CMMMech
CMMMech > Secondary resource > Copper smelter slag

Copper smelter slag secondary resource

Heterogeneous slag generated by copper smelting, distinct from copper ore, flotation tailings, a pure mineral or a recovered copper product. The curated experiment used two historical Polish copper-production slags: crystalline fayalite/glass-rich material (CS) and predominantly glassy material (AS), with different residual copper-bearing phases. These characterized feeds do not define all copper smelter slags. No constituent's criticality designation is inherited.

Microbial & Biochemical Mechanisms (1)

Sulfur-oxidizer-associated metal mobilization from historical slags

bioleaching Microbial

Associated Organisms: Acidithiobacillus thiooxidans (NCBITaxon:930)

Living A. thiooxidans DSM 9463 cultures were associated with acidification and greater copper, zinc and iron mobilization from two historical slags than uninoculated growth medium at the same nominal loading. Sulfur oxidation and acid-mediated dissolution are supported interpretations; the experiment does not isolate direct cellular attack from the changed solution chemistry or quantify dissolution of each mineral phase.

Experimental Context & Analytical Limits:
Laboratory flasks contained the 0.25-0.5 mm slag fraction, mineral-salt medium with 1% w/v elemental sulfur and 2% v/v inoculum pregrown for two weeks. Initial medium pH was 3.5, with free drift during 21 days; agitation was 150 rpm. This record emphasizes the unambiguous 1% pulp-density arm. The paper does not clearly specify incubation temperature, working volume or inoculum cell density. Methods state at least duplicate extractions, without arm-specific replicate counts. Leachates were filtered through 0.45-micrometre PTFE, acidified and analyzed for elements with an Agilent 7700x. Reported extraction fractions refer to the starting slag inventory, not purified-metal recovery, and do not establish industrial deployment.
Curated Evidence Points:
Sections 2.1-2.3, Table 1 and Figure 1 establish two actual copper slags, their distinct phases and the purchased DSM 9463 inoculum. Figure 6 and Section 3.4 support culture-associated mobilization. For AS at 1% loading and 21 days, Section 3.4.2 reports 98.7% Cu and 73.0% Zn extraction. These are source-reported feed-relative values, not a universal slag yield or independent replication.
Table 2 gives final pH 0.90 versus 3.98 for CS and 0.62 versus 4.83 for AS, comparing inoculated and sterile-medium arms at 1% loading. There is no matched-acidity time course isolating a direct cell effect. The post-assay sulfur-settling activity test was positive for biotic leachates and negative for controls; this qualitative proxy does not establish cell counts or exclude every contaminant.
Quantitative discrepancies remain unresolved: CS Cu extraction is 52.1% in the abstract and Section 3.5 but 52.7% with 1981 mg/kg in Section 3.4.1; Section 3.4.3 instead gives 2257 mg/kg for that endpoint. The highest bioleaching loading is 5% in Methods and prose but 3% in Table 2 and Figure 6. The reported 31-fold AS enhancement also conflicts with the Figure 6 control trajectory. None is silently reconciled or used as a precise comparative effect size.
Figures 7-8 show stronger surface alteration after biotic treatment and gypsum-associated AS residue, but selected images and elemental ratios do not quantify complete phase dissolution, a pure gypsum product or residue safety. Chemical acids also mobilized substantial metal in separate 24-48 h assays (Figures 2-5); unlike durations and acidity prevent a blanket microbial-superiority claim. Table 3 is theoretical metal-value accounting, not measured profit, lifecycle performance or an operating recovery plant.

Sources & References

  1. potysz2019: Potysz and Kierczak (2019). Prospective (Bio)leaching of Historical Copper Slags as an Alternative to Their Disposal. Minerals 9(9):542. DOI 10.3390/min9090542; publisher v2 PDF, 24 pages; Sections 2.1-2.3, 3.1-3.6, Tables 1-4 and Figures 1-9.
    https://doi.org/10.3390/min9090542 (accessed 2026-10-11)
  2. dsm9463: DSMZ culture catalogue. Acidithiobacillus thiooxidans DSM 9463, strain designation B-S2, isolated from a bioleaching reactor in Australia; authority identity does not independently authenticate the study stock.
    https://www.dsmz.de/collection/catalogue/details/culture/DSM-9463 (accessed 2026-10-11)
  3. ncbi930: NCBI Taxonomy. Acidithiobacillus thiooxidans, species Taxonomy ID 930.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=930 (accessed 2026-10-11)

Curation History

Timestamp Curator Action Summary
2026-10-11T14:20:21.993288+00:00 Codex (GPT-6; Codex) CREATE Created a distinct copper-smelter-slag resource with source-scoped sulfur-oxidizer-associated metal mobilization, control limitations and unreconciled source discrepancies.

Record source: data/records/copper-smelter-slag.yaml