Recycling of Blast Furnace Slag and Fluorite Tailings into Diopside-Based Glass-Ceramics with Various Nucleating Agents’ Addition
Round 1
Reviewer 1 Report
I think this article has a very good, modern and ecological topic in this area. In the paper very important the technology of recycling area was presented. In the article the information of diopside-based glass-ceramics are produced by recycling blast furnace slag and fluorite tailing with adding additional elements of TiO2, Fe2O3 and Cr2O3 as nucleation agents using a conventional melting method was presented.
The article a lot of experiments and summary of each experiments was included. The article good topic and very good information was characterized. For me the article a lot of appropriate literature’s positions was included. The literature must be improved in form for example in position 2 and 3 the bold in year must be deleted. The conclusion are short but very appropriate to the content of article. In my opinion in paragraph 2 must be competed of more detailed information of plant in China.
Author Response
Response to reviewer 1
I think this article has a very good, modern and ecological topic in this area. In the paper very important the technology of recycling area was presented. In the article the information of diopside-based glass-ceramics are produced by recycling blast furnace slag and fluorite tailing with adding additional elements of TiO2, Fe2O3 and Cr2O3 as nucleation agents using a conventional melting method was presented.
The article a lot of experiments and summary of each experiments was included. The article good topic and very good information was characterized. For me the article a lot of appropriate literature’s positions was included. The literature must be improved in form for example in position 2 and 3 the bold in year must be deleted. The conclusion are short but very appropriate to the content of article. In my opinion in paragraph 2 must be competed of more detailed information of plant in China.
Response: Thanks for your kind reminding and suggestions.
The literatures form of the references 1, 2, 3 and 4 have been corrected in the revised manuscript.
More detailed information of plant in China has been added in the revised manuscript.
The CaO–MgO–Al2O3–SiO2 glass-ceramics are a new type of building decoration materials, which can be prepared using silicate-bearing metallurgical slags as raw materials for both economic and environmental benefits. It was found that a large number of metallurgical slags, including blast furnace slag, steel slag, stainless-steel slag, electric furnace ferronickel slag, copper slag, ferromanganese slag and lead fuming slag, have the potential to serve as the main raw materials for producing CMAS glass-ceramics because of their chemical composition similarities to the products. However, the minor or residual elements, such as chromium, in the slags may directly affect the properties of the glass-ceramics mainly because of their impacts on the nucleation and crystallization in parent glasses which are in need of control. Though, the preparation of glass-ceramics from solid wastes performs promising future, the chemical composition fluctuation and large amounts impurity elements seriously limits the solid wastes usage percentage in the glass-ceramics production plant in China currently.
Reviewer 2 Report
Recycling of Blast Furnace Slag and Fluorite Tailings into Di- 2opside-Based Glass-Ceramics with Various Nucleating Agents Addition is very interesting paper. Some improvement is required
Line 108: nucleating agents powder (what are characteristics of these added powders: size, morphology,...)
Line 177: Figure 4. DSC curves of the parent glass samples A1-A5 (please to add a heating rate and protective atmosphere)
Line 215: Figure 7. DSC curves of the parent glass with different TiO2 content (please to add a heating rate and protective atmosphere)
Line 244: Fig. 10 shows the DSC curves of the parent glass with different Fe2O3 content (in range between ... and ....)
Line 269: Figure 11. XRD patterns and crystallinity of the glass-ceramics with different Fe2O3 content (F1-..., F3-...., F5...)
Line 302: Figure 13. DSC curves of the parent glass with different Cr2O3 content (A3-..., P1-...; P3-....; P5-...; P7-....)
Line 393: With single Fe2O3 or TiO2 addition (in range between ... and ..), the parent glass could real..
Line 404: 6. Patents (please either to check it or delete it)
General question:
- Why did you not use Thermalgravimetric analysis in order to confirm some findings from DSC-analysis
- What is kinetics of recycling and crystallization process
Author Response
Response to reviewer 2
- Line 108: nucleating agents powder (what are characteristics of these added powders: size, morphology,...)
Response: Thanks for your valuable advice.
In this article, the selected nucleating agents include TiO2, Fe2O3, Cr2O3. Considering the purity of the added nucleating agents, the reagent-grade TiO2 (≥99.0%, average particle size ranging from 0.1~0.3μm), Fe2O3 (≥96.0%, particle size less than 5μm), Cr2O3 (AR) powders were purchased from Aladdin company and used in the preparation of glass-ceramics samples by melting method.
The detailed descriptions have been added in the revised manuscript.
- Line 177: Figure 4. DSC curves of the parent glass samples A1-A5 (please to add a heating rate and protective atmosphere)
Response: Thanks for your careful review.
In the DSC testing, the parent glass samples A1-A5 were heated with a heating rate of 10K/min under N2 protective atmosphere.
The detailed descriptions have been added in the revised manuscript.
- Line 215: Figure 7. DSC curves of the parent glass with different TiO2 content (please to add a heating rate and protective atmosphere)
Response: Thanks for your good suggestion.
In the DSC testing, the parent glass samples with different TiO2 content were heated with a heating rate of 10K/min under N2 protective atmosphere.
The detailed descriptions have been added in the revised manuscript.
- Line 244: Fig. 10 shows the DSC curves of the parent glass with different Fe2O3 content (in range between ... and ....)
Response: Thanks for your good suggestion.
Fig. 10 shows the DSC curves of the parent glass with different Fe2O3 content in range between 1wt% and 5wt%. The temperature condition of the DSC testing has been provided in the revised manuscript.
- Line 269: Figure 11. XRD patterns and crystallinity of the glass-ceramics with different Fe2O3 content (F1-..., F3-...., F5...)
Response: Thanks for your good suggestion.
Fig. 11 shows the XRD patterns and crystallinity of the glass-ceramics with different Fe2O3 content in the temperature range between 200oC and 1200oC. The figure caption has been corrected to “Figure 11. XRD patterns, crystallinity and morphologies of the glass-ceramics with different Fe2O3 content (Fe1- with 1wt% Fe2O3 addition, Fe3- with 3wt% Fe2O3 addition, Fe5- with 5wt% Fe2O3 addition)”
- Line 302: Figure 13. DSC curves of the parent glass with different Cr2O3 content (A3-..., P1-...; P3-....; P5-...; P7-....)
Response: Thanks for your valuable advice.
The label of the DSC curves in Figure 13 have been corrected, and the figure caption has been corrected to “Figure 13. DSC curves of the parent glass with different Cr2O3 content (A3- without Cr2O3 addition, Cr1- with 1wt% Cr2O3 addition, Cr2- with 2wt% Cr2O3 addition, Cr3- with 3wt% Cr2O3 addition, Cr4- with 4wt% Cr2O3 addition)”
Figure 13. DSC curves of the parent glass with different Cr2O3 content (A3- without Cr2O3 addition, Cr1- with 1wt% Cr2O3 addition, Cr2- with 2wt% Cr2O3 addition, Cr3- with 3wt% Cr2O3 addition, Cr4- with 4wt% Cr2O3 addition)
- Line 393: With single Fe2O3 or TiO2 addition (in range between … and ..), the parent glass could real..
Response: Thanks for your valuable advice.
The descriptions have been modified as following in the revised paper.
With single Fe2O3 addition (in range between 1wt% and 5wt%) or TiO2 addition (in range between 1wt% and 5wt%), the parent glass could realize surface crystallization, while the single Cr2O3 addition (in range between 1wt% and 4wt%) could promote the crystallization mode transform to three-dimensional volumetric crystallization.
- Line 404: 6. Patents (please either to check it or delete it)
Response: Thanks for your careful work.
We have checked the Line 404 and deleted the “6. Patents” in the revised manuscript.
General question:
- Why did you not use Thermalgravimetric analysis in order to confirm some findings from DSC-analysis
Response: Thanks for your valuable advice.
The nucleation process of slag glass-ceramics is a typical non-uniform nucleation process. The nucleation process needs to overcome a relatively large potential barrier, so it needs to absorb some energy from the outside, and then appears as an endothermic peak on the differential thermal curve. After nucleation, the melt of atoms or groups of atoms to interface migration and growth at the appropriate location under supercooling and over saturation conditions. In the crystal growing up process, the required energy barrier is far less than that in the nucleation process, accompanying by sharply decreasing of the system energy and showing the sharp exothermic peak on the differential thermal curve.
Due to the energy transition in the glass-ceramics heat treatment process, the DSC analysis could be used in this study to evaluate the glass transition temperature and crystallization temperature of the parent glass in the heat treatment process. Due to the sample mass is consistent in the heat treatment process, the thermal gravimetric (TG) analysis is not adequate in this study.
- What is kinetics of recycling and crystallization process
Response: Thanks for your valuable advice.
The crystallization kinetics of glass-ceramics is always conducted to analyze the activation energy of crystallization and the Avrami parameters n. Then, the crystallization mode could be deduced and based on the obtained Avrami parameters n.
The non-isothermal crystallization kinetics could be described using the Kissinger equation as follows:
（1）
where α is the heating rate (K/s), R is the gas constant (8.314 J·mol-1·K-1), Ec is the activation energy of crystallization (J·mol-1), and ν is the pre-exponential factor.
The activation energy Ec and pre-exponential factor v could be calculated by the slope Ec/R and intercept (ln(Ec/R)-lnv) of the fitted line. The Avrami parameters n is employed as an interpretation of the crystallization mechanism, and it can be calculated from the Augis-Bennett equation as following.
（2）
Round 2
Reviewer 1 Report
The publication has been corrected according to the guidelines and should be publishedReviewer 2 Report
This improved paper shall be accepted in present form
