Ultra-Fine Centrifugal Concentration of Bastnaesite Ore

Round 1

Reviewer 1 Report

The manuscript reads like a technical report rather than a scientific paper. The results are dumped into the manuscript without much discussion and comparison to other techniques or other studies. It is more obvious from the reference list. Only 9 references, amongst which there are only 2 journal papers; the rest includes 3 theses, 1 book, and 2 conference papers. This is very unusual for a scientific paper. 

Author Response

The issues have been addressed. 

Reviewer 2 Report

This paper is useful for mineral processing to rare earth ore “bastnaesite” by using gravity concentration of UF Falcon concentrator.

Please check the following things.

In Abstract

Please show the non-abbreviation word of REO at the first appearance.

p.2

line33

In a spinning bowl, please show the reference in this paper, though the mineral processing experts knows it.

Line 39

In UF bowl, please show the reference.

Line 41

In industrial SB, please write the non-abbreviation word of (SB).

Line 43

In Figure 2, please write the scale in the cross sections. Also remove the blue marks.

Please explain more minutely the characteristics of UF Falcon comparing with traditional Falcon in the sentences.

Line 49

In high unit power, please write the power value.

p.3

Line 65

Please show specific gravity (SG) at the first appearance.

Line 67

Please show the no abbreviation word of REE at the first appearance.

Line 101

Please write the reference of ” a Jones riffle”

p.4

Line 136

Please explain P80..

p.6

In the formula of Table 1, please write the subscript in chemical formula.

In Figure 5 and 6, please explain UF T1, T2, T3 and T4 in the sentences.

p.8

In Figure 6, please write the scale.

Line 215

Please explain or refer of State Ease 10,

p.9

In Figure 9, please write (%) in y axis of REO recovery.

P.10

In conclusion, please explain using the actual data value of the experiments.

Author Response

(For sake of clarity, this response is written by Mr. Norgren and submitted via Dr. Anderson)

1) Revised.

2) I am unclear what you are requesting here.

3) I am unclear what you are requesting here.

4) Revised.

5) We are currently attempting to obtain a better quality version of this image.

5) We feel this is addressed within the section itself, given the indication of unit feed tonnages and horsepower.

6) Revised.

7) Revised

8) I am unclear what you are requesting here.

9) I have attempted to address this.

10) I have converted all necessary values into subscripts.

11) I am not entirely clear what is requested here. UF T1, T2, etc... mean UF Falcon test 1, test 2, etc...

12) I am not clear what sort of scale you are interested in seeing on what is now Figure 7.

13) I am not clear what you are requesting.

14) I'm afraid I no longer have access to the proprietary software package in which this figure was generated, thus I have no means of adding the (%) sign to this image.

Reviewer 3 Report

The paper introduces a research work about ultrafine centrifugal concentration on a bastnaesite ore. The subject is of interest for two reasons: one, the use of gravity technologies to ultrafine beneficiation; second, it introduces a greener processing route to REO ore beneficiation, considered critical raw materials.

In general, the paper is well-structured, with a good experimental design and a well-justified discussion. Conclusions are also well justified by the obtained results. English should be revised thoroughly, for some phrases/expressions/words are wrong. Additionally, some minor issues need to be corrected (see the list below)

1-Lines 13-14: “The purposes of this study is to determine the applicability of gravity concentrators to beneficiate bastnaesite and calcite bearing flotation feed material”. Please rephrase it; the title and the subsequent information indicates that only REO minerals are the beneficiation target.

2-Line 28: “Mozley gravity separators” must be replaced by “Mozley multigravity separators (Mozley MGS)”, because Mozley designed other gravity separators different to the MGS.

3-Please improve the quality of Figures 1 and 2.

4-Line 32: “similar principal” should be “similar principle”

5-Line 61: “Mintek’s 2011 study”, please reference it properly.

6-Lines 61-62: It is a conceptual mistake to consider HLS as a separation methodology. HLS is a characterization methodology; the most similar methodology at an operational scale, is heavy media separation. Please rephrase this sentence.

7-Line 73: “Schriner’s 2015 study”, please reference this properly.

8-Line 78: “excessive sanding” please explain the meaning of this expression; perhaps does it mean “excessive settling”?

9-Line 81: please write “four passes” instead of “4 passes”. This mistake must be corrected in several phrases throughout the manuscript.

10-Line 81: please explain “four passes”. Does it mean “cleaning stages”? It can be deduced that cleaning stages are performed on the dense product, but this must be stated clearly.

11-Line 81: “grind time”, please use “grinding time”; this mistake is in several phrases and tables.

12-Line 82: “RPM”, please use “rotational speed, being the units revolutions per minute (rev/min or rpm). Please correct this in several phrases throughout the manuscript.

13-Line 99: “roll spacing”, please use roll crusher “gap” or “set”.

14- Line 142: “stop watch”, please change by “stopwatch”.

15-Line 149: please specify the drying temperature; carbonates and other hydrated minerals can suffer transformations if the temperature is too high.

16-Line 156: “a single unrepresentative sample”. Please clarify this expression or justify why the results of a non-representative sample are provided.

17-Line 167: “XSBE method” please reference this methodology properly.

18-Lines 178 to 181: use the expression “cleaning stages” instead of “passes”

19-Lines 182 and 183: “Additionally, the fact this exhibited any degree of selectivity against calcium, as shown in Figure 6, was also considered favorable”, please rephrase this, it cannot be understood easily.

20-Line 192: “with a new baffled conical feed tank”, please justify in more detail how was selected the new design.

21-Line 217: “desirability surface”, please insert reference here.

22-Line 222: “a 120 minute grind”, please replace by “a 120 min grinding time”

23: Table 2: please show “RPM” and “Grind, min” properly (see comments 11 and 12).

24: Line 226: “Schriner”, please cite properly.

25: Lines 234 to 236: discussion could be improved in terms of hindered settling (gravity concentration is improved when working under a hindered settling regime, that is pulp density higher than 15% solids weight.

Author Response

(For sake of clarity, this response is generated by Mr. Norgren and submitted via Dr. Anderson)

1) I have attempted to address this, but I am unsure if I've succeeded.

2) Revised per recommendations

3) Figure 1 has been replaced with recreated images of a higher quality.

4) Revised

5) Revised, although I am unsure if I've met the proper format.

6) Revised

7) Revised, although I am unsure if I've met the proper format.

8) This I struggled with as the term that Hazen communicated to me was "sanding". However, settling is also appropriate here, so I've replaced it. This and other aspects was one of the key motivations for switching the feed tank.

9) Revised, although it's possible I missed an occurence.

10) You bring up a good point that on its own, "four passes" is not particularly clear. Thus, I have added an entire new Figure to visually show what I meant. It does not mean cleaning stages, but rather in series treatment of a prior pass' tailings.

11) I have attempted to fix this

12) I have fixed this in its first instance, however I feel RPM is still the better term throughout.

13) Revised

14) Revised

15) I've added what appears to be the current setting on the drying oven. I am still consulting my old records to see if an alternative value was previously used however the value given to me sounded familiar.

16) To be blunt, I call it unrepresentative because in hindsight I had performed an improper splitting procedure when isolating it, thus turning it into a specimen. Had I been thinking, I should have subjected it to roll crushing prior to splitting that kilogram worth of material. However, it is the only such data I have, and while the proportions are perhaps a bit skewed, the minerals themselves are indeed proper. In fact, it was because of this mistake that I revised the entire splitting and sample preparation procedure for all samples that underwent the experiments.

17) Revised

18) Due to the inclusion of the new figure I am intentionally continuing to use the term pass as it is not a cleaning stage.

19) I have attempted to address this.

20) To be honest, I simply ordered a duplicate of the feed tank used at Hazen, from Hazen, because the system I had been using just wasn't working well. The baffels was a key addition as the previous unbaffeled system would occasionally cause the entire slurry to simply spin around the outside without even touching the discharge port. Hazen claimed to have considerably more success with their feed tank, and I didn't feel the need to re-invent the wheel after their experiences.

21) I am unclear what you are asking for.

22) Revised

23) Revised

24) While this is an interesting point, I am unsure if I can properly address this. There is also the dichotemy between higher solids and effective ability to pump the slurry. Still, that actually might be one of the better explanations for why, despite being counter-intuitive to what I had read, it seemed the higher percent solids worked better.

Additionally, I have added further discussion regarding follow up scavenger testing.

Round 2

Reviewer 1 Report

Unfortunately, the revised version still reads like a laboratory report rather than a scientific paper, which requires the inclusion of extensive discussions on results.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf