Review Reports - Optimal Alkalinity Model of Ladle Furnace Slag for Bearing Steel Production Based on Ion–Molecule Coexistence Theory

Round 1

Reviewer 1 Report

In order to stably and effectively control the T[O] during the ladle furnace (LF) refining process, the authors established a calculation model of optimal alkalinity for the refining slag CaO–SiO2–Al2O3– 13 MgO–FeO–CaF2 at 1853 K based on the ion-molecule coexistence theory 14 (IMCT). The influence factors are discussed and presented in the manuscript as well. The work was well organized. It can be accepted with minor revision:

Please give some detailed information on the production process as illustrated in Figure 1. It may be difficult for readers to understand the meanings of the drafts in Figure 1. Notions can be added in Figure 1.

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript entitled “Optimal Alkalinity Model of Ladle Furnace Slag for Bearing Steel Production Based on Ion-Molecule Coexistence Theory” (ID: Processes-2246347). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are highlighted in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

Point 1: Please give some detailed information on the production process as illustrated in Figure 1. It may be difficult for readers to understand the meanings of the drafts in Figure 1. Notions can be added in Figure 1.

Response 1: Many thanks for your nice suggestion. According to your nice suggestion, the notions have been added in Figure 1 and the steelmaking process has been described detailedly in subsection 2.1 in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper attempts to establish a calculation model of optimal alkalinity based on the ion–molecule coexistence theory (IMCT) in ladle furnace refining process, and shows some results. Nevertheless, a few of revisions have to be finished before the paper is suitable for publishing in the journal.

1. Model validations: prior to such establishment of the model, a necessary step is to check the validity of this model. It is a pity that in this paper there is not any reported results with respect to such validations.

2. Activity coefficient and activity are very important for the slag in steel refining ladle. Authors can elaborate the relationship between alkalinity and activity. It depends on the thermodynamics of the reaction, so the activity coefficient and activity data of the chemical components in the slag are required.

3. In the results and discussions, it should be deeply described with the quantitative form. For instance, the mathematic expressions and formula can be deduced based on the qualitative results.

Author Response

Dear Reviewer:

Point 1: Model validations: prior to such establishment of the model, a necessary step is to check the validity of this model. It is a pity that in this paper there is not any reported results with respect to such validations?

Response 1: Thanks to the comments of reviewers, the validity of the model has been demonstrated in the reported studies, which is listed in Table 1 in the revised manuscript. Meanwhile, in the discussion part, the relevant results were also discussed and analyzed based on the industrial data, which explained the validity of the model. The laboratory tests will be executed to further verifiy the model calculation and this is our next work. Thanks again.

Point 2: Activity coefficient and activity are very important for the slag in steel refining ladle. Authors can elaborate the relationship between alkalinity and activity. It depends on the thermodynamics of the reaction, so the activity coefficient and activity data of the chemical components in the slag are required.

 Response 2: Many thanks for your nice suggestion. According to your nice suggestion, we have tried our best to find the relevant data. We found that there are many theoretical models for the calculation of activity in molten slag, such as ideal ionic solution model, regular ionic solution model, Masson model, quasichemical equilibrium solution model, Lin and Pelton model, etc (Huang, X.H. Metallurgy Principle of Iron and Steel; Metallurgical Industry Press: Beijing, China, 2013.). Due to the complexity of structural units at high temperature, the relevant thermodynamic data and the theoretical basis of different models all have their own limitations. However, the theoretical model of based on ion-molecule coexistence theory used in this paper can get the ideal calculation results without using the activity coefficient and the activity can be calculated directly from the Gibbs free energy of each equilibrium equation, which has been verified by many reported studies. The relevant contents have been modified in the revised manuscript. Thank you.

Point 3: In the results and discussions, it should be deeply described with the quantitative form. For instance, the mathematic expressions and formula can be deduced based on the qualitative results.

Response 3: Thank you for your suggestion. It is a very meaningful research work to deduce the mathematic expressions and formula for quantitative analysis. The formulas for calculating activity based on IMCT have been derived in the section 2.2. However, it is not well enough to establish the quantitative relationship for the optimum alkalinity. We will try to do this study and verify its validity by experiment in our future work. Thanks again.

Author Response File: Author Response.docx

Reviewer 3 Report

The paper presents a calculation model of optimal alkalinity for the refining slag CaO–SiO2–Al2O3–MgO–FeO–CaF2 at 1853 K based on the ion–molecule coexistence theory, which can give a certain guiding role in the process of refining slag composition optimization for bearing steel production. The paper is overall plain and readable, it can be considered for publication after minor corrections.
(1) It is suggested to make text remarks on the flowchart in Figure 1.
(2) The forms of some chemical formulas should be revised according to publishing standard.
(3) Some sentences in the abstract and conclusion need to be revised for better undertanding.

(4) The grammar errors should be avoided.

Author Response

Dear Reviewer:

Point 1: It is suggested to make text remarks on the flowchart in Figure 1.

Response 1: According to your nice suggestion, the notions have been added in Figure 1 in the revised manuscript.

Point 2: The forms of some chemical formulas should be revised according to publishing standard.

Response 2:Thank you for your valuable suggestion. The chemical formulas have been checked and modified according to publishing standard in the revised manuscript.

Point 3: Some sentences in the abstract and conclusion need to be revised for better undertanding.

Response 3: According to your nice suggestion, some sentences in the abstract and conclusion have been rewritten in the revised manuscript.

Point 4: The grammar errors should be avoided.

Response 4:Many thanks for your nice suggestion. According to your suggestion, we have invited a professional English writing service-MDPI to revise my manuscript (https://www.mdpi.com/authors/english). And, related modified items for spelling, sentence structure, verbtense, text flow, grammar errors and clause construction have been given in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 4 Report

The manuscript reports the optimal alkalinity model of ladle furnace slag for bearing steel production using the ion-molecule coexistence theory (IMCT). The paper reviewed contains interesting results. In my opinion, this article is worth to be published in Processes after minor revision. I have some suggestions that authors may consider:

As the X-axis variable in Figure 4 is not consistent with the other Figures, I suggest that the abscissa in Figure 4 should be expressed in alkalinity and the contents in section 3.3 should be modified according to the revised figure.

Author Response

Dear Reviewer:

Point 1: As the X-axis variable in Figure 4 is not consistent with the other Figures. I suggest that the abscissa in Figure 4 should be expressed in alkalinity and the contents in section 3.3 should be modified according to the revised figure.

Response 1: Thank you for your valuable suggestion. According to your suggestion, the Figure 4 has been redrawn and the content in section 3.3 has been modified in the revised manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

TThe authors have completed the revison as suggested by the referees.