior and the surface will continue for a period of time, making it difficult to obtain transient structure information. (2) Compared with liquid nitrogen, ultra-low temperature media such as liquid oxygen and liquid ammonia are easy to form volatile toxic gases or high concentration accelerants, which has greater potential risks. The liquid temperature of liquid nitrogen is lower than that of other ultra-low temperature media, which can meet the requirements of ideal temperature difference stress. (3) Although the cracking of quartz sand is mainly caused by phase transition cracking, the effect of temperature difference stress is not completely ignored. In fact, quenching cracking is able to form more Me50 pores, which is very important for the liquid to penetrate into the solid. The study of the effect of grinding on the pore structure is to verify whether there is a synergistic strengthening effect between temperature difference stress and mechanical force.
Comments 10: The main reason for the significant reduction of aluminum mentioned by Song et al in Ref. 12 is not water quenching, but microwave chlorination roasting combined with acid leaching and purification. Authors are advised to read Ref. 12 carefully.
Comments 11: Ref. 13 also states that there are similar problems as Ref. 12, water quenching cannot reduce the temperature of the phase transition of α-quartz, and can not improve the purity of quartz sand too much, water quenching is only a means to assist the purification process.
Response 10 and 11: Thank you very much for your comments. The purpose of citing reference [12] and [13] is to emphasize the influence of pretreatment on the purification of quartz sand. Microwave chlorination roasting, water quenching and other measures are essential processes in the purification process of quartz sand. The fundamental purpose is to promote the quartz particles inside and on the surface to produce enough cracks, increase the solid-liquid contact area and penetration path, so as to meet the mass transfer requirements. Therefore, we have modified the relevant description in the paper. Revised content (line 67-69) is updated in the revised manuscript.
Comments 12: In lines 92-94 of page 2, “Based on the BET test results, the effects of calcination temperature, calcination time, quenching frequency… were studied.”, quartz sand is generally in the micrometer level and the micrometer particle size is generally tested and analyzed by mercury injection method, and the sample with nanometer particle size is tested by BET.
Response 12: Thank you very much for your comments. Mercury injection (MIP) is suitable for materials with large pore size range and high porosity, but not suitable for materials with small specific surface area. In the paper, we are more concerned about the nanoscale cracked structure inside the particles, because this is very important for removing internal impurities. Therefore, the choice of mercury injection method is not appropriate.
Comments 13: In Figure 2, the interval time in the third row is 2 h, and the interval time in the fourth row is 4 h. There is no relevant explanation and experimental proof in the experimental conditions. An interval of several hours is optimal for experimental results.
Response 13: Thank you very much for your comments. The time interval in the experiment was chosen to be consistent with the treatment conditions of the initial sample and to avoid unknown effects of changing conditions on the experiment. The question of optimal interval you mentioned is our next research work.
4. Response to Comments on the Quality of English Language Point 1: There are many English grammar errors. It is better to find an English professional translator with a background in mineral processing to edit this article. Response 1: Based on your suggestions, we have carefully proofread the grammar and spelling. According to your suggestions, we are prepared to entrust a professional to revise before publication.
Round 3
Reviewer 2 Report
Comments and Suggestions for Authors1. In Section 3.3, the author still did not explain why 1000 °C was chosen to study the calcination time.
2. This article only gives the curve simulated by the FHH model, and there is still no macroscopic photo and SEM photo of the sample as support. I think it is necessary to add photos of the sample and SEM photos of the corresponding stages.
3. Figure 11 does not show the changes in the pore structure of the quartz sand during the entire calcination process and ultra-low temperature quenching. The various stages in the figure are self-drawn and unconvincing. The state of the quartz sand in the "quenching stage" is unclear. It is unconvincing to show the changes only through a few bar graphs such as Ma, Me, Mi, etc., and it is recommended that the author supplement it.
4. There are problems with Ref. 13. Water quenching cannot reduce the phase transition temperature of α-quartz, nor can it increase the purity of the quartz sand too much. Water quenching is only a means to assist the purification process.
5. The arrows behind Grind in Figure 1 are not parallel. Please adjust them to make them more harmonious.
6. There is an additional bracket after the vertical axis unit in Figure 2. Please confirm.
7. Suggest using continuous and regular numbers for sample labeling, such as 1, 2, 3 or 1, 3, 5 or 2, 4, 6, otherwise it may cause ambiguity.
8. If the article could add a few intuitive SEM photo of the pores, it would be even more perfect.
Comments on the Quality of English LanguageThere are still many English grammatical errors. It would be best to find an English professional translator with a mineral processing background to edit this article.
Author Response
|
Comments 1: In Section 3.3, the author still did not explain why 1000 °C was chosen to study the calcination time. Response 1: Thank you very much for your comments. According to the reviewer's requirements, we have added relevant content. Revised content (line 293-301) is updated in the revised manuscript.
Comments 2: This article only gives the curve simulated by the FHH model, and there is still no macroscopic photo and SEM photo of the sample as support. I think it is necessary to add photos of the sample and SEM photos of the corresponding stages. Response 2: Thank you very much for your comments. According to your suggestion, we have added the corresponding SEM pictures. Revised content (line 164-166, 514-518; 526) is updated in the revised manuscript.
Comments 3: Figure 11 does not show the changes in the pore structure of the quartz sand during the entire calcination process and ultra-low temperature quenching. The various stages in the figure are self-drawn and unconvincing. The state of the quartz sand in the "quenching stage" is unclear. It is unconvincing to show the changes only through a few bar graphs such as Ma, Me, Mi, etc., and it is recommended that the author supplement it. Response 3: Thank you very much for your comments. We consulted with teachers who have a background in mining and made revisions to the manuscript based on your review comments, and added SEM evidence. Revised content (line 553-622) is updated in the revised manuscript.
Comments 4: There are problems with Ref. 13. Water quenching cannot reduce the phase transition temperature of α-quartz, nor can it increase the purity of the quartz sand too much. Water quenching is only a means to assist the purification process. Response 4: Thank you very much for your comments. According to your modification suggestion, we have changed reference R13 and modified the relevant content. Revised content (line 74-80) is updated in the revised manuscript.
Comments 5: The arrows behind Grind in Figure 1 are not parallel. Please adjust them to make them more harmonious. Response 5: Thank you very much for your comments. According to your modification comments, we have made further modifications to the relevant content. Revised content (line 149) is updated in the revised manuscript.
Comments 6: There is an additional bracket after the vertical axis unit in Figure 2. Please confirm. Response 6: Thank you very much for your comments. We have corrected the error in Figure 2. Revised content (line 230) is updated in the revised manuscript.
Comments 7: Suggest using continuous and regular numbers for sample labeling, such as 1, 2, 3 or 1, 3, 5 or 2, 4, 6, otherwise it may cause ambiguity. Response 7: Thank you for raising the question again. The main reasons for not marking in accordance with continuous numbers in this paper are as follows: 1) The number of samples is large, and the use of digital marking will cause reading difficulties for readers; 2) In order to better distinguish the four different influencing factors; 3) The author can know the reference sample more intuitively.
Comments 8: If the article could add a few intuitive SEM photo of the pores, it would be even more perfect. Response 8: Thank you very much for your comments. According to your suggestion, we have added the corresponding SEM pictures. Revised content (line 514-518; 526) is updated in the revised manuscript.
|
|
4. Response to Comments on the Quality of English Language |
|
Point 1: There are many English grammar errors. It is better to find an English professional translator with a background in mineral processing to edit this article. |
|
Response 1: Based on your suggestions, we carefully proofread the grammar and spelling once again. Additionally, we actively consulted professionals in the mining field to revise and improve the issues in the paper. |
Thank you very much for your detailed review of the paper, which has helped us identify and correct many inaccuracies and unreasonable issues in the manuscript.
Author Response File: Author Response.pdf
