A Novel Method of Purifying Metallurgical-Grade Silicon Using Mn as an Impurity Trapping Agent

Zhu, Yunyang; Wu, Jijun; Wei, Kuixian; Zhou, Qiang; Ma, Wenhui

doi:10.1007/s11663-021-02351-y

Cited by 4 publications

(2 citation statements)

References 37 publications

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“…MG-Si can reach the standard of solar-grade polysilicon materials only by greatly reducing the contents of Fe, Al, Ca, Ti, P, B, and other impurity elements. The contents of these typical impurities in MG-Si can be greatly reduced by re ning in a furnace, including blowing re ning [4], slagging re ning [5], solvent re ning [6,7], bubble otation [8], electromagnetic puri cation [9], vacuum melting [10], and directional solidi cation [11]. For example, He [12] et al puri ed MG-Si by injecting oxygen into the silicon lifting package and by re ning it at 1600 ℃ for 2 h. Huang [13] P is a di cult impurity to remove from silicon, and most phosphorus removal methods involve directional removal by furnace re ning or electron beam re ning [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Interaction Between Al and P in Si Solution

Han

Qian

et al. 2022

Silicon

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The effect of impurity interactions on impurity removal e ciency in metallurgical grade silicon (MG-Si) was studied and analyzed to provide a new idea for removing impurities from MG-Si. This paper provides theoretical support for the removal of nonmetallic impurity P during the metallurgical puri cation and preparation of crystalline silicon. The interaction between Al and P in liquid silicon were investigated by directional solidi cation. The effects of different pull-down speeds, re ning temperatures, holding times and Al contents on the distributions Al and P were investigated. The experimental results of the directional solidi cation of the Si-P-Al ternary system showed that from the bottom to the top of the sample, the contents of Al and P gradually increased. This phenomenon veri es the accuracy of the activity interaction coe cient between Al and P in the Si-P-Al ternary system calculated by the model. The mutual attraction between Al and P was also con rmed.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on the Interaction Between Al and P in Si Solution

Han

Qian

et al. 2022

Silicon

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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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Experimental study on the interaction between Al and P in Si solution

Han

Qian

et al. 2022

Preprint

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The effect of impurity interactions on impurity removal efficiency in metallurgical grade silicon (MG-Si) was studied and analyzed to provide a new idea for removing impurities from MG-Si. This paper provides theoretical support for the removal of nonmetallic impurity P during the metallurgical purification and preparation of crystalline silicon. The interaction between Al and P in liquid silicon were investigated by directional solidification. The effects of different pull-down speeds, refining temperatures, holding times and Al contents on the distributions Al and P were investigated. The experimental results of the directional solidification of the Si-P-Al ternary system showed that from the bottom to the top of the sample, the contents of Al and P gradually increased. This phenomenon verifies the accuracy of the activity interaction coefficient between Al and P in the Si-P-Al ternary system calculated by the model. The mutual attraction between Al and P was also confirmed.

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A Novel Method of Purifying Metallurgical-Grade Silicon Using Mn as an Impurity Trapping Agent

Cited by 4 publications

References 37 publications

Experimental Study on the Interaction Between Al and P in Si Solution

Experimental Study on the Interaction Between Al and P in Si Solution

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

Experimental study on the interaction between Al and P in Si solution

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