Study on Process Mineralogy of the Combined Copper Oxide Ore in Tibet and Acid Leaching Behavior with Calcium Fluoride

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Article is interesting paper with interesting practical conclusions. Some suggestions regarding possible improvement:

1. In  Introduction the use of calcium fluoride as a leaching aid to enhance the sulfuric acid leaching of combined copper oxide ore is not sufficiently justified, no references cited.

2.  In part "2. Experiment" methods mineral liberation analysis (MLA) and scaning electron microscope (SEM) not adequately described. 

3. Almost all graphs presented in Figures 5, 8 are linear, what is the reason for choosing the studied ranges  of sulfuric acid concentration, grinding fineness and leaching time?

4. Considering distribution of copper in leaching slag (fig. 9 d), is it possible that low copper recovery is related to the preg-robbing process on limonite?

5. To confirm the identified sulfuric acid-calcium fluoride enhanced leaching mechanism it would be desirable bring оccurrence state of Cu in leaching slag like Table 3.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

- Line 74 the author refers to "hot leaching water", I think it should be hot leaching solution, since the leaching agent is not water, it is sulfuric acid.

-Figure 1, some peaks are not defined in XRD.

- Line 107, tap water was used for all the studies? Was the water characterized? were there metals and other ions present in water. Need to check.

-In experimental method please add the brands and purity of the chemicals used.

- In experimental methos please specify what analytical technique was used to determine the quantities of copper and iron present in the samples before and after leaching. 

- Line 120,, formula 1. Please define metal grade.

- Figure 5 and subsequent figures. Instead of revolving speed please use mixing speed or rotation speed.

- Why S:L ratio was not considered as an optimization parameter of leaching?

- Section 4.2 why fluorides are considered as leaching aids? 

- Please explain with more detail why calcium fluoride is preferred over ammonium fluoride regardless of the leaching improvement. 

- Line 269 please re-write that statement. You can’t make vague statements such as when the amount of sulfuric acid reaches a certain amount.

-Figure 9, show a side-by-side comparison of the electron scanning images of the mineral after conventional leaching and under your method. It will convey results better.

- Line 328 based on what you can conclude that copper and fluorine form copper tetrafluoride, please give a scientific explanation to prove that claim.

- Figure 10, add a color legend with F, H, Cu and sulfate, to enhance readability.

Comments on the Quality of English Language

Please use more scientifically sound and appropiate words in the paper. 

Example: Line 215 the increase is not large, should be changed for the increase is not significant.

Line 207 leaching efficiency is not much affected, change for is not affected greatly/ significantly.

-Please check redundancy in words.

Please consider an overall english revision.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Article is interesting paper with interesting practical conclusions.

Author Response

Comments: Article is interesting paper with interesting practical conclusions.

Response：Thank you very much for the reviewers' affirmation and encouragement to us, and we will redouble our efforts in the future.