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Copper-smelter flue dust secondary resource

Dry-collected particulate residue from copper smelting and converting, represented here by a blend of dust from reverberatory and converter furnaces at the Sarcheshmeh Copper Complex, Iran. One week's samples were mixed in the production ratio of three parts reverberatory dust to two parts converter dust. This processing-derived feed is distinct from furnace slag, natural copper minerals, copper anode slime and its downstream autoclave residue, and the wet copper-shale blast-furnace gas-scrubbing residue curated as Theisen sludge. The study reported 35.8 wt% total copper in the original blend and about 70% of particles finer than 80 micrometers; these are sample-specific assays, not a universal dust specification or recoverable reserve. Acid-preleached dust is an experimental preparation of this owner, not another material record. No criticality-list designation is inherited from copper or other constituents.

Microbial & Biochemical Mechanisms (1)

Mixed-acidophile leaching of acid-pretreated copper-smelter dust

bioleaching Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920), Acidithiobacillus thiooxidans (NCBITaxon:930), Leptospirillum ferrooxidans (NCBITaxon:180)

An adapted, source-identified iron- and sulfur-oxidizing mesophilic consortium was associated with greater copper extraction than source-designated sterile shake flasks. The same culture was used in a two-stage aerated continuous stirred-tank experiment on acid-preleached dust. These observations support a laboratory bioleaching treatment, with chemical acid dissolution and microbial contributions not separately quantified in the continuous system. Proposed preferential oxidation of chalcocite and bornite, and chalcopyrite passivation, are interpretations rather than independently isolated mineral-specific mechanisms or individual-species effects.

Experimental Context & Analytical Limits:
The feed first underwent sulfuric-acid preleaching in rolling bottles at pH 1.5 and 10% wt/vol pulp. Section 2.1 reports dissolution of 65% and 80% of the acid-soluble copper fraction after 60 and 120 minutes, respectively; these are not percentages of total feed copper. The subsequent residue contained source-reported copper sulfides and remaining acid-soluble copper. Neither preleach residue mass yield nor a closed combined chemical-and-biological copper balance is given. The mixed culture was isolated from Sarcheshmeh acid mine drainage, identified by reference to an earlier study, and adapted over two months to increasing dust loading, up to 7% wt/vol, and copper up to 20 g/L. No isolate accession, deposit or sequence verification is supplied in this article. Species identifiers resolve reported names only. Adaptation used 200 mL in 500 mL flasks, 9K medium, pH 1.8, 32 degrees C and 150 rpm; those adaptation details do not establish every condition of the separately tabulated control tests. The reactor experiment used two 3 L vessels, each with 2.1 L working volume, about 200 rpm stirring and air at 1 L per L per minute. Startup used 2% wt/vol preleached dust, 9K medium and 10% vol/vol adapted inoculum at pH 1.8 and 32 degrees C. Reactor 2 started on day 8; continuous feeding began around day 63. Feed loading, residence time and temperature were changed sequentially during one 180-day campaign. They were not independently replicated factorial treatments. The system required sulfuric acid and was net acid consuming; from day 114 acid was added to the feed tank. No industrial microbial operation or isolated copper product was demonstrated despite the source's use of the term pilot plant.
Curated Evidence Points:
Section 2.3 and Table 3 report biological versus sterile-flask copper extractions of 87% versus 39% at 2% wt/vol pulp after 16 days, 88% versus 45% at 4% after 23 days, and 81% versus 47% at 7% after 30 days. These within-condition comparisons support culture-associated enhancement, while the differing durations prevent a simple loading-only comparison. Sterilization procedure, verification of control sterility, replication and uncertainty for these tests are not specified. The source states explicitly that only biological treatments were then run in the reactors, so these flask controls are not matched continuous abiotic comparators.
Table 4 and section 3.2 report final-stage copper extractions of 89.7% for 2% wt/vol feed at 32 degrees C and 2.7 days overall residence time, 90.3% for 4% feed at 32 degrees C and 4 days, and 86.8% for 7% feed at 34 degrees C and 6 days. Residence time is for the two-stage system, not each vessel. These are source-reported extraction values for the preleached experimental feed, not independently reconstructed total-raw-dust recovery or a purified product yield. Table 4 labels its values maxima; Figure 5 shows higher earlier extraction points in the startup interval, so tabulated maxima and plotted time-course values are not treated as interchangeable. Figure 5 uses solid-residue analyses, and aqueous Cu/Fe were measured by atomic absorption; no full uncertainty or copper mass-balance calculation is supplied.
Figures 2–4 and section 3.2 preserve important operational limits. At 7% feed, low redox potential and washout prompted longer residence times, a temporary return to batch operation and a 1000 mL pulp exchange between reactors. This intervention is part of the eventual 6-day result. The system lacked condensers for its first 78 days; even afterward the authors estimated about 10% volume loss per reactor and added no continuous-run makeup water. Thus rising dissolved concentrations are not direct measures of extraction efficiency. Reactor solids eventually reached 9% wt/vol despite 7% feed. The early unadapted culture also showed no observed growth at 5% dust, according to section 3.1. Redox potential was used as an activity proxy rather than a species- resolved measure of growth. Tables 1–2 report bulk assays and mineral-associated copper proportions without a reconciled phase-to-element balance; no mineral-specific recovery fraction is inferred from those proportions.

Sources & References

  1. bakhtiari2008: Bakhtiari F, Atashi H, Zivdar M and Seyed Bagheri SA (2008). Continuous copper recovery from a smelter's dust in stirred tank reactors. International Journal of Mineral Processing 86(1–4):50–57. DOI 10.1016/j.minpro.2007.10.003; original available-online date 26 November 2007. Complete eight-page public author-copy text, Tables 1–4 and original publisher Figures 1–5; especially sections 2.1–2.3 and 3.1–3.2. Local PDF acquisition failed; the research dossier distinguishes web-read text from inspected original figures.
    https://doi.org/10.1016/j.minpro.2007.10.003 (accessed 2026-10-12)
  2. ncbi_ferrooxidans: NCBI Taxonomy 920, Acidithiobacillus ferrooxidans, species; does not authenticate the experimental isolate.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=920&mode=Info (accessed 2026-10-12)
  3. ncbi_thiooxidans: NCBI Taxonomy 930, Acidithiobacillus thiooxidans, species; does not authenticate the experimental isolate.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=930&mode=Info (accessed 2026-10-12)
  4. ncbi_leptospirillum: NCBI Taxonomy 180, Leptospirillum ferrooxidans, species; does not authenticate the experimental isolate.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=180&mode=Info (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T14:50:48Z codex (GPT-6; codex) CREATE Created the dry smelter-dust secondary-resource owner from primary full-text and original-figure evidence, retaining pretreatment, control, taxon, accounting and laboratory-scale limits.

Record source: data/records/copper-smelter-flue-dust.yaml