Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The review article is well written. The review is publishable but it does need a little work.  There are places where the authors have an idea and just jump to the next idea without explaining the previous idea.  There are also some parts that seem out of content to the reader.

Below are minor comment/ Questions for the authors to address before publication.

The authors wrote: “Adjusted using [30].” This has no context to the reader.                                                                                                                                       

The authors wrote:  “The high EOL recycling rate for lead-acid batteries was achieved through government incentives, which might also be necessary to achieve the same success for LIB recycling.” This is not quite correct lead is highly toxic and relatively simple to extracted from lead acid batteries unlike Li+.

Figure 2 needs axis labels

The authors wrote: “The basis for a regulatory framework in view of LIB recycling is laid in the EU battery regulation, an extension of the EU Strategic Action Plan on Batteries [76].” It would be good if the authors expanded on this to give some high light.

Figure 4 there is an E in the X-axis is says “2023E “ what does the mean. This figure needs axis labels

What is the cost/Ton to produce Li, in terms of electricity and fuel.  There is an energy intensity involved in mining and production of a material this should be included for each of the methods.  Should look at the energy cost to make the material VS traditional technology.

  Figure 5 need axis labels

Figure 6 needs axis labels

Figure 8 needs axis labels

The authors wrote: “It could be viewed as a business as usual scenario that will certainly not suffice for reaching 502 climate goals [93].” Is there any government or country adhering to these policies or agreed to goals, many are walking away form these “ideas” as they are not obtainable and too costly.

Figure 9 needs axis labels

Author Response

The authors wrote: “Adjusted using [30].” This has no context to the reader.   I have corrected this issue                                                                                                                               

The authors wrote:  “The high EOL recycling rate for lead-acid batteries was achieved through government incentives, which might also be necessary to achieve the same success for LIB recycling.” This is not quite correct lead is highly toxic and relatively simple to extracted from lead acid batteries unlike Li+. Yes I agree, I have changed the phrasing of this sentence

Figure 2 needs axis labels Axis labels added

The authors wrote: “The basis for a regulatory framework in view of LIB recycling is laid in the EU battery regulation, an extension of the EU Strategic Action Plan on Batteries [76].” It would be good if the authors expanded on this to give some high light. I have added more specific informaiton

Figure 4 there is an E in the X-axis is says “2023E “ what does the mean. This figure needs axis labels This was a typo, it was corrected and labels were added

What is the cost/Ton to produce Li, in terms of electricity and fuel.  There is an energy intensity involved in mining and production of a material this should be included for each of the methods.  Should look at the energy cost to make the material VS traditional technology. This aspect is discussed qualitatively in the discussions of each of the technologies. A quantitatative analysis would require very detailed knowledge which is currently not available for the discussed methods because they are still in research phase. 

  Figure 5 need axis labels The axis data is labelled in the legend, since the two datasets use two different units

Figure 6 needs axis labels The axis data is labelled above the figure

Figure 8 needs axis labels The axis data is labelled above the figure

The authors wrote: “It could be viewed as a business as usual scenario that will certainly not suffice for reaching 502 climate goals [93].” Is there any government or country adhering to these policies or agreed to goals, many are walking away form these “ideas” as they are not obtainable and too costly. The adherence to climate goals is indeed something that is specific for a country and changes over time. For this reason, I have kept climate goals relatively vague as I think it is clear for the reader what I refer to.

Figure 9 needs axis labels The axis data is labelled in the legend, since the two datasets use two different units

Reviewer 2 Report

Comments and Suggestions for Authors

1. The subtitle number on page 21 should be 3.3. There is not any page number in this manuscript.

 

2. Please check through the whole text if the use of technical terms be precise, for example, in line 6 of the 4^th paragraph on page 1: “high electrochemical potential” is incorrect, Li has a very negative reduction potential of -3.04 V. and “its low weight” should be its low atomic weight.

 

3. The full description for USGS in the 2^nd paragraph on page 2 should be provided. The full descriptions for ktpa in section 2.2 and for the short forms in section 2.1.3 should be provided.

 

4. The Introduction does not cover the development history and current status of lithium extraction technology from unconventional brines, which is the theme of this manuscript and must be what Introduction should present.

 

5. In section 2.1.3, the term of Li recycling rate must be explained though it seems straightforward. Figure 1 should be placed under section 2.12 instead of section 2.13. What do the scales of vertical axis of Figure 2 represent? This Figure is not quoted anywhere in the text.

 

 

6. Each curve of Figure 3 must be labelled by the chemical reaction having such delt G^o_T – T relation instead of just a compound. This section (2.1.3) is short of the specific information about the current technology status of recycling spent LiB.

 

7. The manuscript should provide the common major cations in geothermal brines at the begining. In the last paragraph on page 4, what is the reason for picking Mg ion which is often in lower concentration among the cations as benchmark?

 

 

8. The contents before section 3 serve only background information but not directly link with the theme as laid out by the tittle.

 

9. Section 3.1: Geothermal brines and geothermal energy belong to different concepts; their logical relationship should be explained at the beginning of this section.

 

10. Taking for example the subsection that elaborats lithium-ion sieves, it narrates only a series of reported facts in this technical domain but does not touch the fundamental structural characteristics as well as the recoverability/operation life of the sieves in question. This would not help the future readers with comprehending the structure-adsorption selectivity and potentials for improvement. This drawback also exists in the remarks for other technologies.

 

 

11. What is the mechanism allowing ALDH layered adsorbent to strip lithium ion from the brines?

 

12. Does section 3.2.2 suggest a DLE route following the steps from brines to Li cathode and then to Li anode? Please arrange a clear rhetorical way to present this.

 

13. In section 3.2.3 (membrane process), the term ‘fouling-prone membrane’ does not fit the context of this section, the authors should check why this technical term is adopted.

 

14. The three technologies under Membrane Processes (section 3.2.3) basically use Mg²⁺/Li⁺ ratio as a criterion to pick required prior publications. As aforementioned, this cannot substitute the technical features, for example, the design principle, the structural characteristics of membrane, and the separation performances that support the membrane structures.

 

15. The figure on page 23 is labelled by a wrong number. Also, the brine should contain potassium ions, but it is omitted in the feed stock of this figure. It is a significant challenge to separate K+ from Li+ in chemistry.

 

In conclusion, this review provides an overview of the need and current status of the main techniques used to harvest lithium salts from geothermal brines. While it is comprehensive and easy to understand, it lacks technical depth and logical rigor; therefore, it is better suited for readers seeking a basic understanding of the key components of this industrial endeavor.

 

Author Response

Thank you for your review,

Please refer to the word file for my reply.

Kind regards,
Emiel

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The article under review analyzes the current state of lithium consumption and extraction. The review examines both traditional and new extraction methods. This is due to the significantly increased consumption of lithium and the emerging challenges of its extraction.

The article has a number of questions and comments:

- the abstract and conclusions do not mention the results of this review;

- the review does not discuss the Aluminate precipitation method or the Aluminum layered double hydroxide chloride precipitation method;

- a significant portion of the article under review can be found in articles by battery manufacturers or consulting/economic companies. This raises questions about the relevance of the review submitted for consideration;

- a large number of modern articles can be found on the development of lithium-free batteries that use sodium-based electrodes, etc. This fact should be added to the review as one of the points regarding reducing lithium consumption;

- after Figure 9 comes Figure 11, so Figure 10 is omitted;

- Figure 1 appears again on page 23;

- the bibliography contains double numbering;

Author Response

Dear reviewer,

Thank you for your critical revision. Please refer to the word document for my replies. 

Kind regards,
Emiel

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

In my opinion, the article has not become better.

Author Response

Hi, 

I have made some major changes to the manuscript. I have done the best I can to take into account your comments. Apologies if it is not up to your standards, it is the best I can do.

Thanks again four your critical review, as it has certainly improved my understanding of the subject.

Kind regards,
Emiel

Author Response File: Author Response.pdf