Impact of Substituting Coke with Biomass on the Mineralogical Composition of the Iron Ore Agglomerate

Round 1

Reviewer 1 Report

The manuscript studied the effect of substituting coke breeze with biomass on the phases of resultant sinters. While reviewing the manuscript, the follow issues have particularly distracted the reviewer:

• Clearly with increasing the substitution of coke breeze, the sinter became weaker. So if the standard sinter from coke breeze achieved the quality required by the blast furnace, the other sinters with biomass substitution would not meet the quality requirements and could not be charged into the blast furnace. Therefore, in the real sintering operation, one wont produce the sinter under the conditions used by the authors. Consequently, the knowledge obtained from the manuscript is useless.
• The effect of thermal conditions on sinter mineral phases is well known. There is nothing new throughout the manuscript.
• In the conclusion, the authors claimed that it is possible to substitute about 50% coke with lignin in the agglomeration. Only based on sinter phases, it is not sufficient to make such a conclusion. The process performance and sinter quality are much more important in decision making.
• The manuscript reads very repetitive. Lots of lengthy description is not needed. For example the description from Line 153 to 182 is not needed. Line 185 to 196 may be relocated to the experimental section to describe the characteristics of fuels used in the experiments. General description of sinter phases in Line 217-260 is not needed in the results and discussion.
• FeO is often used as an indication of flame temperature of a sintering bed. A higher sinter FeO content indicates a higher flame temperature. It is not clear why A3 achieved a lower flame temperature but higher FeO content.
• Figure 2 shows localised optical images of sinters A0-A3. It is very difficult to generalise things from one localised image. For example, based on the thermal conditions achieved for A0-A3, the amount of melt decreased from A0 to A3, consequently the amount of unreacted relicts increased. However Figure 2a shows a relict particle, however no relit particles are observed in the Figures 2b-2d.

 

Apart from the key concerns above, below are the other issues identified during the reviewing process:

• Terminlogy issues. Agglomeration/agglomerate referring to a number of processes involving size enlargement. The process in the manuscript refers specially to the sintering/sinter. It would be more appropriate to be more specific. Similarly “bonding phase” instead of “bond phase”, “sinter mixtures” instead of “agglocharges”
• In Lines 43 and 45, 64, are you referring to “quality parameters” instead of “qualitative parameters”?
• In Line 60, are you referring to gangue minerals instead of tailings.
• Lines 90 and 132, there are strange characteristics.
• Line 59, is the mineralogy composition same as the phase composition?
• Lines 96 and 101, do you mean “experimental sintering” by saying model sintering.
• In Table 1, it is inappropriate to list 65.57%Fe2O3 in the magnetite concentrate.
• In Table 3, please list the base on which the data was reported.
• In Line 121, do you mean “fixed carbon” by saying “bound carbon”. If so, given the huge difference in fixed carbon between coke breeze and biomass and small difference in calorific values, it is unlikely the share of bound carbon remained roughly constant in all cases, as the author claimed.
• The scale bars in Figure 2 are not clear and key phases, particularly those mentioned in the text, need be labelled in the images.

Author Response

Dear reviewer,

all comments are in attached file. 

Author Response File: Author Response.pdf

Reviewer 2 Report

I recommend to change the title, making it preciso what types of agglomerate you are dealing with. For exemple:

Impact of substituting coke with biomass on the phase composition of iron ore sinter agglomerate

Other remarks:

 

line 40 such as sintering and agglomeration processes

sintering is an agglomeration process. What are you meaning with this redundandy?

lines 46 and 47: Hence such conditions need to be maintained that will enable the production of 47 sufficient amount of melt 

Bad english. Not clear.

 

line 55: – is replaced with biomass

by biomass, not with (seems better...)

 

line 90: ???

 

line 101: what is Model sintering? Why not just sintering or experimental sintering?

 

Table 1 - XRF spectrometry? Indicate clearly in the text and table.

 

Line 112: ore/concentrate ratio

Need to be explained what is this ration

 

line 128: is a by-product produced by distillation of wood

better: is a by-product of the distillation of wood

 

line 132: ???

 

line 173: amount of used agglomeration fuel

suggest to remove used

 

line 178: which then affect the mechanical properties of the agglomerate

suggestion: which then affect its mechanical properties

 

line 186: fixed carbon in a combustible

why not just fixed carbon. ?

 

line 198: XRF analysis

better: XRF spectrometry

 

Table 5: I think you mean "basicity index"

 

Table 6: it is not clear which are the experiments A0 to A3. This has to be explained in the text

The chemical composition of standard agglomerate (A0 - 0 % of lignin) and agglomerate with 262 alternative fuel (A1 - 20 %, A2 - 50 %, A3 - 86 % of lignin) – biomass – is documented in Table 6. (if this is the case)

 

line 332: legend of the figure out of the page where the figure is. Correct.

 

lines 333 to 339 - voids?

 

Table 7 - Identified phase composition

I propose Estimated phase composition

 

line 452 - A new phase of wüstite (FeO)

A new phase - wüstite (FeO) - 

 

line 503 - The presented paper

This paper

 

 

Author Response

Dear reviewer,

all comments are in attached file.

Author Response File: Author Response.pdf