A Review of Top-Submerged Lance (TSL) Processing—Part I: Plant and Reactor Engineering
, Markus A. Reuter 1, Michael Stelter 1, Markus Reinmöller 2, Martin Gräbner 3, Andreas Richter 3 and Alexandros Charitos 1,*Round 1
Reviewer 1 Report
The authors submitted an extensive and in-depth review of the Top Submerged Lance (TSL) Smelting technology. In addition to referencing traditional sources, the authors also provided valuable insights from their own research, investigations, and on-site excursions. This review could serve as a textbook for teaching at universities. Its publication is highly recommended.
There are few recommendations for improving the text:
- The Graphical Abstract does not accurately represent the topics covered in the review. Furthermore, the relationship between TSL technology and a sustainable metallurgy flowsheet is not addressed in the text. It would be adequate to include a schematic overview of TSL.
- The referencing in certain sections of the review appears to be insufficient. While it's apparent that the authors are well familiar in the topics, it is advisable to include references to support new information that is presented in the manuscript for the readers.
- The cohesiveness of the review can be improved, particularly in Parts 5 and 6 which seem slightly disconnected from the previous text. A clearer and more logical structure could be achieved by organizing the review around the developmental stages of TSL technology, including its historical patents, implementation, current usage, and future prospects.
Author Response
We thank the reviewer for the kind words. We also thank the reviewer for the comments provided.
Please see below with regard to our responses to the comments recieved.
1. With regard to the graphical abstract:
Answer: We feel that the graphical abstract depicts substantial aspects of the review topics covered in Part I.
For example, the lance, refractory, feed and freeboard aspects with regard to the TSL reactor are discussed within Part I. Hence, the TSL is depicted within the graphical abstract.
In addition, periphery equipment are discussed in the review such as settling furnaces and hence, these are depicted also within the graphical abstract.
Off-gas stream arrangement aspects unique to the TSL are also analyzed within the review and hence, the off-gas stream is depicted within the graphical abstract.
The ability of the TSL to handle different materials (from fines through the lance to moist granulated feed) is a key engineering aspect of the TSL. Also the fact that it can cope with concentrate or recycling material feed or a combination thereof is a key aspect of the technology, implying its versatility.
We think that above engineering aspects are best depicted together, in their natural sequence, which is the reason behind the graphical abstract chosen.
Nonetheless, the reviewer is right to note that sustainability aspects with regard to TSL processing are not the key focus of Part I, as these are analyzed in our view in depth within Part II. However, the processes which the TSL serves are mentioned in Part I and are linked to the TSL engineering aspects.
Hence, we believe that the graphical abstract depicts the Part I content on the one hand, while on the other hopefully raises interest to Part II, which has no extra graphical abstract itself.
2. With regard to the reviewer comment "- The referencing in certain sections of the review appears to be insufficient. While it's apparent that the authors are well familiar in the topics, it is advisable to include references to support new information that is presented in the manuscript for the readers."
Answer: We have reviewed the article and made changes to improve clarity with regard to the concepts analyzed. Considering that the TSL development has been a process that has taken place within the span of decades we have tried to balance newest and older references alike.
3. With regard to the reviewer comment: "- The cohesiveness of the review can be improved, particularly in Parts 5 and 6 which seem slightly disconnected from the previous text. A clearer and more logical structure could be achieved by organizing the review around the developmental stages of TSL technology, including its historical patents, implementation, current usage, and future prospects.
Answer: We agree with the reviewer that above aspects mentioned are of great importance. Aspects associated to "current usage and future prospects" are essentially the key focus of Part II of these series of papers, where the metallurgy of primary-, secondary-, mainstream and developing processes are discussed. Hence, the current usage and future prospects with regard to primary tin metallurgy, primary and secondary copper recycling (including WEEE recycling and PGM recovery), primary and secondary lead recycling (including lead-acid battery recycling), nickel and zinc metallurgy (including zinc recovery from waste streams) are reviewed there. In Part II we also look at emerging processes such as the treatement of ashes and Spent Pot Lining.
In Part I of these series of papers we have focused within historical and contemporary patents looking at the engineering implementation of reactor and plant components from the TSL itself and periphery equipment. Sections 5 and 6 are in our view important to the review to understand engineering developments with regard to the lance (section 5) and further key technological features (in section 6).
Reviewer 2 Report
1. This is an excellent technology review of TSL smelting. It was a pleasure to read. Thank you for the contribution.
2. Please increase the text size in Figures 1, 7,8, 22, and 34 for improved readability.
3. The sentence in Line 93 is missing a period.
4. The text in Table 2 could probably be condensed to take up less space and put in portrait instead of landscape.
Author Response
We thank the reviewer for the comments.
Please see below for our respective response.
Answer to comment 1: We thank the reviewer for the kind words.
Answer to comment 2: The comment has been accepted and the suggestion has been implemented.
Answer to comment 3: The comment has been accepted and the suggestion has been implemented.
Answer to comment 4: In two cases, Table 2 has been edited for clarity, however we felt that it was not possible to condense the information to that extent that would allow landscape representation.
Reviewer 3 Report
This manuscript was well organised detailing the technical engineering of TSL key components. It contains publishable and very useful information for smelting industries.
Author Response
We thank the reviewer for the kind words.
Reviewer 4 Report
Please see the attached marked up document for minor corrections.
A nice review paper.
Comments for author File: 
Comments.pdf
Only very minor corrections required.
Author Response
We thank the reviewer for the comments.
The comments noted within the supplied .pdf file have been addressed.
