Towards the Circularity of the EU Steel Industry: Modern Technologies for the Recycling of the Dusts and Recovery of Resources

Round 1

Reviewer 1 Report

In text subscipts must be used - for example CO_2, not CO2.

I suggest to explain the abbrevation ISM.

In abstract is stated 2.1 emission of CO2 per ton of crude steel (integrated route) and on the Page 2, row 46, there is value 1.85.

In paper is in page 2, row 53 stated, that Fe and Zn are precious elements.

Precious metals are defined: Au, Ag, Pt, Pd, Ir, Os, Ru, Rh. Fe and Zn are basic metals. The same mistake is on page 4 as well as on the page 10.

Figure 1: SMD is not Secondary Metallurgy Slag.

Page 2, row 67 - what 5-30 kg ??? dust?

Page 3: row 82 FeO and not Feo

Page 4, row 116 - Zn is used for galvanizing - it is true, but not to produce stainless steel.

Page 8, row 288, a lot of brackets.

Page 11, row 380, there is no C-source in Fig. 8

Page 11, row 398 - it is not expensive to supply of FeO to the slag?

Author Response

All remarks are implemented. Thank you for your indication

Reviewer 2 Report

1.The paper has reviewed the option for recycling of the dusts and recovery of resources. The introduction of pyrometallurgy is quite comprehensive.Why is it all pyrometallurgical treatment, no hydrometallurgical treatment introduction? As

2. Provide phase (XRD, SEM-EDS) of dusts and recovery of resources

3. About Figure 2, is there a comparison of cost, energy consumption and environmental parameters ?

4. Figure 8 with too low resolution, improve it

Author Response

1. In row 136, two references about the hydrometallurgical routes (Ezinex [20], Zincex [21]), were added.
2. "We refer to [11] for an extensive overview about the morphological structure of the phases present in such streams", added in row 61
3. Table 2 is added (row 492)
4. Figure 8 has been replaced

Thank you for your remarks

Reviewer 3 Report

It is a quite good review paper to the cecycling of steelmaking dust in EU. I think some improvements will make this paper more meaningfull to readers.

(1) I suggest the authors to add a Table summarizing the products, CO₂ emission per ton of iron, electricity and total energy consumption and so on, for readers easily compare those processes mentioned in your paper.

(2) Is there any process can separate Zn as a metal rather than ZnO?

(3) For the RecoDust process mentioned in section 3.2, where did Fe go (see Fig. 9, please)?

Author Response

1. Table 2 at row 492 was added
2. (3) (PDF) Overview of Zinc Production in Imperial Smelting Process (researchgate.net)   In Imperial Smelting process, there is the production of metallic lead, the simultaneous production of lead metal is an advantage of the process, because the assay of most of the recycling materials shows beside zinc also lead. The ISP does not produce a lead containing residues like other zinc-making processes do.
3. Figure 9 was updated

Thank you for your remarks

Reviewer 4 Report

Dear authors your manuscript is very interesting. I will offer some comments to improve it:

- You should consider processes 'Romelt' and 'Primus'

- It would be better if you add to comparison table for all processes

- The name of manuscript The title of the manuscript should be changed. For example 'Modern techniques for zinc and iron recovery from metallurgical wastes: a brief review' or similar. 

Several comments in attached pdf also 

Comments for author File: Comments.pdf

Author Response

• paragraph 2.5 (row 358) was added with a description of PRIMUS and ROMELT  processes
• Table 2 (row 492) was added
• the title was modified, but we prefer focus the paper on circularity of this approach.

In pdf the answer of your remarks, all inplemented in the new paper version

Thank you for your indication  

Author Response File: Author Response.pdf