Selective Dissolution of Nd2O3 from the Mixture with Fe2O3 and Ga2O3 by Using Inorganic Acid Solutions Containing Ethylene Glycol
Round 1
Reviewer 1 Report
This article mainly discusses the advantages of using ethylene glycol as a solvent and the type of acid in the process of separating neodymium oxide. The effects of variables such as temperature, feed flow rate, and reaction time on the efficiency of the separation process of neodymium oxide from the iron oxide and gallium oxide mixture were investigated.
The results show that in this separation process, the use of sulfuric acid has better selectivity than hydrochloric acid. The concentration of sulfuric acid used was lower, but the rate of separation was somewhat slower. The addition of ethylene glycol inhibits the dissolution of iron oxide and gallium oxide from the oxide mixture, enabling selective dissolution of neodymium oxide. An optimized neodymium oxide separation process was obtained. It is suggested that the paper can be published after minor revisions.
1. In line 29 the penultimate word should be mud
2. It would be better to carry out a comprehensive comparative study of the two test groups (1M hydrochloric acid and 0.05M sulfuric acid). In addition, the raw material cost of the two methods needs to be analyzed.
3. This paper adopts a variety of methods for recovering rare earth elements from laterite ore and NdFeB magnets. It is necessary to explain the reasons for adopting these methods and compare their advantages and disadvantages. It should be noted that ethylene glycol mixed with nitric acid will form ethylene glycol dinitrate, posing a risk of explosion.
Author Response
The manuscript has been revised according to the comments.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article is devoted to the search for methods for the recovery of rare earth metals from production waste. In general, the presented study is quite interesting and promising not only from a fundamental point of view, but also from a further practical application. The article corresponds to the declared journal and can be accepted for publication in the future after the authors answer a number of questions that have arisen during its analysis.
1. The abstract needs to be improved, the authors should reflect in more detail the novelty and practical significance of the work.
2. The authors should explain in more detail the choice of a model mixture, which is close in composition to red mud, should provide a comparative table or a detailed description of the comparison of compositions, not only with a description of the types of known composition, but also compared with the selected system for research.
3. For all values ​​determined, authors should present measurement errors or describe how the observed values ​​were obtained.
4. The authors should substantially revise the presented experimental results and their discussion. In the presented form, they resemble more an analytical report on the work done than a scientific article.
5. All formulas used should be referenced.
6. Conclusion requires significant revision and optimization, as well as reflection of further research prospects.
Author Response
The manuscript has been revised according to the comments.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
I have read your manuscript "Selective dissolution of Nd2O3 from the mixture with Fe2O3 and Ga2O3 by using inorganic acid solutions containing ethylene glycol"
with attention and interests. It is in scope of metals journal no doubt. It seems to be interesting for the readers. However I have a few comments and suggestions which could be helpful for you in improve your paper.
1. Line 30. I suggest to extend the range of examples to alloy additives for tungsten plasmatron cathodes significantly increasing thermal stability by below reference
DOI 10.1016/j.jajp.2022.100111
2. Section Results and Discussion
I suggest to mention about the measure resolution of mass, temperature and time regarding to range of physical quantity measurement error and statistical reliability of experiments.
Rest of the paper seems to be clear.
Regards
Author Response
The manuscript has been revised according to the comments.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors answered all the questions posed, the article can be accepted for publication.
