Silicon Recovery from Si Sawing Waste through Slag Refining

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.

Download Full-text

Effects of K2CO3 Addition on Inclusions in High-Carbon Steel for Saw Wire

High Temperature Materials and Processes ◽

10.1515/htmp-2017-0030 ◽

2018 ◽

Vol 37 (8) ◽

pp. 701-709 ◽

Cited By ~ 1

Author(s):

Liangjun Chen ◽

Weiqing Chen ◽

Yang Hu ◽

Zhaoping Chen ◽

Yingtie Xu ◽

...

Keyword(s):

Carbon Steel ◽

Melting Temperature ◽

High Carbon Steel ◽

Weight Ratio ◽

New Method ◽

Graphite Tube ◽

Resistance Furnace ◽

High Carbon ◽

Slag Refining ◽

Addition Amount

AbstractIn order to avoid the formation of crack initiation sites, inclusions in high-carbon steel for saw wire are strictly required to have excellent deformability. However, it is hard to achieve this goal with only conventional inclusion softening art, such as Si-Mn deoxidation and low basicity top slag refining. Therefore, a new method should be put forward to enhance the deformability of inclusions. Low melting temperature inclusions are widely considered to have good deformability, hence, adding K (potassium) into inclusions may become a potential new method to better enhance the deformability of inclusions due to the pronounced effect of K2O on lowering the melting temperature of inclusions. In the present study, the influences of Fe/K2CO3 (weight ratio), K2CO3 addition amount and reaction time on inclusions were investigated by using a graphite tube resistance furnace. Through this study, a solution to adding K into inclusions effectively by K2CO3 addition was developed and the melting temperature of inclusions was significantly reduced. In addition, the reaction mechanism between K2CO3/slag/steel/inclusion was deduced and the relation between deformability and crystallinity of inclusions was also briefly discussed.

Download Full-text

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

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(14)63183-6 ◽

2014 ◽

Vol 24 (4) ◽

pp. 1231-1236 ◽

Cited By ~ 39

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

Download Full-text

Improved removal of boron from metallurgical-grade Si by CaO-SiO 2 -CaCl 2 slag refining with intermittent CaCl 2 addition

Vacuum ◽

10.1016/j.vacuum.2017.05.025 ◽

2017 ◽

Vol 143 ◽

pp. 7-13 ◽

Cited By ~ 4

Author(s):

Chenghao Lu ◽

Tianyu Tang ◽

Zhilin Sheng ◽

Pengfei Xing ◽

Xuetao Luo

Keyword(s):

Slag Refining

Download Full-text

Interfacial reactions between impurities and slag onset of Si purification by slag addition

Metallurgical Research & Technology ◽

10.1051/metal/2021096 ◽

2021 ◽

Vol 119 (1) ◽

pp. 101

Author(s):

Yaqiong Li ◽

Yunlong Yu ◽

Lifeng Zhang ◽

Zhengtao Li

Keyword(s):

Reaction Time ◽

Removal Efficiency ◽

Removal Rate ◽

Interfacial Reactions ◽

Refining Process ◽

Short Reaction Time ◽

Impurity Removal ◽

Slag Refining ◽

Al Distribution ◽

Distribution Behavior

The interfacial reactions between impurities (Al and Ti) and slag onset of Si purification by 51 mol% SiO2–34 mol% CaO–15 mol% MgO slag addition were studied to enhance impurity removal efficiency from Si. The Al distribution behavior at the Si/Slag interface was investigated; a short reaction time (10 s) resulted in the formation of successive SiO2–CaO–MgO–Al2O3 layers in the slag with a thickness of 10 µm; increasing the reaction time (60 s) resulted in the entire ternary slag being changed into SiO2–CaO–MgO–Al2O3 quaternary slag due to the diffusion of Al2O3. It was shown that the highest impurity removal rate of Al could be achieved at the onset of the slag refining process. Based on the Ti distribution at the Si/slag interface, the slag refinement with 51 mol% SiO2–34 mol% CaO–15 mol% MgO had no effect on Ti removal.

Download Full-text

Impurity Removal from Diamond-Wire Cutting Waste by Slag Refining and Electromagnetic Stirring

JOM ◽

10.1007/s11837-020-04184-7 ◽

2020 ◽

Vol 72 (7) ◽

pp. 2648-2655 ◽

Cited By ~ 1

Author(s):

Yunyang Zhu ◽

Jijun Wu ◽

Qiliang Wang ◽

Wenhui Ma ◽

Kuixian Wei ◽

...

Keyword(s):

Electromagnetic Stirring ◽

Diamond Wire ◽

Impurity Removal ◽

Slag Refining ◽

Wire Cutting

Download Full-text

A Review of Slag Refining of Crude Silicon

JOM ◽

10.1007/s11837-020-04470-4 ◽

2020 ◽

Vol 73 (1) ◽

pp. 260-281

Author(s):

Sridevi Thomas ◽

Liuqing Huang ◽

Mansoor Barati

Keyword(s):

Slag Refining

Download Full-text

The Slagging Model Research of Refining-Slag for High Aluminum Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.90 ◽

2012 ◽

Vol 602-604 ◽

pp. 90-95

Author(s):

Min Zhang ◽

Jian Hua Zeng ◽

Xing Di Yang ◽

Yao Xian Zeng

Keyword(s):

Prediction Model ◽

Reduction Reaction ◽

Refining Slag ◽

Activity Prediction ◽

Slag Refining ◽

Coexistence Theory ◽

Model Research ◽

High Aluminum Steel ◽

Si Content ◽

High Aluminum

To accurately control the Si content and ensure the function of slag refining in high aluminum steel, the direction and limits of reduction reaction for SiO2 were analyzed based on the thermodynamics. In addition, the thermodynamic prediction model of multi-element slag was studied. Then, a slag activity prediction model was established based on the coexistence theory. Using the model, the suitable ladle slag composition for high aluminum steel was calculated.

Download Full-text