Physical Chemistry of Metallurgical Processes

Shamsuddin, M.

doi:10.1002/9781119078326

Cited by 32 publications

(20 citation statements)

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“…In the roasting process of sulfidic tailings, two general mechanisms of roasting have been identified: i) oxidative roasting, which converts metal sulfide to metal oxide, thereby also forming SOx (SO2 or SO3) gas, and ii) sulfation roasting, which converts metal sulfide and O2 gas to metal sulfate. In reality, however, the roasting process of a heterogeneous material, such as tailing, is complex and advanced characterization techniques are required to identify the phase transitions that a specific material undergoes during roasting (Shamsuddin, 2016).…”

Section: Introductionmentioning

confidence: 99%

Sulfidic mine tailings and marl waste rock as compatible resources in a microwave-assisted roasting process

Everaert

Lemmens

Atia

et al. 2020

Journal of Cleaner Production

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Copper (Cu) is a popular commodity metal, and novel technologies are being developed to extract Cu from low-grade sources, such as sulfidic tailings. Roasting of tailings allows efficient Cu extraction and reduces environmental risks associated with tailing storage. However, conventional roasting is energyintensive and releases harmful sulfur oxide gas (SOx). This study combines two mining wastes, sulfidic tailing and carbonate-rich waste rock (marl), in an energy-efficient microwave-assisted roasting step to simultaneously oxidize sulfide minerals and fixate formed SOx gas as sulfates. The roasting procedure was first optimized via conventional roasting (varying temperature, mixing ratio) by characterizing roasted materials (XRD/Rietveld, SEM-EDX, XRF, TGA-MS). Later, these optimized conditions were tested with microwave-assisted roasting. Subsequently, the influence of roasting treatments on Cu extraction was examined via ammoniacal leaching. Results showed that sulfate formation (SOx fixation) was highest for roasting at 500 °C via conventional roasting and increases with increasing marl content. Microwave-assisted roasting at 500 °C performs slightly below conventional roasting, as FeS2 was not fully oxidized. Marl addition negatively affects Cu extraction, likely because it limits the formation of water-soluble CuSO4. This study demonstrates the potential of mixing marl with tailings to control SOx emissions during roasting, but also shows limitations in terms of Cu extraction.

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Section: Introductionmentioning

confidence: 99%

Sulfidic mine tailings and marl waste rock as compatible resources in a microwave-assisted roasting process

Everaert

Lemmens

Atia

et al. 2020

Journal of Cleaner Production

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“…Moreover, the temperature influences the solubility of elements in iron. [44] Further investigations should verify if the observed decreased inclusion area is an effect of the slightly different process parameters or the addition of titania in the filter coating.…”

Section: Discussionmentioning

confidence: 99%

“…Due to the high temperatures (1580 °C), titania has the potential to influence grain growth of alumina during sintering . In addition, it might be partially reduced by dissolved carbon or aluminum of the melt under these condition, and it might influence the interactions, as discussed below. Furthermore, it has to be noted that up to now, no data are available to what extent the observed layer build‐up on the filter surface originates from the alumina filter, e.g., by dissolution and precipitation reactions with the melt, or from deposited inclusions …”

Section: Discussionmentioning

confidence: 99%

Interactions between Carbon‐Bonded Alumina Filters and Molten Steel: Impact of a Titania‐Doped Filter Coating

et al. 2019

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Herein, the influence of adding titania to the carbonaceous alumina coating of Al2O3–C filters on the interactions with molten steel is investigated. Therefore, coated filters are immersed for 30 s in molten steel (42CrMo4) at 1580 °C. Mainly by microstructural and chemical analyses, the immersed filters as well as the solidified steel are characterized. Due to the reducing atmosphere of the heat treatment during sample manufacturing, the formation of aluminum titanate phases in the coating is not observed. During immersion, on the one hand, titania acts as the sintering agent for alumina within the coating and for precipitated alumina inclusions from the melt. On the other hand, dissolved titanium in the melt decreases the surface tension and thus increases wetting of the steel melt on the filter surface. The results indicate that more but smaller alumina inclusions remain in the solidified steel if titania is added to the coating. Thus, the modification of alumina inclusions by adding titania to the filter coating presents a way to tailor these inclusions depending on the product's application.

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“…It is well known that the driving force of phase transformation is the free energy change, DG, before and after phase transformation. Additionally, DG can be expressed as a function of the supercooling degree, DT, which has a directly proportional relationship with cooling rate, following the formula DG = DHÁDT/T [31], where DH is the latent heat of phase transformation which is a positive value for c 0 phase transformation. It indicates that there is a directly proportional relationship between DG and DT.…”

Section: Evolution Of the Carbides And Grain Boundariesmentioning

confidence: 99%

Influences of Cooling Rate After Solution Treatment on Microstructural Evolution and Mechanical Properties of Superalloy Rene 80

Gao

Hou

Dong

et al. 2016

Acta Metall. Sin. (Engl. Lett.)

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Influences of the cooling rate after solution treatment on microstructural evolution and mechanical properties of Rene 80 nickel-based superalloy were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and mechanical test. Results showed that the high cooling rate decreased the size of secondary c 0 particles in the supersaturated matrix, but led to a high coarsening rate of c 0 particles during subsequent aging treatment. Despite various coarsening rates, the size and morphology of c 0 particles in the final microstructures of all samples were close due to the long enough holding time to an equilibrium state. During the aging of 870°C/2 h, primary MC started to decompose with the carbide reaction: MC ? c ? M 6 C or M 23 C 6 ? c 0 . And a number of observations showed that the coarsening of c 0 particles on grain boundaries resulted in the depletion of c 0 during aging treatment. The test results indicated that high cooling rate resulted in the presence of quench crack, and the air cooling method following solution treatment was an optimum heat treatment method for Rene 80.

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Physical Chemistry of Metallurgical Processes

Cited by 32 publications

References 0 publications

Sulfidic mine tailings and marl waste rock as compatible resources in a microwave-assisted roasting process

Sulfidic mine tailings and marl waste rock as compatible resources in a microwave-assisted roasting process

Interactions between Carbon‐Bonded Alumina Filters and Molten Steel: Impact of a Titania‐Doped Filter Coating

Influences of Cooling Rate After Solution Treatment on Microstructural Evolution and Mechanical Properties of Superalloy Rene 80

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