Verification of Possibility of Molten Steels Decopperization with ZnAl₂O₄

Round 1

Reviewer 1 Report

1.The sentence on the lines 139-140 needs to be changed.

2.The data points shown in Figure 5c should be reported in the form of mean value plus an error bar. 

3.The statement of the complete conversation of Al₂O₃ and ZnO to ZnAl₂O₄   reaction product is given on the lines 83, 84. The corresponding XRD pattern must be added to the manuscript to prove this.

4.The information on the diffusion of the Fe-Cu alloys into the ZnAl₂O₄ substrate with enhanced porosity is presented by lines 216, 217. However, this parameter is not disccused in detail in the manuscript.

5.The "Conclusions" section should be added to the manuscript.

Author Response

Dear reviewers.

First of all, thank you for the fruitful comments.

Reviewer 1

1. The sentence on lines 139-140 was changed.
2. The presented value was area analysed with the aid of EDX, therefore, only one value was revealed from the analysis.
3. XRD analysis revealed 96.6 wt% ZnAl₂O₄ and 3.4 wt% ZnO. XRD pattern was added in the manuscript.
4. The enhanced porosity of ZnAl₂O₄ substrates was caused by the reduction of the ZnO phase in the substrates, it was already mentioned in the text in line 161.
5. The conclusion was changed.

Reviewer 2 Report

Dear Authors,

The topic of this paper (decopperization of molten steels with ZnAl₂O₄) is worth of investigation. The content of the study is clearly and succinctly presented. However, the content is not rich enough. The number of references is more or less acceptable. The results are beneficial for the steel industry. As a decision, I would like to recommend the paper for publication in the present form. The followings are a few suggestions to improve the overall quality of the paper.

• Please add Fe-Cu alloys to the keywords.
• The introduction part must be rewritten. The introduction should be a highly systemized review of the work that has been done. Also, drawback or the superiority of the proposed method in comparison to the existing methods and the relevant literature need to be highlighted.
• The authors should clarify the novelty of this paper and identify what the main difference is between present study and studies published.
• Please provide XRD results for section 2.1.
• Please mention the temperature in line 112.
• Line 166: The first letter should be capital.
• Why was the Cu loss at a minimum level in 1% Cu ZnAl₂O₄ (in comparison to 1% Cu Al₂O₃)?

Author Response

Point 1-6 has been replied to in the modified manuscript.

Point 7:
In the present investigation, we found that the Cu loss was mainly contributed by the copper evaporation, only a small percent of copper was diffused into the ZnAl₂O₄ substrates along with liquid Fe-Cu alloy. Oxygen as a surfactant accumulates on the molten Fe-Cu surface and blocks the free sites for copper evaporation. Therefore, when the oxygen content in the molten Fe-Cu alloys is high, the copper evaporation can be restraint. After interacting molten Fe-Cu 1% Cu with the ZnAl₂O₄ case, molten Fe-Cu absorbed oxygen from the side of ZnAl₂O₄, which could strongly prevent the copper evaporation.

Author Response File: Author Response.pdf