Recovery of Lithium from Simulated Secondary Resources (LiCO3) through Solvent Extraction
Round 1
Reviewer 1 Report
It is an interesting article on Lithium recovery by Solvent Extraction.
Recommendations:
1.- Review carefully the entire manuscript since some typo errors are detected. For instance:
Line 47: hydrometallurgy instead Hydrometallurgy.
Line 48: biological instead Biological.
Line 83: Nickel instead Nickle.
Line 95: Li2CO3 instead Li2Co3
Line 97: HCl instead HCL
Line 140: several instead serval.
Line 256: NiSO4 instead NiSO4.
Line 257: H2SO4 instead H2SO4.
Line 304: Li2CO3 instead Li2CO3.
Line 313: Li2CO3 instead Li2CO3.
Line 329: Li2CO3 instead Li2CO3.
2.- Use g / L instead of ppm for concentration.
3.- Add purity and reagents suppliers in methodology part. For example: Lithium Carbonate (Line 95), Cobalt (II) Carbonate (Line 96), HCl (Line 97), n-butanol trioctylamine (TOA) (Line 100) ,4-methyl-2-pentanol (MIBC), bis(2-ethylhexyl) phosphate (DEHPA), dichloromethane (Line 101), trioctylphosphine oxide (TOPO), kerosene (Line 102).
4.- How did you select the concentration: DEHPA 0.06 M?
5.- Improve Figures.
Figure 2, remove “Compare Extraction Efficiency Various Extractant”.
Figure 3, remove “STUDY EXTRACTION EQUILIBIRUM”.
Figure 4, in CONCENTRATION: EFFECT OF PH, what are the units of the concentration, mg/L?
Figure 5, in Figure 5a, change or decrease the number of decimal places, and what are the units of the concentration, mg/L?
Figure 8, remove “SELECTIVITY: EFFECT OF MIX ION IN SOLUTION”. In Figure 8a change the number of decimal places.
6.- The results of section 3.1 should be more synthetic. Which are the extractants concentrations? and pH is initial or in equilibrium?
7.- Section 3.1 (lines 166-209), shows different extraction mechanisms and extractants, however, this section should discuss the results. You can move this information to Introduction part.
8.- In line 306, what it means “minimum 9.95 % confidence”, it is correct?.
9.- Higher Lithium and Cobalt concentrations have been reported in the bibliography (Reference 28).
Why did you use very low concentrations for your study?
10.- The extraction mechanism is not shown really.
11.- Usually, in the industry, the metals extraction process takes some minutes, your method to recovery Lithium spends hours, you should think about this.
Author Response
Please refer attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript is presented on an interesting topic of Li recovery using several different types of solvents. However, I found the whole manuscript is poorly structured and written, while some details of the work are also not clear. Therefore, I would suggest a substantial Major Revision before it could be considered for publication. Some problems are listed below.
- The title of the work only highlights the solvent DEHPA. However, this is only one of the extractant they have tested, although it is the best one. A better title that matches the whole content is recommended.
- In the results and discussion part (page 5), the authors provided a very detailed introduction of different types of extractants. On page 7, the authors also tabulated an exhaustive review of literature on the effect of pH on Li recovery. Such contents are not supposed to present in the results and discussion part.
- The data in Figure 2 and Figure 3 seem to be inconsistent. In Figure 2, the extraction efficiency of DEHPA after 2 hr is 75% but in Figure 3 it is only around 50%. The authors should check the data correctness carefully.
- There are many poorly written sentences, even grammar and spelling mistakes throughout the manuscript. I strongly suggest the authors polish English writing throughout the manuscript.
Author Response
Please refer attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The article was improved, however is important to be careful with next points:
Line 297: "The optimum conditions for lithium ion extraction were studied to determine the highest 297 separation efficiency in order to combine solvent extraction with electrodialysis.
A statistical study is not presented to find the optimal conditions, in this work.
Line 202: "10 ppm of lithium/cobalt and 2 ppm of lithium/cobalt solutions."
and line 338: "10 g/L and 2 g/L of lithium solution".
At line 202, and 338, is not clear what concentrations were finally used in the experiments, ppm(mg/L) or g/L?.
Line 398: Figure 4 shows units in mg.
It is correct or not?.
Line 478: Figure 5 shows units in mg/L.
It is correct or not?.
Recommendation:
1) Again, extraction mechanism is not shown, it should be improved. (Chenglong Shi, et al, Separation and Purification Technology 172 (2017) 473–479).
2) Is very important reorganize the text. Check full text.
3) Introduction part is extense, is not necessary to write a lot about, because this information is in the classic solvent extraction books as "Solvent extraction principles and practice", (J. Rydberg et al, 2004).
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors have provided a fine revision of their manuscript. I would suggest the acceptance.
Author Response
The reviewer already provided the acceptance note below.
Round 3
Reviewer 1 Report
Thanks for the new version of the manuscript.
