Influence of the Application of a Sound Field on the Flow State Reduction of Newman Fine Iron Ore
Round 1
Reviewer 1 Report
The paper is well written with good experimental results. The results are well discussed with the support of relevant theories. The equation for viscus forces (eq. 14) is not clear.
There are need for improvements on some figure caption and equations. For example Figure 13,14; equation16.
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #1“(1) 1. The equation for viscus forces (eq. 14) is not clear.”
Response: The eq. 14 is calculated by the following equation:
“ ” (14)
2) Reviewer #“1(2). Figure 13,14 need some improvements”
Response: Figure 13,14 was modified in page 13-14
Figure 13. Surface roughness limits particle proximity. Figure 14. surface structure enhances tight contact.
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript deals with a study on the study of the reduction of Newman fine iron ore under sound-assisted fluidization. In particular, the effect of the power and frequency of the acoustic field has been investigated.
Even though the topic is interesting, the paper is not acceptable for publication in the present form. Some issues should be addressed before publication on the Processes journal.
Specific comments
1) The Author mistakenly uses the term “ultrasound”. Ultrasound is defined as a sound wave characterized by frequencies greater than 20 kHz, which is clearly not the case since in this work the sound frequencies are varied in the range 50-500 Hz. Therefore, there is no ultrasound/ultrasonic field. A standard sound-assisted fluidization is employed in this work.
2) The introduction section needs to be improved. As stated in the abstract, the fluidization quality can be improved by applying different assisting technologies involving the application of external forces (e.g. vibration, magnetic field, acoustic field, electric field, etc.). However, nothing is disclosed about these possible techniques in the introduction, which is the most proper place. Moreover, besides discussing about this, providing at least a brief description of the available technological alternatives, the Authors should explain why they decided to use sound-assisted fluidization. What are the advantages of sound-assisted fluidization with respect to all the other alternatives? The reading of the following works may be of use to the Authors:
a. Materials (Basel)., Vol. 14, pp 672, 2021. https://doi.org/10.3390/ma14030672
b. Ind. Eng. Chem. Res., Vol. 59, pp 3593–3605, 2020. https://doi.org/10.1021/acs.iecr.9b04901
c. Chem. Eng. Res. Des., Vol. 133, pp 347–387, 2018. https://10.1016/j.cherd.2018.03.034
d. Journal of Nanoparticle Research, 14, 737. https://doi.org/10.1007/s11051-012-0737-4.
e. Soft Matter, Vol. 9, pp 8792, 2013. https://doi.org/10.1039/c3sm50780g
f. Particuology, 5, 61–70. https://doi.org/10.1016/j.cpart.2007.01.001
g. International Review of Chemical Engineering, 4, 16–50.
3) The Author should better motivate their work, especially highlighting the novelty with respect to other works already available in the literature
4) Several grammatical errors/typos can be found throughout the manuscript. It should be carefully revised from this point of view.
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #“2(1). The Author mistakenly uses the term “ultrasound”.
Response: The “ultrasonic field” has been changed to “sound field”in article.
2) Reviewer #“2(2). e.g. vibration, magnetic field, acoustic field, electric field is disclosed about these possible techniques in the introduction.
Response:The sentence“There are some researches on improving the fluidization quality of viscous particles by using vibration force field. Mori et al. [34] first applied a new type of vibrated fluidized bed to study the vibration fluidization of single and multi-component fine particles. Zhu Qingshan, Li Hongzhong et al. [34] have carried out experimental research on the fluidization mechanism of ultrafine particles in magnetic field, and found that the magnetic field can effectively eliminate the channel flow in the fluidized bed, so that the stable fluidization operation can be realized. However, magnetic fluidization is only effective for ferromagnetic particles or mixed particles with ferromagnetic particles, but not for non ferromagnetic particles.” was added from page2 line 51-59.
3) Reviewer #“2(3). What are the advantages of sound-assisted fluidization with respect to all the other alternatives?
Response: The sentence“The introduction of sound field can not only improve the mass transfer and heat transfer efficiency, but also significantly reduce the size of agglomerates and the initial fluidization velocity, thus significantly improving the fluidization quality” was added from page2 line 59-62.
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Reviewer 3 Report
This is an interesting manuscript on the influence of ultrasound on fluidized iron particles. The English writing is fine. The manuscript addresses fluidization improvement in ironmaking processes, by adding an external field (ultrasound). The paper has however, the following issues that have to be addressed before publication is granted:
Major Issues
- The experimental data reported in different Figures 4-11 are not provided with the standard deviations for repeats. Thus, one cannot grasp well and on this basis the true meaning of reported experimental trends on metallization rate, sticking ratio, Umf, particle concentration radial distribution, DP, height of the bed. In other word, statistics are missing on the reported experimental data.
- The paper appears not to address the effect of humidity which is a major factor influencing intraparticle forces and consequently agglomeration in fluidized bed processes. One would expect, the humidity influence is a very important factor in an industrial process, where hydrogen (reducing gas) is likely coming from steam reforming.
- The theoretically based justification of the ultrasound influence is considered via various equations (Eqs 6-31). As far as one can see, authors provide qualitative explanations only, with little effort developed to establish the provided equations applicability on a quantitative basis. This can be achieved using statistically based data fitting with evaluation of parameters with 95% confidence intervals. This is in our view, essential in the present paper.
Minor Issues
- The is a problem with the symbols used in Eq(14)
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #“3(1).In other word, statistics are missing on the reported experimental data”.
Response: Table 4 was added in page 8 and double clicking the graph 9 and 10 can see the data
Table 4 The relation table of minimum fluidization speed and frequency
|
frequency |
50 |
100 |
150 |
200 |
300 |
400 |
500 |
|
fluidization velocity |
0.061 |
0.057 |
0.051 |
0.053 |
0.057 |
0.062 |
0.065 |
2) Reviewer #“3(2). The paper appears not to address the effect of humidity which is a major factor influencing intraparticle forces and consequently agglomeration in fluidized bed processes”.
Response: The samples in this paper are all dried, and this paper mainly studies the effect of sound field on the reduction of iron ore powder. We will do further research on humidity in the future.
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Author Response File: Author Response.pdf
Reviewer 4 Report
The paper consists of two parts. The first part is devoted to direct experimental data on fluidization of iron ore particles with the accent to metallurgy, the second part is devoted to the attempt to collect various data on the influence of ultrasonic waves on fluidization.
The comments to the manuscript are listed below.
- The topic of the paper is “Influence of the application of an ultrasonic field…”. However, the source of ultrasonic sound (waves) is not described at all.
- The hydrodynamics of the process is not clear explained. Was it a batch, semi-batch, or continuous process? If continuous, what was the design of the feeding system for multicomponent powder?
- Fig.7. The minimum is very sharp. Can it be explained somehow?
- Fig.8 concerns the radial particle concentration distribution.
- how was the local particle concentration distribution measured?
- what is the parameter of each line? Its value is indicated is the rectangles but is not explained what it means.
- What is the parameter for the curves in Figs.9-11?
- Fig.12. Why the h-axis begins with a negative value?
- I have no idea why the section 4 was included in the paper. It contains a lot of uncoordinated formulae for various forces and energies that can be found in fine particle fluidization and were obtained by somebody else. Practically no graphs, no comparison of them, and no way how to use them in practical calculation of a fluidized bed process.
- This section is mentioned in the conclusions as the statement “… energy provided by the sound field can break the large agglomerates…” that is clear without the section.
- The paper contains a lot of symbols but does not contain the section Nomenclature, that makes reading the paper very difficult.
According to my viewpoint the paper does not contain new and important results on the fluidized bed process itself but can be interesting from metallurgy viewpoint. This is why I can recommend it for publication after its correction due to the above comments.
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #“4(1). The source of ultrasonic sound (waves) is not described at all”.
Response: The sentence “It is mainly composed of fluidized bed, acoustic duct, acoustic generation system and test system” was added in page 2,lines75-76. The sentence “The sound wave generating system consists of a signal generator and a loudspeaker. The generator is used to obtain the positive dark wave of a specific frequency, which is amplified by a power amplifier and then sent to the loudspeaker to generate sound wave. The sound wave enters the fluidized bed through an acoustic waveguide” was added in page 3,lines 86-89.
2) Reviewer #“4(2).What was the design of the feeding system for multicomponent powder”?
Response:
The place marked in red in the picture is the feeding port. The lid can be opened, and the mineral powder is added in from here.
3) Reviewer #“4(3). Fig.7. The minimum is very sharp. Can it be explained somehow”?
Response: The sentence “This is mainly because when the frequency of sound wave is too low, the vibration period is too long, which causes the particles to quickly restore the bond after the initial disturbance; when the frequency is too high, the vibration period is too short, which causes the particles not to follow, both of which weaken the effect of sound wave, and even have no effect when the frequency is too low or too high. When the frequency changes in the range of 150Hz, the fluidization of ultrafine particles in the process of fluidization has been eliminated, such as channeling, surge and other fluidization phenomenon, can achieve complete fluidization, fluidization quality is very good. However, when the frequency is lower than or higher than 150Hz, the fluidization phenomena such as piston flow and flow channel appear in the process of fluidization, and the fluidization quality decreases” was added in page 8,lines219-229.
4) Reviewer #“4(4). What is the parameter for the curves in Figs.9-11”?
Response:Δp: bed pressure drop; u (mm/s): fluidization velocity; (H-H0)/H0: bed expansion rate
5) Reviewer #“4(5). Fig.12. Why the h-axis begins with a negative value”?
Response:A negative number indicates that the particles have collided or bonded.
6) Reviewer #“4(6).This section is mentioned in the conclusions as the statement “… energy provided by the sound field can break the large agglomerates…” that is clear without the section.
Response: In this part, I make a further explanation through the phase structure diagram and mathematical expression
7) Reviewer #“4(7).The paper contains a lot of symbols but does not contain the section Nomenclature, that makes reading the paper very difficult.
Response: All the formulas are listed below：
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|
(1) |
Where η represents the metallization rateï¼›MFe stands for metal iron, gï¼›TFe stands for total iron, g
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Ω=Msticking/Mtotal |
(2) |
Where Mtotal is the total quantity of the reduced materials, which is used to evaluate the quality of the reduced total materials of fine iron ore, gï¼›Ω is binding ratioï¼›Msticking refers to the amount of reduced adhesive substance, which is used to evaluate the quality of reduced adhesive substance of fine iron ore, g;
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Mtotal = Msticking + Munsticking |
(3) |
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(4) |
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(5) |
Where: α is attenuation caused by acoustic absorption, dB/100m;T is the absolute temperature, K;P* is relative atmospheric pressure; μmaximum is the maximum intensity loss per wavelength.fr is the relaxation frequency with great loss per unit wavelength, Hz; f is the frequency of the sound wave, Hz.
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(6) |
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(7) |
where L is the height of the static bed, R is the gas constant (286.7J/(kg·K)), T is the absolute temperature of the fluidized bed and is assumed to be 298 K, ρg and pp are the densities of gas and particles, respectively, and are 1.185 kg/m3 and 2500 kg/m3, respectively. Bed voidage εb is 0.4. For 10μm particles, the resonant frequency is approximately 100 Hz. When the sound wave frequency is greater than the resonant frequency, the attenuation coefficient of the sound wave in the fluidized bed increases significantly with increasing frequency, and the sound pressure decreases rapidly.
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(8) |
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(9) |
where Ha is the Hamaker constant, usually in the order of 10-20J, hij is the distance between the surface of particle I and particle j, and hiw is the distance between the surface of particle I and the wall.
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(10) |
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(11) |
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（12） Where γ is the surface energy constant per unit area. （13） Where hct is the shear distance, which is 4.0×10-10m. （14） （15） |
Where, A is Hamaker constant, determined by material properties, and his Lifshitz constant. fs is the corresponding area, and Z0 is the shortest distance between two solids.
（16）
Where, and are two kinds of electron affinity for solid contact.
（17）
Where, Q is the charge of the particle; R is the particle radius; Z is the adhesion distance; ε0 is the dielectric constant in the vacuum.
（18）
Where, ∆U is the contact potential difference.
（19）
where spl is the sound pressure level, in decibels, μref is the reference speed (4.83×10-8m/s), and μac is the acoustic velocity. The speed of sound increases exponentially with the sound pressure
Thank you and best regards.
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(20) |
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(21) |
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(22) |
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(23) |
Where, μac,max is the peak velocity of acoustic wave. is the attenuation coefficient of sound wave in unit direction. is the angular velocity.K is the wave number of the damped wave. is the phase Angle. ρ is the density of the gas.c0 is the speed of sound at 15 degreescelsius and one standard atmosphere. The order of magnitude of the general b value is usually 10-5kg/(m·s).
（24）
Where, Vp is the volume of a single particle. μac is the acoustic velocity. vP is the particle velocity.β is the gas-solid correlation coefficient.
（27）
Where, μ is gas velocity; umf,a is the minimum fluidization velocity of the cluster.
（28）
Where, da1 is the aggregate diameter;ρa1 is the cluster density.
（29）
Where, ω is angular velocity; A is the amplitude; c is the speed of sound; ρf is the fluid density.
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(30) |
Where： is bed void fraction; AH is Hamaker constant; Z0 is the initial spacing of two aggregates when they are just broken. dp is the mean diameter of particles.
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript has been revised and can be now accepted for publication.
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #“2(1). The Author mistakenly uses the term “ultrasound”.
Response: The “ultrasonic field” has been changed to “sound field”in article.
2) Reviewer #“2(2). e.g. vibration, magnetic field, acoustic field, electric field is disclosed about these possible techniques in the introduction.
Response:The sentence“There are some researches on improving the fluidization quality of viscous particles by using vibration force field. Mori et al. [34] first applied a new type of vibrated fluidized bed to study the vibration fluidization of single and multi-component fine particles. Zhu Qingshan, Li Hongzhong et al. [34] have carried out experimental research on the fluidization mechanism of ultrafine particles in magnetic field, and found that the magnetic field can effectively eliminate the channel flow in the fluidized bed, so that the stable fluidization operation can be realized. However, magnetic fluidization is only effective for ferromagnetic particles or mixed particles with ferromagnetic particles, but not for non ferromagnetic particles.” was added from page2 line 51-59.
3) Reviewer #“2(3). What are the advantages of sound-assisted fluidization with respect to all the other alternatives?
Response: The sentence“The introduction of sound field can not only improve the mass transfer and heat transfer efficiency, but also significantly reduce the size of agglomerates and the initial fluidization velocity, thus significantly improving the fluidization quality” was added from page2 line 59-62.
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors continue without addressing 2 issues from my first review:
a) There is no statistics supporitng the data reported: standard deviations for repeats are a must in every single graph.
b) There is no quantitative connection of the proposed equations (models) with the data reported. This is needed indeed.
Without this information publications should not be granted.
Author Response
Dear editors and reviewers,
I am very grateful to your comments for the manuscript. Here below is our description on revision according to the reviewer’s comments and the changes in the manuscript within the document have been tracked by using the red colored text.
1) Reviewer #“3(1). There is no statistics supporitng the data reported: standard deviations for repeats are a must in every single graph.
Response: Figure 7 and 8 were modified in page 9; Figure 9 and 10 were modified in page 10; Figure 11 was modified in page 11.
Figure 7. Influence of frequency on minimum fluidization velocity.
Figure 8. Radial distribution of particle concentration at different acoustic frequencies.
Figure 9. Pressure drop velocity curve of bed in silent field
Figure 10. Bed expansion velocity curve in silent field.
Figure 11. Bed pressure drop - velocity curve under different sound pressures.
2) Reviewer #“3(2). There is no quantitative connection of the proposed equations (models) with the data reported.”.
Response: Fig17 was added in page 17 and the sentence “According to the experimental results and formula (26), we can get the influence of different power on the fluidization effect, as shown in Figure 17.” Was added in page 18 line 466-467.
Figure 17 The functional relationship between power and bond ratio
Fig19 was added in page 20 and the sentence “When the sound field frequency is fixed, with the increase of sound field power, the intensity of sound field per unit area of agglomerated iron ore powder increases, the agglomerate diameter decreases, and the iron ore powder fluidizes, which is consistent with formula 26. As can be seen from the figure19” Was added in page 20 line 520-524.
Figure 19 The relation between the intensity of sound field and the diameter of the agglomeration
Thank you and all the reviewers for the kind advice.
Sincerely yours，
Dr. Xu
Round 3
Reviewer 3 Report
Everthing is fine.
