| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 212010 | Hydrometallurgy | 2015 | 9 Pages |
•Silicon microstructure evolution under attack by different lixiviants was revealed.•One-step leaching with the HCl + HF mixture resulted in achieving the required purity of SOG-Si for Ti, Mn, V and Mg.•The acid leaching process of Si–Ca alloy was under chemical reaction control.
To explore the potential of acid leaching in purifying metallurgical grade silicon (MG-Si) for solar cell applications, the effect of silicon microstructure on its leaching behavior was systematically investigated in the present work by a combination of alloying refining with acid etching. The microstructure evolution of silicon was revealed before and after acid etching with different lixiviants. Calcium-containing precipitates were found in MG-Si after alloying with calcium. The etching results showed that the leaching behavior of impurity inclusions strongly depended on the composition of the major impurities. HCl + HF mixture was an effective lixiviant for dissolving impurity inclusions in both MG-Si and its alloy with calcium. The impurity removal efficiency of acid leaching of MG-Si was efficiently improved after alloying. Moreover, the kinetics of acid leaching of MG-Si after alloying with calcium was further discussed based on cracking shrinking model.
