Recovery of Rare Earth Oxides from Flotation Concentrates of Bastnaesite Ore by Ultra-Fine Centrifugal Concentration
Round 1
Reviewer 1 Report
Manuscript ID: metals-1309643
Title: Ultra-Fine Centrifugal Concentration of Rare Earth Flotation Concentrates
Authors: Alex Norgren and Corby Anderson
The article is devoted to solving practical problems of the enrichment process. The article presents figures of installations and a flowcharts of the enrichment processes. This is a positive moment. However, it is necessary to improve the quality of the figures, remove the values in inches, improve the description of the methodology and significantly improve the section on conclusions and sources:
Title must be changed. Recovery of Rare Earth Oxides from Flotation Concentrate of Bastnaesite Ore by Ultra-Fine Centrifugal Concentration.
Figure 1. Poor quality of the inscriptions in figure 1. The clarity of the figure needs to be improved.
Line 81, 91. Authors must use metric numbers (3/8”; half inch diameter)
Section 2. Authors must add information about XRF, SEM and Particle size distributions equipment’s and write equations for calculations yield, grade, and recovery.
Table 1. Authors must add XRD and chemical compositions of samples before and after concentration.
Figure 7-9. Modify the figures so that the X-axis starts at 40% of REO recovery.
Conclusions. The conclusions should be significantly improved. Authors should add information on the values of the yield, grade, and recovery of REO by enrichment process (Ultra-Fine Centrifugal Concentration). Use paragraphs 1) 2) etc.
References. Authors used only six links. Even though the article has serious practical application, it is necessary to use more links. Articles about ore enrichment are published regularly. There are even systematic reviews (Application of Enhanced Gravity Separators for Fine Particle Processing: An Overview https://doi.org/10.1007/s40831-021-00343-5). Authors are required to significantly increase the number of links, especially to peer-reviewed articles.
Author Response
The title has been changed per your recommendation.
I am simply not capable of addressing Figure 1 as this was the native resolution of the original image. I do not have the capability to reproduce it manually. Your comment did draw attention to the fact that the caption was incorrect however.
Additionally, the mineralogy report from the external laboratory did not detail specifics about the XRD and SEM, nor am I capable of reaching them during a weekend to request this information.
I did include additional after results in Table 1 for both the penultimate concentrate and tailings from the multistage open circuit test.
I revised the axis for Figures 7-9, and I agree this is a better way to present it.
I did significantly augment the conclusions section, as well as provided some additional context to the numbers as they appear in the body of the work.
Although I did add some additional references, I am afraid I was not capable of augmenting it to the extent you've requested. I will however say that the thesis this was part of included 74 unique citations, and that this subset represented the most directly relevant of those to the content of this paper.
Reviewer 2 Report
The authors of this manuscript determined the applicability of centrifugal concentrators to beneficiate Ultra-Fine (UF) bastnaesite and calcite bearing flotation concentrates. The topic of the manuscript is interesting and fits well with the scopes of metals. However, the manuscript needs a minor revision before its publication, there are some concerns that the reviewer believes that should be appropriately addressed:
- The full name of “REO” should be given when it appears in the abstract the first time to make it comprehensible to the scientifically literate general public;
- Supplementing images of equipment and materials can make the manuscript more vivid and add credibility;
- More numeric findings can be supplemented in conclusions;
- Discussing the limitations, comparative advantages to the extant methods, and commercial prospects of this process can better prove the effectiveness of the method from the side.
Author Response
1) I've addressed this per your recommendation.
2) I'm afraid I was unable to include this at this time, however I concede it would have been a valuable addition.
3 / 4) I have expanded upon the implications of some of the numeric findings within the body. In regards to the conclusion however, I determined that this was the best place to address your 4th remark in a qualitive nature. I not only addressed the conditions that would render an UF Falcon more or less economically attractive than alternative flowsheets, but also how future changes to the technology could impact these considerations.
4) I also address the fact that this study, while not the goal, ended up demonstrating that UF Falcons can be used on feeds with a high heavy mineral content, which is a significant departure from most literature. This seemed worthwhile to highlight, as it expands the potential versatility of the UF Falcon beyond simply the scope of REE minerals.
Round 2
Reviewer 1 Report
Figure 1 is still of poor quality. If the author does not have access to the source, is that a reason for accepting this fact? Why do other authors correct figures in their articles? If you compare figure 1 and figure 10 or 11, this is a completely different level. How I can accept the quality of figure 1?
If you cannot be reached with another scientists on weekends, please contact on a business day. This article is devoted to enrichment, that is, obtaining various fractions. Why artilce does not contain XRD of concentrates? How is this possible?
Table 1. Authors should add X-ray and chemical compositions of samples before and after concentration. Because this article is about flotation process. What concentrates are obtained as a result? This information is not included in the article. Why is there no chemical composition? This is the standard method of analysis.
The number of references is very small and again these are conferences. Why are there no links to scientific articles? Nobody will see this article, since there are no links. Due to the fact that the list of references is small, the citation rate of the article will be small.
Author Response
1) Thank you for clarifying what you were looking for, I have since recreated the content of the Figure as two separate figures in the same style as what was formerly Figures 10 and 11.
2) Despite my efforts, I have still been unable to contact the laboratory despite it being the business week.
3) I've added a subsequent table to better illustrate the other pre and post flotation materials. Thank you for clarifying what you were looking to see.
4) I have further bolstered this section.
As a final note, I'd like to clarify that this and the previous response were actually written by Mr. Norgren rather than by Dr. Anderson. With all due respect, I (Mr. Norgren) no longer (for the moment) have ready access to most scientific journals in light of my pandemic induced employment situation, and I'm afraid the previous editing window did not mix well with my shift schedule.
I do actually appreciate the effort you have put in to force me to improve this paper as much as possible. For that, you do have my thanks.
-Alex
Round 3
Reviewer 1 Report
The pandemic is not a reason not to add data on the chemical and mineral composition of fractions after flotation.
Author Response
The issues have been addressed.
