Investigation of the phase composition of accretions formed into WHB under flash smelting of copper concentrate

Stefanova, V.; Shentov, D.; Mihailova, Irena; Iliev, Peter

doi:10.3103/s106782121201021x

Cited by 4 publications

(5 citation statements)

References 4 publications

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“…However, the two phases were not found by XRD in Figure 6, suggesting that the phases were not present in crystalline form but were amorphous. This result is consistent with Stefanova et al, [40] who investigated phase compositions of the WHBD from FSF smelting and pointed that copper and zinc may form amorphous phases with iron oxides.…”

Section: Enrichment Of Elements In Flue Dustsupporting

confidence: 92%

Characterization of Copper Smelting Flue Dusts from a Bottom-Blowing Bath Smelting Furnace and a Flash Smelting Furnace

Chen

Zhao

Taskinen

et al. 2020

Metall Mater Trans B

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The smelting technology and flue dust treatment have an influence on the physical and chemical characteristics of flue dusts collected in copper smelting. We characterized flue dusts from a Bottom-Blowing Bath Smelting (BBS) process and from a Flash Smelting (FS) process by determining their comprehensive physical, chemical, and mineralogical characteristics. Annual flue dust generation data showed that the rate of the BBS process (2 to 3 pct) was clearly lower than that of FS process (5 to 6 pct). The results revealed that copper smelting flue dusts from the FS exhibited a larger entrainment of solids and a smaller particle size than the BBS. The crystallographic and chemical compositions of the samples indicated that the FS flue dusts have a higher degree of crystallinity than those of the BBS. Fe 3 O 4 , CuSO 4 and PbSO 4 , Fe 3 O 4 , CuFe 5 O 8 were the predominant crystalline phases in the FS and BBS flue dusts, respectively. In the FS and BBS flue dusts, amorphous multicomponent Cu-Zn-FeO x and Cu-Zn-S phases were formed, respectively. Mineralogical examinations and a stepwise chemical extraction confirmed that the majority of arsenic existed in amorphous form and mostly as pentavalent As 5+ arsenate or As 2 O 5 except that in BBS-ESPD.

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Section: Enrichment Of Elements In Flue Dustsupporting

confidence: 92%

Characterization of Copper Smelting Flue Dusts from a Bottom-Blowing Bath Smelting Furnace and a Flash Smelting Furnace

Chen

Zhao

Taskinen

et al. 2020

Metall Mater Trans B

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“…Two crystal structures were determined for synthetic CuFe 2 O 4 , one with cubic symmetry (Fd3m; [5,6]), and a second with tetragonal symmetry (space group I4 1 /amd; [7]. An anthropogenic cuprospinel of composition (Cu 2+ 0.85 Zn 0.09 Fe 2+ 0.06 )(Fe 3+ 1.87 Al 0.1 Si 0.03 )O 4 with cubic symmetry was identified from accretions deposited into a waste heat boiler under the flash smelting of copper concentrate [8]. We note the presence of Zn in the analyzed spinel.…”

Section: Introductionmentioning

confidence: 99%

“…Such data was included as a distinct 'delafossite' field for the optimization of specific applications within existing diagrams for the system Cu-Fe-O [18]. The excess Cu in delafossite, giving the formula Cu 1.07 Fe 0.93 O 2 , was also determined in the study of Stefanova et al [8].…”

Section: Introductionmentioning

confidence: 99%

Copper-Bearing Magnetite and Delafossite in Copper Smelter Slags

Gezzaz,

Ciobanu,

Cook

et al. 2023

Minerals

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The cooling paths and kinetics in the system Cu-Fe-O are investigated by the empirical micro- and nanoscale analysis of slags from the flash furnace smelter at Olympic Dam, South Australia. We aim to constrain the exsolution mechanism of delafossite (Cu1+Fe3+O2) from a spinel solid solution (magnetite, Fe3O4) and understand why cuprospinel (CuFe2O4) is never observed, even though, as a species isostructural with magnetite, it might be expected to form. Flash furnace slags produced in the direct-to-blister copper smelter at Olympic Dam contain four Cu-bearing phases: Cu-bearing magnetite, delafossite, metallic copper, and cuprite. Delafossite coexists with magnetite as rims and lamellar exsolutions, as well as bladed aggregates, associated with cuprite within Si-rich glass. The empirical compositions of magnetite and rim delafossite are (Fe2+6.89Cu2+0.86Co0.13Mg0.15Si0.02)8.05 (Fe3+15.52Al0.41Ti0.01Cr0.01)15.95O32, and (Cu1+0.993Co0.002Mg0.002)0.997(Fe3+0.957Al0.027Ti0.005Si0.004)0.993O2, respectively. The measured Cu content of magnetite represents a combination of a solid solution (~6 mol.% cuprospinel endmember) and exsolved delafossite lamellae. Atomic-resolution high-angle annular dark field scanning transmission electron microscope (HAADF STEM) imaging shows epitaxial relationships between delafossite lamellae and host magnetite. Defects promoting the formation of copper nanoparticles towards the lamellae margins suggest rapid kinetics. Dynamic crystallization under locally induced stress in a supercooled system (glass) is recognized from misorientation lamellae in delafossite formed outside magnetite grains. The observations are concordant with crystallization during the cooling of molten slag from 1300 °C to <1080 °C. Melt separation through an immiscibility gap below the solvus in the system Cu-Fe-O is invoked to form the two distinct delafossite associations: (i) melt-1 from which magnetite + delafossite form; and (ii) melt-2 from which delafossite + cuprite form. Such a path also corroborates the published data explaining the lack of cuprospinel as a discrete phase in the slag. Delafossite rims form on magnetite at a peritectic temperature of ~1150 °C via a reaction between the magnetite and copper incorporated in the oxide/Si-rich melt. The confirmation of such a reaction is supported by the observed misfit orientation (~10°) between the rim delafossite and magnetite. HAADF STEM imaging represents a hitherto underutilized tool for understanding pyrometallurgical processes, and offers a direct visualization of phase relationships at the smallest scale that can complement both experimental approaches and theoretical studies based on thermodynamic modelling.

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“…[7,11] However, many industrial reports describe other approaches to minimize problems with flue dust. These can be distinguished into three mechanisms: (i) adding additional oxygen or air for after-burning and dust sulfation, [13,16,18,19] (ii) adding additional substances to change the flue dust properties (e.g., soda ash [20] ), and (iii) changing the temperature and velocity profile within the WHB. [16,21,22] The last approach is based on the limited temperature range for flue dust to be sticky, meaning that rapid cooling and dust removal in the radiation section can prevent surface fouling in the convection section.…”

Section: Introductionmentioning

confidence: 99%

“…Comparable studies exist for the accretions from the gas uptake and radiation section. [19,27] Not only industrial experience but also Computational Fluid Dynamics (CFD) simulations can provide new insights into the complex flow behavior in the WHB. [4,7] Previous CFD studies focused on dust flow and settling in the radiation section.…”

Section: Introductionmentioning

confidence: 99%

CFD Study on the Physical Behavior of Flue Dust in an Industrial-Scale Copper Waste Heat Boiler

Schmidt

Montenegro

Reuter

et al. 2021

Metall Mater Trans B

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The Flash Smelting Furnace (FSF) is one of the most common reactors for the primary smelting of copper concentrates. Its smooth operation depends on the availability and performance of the downstream Waste Heat Boiler (WHB). The WHB is especially sensitive to problems with its flue dust handling, such as the formation of accretions, which can lead to downtime and equipment failures. Due to the limited accessibility and the harsh conditions of the WHB, experimental studies are challenging. Therefore, CFD simulations can be a promising option to increase knowledge and evaluate a range of options. The present study investigates the physical behavior of flue dust in an industrial-scale WHB via a three-dimensional CFD model. Size-dependent particle sedimentation and the risk areas for flue dust accretions are predicted, finding good agreement with industrial experience and data from the literature. To make the evaluation of accretion risk zones possible, a new sticking function for flue dust is developed. The results are validated against dust samples. Finally, operational recommendations for minimizing flue dust accretions are derived.

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Investigation of the phase composition of accretions formed into WHB under flash smelting of copper concentrate

Cited by 4 publications

References 4 publications

Characterization of Copper Smelting Flue Dusts from a Bottom-Blowing Bath Smelting Furnace and a Flash Smelting Furnace

Characterization of Copper Smelting Flue Dusts from a Bottom-Blowing Bath Smelting Furnace and a Flash Smelting Furnace

Copper-Bearing Magnetite and Delafossite in Copper Smelter Slags

CFD Study on the Physical Behavior of Flue Dust in an Industrial-Scale Copper Waste Heat Boiler

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