Effects of Temperature, Alkali Source, and Mg/Al Ratio on Phase Purity and Yield of Hydrothermal Synthesized Smectites

[Comment]  English language and style are fine/minor spell check required.

●    Reply: The authors highly appreciate the kind and helpful suggestions of the reviewer. The revised manuscript has been edited for spelling and grammar by a professional English editor.

[Comment]  This manuscript seeks to present a new method for preparing phyllosilicate minerals. Much of the focus is on the use of the "Taguchi method" to optimizethe synthesis. While the method appears to work to find the ideal conditions to obtain some smectite-like phases, the impact of this observation is minimal at best. There are many many reports on how to make these materials, and the final result is not unique compared to those already in the literature.

●    Reply: The authors understand there were many reports about how to synthesis smectite, however, to the best of the authors’ knowledge, few studies had quantitatively discussed phase purity and yield for smectite synthesis. This study used the experimental design method to evaluate the effects of reaction temperature, alkali sources, and Mg/Al ratio on the phase purity and yield of hydrothermal synthesized smectites under the interaction of other eight factors. The results can avoid bias and get more realistic factors influence situation. In addition, the optimized synthetic parameters in this study also significantly improve the phase purity and yield of synthetic smectite.

[Comment]  The worst part is that the crystallinity is actually exceptionally poor compared to those other methods.

●    Reply: Crystallinity is indeed one of the indicators for measuring the effectiveness of synthetic minerals, but yield and phase purity are equally important. For smectite minerals, ion exchange capacity is also an important indicator of mineral application properties. This study focused on improving yield and phase purity. In addition, according to the results of subsequent unpublished studies, the smetite synthesized in this study had a very good ion exchange capacity.

[Comment]  The manuscript reads more like a tutorial on how to optimize synthetic conditions, which does not seem within the scope of the journal readership. At best, this seems suitable for a j chem ed type journal.

●    Reply: Although this study used optimized experimental methods, it aimed to obtain the conditions for the synthesis of smectite minerals, and to understand the effects of different factors on the formation of smectite. Therefore, the result should be highly related to the field of mineralogy.

[Comment]  English language and style are fine/minor spell check required.

●    Reply: The authors highly appreciate the kind and helpful suggestions of the reviewer. The revised manuscript has been edited for spelling and grammar by a professional English editor.

[Comment]  The manuscript gives a detailed description of employing Taguchi method to perform hydrothermal synthesis of trioctahedral smectites. The manuscript can be accepted after minor revision.

●    Reply: The author is very grateful to the reviewer’s affirmation.

[Comment]  1# Abbreviation should be given full name when they first appear, such as TEOS, BGMN, DOF.... So many abbreviations without full names make the manuscript difficult to read.

●    Reply: All the abbreviations in our manuscript have been given their full names to make manuscript easy to read. Please refer to table 2, lines 165 and 207. However, BGMN is a name of software developed chiefly by Dr. Galerie Jörg Bergmann, there might be no suitable full name for it.

[Comment]  2# Figure 5 and 6 are both XRD. However, in Figure 5, it looks like the background of all samples is not deducted but Figure 6 deducted.

●    Reply: The reason is that Figure 5 was intended to show that all products have no impurity phase, the original XRD diffraction pattern was retained and the background was not removed. On the other hand, Figure 6 was intended to compare the positional changes of the 001 diffraction peaks, so the background was removed for ease of comparison.

[Comment]  3# In Figure 7, it is obvious that the first peak is 87.8 ^oC not between 100- 200 ^oC..

●    Reply: It should be less than 100 - 200^oC, the manuscript has been revised to 'TGA showed that the first mass loss occurred at a temperature of about 87.8°C, less than 100 - 200°C, and was induced by water adsorption on the smectite surface during the heating process, resulting in a weight loss of about 8.3%. Please refer to page 13, lines 259.

[Comment]  Smectite minerals are widespread in nature, however, like many natural minerals they contain various impurities in different amounts.

The authors of submitted manuscript investigated the hydrothermal synthesis to produce the smectite. The effects of temperature, alkali and Mg/Al ratio on phase purity were investigated. The experimental measurements were evaluated with Rietveld refinement in quantitative phase analysis of the prepared samples.

This work is interesting.

●    Reply: The author is very grateful to the reviewer for the careful review and affirmation.