Silicon Recovery Via the Acid Leaching of a Si-Ca-Al Alloy Produced by the SisAl Process

Zhu, Mengyi; Arntsen, Anne Sofie; Safarian, Jafar

doi:10.2139/ssrn.4123122

Cited by 1 publication

(3 citation statements)

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“…Overall calculations show that the significance ers is a function of the reaction with CaO and/or reduction by Ca. A major phase observed in experiments, the most probable rate-limitin decrease in this phase are Equation (11) and/or Equation (17).…”

Section: Dissolution Mechanismmentioning

confidence: 96%

“…The CaO-SiO 2 slag, under these conditions, reduces to yield typical weight percentages of 48-52% Al 2 O 3 , 40-45% CaO, and 3-13% SiO 2 [7,9]. The silicon alloy can undergo further refinement to produce metallurgicalgrade silicon (MG-Si), while the slag can be subjected to hydrometallurgical treatment to produce either metallurgical-grade alumina (MGA) or high-purity alumina (HPA) [8,[10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Overall calculations show that the significance of the product layers is a function of the reaction with CaO and/or reduction by Ca. As CaAl 4 O 7 was the major phase observed in experiments, the most probable rate-limiting reactions for the decrease in this phase are Equation(11) and/or Equation (17). Hypothetical dissolution paths of CaAl 12 O 19 (s) and CaAl 4 O 7 (s) are drawn in…”

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confidence: 99%

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

Philipson,

Wallin,

Einarsrud

2024

Materials

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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.

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Section: Dissolution Mechanismmentioning

confidence: 96%