Study on the Grinding Kinetics and Magnetic Separation of Low-Grade Vanadiferous Titanomagnetite Concentrate
Round 1
Reviewer 1 Report
The present manuscript is interesting and useful. The design of the experiments is clearly described, and the results are interesting. Both, text and figures clearly exhibit these results. In addition, the conclusions well summarize the principal aim of the manuscript. In my opinion, the present work could be accepted for publication in the journal.
Author Response
March 23st, 2022
Dear Reviewers
On behalf of all the authors (Jinsheng Liu, Zhenxing Xing, Gongjin Cheng, Xiangxin Xue, Xueyong Ding) of this paper - “Study on grinding kinetics and magnetic separation of low-grade vanadiferous titanomagnetite concentrate”, I would like to express my gratitude to you for the careful review and the very valuable suggestions and comments you have given. After our careful discussion and study, we made point-to-point more detailed revisions to the manuscript in response to the review comments.
We appreciate your recognition of our research and your comments on our paper. We will still work on further revisions of the paper under the guidance of our editors to satisfy the requirements for publication.
Thanks again to you for your suggestions and comments. Should there be any questions, please do not hesitate to contact me further.
Sincerely yours,
Jinsheng Liu, Ph.D.
Department of Resource and Environment
School of Metallurgy, Northeastern University
Shenyang, PR China
E-maill address:[email protected]
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This article is written on a rather hot topic: increasing the efficiency of processing of vanadiferous titanomagnetite concentrate .
The article is well structured, the material is presented in a logical sequence.
There are a number of questions and comments on the article:
- The purpose of the paper is not clearly expressed in the introduction. This information should be given.
- What equipment was used for the research. Not all information about the equipment is given in paragraph 2.
- What was the mass of the sample when the study on grinding and magnetic separation was carried out.
- The distribution of elements (all major elements) into particle size classes according to the grinding time should be given. Information can be given on unlocking. This will allow a more comprehensive evaluation of the impact of the grinding time.
The article is of scientific and practical interest for specialists working in the mining and metallurgical industry.
Author Response
March 23st, 2022
Dear Reviewers
On behalf of all the authors (Jinsheng Liu, Zhenxing Xing, Gongjin Cheng, Xiangxin Xue, Xueyong Ding) of this paper - “Study on grinding kinetics and magnetic separation of low-grade vanadiferous titanomagnetite concentrate”, I would like to express my gratitude to you for the careful review and the very valuable suggestions and comments you have given. After our careful discussion and study, we made point-to-point more detailed revisions to the manuscript in response to the review comments. The following is a point-by-point response to the comments of the reviewers.
Point 1: The purpose of the paper is not clearly expressed in the introduction. This information should be given.
Response:
The purpose of the study has been added in the introduction. The purpose of this paper is to obtain a better knowledge of the mineral phases composition and grinding characteristics of LVTC, to provide a reference for its large-scale grind-ing, and to improve the recovery and utilization of valuable metals such as Fe and Ti.
Point 2: What equipment was used for the research. Not all information about the equipment is given in paragraph 2.
Response:
Equipment used for the research in this paper was a laboratory-scale damp mill, a laser particle size analyzer, a scanning electron microscopy, a dichotomizer, a laboratory-scale magnetic separation tube, and a polycrystalline powder X-ray diffraction analyzer. The laboratory-scale damp mill is manufactured by Zhengchang Mineral Processing Equipment Co. from Jiangxi, China, the model number is XMQ150/50. The laser particle size analyzer is manufactured by Malvern Panalytical Ltd from Malvern, UK, the model number is Mastersizer 3000. The scanning electron microscopy is manufactured by German Zeiss Microscope Ltd from Oberkochen, Germany, the model number is ULTRA PLUS. The dichotomizer is manufactured by Minsheng Development of Science and Technology Co. from Henan, China, the model number is 5E-TR 9×32. The laboratory-scale magnetic separation tube is manufactured by Zhengchang Mineral Processing Equipment Co. from Jiangxi, China, the model number is XCGQ(S)-50. The polycrystalline powder X-ray diffraction analyzer is manufactured by PANalytical B.V. from Almelo, Netherlands, the model number is X’Pert Pro. All information about the equipment has been added in paragraph 2.
Point 3: What was the mass of the sample when the study on grinding and magnetic separation was carried out.
Response:
In this study, the mass of the sample on grinding was 300 g each time, and 128.5 ml of water was added as grinding aid according to a solid-liquid ratio of 7/3. Then, the ground product was dichotomized several times to obtain homogeneous magnetic separation feed samples, each time about 20 g of homogeneous magnetic separation feed sample was separated by magnetic separation in a laboratory-scale magnetic separation tube.
Point 4: The distribution of elements (all major elements) into particle size classes according to the grinding time should be given. Information can be given on unlocking. This will allow a more comprehensive evaluation of the impact of the grinding time.
Response:
Indeed, as you suggest, information on the distribution and unlocking of elements (all major elements) into the particle size classes according to the grinding time could allow a more complete assessment of the impact of the grinding time. However, the focus of this paper is to study the variation of LVTC particle size distribution with grinding time, i.e., the grinding kinetics study. In this paper, the distribution of the major elements in the grinding products at different times can also be verified by the variation of the recovery rate of each major element in the subsequent magnetic separation experiments. In addition, the most significant feature of the material LVTC in this study is that the grade of Fe is very low while the grade of Ti is significantly higher than other types of vanadiferous titanomagnetite concentrate. Therefore, the composition and distribution of Fe- and Ti-bearing phases and the recovery in LVTC were investigated as a priority in this paper. And, in my opinion, all this completely achieves the main purpose of this paper on LVTC grinding kinetics and magnetic separation recovery. Of course, it is undeniable that you have given us another perspective on LVTC grinding research in the right direction. Under the guidance of your suggestions, we will follow up with a more in-depth and detailed research of LVTC in our subsequent work.
These are my point-by-point responses to the comments and suggestions. We appreciate your recognition of our research and your comments on our paper. And, the relevant improvements have been reflected in the submitted revised manuscript.
Thanks again to you for your suggestions and comments. Should there be any questions, please do not hesitate to contact me further.
Sincerely yours,
Jinsheng Liu, Ph.D.
Department of Resource and Environment
School of Metallurgy, Northeastern University
Shenyang, PR China
E-maill address:[email protected]
Author Response File: Author Response.pdf
Reviewer 3 Report
Study on Grinding Kinetics and Magnetic Separation of Low- Grade Vanadiferous Titanomagnetite Concentrate is very interesting paper. Some improvement is required.
Line 56:However, grinding is an extremely energy-consuming operation and dangerous process in case of the very fine powders because of the flammability of product
Line 87: It contains not only a great deal of FeO (no Fe2O3? no Fe3O4?) Is FeO magnetic powder?
Line 101:Table 1. Chemical compositions of the LVTC/mass, %.(what is the grain size of this analyzed powder?
Line 192: Furthermore, when the grinding time rises (in which interval), the particle size reduces dramatically (which value?) while the SSA increases sharply (in which range?).
line 196: the number of fine particles decreases, then slightly increases, (how did you determine the number of particle size? What is the number of fine particles?)
Line 265: d is the particle size; (what is a shape of particles? Spherical?) Regarding SEM- analysis the particles have irregular form)
Line 294: table 6: Gringing time (please to write: grinding time)
Line 341, 342: On the contrary, the recovery ratios of Fe and TiO2 in the tailings is positively correlated with the grinding time. Can you offer the chemical analysis of powder after maximal grinding time, in order to confirm this statement regarding the content of iron and titanium oxide.
Line 374: Please to check title for x-axis at Figure 13.
Conclusion
Line 379: recover valuable components such as Fe and Ti in this study, (no information about vanadiumI Is vanadium present in final concentrate?)
Line 387: the surface morphology of the LVTC particles is slightly coarser (no spherical particles in structure?)
Line 399, 400: Titanomagnetite, ilmenite, and titanite are still the predominant phases in all products (can you offer Rietveld XRD-analysis),
Author Response
March 23st, 2022
Dear Reviewers
On behalf of all the authors (Jinsheng Liu, Zhenxing Xing, Gongjin Cheng, Xiangxin Xue, Xueyong Ding) of this paper - “Study on grinding kinetics and magnetic separation of low-grade vanadiferous titanomagnetite concentrate”, I would like to express my gratitude to you for the careful review and the very valuable suggestions and comments you have given. After our careful discussion and study, we made point-to-point more detailed revisions to the manuscript in response to the review comments. The following is a point-by-point response to the comments of the reviewers.
Point 1- Line 56: However, grinding is an extremely energy-consuming operation and dangerous process in case of the very fine powders because of the flammability of product
Response:
Your suggestions have been accepted and we have improved the manuscript. Line 56 – Line 60 has been changed to the following:
However, grinding is an extremely energy-consuming operation and dangerous process in case of the very fine powders because of the flammability of product. Therefore, it is of great significance to study the grinding kinetics of low-grade VTM and to determine a suitable grinding operation regime to improve magnetic separation recovery efficiency and reduce energy consumption and flammability.
Point 2- Line 87: It contains not only a great deal of FeO (no Fe2O3? no Fe3O4?) Is FeO magnetic powder?
Response:
Line 87 expression is based on the chemical composition analysis of the LVTC in Table 1. The content of TFe and FeO in LVTC was determined by chemical titration, representing the percentage of total Fe and Fe2+ in LVTC, respectively. The LVTC contains not only FeO, but also Fe2O3 and Fe3O4. The content of Fe2+ and TFe are given only to make it easier to distinguish the difference between the content of TFe, Fe2+ and Fe3+. In addition, the amount of FeO represents not only the magnetite powder but also the total amount of FeO contained in ilmenite, titanite and other minerals. The original expression in the manuscript was indeed inaccurate, and it has been revised, as following:
It contains not only a great deal of Fe, Ti, Si and Ca, but also a lot of Al, V and Mg, as well as other valuable elements.
Point 3- Line 101: Table 1. Chemical compositions of the LVTC/mass, %. (what is the grain size of this analyzed powder?)
Response:
In this study, the chemical compositions of LVTC determined by X-ray fluorescence (XRF) and chemical method, the grain size of this analyzed powder was less than 200 mesh, and the result is presented in Table 1.
Point 4- Line 192: Furthermore, when the grinding time rises (in which interval), the particle size reduces dramatically (which value?) while the SSA increases sharply (in which range?).
Response:
Line 192 is a general depiction and analysis of the electron microscopy scans of LVTC with different grinding times in Figure 5, which cannot be quantified in detail, and therefore specific values of particle size and specific surface area (SSA) are not available. Although the specific value cannot be given, it does not affect the meaning to be conveyed. Because it can also be seen from Figure 3 in the manuscript, the average particle size dramatically decreases from 58.9 μm to 21.2 μm when grinding time was increased from 0 min to 20 min, which in turn leads to an increase in the specific surface area (SSA), as can be verified in the subsequent Table 6 in the manuscript. Therefore, Line 192 has been improved, as following:
Furthermore, when the grinding time rises from 0 min to 20 min, the particle size reduces dramatically while the SSA increases sharply.
Point 5- line 196: The number of fine particles decreases, then slightly increases, (how did you determine the number of particle size? What is the number of fine particles?)
Response:
Similar to the way of the meaning is expressed in Line 192, this is a description of the electron microscopy scanning picture of LVTC during the grinding process. It is a general depiction and analysis of particle size and the number of particle size by comparing the particle diameter in the SEM map with the scale size. The specific number of various size particles can be referred to the particle size distribution of LVTC with grinding time in Figure 3a and the following Table1.
Table1 Particle size distribution of different size particles
|
Size/μm |
Differential passing/% |
|||||
|
0 min |
10 min |
20 min |
30 min |
40 min |
50 min |
|
|
0.01~0.405 |
0 |
0 |
0 |
0 |
0.08 |
0.09 |
|
0.405~1.28 |
1.19 |
3.24 |
4.51 |
5.05 |
6.04 |
6.75 |
|
1.28~4.58 |
5.76 |
12.36 |
15.9 |
18.14 |
19.97 |
22.1 |
|
4.58~16.4 |
18.14 |
33.92 |
38.89 |
44.23 |
43.96 |
43.23 |
|
16.4~58.9 |
44.75 |
45.16 |
39.06 |
30.55 |
26.39 |
23.71 |
|
58.9~211 |
30.17 |
5.3 |
1.68 |
2.04 |
3.54 |
1.69 |
|
＞211 |
0 |
0 |
0 |
0 |
0 |
0 |
In addition, since this section is only a general description of the particles in the SEM image, the fine particles defined here are only a relative fine particle to the coarse particles in the unground LVTC, thus it is not possible to give a specific value for the number of fine particles. But thanks again for your suggestions and reminders, which are very beneficial for the next stage of our research on LVTC.
Point 6- Line 265: d is the particle size; (what is a shape of particles? Spherical?) Regarding SEM- analysis the particles have irregular form)
Response:
As you can see from the SEM image, most of the LVTC particles are irregularly shaped and not a single regular spherical shape. Therefore, d in the manuscript represents the equivalent diameter of the LVTC particle, i.e. the diameter of a certain spherical particle with the same behavior as the equivalent diameter of this particle. In this study, the medium particle size D50 is used to represent the particle size, i.e. the particle size that corresponds to the cumulative percentage of size distribution of LVTC particles reaching 50 %. Therefore, the size of the original LVTC particle can be obtained from Figure 3b and is approximately 35.3 μm.
Point 7- Line 294: table 6: Gringing time (please to write: grinding time)
Response:
Thanks for the reminder that it was my problem with the spelling error and have corrected it in the manuscript. “Gringing time” in table 6 has been modified to “Grinding time”.
Point 8- Line 341, 342: On the contrary, the recovery ratios of Fe and TiO2 in the tailings is positively correlated with the grinding time. Can you offer the chemical analysis of powder after maximal grinding time, in order to confirm this statement regarding the content of iron and titanium oxide.
Response:
Table 2 below shows the results of chemical analysis of LVTC powder after maximum grinding time. As can be seen, the chemical composition of LVTC did not change significantly after grinding, and the results were similar to those of the original sample. This is very reasonable, because grinding only changes the particle size of the sample, and the chemical composition of the sample does not change significantly until it is separated by magnetic separation. Therefore, the study of the recoveries of iron and titanium oxide only requires the analysis of the recoveries of LVTC powders obtained with different grinding times at the same magnetic field strength, as expressed in Figure 12 of the manuscript, Line 341 and Line 342 are analyzed according to Figure 12. In my opinion, it is sufficient without adding the results of the chemical analysis of the LVTC powder after maximum grinding time to the manuscript.
Table 2 Chemical compositions of LVTC powder after maximal grinding time /mass, %.
|
TFe |
FeO |
TiO2 |
SiO2 |
CaO |
Al2O3 |
V2O5 |
MgO |
MnO |
ZnO |
SrO |
K2O |
Na2O |
SO3 |
|
42.86 |
17.95 |
17.11 |
11.73 |
5.13 |
2.75 |
2.63 |
0.97 |
0.66 |
0.08 |
0.07 |
0.06 |
0.03 |
0.03 |
Point 9- Line 374: Please to check title for x-axis at Figure 13.
Response:
Thanks for the reminder that it was my problem with the spelling error and have corrected it in the Figure 13. The x-axis in Figure 13, “2-Thera, degree” has been revised to “2-Theta, degree”.
Point 10- Line 379: recover valuable components such as Fe and Ti in this study, (no information about vanadiumI Is vanadium present in final concentrate?)
Response:
As we all know, V in LVTC is present along with Fe and Ti, wrapped in the atomic lattice of magnetite and ilmenite. Grinding and magnetic separation do not completely separate it, so the final magnetic concentrate contains a certain amount of V. However, the content of vanadium is still in an insignificant position compared to iron and titanium. And this study focuses on the grinding kinetics of LVTC and the separation and recovery of Fe and titanium oxide during the magnetic separation process. Therefore, the information about V in final concentrate is not given in this paper. Thanks for your suggestions and guidance, we will conduct a more in-depth and detailed investigation of the separation and recovery of V in a subsequent study.
Point 11- Line 387: the surface morphology of the LVTC particles is slightly coarser (no spherical particles in structure?)
Response:
Line 387 belongs to the conclusion of the manuscript, which focuses on a summary of the main characteristics of the surface micromorphology of LVTC during the grinding process by different grinding time. As can be seen from SEM images of Figure 5 in the paper, the surface morphology of the LVTC particles is slightly coarser when grinding for 10 min, and it becomes rougher as the grinding time increases. In addition, due to the special physical properties of LVTC, it is easy to dissociate and fragment, and the structure after grinding is almost all irregular blocky or flocculent particles, hardly any spherical shape. Alternatively, there are only a few nearly spherical particles, and no perfectly spherical particles. or just some nearly fine spherical particles, no perfectly spherical particles, which can also be seen from the Figure 5 in the paper.
Point 12- Line 399, 400: Titanomagnetite, ilmenite, and titanite are still the predominant phases in all products (can you offer Rietveld XRD-analysis).
Response:
Line 387 belongs to the conclusion of the manuscript, which focuses on a summary of the main characteristics of the mineral composition of the LVTC particles obtained by optimal grinding time and following magnetic separation. And, the Rietveld XRD-analysis of magnetic separation products at optimal grinding time of 20 min have been shown in the Figure 13 of the paper. It can be seen that titanomagnetite, ilmenite, and titanite are still the predominant phases in all magnetic separation products at optimal grinding time of 20 min. The original expression does have some problems, and the description is not accurate enough. Therefore, we have made modifications in the paper, as following:
Titanomagnetite, ilmenite, and titanite are still the predominant phases in all magnetic separation products at optimal grinding time of 20 min, but the intensity or content of these three minerals varies amongst magnetic separation products.
Figure 13. XRD patterns of magnetic separation products at optimal grinding time of 20 min.
These are my point-by-point responses to the comments and suggestions. We appreciate your recognition of our research and your comments on our paper. And, the relevant improvements have been reflected in the submitted revised manuscript.
Thanks again to you for your suggestions and comments. Should there be any questions, please do not hesitate to contact me further.
Sincerely yours,
Jinsheng Liu, Ph.D.
Department of Resource and Environment
School of Metallurgy, Northeastern University
Shenyang, PR China
E-maill address:[email protected]
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors responded to all questions and comments. The article can be published
