Ca-Si Alloy Addition Followed by Acid Leaching as a Route to Solar-Grade Silicon

2014 ◽  
Vol 881-883 ◽  
pp. 1562-1567
Author(s):  
Peng Zou ◽  
Kui Xian Wei ◽  
Wen Hui Ma ◽  
Ke Qiang Xie ◽  
Ji Jun Wu ◽  
...  
Keyword(s):  
Phosphorus Content ◽  
Low Cost ◽  
Acid Leaching ◽  
Impurity Phase ◽  
Solar Grade Silicon ◽  
Metallurgical Grade Silicon ◽  
Before And After ◽  
Alloy Addition ◽  
Grade Silicon ◽  
Leaching Condition

In present, refining of metallurgical grade silicon is one of the promising routes to low-cost solar grade silicon for solar cells. Alloying with Ca has shown a great potential as efficient refining method of MG-Si in combination with acid leaching. Compared with Ca metal, Ca-Si alloy is cheaper and more secure. Great removal of impurity depends on microstructure of MG-Si after alloyed with Ca-Si alloy. In the work, the change of impurity phase which was performed by the change of the microstructure of MG-Si before and after alloyed with Ca-Si alloy has been analyzed. It was determined that CaSi2phase contained significant phosphorus content after alloying with Ca-Si alloy, It also investigated the optimal acid leaching condition after leaching, which confirmed that metallurgical grade silicon with Ca-Si alloy addition followed by acid leaching could be a potential route to remove phosphorus from MG-Si.

Comparison between slag refining processes for B removal with metallurgical grade silicon and Si–Sn alloy

2018 ◽  
Vol 115 (3) ◽  
pp. 312 ◽  
Author(s):  
Rowaid Al-khazraji ◽  
Yaqiong Li ◽  
Lifeng Zhang
Keyword(s):  
Removal Efficiency ◽  
Acid Leaching ◽  
Experimental Results ◽  
Mass Ratio ◽  
Metallurgical Grade Silicon ◽  
Clear Effect ◽  
Slag Refining ◽  
Before And After ◽  
Grade Silicon ◽  
Refining Processes

Boron (B) removal by slag refining using CaO–SiO2–CaCl2 was investigated in metallurgical-grade silicon (MG-Si) and 75 wt% Si–Sn alloy. Experiments were conducted at 1500 °C for 15 min. The microstructure was characterized before and after refining. The effects of acid leaching, basicity, and slag/Si mass ratio on B removal were investigated. Experimental results showed that acid leaching had no effect on B removal from MG-Si but had a clear effect on the refined Si–Sn alloy after slag refining. The final B concentration was highly affected by the CaO/SiO2 mass ratio with minimum value, where the content of B was reduced from 18.36 ppmw to 5.5 ppmw at the CaO/SiO2 = 1.2 for MG-Si slag refining and from 18.36 ppmw to 3.7 ppmw at CaO/SiO2 = 1.5 for 75 wt% Si–Sn alloy. Increasing the slag mass ratio by 2:1 mass ratio also increased B removal efficiency by approximately 15–20% more than an increase by 1:1.

Effect of Sodium-Based Slag Treatment on the Distribution of Impurities in Metallurgical Grade Silicon

2013 ◽  
Vol 690-693 ◽  
pp. 949-953
Author(s):  
Ming Fang ◽  
Cheng Hao Lu ◽  
Hui Xian Lai ◽  
Liu Qing Huang ◽  
Juan Chen ◽  
...  
Keyword(s):  
Slag Phase ◽  
Homogeneous Distribution ◽  
Solar Grade Silicon ◽  
Metallurgical Grade Silicon ◽  
Metal Impurities ◽  
Precipitated Phase ◽  
Slag Treatment ◽  
Before And After ◽  
Grade Silicon ◽  
Metallic Impurities

The distribution of impurities in metallurgical grade silicon before and after slag treatment was investigated for the purpose of upgrading metallurgical grade to solar grade silicon. It was found that metal impurities co-deposited with silicon and formed different intermetallics in the precipitated phase, and these intermetallics such as Si-Fe, Si-Ni, Si-Ti-V and Si-Ca-Al-Fe were substituted by Si-Fe-Ti-V after treatment of Na2CO3-SiO2 slag. Non-metallic impurities B and P were nearly homogeneous distribution in metallurgical grade silicon before and after slag treatment. Moreover, a particular analysis of the microstructure of slag has been carried out, it was determined that metal impurities Al and Ca could easily migrate from silicon to slag phase in the refining process.

Refining of Metallurgical Grade Silicon by Acid Leaching

2010 ◽  
Vol 156-157 ◽  
pp. 566-569 ◽  
Author(s):  
Dong Liang Lu ◽  
Yu Yan Hu ◽  
Tao Lin ◽  
Yu Liu ◽  
Bo Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Emission Spectroscopy ◽  
Acid Leaching ◽  
Atomic Emission ◽  
Solar Grade Silicon ◽  
Plasma Atomic Emission ◽  
Metallurgical Grade Silicon ◽  
Photovoltaic Applications ◽  
Orthogonal Methods ◽  
Grade Silicon

Solar grade silicon (SoG-Si) is the key material for photovoltaic applications. In this study, the silicon grain size, concentration of HF, leaching time and leaching temperature were investigated by orthogonal methods. The results showed that the silicon grain size is the most important factor for the purification of silicon. Furthermore, the obvious removal efficiency of iron and aluminum was observed when the mannitol used as the chelated reagent in HF leaching process. Inductive coupled plasma atomic emission spectroscopy (ICP-AES) results indicated that the purity of the samples improved to a large extent with the chelated reagent.

Purification of Metallurgical-Grade Silicon by Acid Leaching

Silicon ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 1979-1987 ◽  
Author(s):  
Farzad Ebrahimfar ◽  
Mahdi Ahmadian
Keyword(s):  
Acid Leaching ◽  
Metallurgical Grade Silicon ◽  
Grade Silicon

scholarly journals Slag Treatment Followed by Acid Leaching as a Route to Solar-Grade Silicon

JOM ◽  
2012 ◽  
Vol 64 (8) ◽  
pp. 957-967 ◽  
Author(s):  
Yulia V. Meteleva-Fischer ◽  
Yongxiang Yang ◽  
Rob Boom ◽  
Bert Kraaijveld ◽  
Henk Kuntzel
Keyword(s):  
Acid Leaching ◽  
Solar Grade Silicon ◽  
Slag Treatment ◽  
Grade Silicon

Production of solar-grade silicon by refining of liquid metallurgical-grade silicon

1999 ◽  
Author(s):  
Chandra P. Khattak ◽  
Frederick Schmid ◽  
David B. Joyce ◽  
Eugene A. Smelik ◽  
Mark A. Wilkinson
Keyword(s):  
Solar Grade Silicon ◽  
Metallurgical Grade Silicon ◽  
Grade Silicon

Purification of metallurgical-grade silicon via acid leaching, calcination and quenching before boron complexation

2013 ◽  
Vol 139 ◽  
pp. 64-72 ◽  
Author(s):  
Yan-Hui Sun ◽  
Qi-Hui Ye ◽  
Chang-Juan Guo ◽  
Hong-Yu Chen ◽  
Xu Lang ◽  
...  
Keyword(s):  
Acid Leaching ◽  
Metallurgical Grade Silicon ◽  
Grade Silicon

Reductive Removal of Phosphorus in Silicon Using CaO-CaF2 Slag

2013 ◽  
Vol 750 ◽  
pp. 284-287 ◽  
Author(s):  
Hiroaki Kawamura ◽  
Yutaka Yanaba ◽  
Takeshi Yoshikawa ◽  
Kazuki Morita
Keyword(s):  
Acid Leaching ◽  
Calcium Content ◽  
Molten Silicon ◽  
Metallurgical Grade Silicon ◽  
Slag Treatment ◽  
High Fraction ◽  
Wet Chemical ◽  
Grade Silicon ◽  
Removal Fraction ◽  
P Removal

In order to verify an alternative metallurgical process of phosphorus removal for solar grade silicon (SOG-Si), slag treatment of metallurgical grade silicon (MG-Si) was conducted followed by acid leaching in the present study. MG-Si containing certain amount of phosphorus and calcium was equilibrated at 1723 and 1773 K with several compositions of the CaO-CaF2 slags and phosphorus in molten silicon was confirmed to be removed into slag phase also by reducing reaction as a form of phosphide ion, P3-, in addition to the phosphate ion, PO43-. These contents were separately determined by a wet chemical analysis method developed by ourselves. Although the distribution ratio of phosphorus could not exceed the highest reported values of 3, subsequent leaching brought about considerably high fraction of P removal. The removal fraction of 95.6% was attained when 5 g of silicon was treated with 10 g of the slag at 1773 K followed by the acid leaching, which would be much higher than that expected by the ordinary oxidizing slag treatment. Although the possibility of reducing dephosphorization by slag treatment was clarified, more effective condition should be pursued by changing slag composition, calcium content of silicon, temperature, etc.

Purification of metallurgical grade silicon by acid leaching

1990 ◽  
Vol 23 (2-3) ◽  
pp. 237-246 ◽  
Author(s):  
I.C Santos ◽  
A.P Gonçalves ◽  
C.Silva Santos ◽  
M Almeida ◽  
M.H Afonso ◽  
...  
Keyword(s):  
Acid Leaching ◽  
Metallurgical Grade Silicon ◽  
Grade Silicon
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