New Insights into Silicon Purification by Alloying–Leaching Refining: A Comparative Study of Mg–Si, Ca–Si, and Ca–Mg–Si Systems

Mengyi Zhu,Jafar Safarian,Kai Tang,Sheng Ying Yue

doi:10.1021/acssuschemeng.0c05564

Abstract

In the present work, a comparative study of the silicon alloying–leaching purification process was carried out on the recently developed Mg–Si system, the Ca–Si system, and the novel ternary Ca–Mg–...

Highlights

The contribution of solar energy to the world’s total energy supply has grown significantly in the past two decades
The negative values of the Ca−Mg−Si subsystems indicate the formation of the ternary intermetallic of the Ca−Mg−Si alloy system
In the Ca−Si alloy, the main precipitate was CaSi2 and it led to the formation of a viscous byproduct siloxene during acid leaching along with a strong cracking effect

Summary

Introduction

The contribution of solar energy to the world’s total energy supply has grown significantly in the past two decades. Considerable research has been performed to study the impurity extraction from MG-Si by acid leaching.[4−12] It has been found that most of the metallic impurities can be effectively extracted by adjusting a variety of processing parameters like leaching temperature, time, acid combination, and particle size, but the effective P extraction by direct leaching of MG-Si still remains a challenge. Even though it has been theoretically and experimentally confirmed that P tends to segregate along Si grain boundaries,[13] its segregation coefficient (kp = 0.35) is still

Methods

Results

Conclusion