Short Communication

Low-temperature enhancement in the extraction of phosphorus from metallurgical-grade silicon by simultaneously re-constructing phosphorus-rich phases of Ca₃P₂ and CaAl₂Si₂-P

¹ School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China
² College of Energy and Environment Science, Yunnan Normal University, Kunming 650500, China
³ Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang 110819, China
⁴ School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China

^* e-mail: leejc2011@163.com

Received: 7 March 2024
Accepted: 6 May 2024

Abstract

A novel method of combined Si-Al solvent refining with CaCl₂-CaF₂-CaO molten salt treatment for phosphorus removal from metallurgical-grade silicon was investigated. With the mass ratio of salt (45 wt.%CaCl₂–45 wt.%CaF₂–10 wt.%CaO) to the alloy (phosphorus-doped Al-Si) being 1:1, phosphorus-rich phases of Ca₃P₂ and CaAl₂Si₂-P were successfully reconstructed at 1250 °C for 1 h. After acid leaching, phosphorus content decreased from 3 wt.% to 0.24 wt.%, corresponding to a phosphorus removal rate of 91.95%.