Al-50％Si合金电磁定向凝固提纯过程中初晶硅富集行为研究
Effect of Electromagnetic Directional Solidification and Purification on Primary Silicon Enrichment Behavior in Al-50％Si Alloy
刘家旭 1张银涛 1唐洪 1陈嘉慧 1陈广玉 1何占伟 1赵紫薇 1高忙忙1
作者信息
- 1. 宁夏大学材料与新能源学院,宁夏光伏材料重点实验室,银川 750021
- 折叠
摘要
采用Al-Si合金提纯制备多晶硅过程中,初晶硅的富集可以有效减少后续酸洗过程中铝和酸的消耗,进而降低高纯初晶硅的分离成本.电磁定向凝固具有工艺简单、可控性强等优点,是目前提纯制备多晶硅最佳方法之一,但各工艺参数对初晶硅的富集影响规律还缺乏系统研究.为此,本文研究了初始凝固温度、坩埚初始位置和下移速率对Al-50％Si(质量分数)合金凝固过程中初晶硅富集行为的影响,并对富集区内初晶硅晶粒的形貌进行了表征.结果表明,初始凝固温度为950 ℃,坩埚初始位置为-5 mm及坩埚下移速率为2 mm/h时,初晶硅主要富集在铸锭的下部区域,最高富集率为79.1％,是最佳的工艺组合.同时,随着初晶硅富集程度的增加,初晶硅晶粒由盘片状向粗大的球状转变,这有利于降低初晶硅的夹杂,并提高其纯度.
Abstract
In the process of preparing polycrystalline silicon using Al-Si alloy purification,the enrichment of primary silicon can effectively reduce the consumption of aluminum and acid in the subsequent pickling process,thereby lowering the separation cost of high-purity primary silicon.Electromagnetic directional solidification is one of the best methods for preparing polycrystalline silicon currently due to its advantages such as simple process and strong controllability.However,there is a lack of systematic research on how various process parameters affect the enrichment of primary silicon.Therefore,this study investigates the effects of initial solidification temperature,crucible initial position,and descent rate on the behavior of primary silicon enrichment during the solidification process of Al-50％Si(mass fraction)alloy,and characterizes the morphology of primary silicon grains within the enrichment zone.The results show that when the initial solidification temperature is 950℃,the initial crucible position is-5 mm,and the crucible descent rate is 2 mm/h,primary silicon is mainly concentrated in the lower part of the ingot with a maximum enrichment rate of 79.1％,which is the optimal combination of processes.At the same time,as the degree of primary silicon enrichment increases,the primary silicon grains change from"disk-like"to coarse"spherical",which helps reduce the inclusion of primary silicon and improve its purity.
关键词
Al-Si合金/电磁定向凝固/初晶硅/硅富集/温度梯度/初晶硅形貌Key words
Al-Si alloy/electromagnetic directional solidification/primary silicon/silicon enrichment/temperature gradient/primary silicon morphology引用本文复制引用
基金项目
国家自然科学基金(52164047)
中国科学院"西部之光"人才培养计划(XAB2022YW10)
宁夏自然科学基金(2021AAC03064)
出版年
2024
国家科技期刊平台
NSTL
万方数据