scholarly journals Boron removal from metallurgical grade silicon using a FeCl2 molten salt refining technique

2013 ◽  
Vol 49 (3) ◽  
pp. 257-261 ◽  
Author(s):  
B.J. Jia ◽  
J.J. Wu ◽  
W.H. Ma ◽  
B. Yang ◽  
D.C. Liu ◽  
...  
Keyword(s):  
Molten Salt ◽  
Boron Concentration ◽  
Metallurgical Process ◽  
Mass Ratio ◽  
Solar Grade Silicon ◽  
Boron Removal ◽  
Metallurgical Grade Silicon ◽  
Slag Refining ◽  
Grade Silicon ◽  
Refining Time

The slag refining for boron removal from metallurgical grade silicon is a promising metallurgical process for producing solar grade silicon. In this paper, FeCl2 molten salt has been used as a new refining agent to remove boron from MG-Si. The effects of refining time and mass ratio of MG-Si to FeCl2 molten salt on boron removal have been investigated in detail. The results showed that boron can be efficiently removed in form of BCl3 and boron concentration in MG-Si was successfully reduced from 22?10-6 to 4?10-6 at 1823K for 2 h with the mass ratio of FeCl2 molten salt to MG-Si for 1.0. The rate equation of boron removal using FeCl2 molten salt was proposed and established in kinetic, which showed a large difference in removal limitation of boron compared with thermodynamics.

Removal of Boron from Metallurgical Grade Silicon by Chloride Molten Salt

2013 ◽  
Vol 634-638 ◽  
pp. 3084-3087
Author(s):  
Bin Jie Jia ◽  
Ji Jun Wu ◽  
Wen Hui Ma ◽  
Yan Long Li
Keyword(s):  
Molten Salt ◽  
Thermodynamic Analysis ◽  
Boron Content ◽  
Induction Furnace ◽  
Solar Grade Silicon ◽  
Medium Frequency ◽  
Metallurgical Grade Silicon ◽  
Grade Silicon ◽  
Refining Time ◽  
Boron Chloride

Removal of boron is one of the greatest barriers in the process of upgrading metallurgical grade silicon (MG-Si) to solar grade silicon (SoG-Si). In this work, a chloride molten salt was used as a new refining reagent for removal of boron from MG-Si. The theoretical supporting for chloride molten salt refining was studied by the thermodynamic analysis at first, which testified that boron could be volatilized and removed from MG-Si melt by generating the gaseous boron chloride species. Then the experiments for the removal of boron were carried out using the chloride molten salt with the different conditions of refining time and the ratio of chloride molten salt to MG-Si. The results showed that the boron content in refined silicon was successfully reduced from 22.0×10-6 to 3.0×10-6 in a medium frequency induction furnace at 1695 K for 2h.

scholarly journals Removing boron from metallurgical grade silicon by a high basic slag refining technique

2014 ◽  
Vol 50 (1) ◽  
pp. 83-86 ◽  
Author(s):  
J.J. Wu ◽  
M. Xu ◽  
K.B. Liu ◽  
W.H. Ma ◽  
B. Yang ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Boron Concentration ◽  
Basic Slag ◽  
Mass Ratio ◽  
Purification Method ◽  
Metallurgical Grade Silicon ◽  
Slag Refining ◽  
Thermodynamic Relationship ◽  
Grade Silicon ◽  
Maximal Distribution

A new purification method of removing boron from metallurgical grade silicon (MG-Si) using a high baisicity slag was developed in this paper. The typical impurities Al, Ca, Ti, B, P etc in MG-Si can be removed by the binary calcium sillicate slag and it is especially efficient for removing impurity Boron. It was found that the maximal distribution coefficient of boron between calcium sillicate slag and silicon reaches to 1.57 when the mass ratio of CaO/SiO2 was 1.5 and the composition was 60%CaO-40%SiO2. It showed that the oxidizability of calcium sillicate slag was affected and restricted by the basicity and the mass ratio of acid oxide SiO slag according to the thermodynamic relationship. The boron concentration in MG-Si can be reduced from 18x10-6 to 4.5x10-6 and 1.4x10-6, respectively, when using the ternary slags 40.5%CaO-49.5%SiO2-10%Li2O and 32CaO-38%SiO2-30%Li2O.

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.

Boron removal in purifying metallurgical grade silicon by CaO–SiO2 slag refining

2014 ◽  
Vol 24 (4) ◽  
pp. 1231-1236 ◽  
Author(s):  
Ji-jun WU ◽  
Yan-long LI ◽  
Wen-hui MA ◽  
Kui-xian WEI ◽  
Bin YANG ◽  
...  
Keyword(s):  
Boron Removal ◽  
Metallurgical Grade Silicon ◽  
Slag Refining ◽  
Grade Silicon

Boron removal from metallurgical-grade silicon by CaO–SiO2 slag refining

Rare Metals ◽  
2015 ◽  
Vol 34 (7) ◽  
pp. 522-526 ◽  
Author(s):  
Kui-Xian Wei ◽  
Hai-Fei Lu ◽  
Wen-Hui Ma ◽  
Yan-Long Li ◽  
Zhao Ding ◽  
...  
Keyword(s):  
Boron Removal ◽  
Metallurgical Grade Silicon ◽  
Slag Refining ◽  
Grade Silicon

Boron removal from metallurgical grade silicon using a CaO–Li2O–SiO2 molten slag refining technique

2012 ◽  
Vol 358 (23) ◽  
pp. 3079-3083 ◽  
Author(s):  
Jijun Wu ◽  
Wenhui Ma ◽  
Binjie Jia ◽  
Bin Yang ◽  
Dachun Liu ◽  
...  
Keyword(s):  
Molten Slag ◽  
Boron Removal ◽  
Metallurgical Grade Silicon ◽  
Slag Refining ◽  
Grade Silicon

The Rate of Boron Removal from Molten Silicon by CaO-SiO2 Slag and Cl2 Treatment

2012 ◽  
Vol 31 (4-5) ◽  
pp. 471-477 ◽  
Author(s):  
Hiroshi Nishimoto ◽  
Youngjo Kang ◽  
Takeshi Yoshikawa ◽  
Kazuki Morita
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Molten Slag ◽  
Refining Process ◽  
Molten Silicon ◽  
Solar Grade Silicon ◽  
Boron Removal ◽  
Present Experimental Condition ◽  
Slag Refining ◽  
Grade Silicon

AbstractIn order to optimize a boron removal process by slag refining to obtain solar grade silicon, the rate of boron removal from molten silicon using CaO-SiO2 slag was investigated at 1823 K in an Ar atmosphere. The rate of boron removal was found to be controlled by mass transfer in molten slags, and the mass-transfer coefficient of boron in molten slag in the present experimental condition was evaluated. Some experiments on chlorination of boron in silicon and that of borate in slag using Cl2 gas were also carried out. Experimental results showed that the slag refining process with chlorination was proposed as a promising method for the boron removal from molten silicon.

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