Hg/Se/PbSO4 Recovery by Microwave-Intensified HgSe Pyrolysis from Toxic Acid Mud
Round 1
Reviewer 1 Report
Comments to the authors
Manuscript metals-1740809
Title: Hg/Se/PbSO4 recovery by microwave-intensified HgSe pyrolysis from toxic acid mud
General comments:
The present study aimed the recovery of Hg, Se and Pb from nonferrous smelting process by microwave roasting. HgSe is separated by pyrolysis. The manuscript is interesting and is in accordance with the Metals journal.
A few recommendations are addressed to the authors:
- Is the goal the recovery of metals or the waste treatment?
- Is there any other alternative for treatment for comparison?
- Mercury is sill used in artisanal mining for Au recovery, and it must be cited in the Introduction (see https://doi.org/10.1016/j.jwpe.2020.101154)
- Table 1 – how the chemical analysis was carried out? Which equipment was used?
- The use of thermodynamic simulation should be discussed in the light of wastes treatment (for instance, https://doi.org/10.1016/j.jre.2020.02.019; https://doi.org/10.1002/cjce.23845; https://doi.org/10.2320/matertrans.M2016016);
- Is it possible to simulate the microwave treatment in FactSage? If so, how?
- The units must be close to the numbers. For instance, Page 7 line191-193;
- Figure 10 – please, present the mass balance for Hg, Se and Pb to the process proposed
Author Response
Point 1: Is the goal the recovery of metals or the waste treatment?
Response 1: My goal is the recovery of metals.
Point 2: Is there any other alternative for treatment for comparison?
Response 2: This article has selected the current mainstream mercury recovery technologies with better effects for comparison. Some treatment that are not very effective have not been compared.
Point 3: Mercury is sill used in artisanal mining for Au recovery, and it must be cited in the Introduction (see https://doi.org/10.1016/j.jwpe.2020.101154)
Response 3: The article has been cited in the Introduction，as the first reference. (https://doi.org/10.1016/j.jwpe.2020.101154)
Point 4: Table 1 – how the chemical analysis was carried out? Which equipment was used?
Response 4: The composition of the dried MAM was determined by X-ray Fluorescence Spectrometer(XRF), already added in the line 89.
Point 5: The use of thermodynamic simulation should be discussed in the light of wastes treatment (for instance, https://doi.org/10.1016/j.jre.2020.02.019; https://doi.org/10.1002/cjce.23845; https://doi.org/10.2320/matertrans.M2016016);
Response 5: Through thermodynamic calculation, the reaction process of MAM in different temperature range was revealed. The pyrolysis temperature range of MAM is found, which provides a temperature range for thermogravimetric test. Together with thermogravimetric analysis, the starting temperature of MAM pyrolysis and the temperature when gasification decomposition reaches the maximum are proved. The article gave me some inspiration and has been cited in the Thermodynamics analysis, as the 34th reference (https://doi.org/10.1016/j.jre.2020.02.019).
Point 6: Is it possible to simulate the microwave treatment in FactSage? If so, how?
Response 6: Sorry, I haven't touched the application of microwave in FactSage.
Point 7: The units must be close to the numbers. For instance, Page 7 line191-193.
Response 7: The units havebe close to the numbers.
Point 8: Figure 10 – please, present the mass balance for Hg, Se and Pb to the process proposed.
Response 8: Fig. 10 wants to express the concept of recycling process. The experimental products Hg, H2SeO3 and PbSO4 are not weighed, so the mass balance cannot be calculated.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I have some minor comments:
Chapter "Experimental"
Which method was used to determine the chemical composition? Please describe the methodology.
Table 1 The sum of the chemical components is 86.87% and what is the rest 13,13%?
Please describe the methods: XRD and the field emission scanning electron microscope.
Chapter "Thermogravimetric analysis"
Reactions (1), (2), (3), (4) are a repetition of the reactions from table 2
Author Response
Point 1: Which method was used to determine the chemical composition? Please describe the methodology.
Response 1: The composition of the dried MAM was determined by X-ray Fluorescence Spectrometer(XRF), already added in the line 89.
Point 2: Table 1 The sum of the chemical components is 86.87% and what is the rest 13,13%?
Response 2: The remaining element basically oxygen. XRF cannot measure the specific content of oxygen, so the oxygen content is not marked in Table 1.
Point 3: Please describe the methods: XRD and the field emission scanning electron microscope.
Response 3: I have described the methods of XRD and the field emission scanning electron microscope in line 138-141.
Point 4: Chapter "Thermogravimetric analysis". Reactions (1), (2), (3), (4) are a repetition of the reactions from table 2.
Response 4: In order to make the thermodynamic calculation in Figure 4 more intuitive, I put the reaction formula on the thermodynamic calculation diagram.
Author Response File: Author Response.pdf
