Comparisons of Acid and Water Solubilities of Rice Straw Ash Together with Its Major Ash-Forming Elements at Different Ashing Temperatures: An Experimental Study
Round 1
Reviewer 1 Report
The reviewed paper entitled ”Comparisons of Acid and Water Solubilities of Rice 2 Straw Ash together with Major Elements at Different 3 Ashing Temperatures: An Experimental Study” concerns biomass ashes recycling and nutrients recovery. It is a continuation of previous research in this area conducted by the authors.
The manuscript was prepared very carefully. The introduction is a background for research presented afterwards. The research methodology was described in detail and comprehensively. The results of the research were clearly presented and well interpreted. The discussion of the results was supported by the latest literature reports on the subject. The content of the work has been illustrated very well. The conclusions are clear and precise and corelate to carried out research. They also have a utilitarian meaning in the context of sustainable agriculture development.
There is WSA and ASA in the caption of Figure 5 and there should be WSA and ASA
In Figure 6 there is ASP and should be ASAP
Author Response
Thank you so much for your time and efforts! We profoundly appreciate your comments toward the improvement of the paper and we hope what we have addressed the majority of your comments. Responses to your comments along with a description of the changes made on the manuscript are given below.
Point 1: The reviewed paper entitled ”Comparisons of Acid and Water Solubilities of Rice Straw Ash together with Major Elements at Different Ashing Temperatures: An Experimental Study” concerns biomass hes recycling and nutrients recovery. It is a continuation of previous research in this area conducted by the authors.
Response 1: Thank you very much for your comments on our manuscript.
Point 2: The manuscript was prepared very carefully. The introduction is a background for research presented afterwards. The research methodology was described in detail and comprehensively. The results of the research were clearly presented and well interpreted. The discussion of the results was supported by the latest literature reports on the subject. The content of the work has been illustrated very well. The conclusions are clear and precise and corelate to carried out research. They also have a utilitarian meaning in the context of sustainable agriculture development.
Response 2: Thank you very much for your comment! At the same time, we would like to thank you very much for your affirmation of our research content and introduction writing.
Point 3: There is WSA and ASA in the caption of Figure 5 and there should be WSA and ASA, In Figure 6 there is ASP and should be ASAP.
Response 3: Thank you very much for your carefulness and comment! You are right. We are sorry for the inaccurate expression. Combined with your comment, we have revised the expression from ASP to ASA,P as shown in the Figure below. However, it should be noted that, like Ca and Mg, P in rice straw ash is almost insoluble in water. As a result, the correlation of the P solubility with the ashing temperature were not given. This is why you didn't see WSA,P in Figure 6. (page 11, lines 556-557)
In addition, combined with another reviewer’s comments, the Figures 5, 7, 8, 9, 10 and 11 also were revised. (page 10, lines 502-505; page 11, lines 580-581; page 12, lines 602-603; page 12, lines 612-613; page 13, lines 635-636; page 13, lines 646-647)
Thank you again for your time and efforts!
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article needs a minor revision befoacceptnace; specilly in termss of English language and also need to provide detailed comparison of results with previous studies.
Author Response
Thank you so much for your time and efforts! We profoundly appreciate your comments toward the improvement of the paper and we hope what we have addressed the majority of your comments. Responses to your comments along with a description of the changes made on the manuscript are given below.
Point 1: The article needs a minor revision befoacceptnace; specilly in termss of English language and also need to provide detailed comparison of results with previous studies.
Response 1: Thank you very much for your comment! The English writing has been improved by an English speaking language editor this time.
In addition, combined with your comment, comparisons of the acid and water solubilities of rice straw ash together with major ash-forming elements at different ashing temperatures were further carried out. At the same time, some discussions with the published literatures were added this time. The details are as follows:
(1) In 3.2 section, the comparisons and discussions of the acid and water solubilities of rice straw ashes were further carried out. (page 8, lines 356-358 and 361-365; page 9, lines 386-388 and 391-393)
(2) In 3.3.1 section, the comparisons and discussions of the acid and water solubilities of macronutrients K, P were further carried out. (page 9, lines 422-424; page 10, lines 509-513 and 524-529; page 11, lines 558-560)
(3) In 3.3.2 section, the comparisons of the acid and water solubilities of medium nutrients Ca, Mg were further carried out. (page 11, lines 567-569 and 572-574)
(4) In 3.3.3 section, the discussions of this work were further added as follows:
From the comparison results of two solubilities of different nutrient elements mentioned above, it is not difficult to find that the acid solubilities of the major ash forming elements are always higher than the water solubilities of those. When the ashing temperature is less than 600 °C, their solubilities are basically higher than 50%. Especially, most of P, Ca and Mg are acid-soluble but water-insoluble. This conclusion is also confirmed by some previous work [1, 2]. Hence, to better realize the closed cycle of nutrients in rice straw, the following two principles should be followed: (1) the ashing temperature should not be higher than 600 °C, (2) the rice straw ash should be applied to acidic soil. (page 13, lines 648-654)
(5) In 4 section, combined with another reviewer’s comments, we added another result from this work as follows:
When the ashing temperature of rice straw is lower than 600 °C, the rice straw ash will have a higher accessible (soluble or bioavailable) nutrient content. Otherwise, most of nutrients contained in the ash will be sintered or released with the flue gas. (page 14, lines 673-675)
Thank you again for your time and efforts!
1. Andrea Jordan, C.; Akay, G., Speciation and distribution of alkali, alkali earth metals and major ash forming elements during gasification of fuel cane bagasse. Fuel 2012, 91, (1), 253-263.
2. Werkelin, J.; Skrifvars, B.-J.; Zevenhoven, M.; Holmbom, B.; Hupa, M., Chemical forms of ash-forming elements in woody biomass fuels. Fuel 2010, 89, (2), 481-493.
Author Response File: Author Response.docx
Reviewer 3 Report
English writing will need to be improved on in the paper. For example, Line 138 should read presented work and not present work. This includes others not indicated.
Page 9; Equations in R2, R3 and R4 should be checked for proper balancing of Oxygen on both sides of the equations
Page 11; Figures 7 & 8 will need to signify the water solubility as indicated in the graphs
In general, the materials and methods section should be re-written to reflects the introduction and aims of the paper.
Author Response
Thank you so much for your time and efforts! We profoundly appreciate your comments toward the improvement of the paper and we hope what we have addressed the majority of your comments. Responses to your comments along with a description of the changes made on the manuscript are given below.
Point 1: English writing will need to be improved on in the paper. For example, Line 138 should read presented work and not present work. This includes others not indicated.
Response 1: Thank you very much for your carefulness and comment! Combined with your comment, these inappropriate expressions have been revised in the manuscript this time. In addition, the English writing has been improved by an English speaking language editor this time.
Point 2: Page 9; Equations in R2, R3 and R4 should be checked for proper balancing of Oxygen on both sides of the equations
Response 2: Thank you very much for your carefulness and comment! We are sorry for the inaccurate expression. Combined with your comment, we have checked for proper balancing of Oxygen on both sides of the equations in R2, R3 and R4. (page 9, lines 397-398 and 403-404; page 10, lines 514-515)
Point 3: Page 11; Figures 7 & 8 will need to signify the water solubility as indicated in the graphs
Response 3: Thank you for your comment and reminding! Sorry for that. Combined with your comment, we have revised the Figures 7 and 8. However, it should be noted that, like P, Ca and Mg in rice straw ash are almost insoluble in water. As a result, the correlations of Ca and Mg solubilities with the ashing temperature were not given in Figures 7 and 8. This is why you didn't see WSA,Ca and WSA,Mg in Figures 7 and 8. (page 11, lines 580-581; page 12, lines 602-603)
In addition, combined with another reviewer’s comments, the Figures 5, 6, 9, 10 and 11 also were revised. (page 10, lines 502-505; page 11, lines 556-557; page 12, lines 612-613; page 13, lines 635-636; page 13, lines 646-647)
Point 4: In general, the materials and methods section should be re-written to reflects the introduction and aims of the paper.
Response 4: Thank you for your reminding and comment! We are sorry that the table of contents of the materials and methods section in the manuscript was inaccurately expressed, bringing the confusion to reading. Therefore, combined with your comment, the materials and methods section in the manuscript have been revised this time. The table of contents of the materials and methods section have been revised from the table of contents 1 to the table of contents 2 as shown in Table 1 below (see word file or the revised manuscript).
As an important follow-up work of our previous study, this manuscript presents a systematic experimental investigation on the acid solubilities of both rice straw ash and its major elements produced from combustion at 400-800 °C, and compared with the corresponding water solubilities obtained from authors’ previous work. It should be noted that in the authors’ previous work [1], the dissolution process of the straw ash in water, the methods of calculation of the water solubility of both rice straw ash and its elements have been given in detail. Hence, in order to avoid the identical content, they were not given again in the materials and methods section in the presented work. In this regard, we have also made relevant explanations in the submitted manuscript this time, as detailed in the manuscript. (page 6, lines 270-273)
We hope what we have addressed your comment on the materials and methods section.
Thank you again for your time and efforts!
1. Zhang, Y.; He, F.; Gao, Z.; You, Y.; Sun, P., Effects of ash-forming temperature on recycling property of bottom ashes from rice residues. Fuel 2015, 162, 251-257.
Author Response File: Author Response.docx
