Innovative Utilization of Aluminum-Based Secondary Materials for Production of Metallurgical Silicon and Alumina-Rich Slag

Philipson, Harald; Solbakk, Gjermund L.; Wallin, Maria; Einarsrud, Kristian Etienne; Tranell, Gabriella

doi:10.1007/978-3-030-92529-1_135

Cited by 4 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At 1600 and 1650 • C, the Si content tends to decrease, and Al and Ca tend to increase over time. Overall, only Si tends to get closer to the calculated thermodynamic equilibrium with time, while Ca and Al tend to converge towards a lower and higher value, respectively, the latter consistent with published research that reached close to, or reached, thermodynamic equilibrium [8,9,19,20].…”

Section: Al Alloy Compositionsupporting

confidence: 88%

“…A significant increase in the reduction of SiO2 and CaO occurs from 1550 °C to 1600 °C. The results at 1600 °C and 1650 °C correspond to results in published work [8,9,19,20], indicating that local equilibrium or partial equilibrium is established instantly at these temperatures. The only obvious overall trend with time was seen for 1550 °C, where Al2O3 tends to increase and SiO2 and CaO decrease.…”

Section: Al Alloy Compositionsupporting

confidence: 86%

“…By assuming that the measured Al alloy compositions in Figure 7 were in contact with pure CaAl 4 O 7 , it was possible to calculate the equilibrium shown in Table 3 The concentrations in the product bulk slag in contact with the Si alloy droplets are shown in Table 4. A significant increase in the reduction of SiO 2 and CaO occurs from 1550 • C to 1600 • C. The results at 1600 • C and 1650 • C correspond to results in published work [8,9,19,20], indicating that local equilibrium or partial equilibrium is established instantly at these temperatures. The only obvious overall trend with time was seen for 1550 • C, where Al 2 O 3 tends to increase and SiO 2 and CaO decrease.…”

Section: Al Alloy Compositionsupporting

confidence: 86%

“…Previous investigations involving the same components have revealed that the reaction is rapid and approaches thermodynamic equilibrium under inductive stirring conditions in laboratory-scale experiments and under a combination of inductive stirring and gas purging in pilot-scale experiments. Studies examining the impact of varying Al-SiO 2 stoichiometry and slag composition have resulted in fluctuations in both raw material yield and process stability, yet the mechanisms remain poorly understood [7,19,20]. In successful operations, the less dense Si alloy typically floats on top of the slag, albeit with varying degrees of metallic droplet entrainment in the slag phase.…”

Section: Introductionmentioning

confidence: 99%

“…Although the viscosity of the slag can undergo significant changes during conversion, it generally remains lower for the metal phase compared to the slag phase. Furthermore, under the recently demonstrated raw material conditions [7,9,19,20], the slag-to-metal mass ratio ranges from 3 to 4, indicating that, intuitively, components in the slag must transfer across longer distances than their counterparts in the metal phase within an industrial furnace.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Investigation of Liquid–Liquid Reaction Phenomena of Aluminum in Calcium Silicate Slag

Philipson,

Wallin,

Einarsrud

2024

Materials

View full text Add to dashboard Cite

To achieve better process control of silicon (Si) alloy production using aluminum as a reductant of calcium silicate (CaO-SiO2) slag, it is necessary to understand the reaction phenomena concerning the behavior of formed phases at the metal-slag interface during conversion. The interfacial interaction behavior of non-agitated melt was investigated using the sessile drop method for varying time and temperature, followed by EPMA phase analysis at the vicinity of the metal–slag interface. The most remarkable features of the reaction were the accumulation of solid calcium aluminate product layers at the Al alloy–slag interface and spontaneous emulsion of Si-alloy droplets in the slag phase. The reduction is strictly limited at 1550 °C due to the slow transfer of calcium aluminates away from the metal-slag interface into the partially liquid bulk slag. Reduction was significantly improved at 1600–1650 °C despite an interfacial layer being present, where the conversion rate is most intense in the first minutes of the liquid–liquid contact. A high mass transfer rate across the interface was shown related to the apparent interfacial tension depression of the wetting droplet along with a significant perturbed interface and emulsion due to Kelvin–Helmholtz instability driven by built-up interfacial charge at the interface. The increased reaction rate observed from 1550 °C to 1600–1650 °C for the non-agitated melt was attributed to the advantageous physical properties of the slag phase, which can be further regulated by the stoichiometry of metal–slag interactions and the composition of the slag.

show abstract

Section: Al Alloy Compositionsupporting

confidence: 88%

Section: Al Alloy Compositionsupporting

confidence: 86%

Section: Al Alloy Compositionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Investigation of Liquid–Liquid Reaction Phenomena of Aluminum in Calcium Silicate Slag

Philipson,

Wallin,

Einarsrud

2024

Materials

View full text Add to dashboard Cite

show abstract

Pilot-Scale Aluminothermic Production of Silicon Alloy and Alumina-Rich Slag

Zhu,

Philipson,

Blandhol

et al. 2024

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

As global demand for silicon (Si) and alumina continues to surge, the significance of developing more sustainable production methods has intensified. The SisAl process represents a path-breaking approach to producing Si and alumina by utilizing side streams from the silicon and aluminum industries. In the present work, a comprehensive series of pilot-scale trials was conducted to assess the scalability and validity of the SisAl process. The influences of reductant raw materials, charging methods, input material ratios, and other processing parameters were also investigated. On coupling between thermodynamic calculations and experimental results, it was demonstrated that the SisAl process is stable and controllable at a pilot scale. The typical composition of the produced Si alloy ranges from 70 to 75 wt % Si, 15–18 wt % Ca, and 8–10 wt % Al. The produced CaO-Al 2 O 3 -based slag has a composition of 48–57 wt % Al 2 O 3 , 40–45 wt % CaO, and 3–13 wt % SiO 2 . Furthermore, various reductants, including Al blocks, dross, and scraps, were evaluated in the pilot trials, yielding comparable outcomes, with alloy composition differences only within approximately 3 wt % under the same parameter conditions, demonstrating the versatility of raw materials selection in the SisAl process. Moreover, it was found that acidic slag exhibited better features for future upscaling than the neutral slags, with a 5 wt % higher Si content in the alloy and a 4 wt % increase in Al 2 O 3 content in the slag phase. Additionally, the chemical composition of the products was shown to be controllable by adjusting the stoichiometry of the input materials (Al/SiO 2 ratio). As the charged stoichiometry increases from 1 to 1.2, the Si content in the alloy significantly decreases from 73 to 63 wt %, while the Al content correspondingly increases from 9 to 18 wt %. Further investigation into processing parameters, such as charging method, slag prefusion, and stirring methods, has also revealed valuable insights toward the continued upscaling of the SisAl process to a potentially innovative, sustainable, low-carbon industrial process.

show abstract

Preliminary Techno-Economic Considerations of the Sisal Process - Closing Materials Loops through Industrial Symbiosis

Philipson,

Blandhol,

Engvoll

et al. 2022

SSRN Journal

View full text Add to dashboard Cite

Innovative Utilization of Aluminum-Based Secondary Materials for Production of Metallurgical Silicon and Alumina-Rich Slag

Cited by 4 publications

References 12 publications

Investigation of Liquid–Liquid Reaction Phenomena of Aluminum in Calcium Silicate Slag

Investigation of Liquid–Liquid Reaction Phenomena of Aluminum in Calcium Silicate Slag

Pilot-Scale Aluminothermic Production of Silicon Alloy and Alumina-Rich Slag

Preliminary Techno-Economic Considerations of the Sisal Process - Closing Materials Loops through Industrial Symbiosis

Contact Info

Product

Resources

About