Boron removal from metallurgical-grade silicon using lithium containing slag

Ding, Zhao; Ma, Wenhui; Wei, Kuixian; Wu, Jijun; Zhou, Yang; Xie, Ke

doi:10.1016/j.jnoncrysol.2012.06.031

Cited by 91 publications

(24 citation statements)

References 20 publications

(29 reference statements)

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“…Metallurgical synthesis of SoG−Si has recently been reported as a promising approach for photovoltaics, which is a combination of steps including acid leaching, slag treatment, vacuum refining, plasma refining, solvent refining, molten slat refining, electron beam refining, or directional solidification . Metal impurities in SoG−Si can be reduced to the required levels by directional solidification.…”

Section: Introductionmentioning

confidence: 99%

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

et al. 2019

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Metallurgical synthesis of solar grade silicon (SoGÀ Si) is an existing challenge due to the strict chemical composition of silicon for solar cells. Here, we report a green and facile approach to synthesize high-purity silicon (99.98 wt%, 0.12 ppmw B and 0.18 ppmw P) for solar cells by the carbothermic reduction of SiC with SiO 2 in a vacuum graphite resistance furnace. Catalyst of Fe 2 O 3 plays the role of reducing the concentration of CO (g) , lowering the energy consumption and improving the purity and yield of silicon. The present work is one-step to obtain silicon with less B and P, but it is composed of silicon synthesis, oxidation refining, vacuum refining and blowing refining, which discloses an innovative chemical concepts of in-situ synthesis combined with refining. According to the characterizations of the reacted SiC particles performed by XRD, Raman, PL, XPS, SEM and TEM, the morphologies and formation mechanisms of the in-situ silicon from the horizons of atomic scale were revealed for the first time. It was evidenced conclusively that the SiÀ C bonding is broken from the (006) planes of 6H-SiC at 1850°C by the reaction of SiC (s) + 2SiO 2(l) = 3SiO (g) + CO (g) , and then the silicon nucleates on the (101) planes of 6H-SiC and grows along the [111] direction at 1950°C via the vapor-solid reaction of SiO (g) + SiC (s) = 2Si (l) + CO (g) .High-purity SiO 2 (low content of B and P) can be achieved relatively easily, whereas it is difficult for carbon materials. Herein, it is urgent to use a high-purity reducing agent. [23,24] In fact, the actual reduction process of reaction (1) is much more complicated, which includes the formation of intermediate species, such as SiO (g) and SiC. Meanwhile, SiC is a significant reactant for the production of silicon. [25,26] The concentration of B and P in SiC can be controlled under 0.1 ppmw, [27] which meets the required level for solar cells. Herein, high-purity SiC is proposed as the reducing agent.

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Section: Introductionmentioning

confidence: 99%

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

et al. 2019

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“…So the addition of CaF 2 can expand the range of basicity and facilitate the removal of B. In case of using lithium compounds with slag, Wu et al [25], Ding et al [26], and Lai et al [27] [30] added CaCl 2 to CaO-SiO 2 slag, which reduced the melting point and viscosity of slag. B can react with the slag at the slag/Si interface, and then enter into the slag as BO 1.5 .…”

Section: Mg-si Purification By Slag Refining Using Ternary Slag Systemmentioning

confidence: 99%

Application of slag refining technique to metallurgical grade silicon purification process: A review

Al-khazraji¹

2018

Funct.Mater.

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The photovoltaic generates electricity through direct conversion of sunlight, has fastgrowing recently due to high global energy demand. Photovoltaic main material is silicon which needs refining process to fulfill the requirements. In this paper, the principle of silicon-slag refining was introduced and several types of imposing slag were reviewed. Boron removal from silicon using Si-based alloy and novel slag with active component were mentioned, and effects of slag refining processing parameters were discussed. According to the investigations, slag refining technique can remove a large amount of boron from MG-Si, and the potential industrial applications of slag refining technique were proposed.Представлен принцип переработки кремниевого шлака, рассмотрены несколько типов шлака. Было упомянуто об удалении бора из кремния с использованием сплава на основе кремния (Si) и нового шлака с активным компонентом, обсуждается эффект от процесса рафинирования шлака. Согласно исследованиям, процесс рафинирования шлака может удалить большое количество бора из MG-Si (металлургического кремния), а также предложена потенциальная промышленная технология рафинирования шлака. Технологія переробки шлаку для металургійного процесу очищення кремнію: огляд. Rowaid Al-khazraji, Yaqiong Li, Lifeng ZhangПредставлено принцип переробки кремнієвого шлаку, розглянуто кілька типів шлакових систем. Розглядається видалення бору з кремнію з використанням сплаву на основі кремнію (Si) та нового шлаку з активним компонентом, обговорюваються наслідки від параметрів рафінування шлаку. За даними досліджень, технологія рафінування шлаку дозволяє видалити велику кількість бору з MG-Si (металургійного кремнію), запропоновано потенційне застосування у промисловості технологій рафінування шлаку.

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“…However, it is an expensive and pollution-heavy chemical process, although the quality of the manufactured SOG-Si is high. In order to overcome the cost and pollution issues, more efficient and low-cost metallurgical processes are employed to achieve SOG-Si from metallurgical grade silicon (MG-Si), such as vacuum refining [1], slag refining [2,3], directional solidification [4,5], plasma refining [6], electron beam melting [7,8], solvent refining [9], and so on.…”

Section: Introductionmentioning

confidence: 99%

Influence of Growth Velocity on the Separation of Primary Silicon in Solidified Al-Si Hypereutectic Alloy Driven by a Pulsed Electric Current

Zhang

et al. 2017

Metals

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Investigating the separation of the primary silicon phase in Al-Si hypereutectic alloys is of high importance for the production of solar grade silicon. The present paper focuses on the effect of growth velocity on the electric current pulse (ECP)-induced separation of primary silicon in a directionally solidified Al-20.5 wt % Si hypereutectic alloy. Experimental results show that lower growth velocity promotes the enrichment tendency of primary silicon at the bottom region of the sample. The maximum measured area percentage of segregated primary silicon in the sample solidified at the growth velocity of 4 µm/s is as high as 82.6%, whereas the corresponding value is only 59% in the sample solidified at the growth velocity of 24 µm/s. This is attributed to the fact that the stronger forced flow is generated to promote the precipitation of primary silicon accompanied by a higher concentration of electric current in the mushy zone under the application of a slower growth velocity.

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Boron removal from metallurgical-grade silicon using lithium containing slag

Cited by 91 publications

References 20 publications

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Application of slag refining technique to metallurgical grade silicon purification process: A review

Influence of Growth Velocity on the Separation of Primary Silicon in Solidified Al-Si Hypereutectic Alloy Driven by a Pulsed Electric Current

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Boron removal from metallurgical-grade silicon using lithium containing slag

Cited by 91 publications

References 20 publications

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO2

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO2

Application of slag refining technique to metallurgical grade silicon purification process: A review

Influence of Growth Velocity on the Separation of Primary Silicon in Solidified Al-Si Hypereutectic Alloy Driven by a Pulsed Electric Current

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Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂