Leaching behavior of impurities in metallurgical grade silicon subjected to electromagnetic strengthening

Li, Sheng; Deng, Xiaocong; Zhang, Cong; Wen, Jun; Wu, Jijun; Wei, Kuixian; Ma, Wenhui

doi:10.1016/j.jallcom.2020.154888

Cited by 18 publications

(4 citation statements)

References 27 publications

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“…During the formation of MGSRS, no elemental iron was observed; therefore, it is inferred that iron was introduced in the grinding process. The Si-Fe-Ti phase usually exists in silicon particles [24], and it is symbiotically associated with silicon particles in the process of MG-Si secondary re ning.…”

Section: Microscopic and Compositional Of Silicon/slag Liberationmentioning

confidence: 99%

Effect of Grinding Liberation on Recovery of Silicon from MG-Si Waste Slag by Flotation

Tan,

Han,

Wei

et al. 2024

Silicon

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Metallurgical-grade silicon-re ned waste slag (MGSRS) was produced during the MG-Si re ning production process, which occupies huge amounts of land resources, caused the loss of nearly 110,000 tons of MG-Si every year. Though, it is of great signi cance to recover the elemental silicon in MGSRS.However, because silicon is tightly wrapped by slag and di cult to separate, resulting in the di culty of silicon recovery. In this study, silicon recovery powders were obtained through the process of grinding liberation and otation separation. The effect of grinding time on the liberation of MGSRS and the otation recovery of silicon was studied. The liberation mechanism of MGSRS was further discussed. The results showed that the liberation degree of silicon particles was 79.45% (grinding for 15 min), which was 7.94% higher than that of silicon particles after 5 min grinding time, and 77.15% of the silicon particles were fully liberated. The otation recovery of silicon can increase from 10.5-78.7% with the appropriate collector. Mechanism study shows that during the grinding process, silicon was separated along the (111) surface, and Ca 2 Al 2 SiO 7 had the largest amount of liberation along the (211) plane. More unsaturated sites of aluminum and calcium ions were observed on the silicate surface, which were favorable for adsorption with the reagent and bene cial to the silicon recovery. These results indicated that the silicon and slag of MGSRS can be su ciently separated through grinding and otation, and the purity of recovered silicon is about 70%. The silicon resources in MGSRS were recovered economically and could be used as the raw materials for the preparation of silicon alloy and high purity silicon.

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Section: Microscopic and Compositional Of Silicon/slag Liberationmentioning

confidence: 99%

Effect of Grinding Liberation on Recovery of Silicon from MG-Si Waste Slag by Flotation

Tan,

Han,

Wei

et al. 2024

Silicon

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“…Acid leaching has been widely used in the purification of MG-Si [12,19] and diamond wire saw silicon powder [20][21]. In [22].…”

Section: Thermodynamic Analysis Of Mgsrs Acid Dissolution Separationmentioning

confidence: 99%

Determination of Silicon Content in Metallurgical-Grade Silicon Refined Slag using Two-Step Dissolution Chemical Analysis Method

Tan,

Han,

Wei

et al. 2023

Silicon

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Under the demand of global green and low-carbon development, it is urgent to recycle silicon from metallurgical-grade silicon refined slag (MGSRS).Content of elemental silicon (Si) in MGSRS is the key of silicon recovery, and directly affects the selection and economic value of the silicon recovery technology.In this study, a two-step dissolution chemical analysis method is proposed to separate and determine the silicon and other silicon phases content of MGSRS. First, the silicate in the MGSRS was dissolved by hydrochloric acid to obtain the silicate content, and mixed particles containing silicon and silicon carbide (SiC) were separated. Second, silicon was dissolved by a mixture of nitric and hydrofluoric acid (HF/HNO3), and the SiC particles were separated, then the Si and SiC content were determined respectively. During the two steps, the dissolution effect and repeatability of silicate and silicon with different acid was studied. Finally, The silicon content in MGSRS measured by the two-step chemical method was 21.84±0.53%, under the condition of volume ratio of HNO3:HF is 1:1 and reaction time is 1h. This method breaks the situation that the content of elemental silicon in MGSRS is estimated only by experience. It has a positive impact on the further development of silicon recovery from MGSRS and can reduce environmental pollution.

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“…Numerous studies have discussed the removal of Fe from raw MGS, most of which focus on methods including acid leaching after grinding MGS into powders, directional solidification, external fields, or liquation refining (using alloys to absorb impurities). A few of these methods have proven to be effective for impurity removal [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. However, simple grade control of raw materials, resulting in lower impurity inputs, is still the most common method utilized for refinement in the MGS manufacturing industry.…”

Section: Introductionmentioning

confidence: 99%

Iron Removal from Metallurgical Grade Silicon Melts Using Synthetic Slags and Oxygen Injection

Long

Luo

L³

et al. 2022

Materials

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Novel SiO2-CaO-CaF2-R2O-MgO based synthetic slags (R2O represents alkali metal oxides) with varied binary basicity values were used with oxygen injection to refine silicon melts and remove Fe from metallurgical-grade silicon. Silicon samples and slags at the silicon-slag interfaces were obtained during refinement. The compositions of the silicon samples were analyzed, and the quenched slag samples and mild cooling slags from the final crucible were inspected using scanning electron microscopy and energy dispersive X-ray spectroscopy. After 15 min of refinement, the Fe removal rate ranged from 52.3 to 60.1 wt%. During the refining process, the Fe-concentrated phase formed within the silicon droplets and was then transferred to the silicon-slag interfaces and wetted with slags. The Fe-concentrated phase at the silicon-slag interface can dissolve directly in the slags. It can also be transferred into the slag phase in the form of droplets, which can be affected by the binary basicity of the slags. Ti removal demonstrated a similar mechanism. Fe-bearing crystals were not detected in the quenched slag samples obtained during refinement, while complex Fe-bearing phases were detected in the final slag. This study demonstrates Fe removal from metallurgical-grade Si using slag refining methods and reveals the removal mechanism during the refinement.

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Leaching behavior of impurities in metallurgical grade silicon subjected to electromagnetic strengthening

Cited by 18 publications

References 27 publications

Effect of Grinding Liberation on Recovery of Silicon from MG-Si Waste Slag by Flotation

Effect of Grinding Liberation on Recovery of Silicon from MG-Si Waste Slag by Flotation

Determination of Silicon Content in Metallurgical-Grade Silicon Refined Slag using Two-Step Dissolution Chemical Analysis Method

Iron Removal from Metallurgical Grade Silicon Melts Using Synthetic Slags and Oxygen Injection

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