单晶及多晶硅切割废料中的高纯硅回收

摘要

To improve the recovery of high purity silicon from cutting loss slurry,the sediment process and conditions are optimized.According to the physical and chemical character of mono-/poly-silicon cutting loss slurry,a system of water/polyethylene glycol=（8～9）∶1 with a few inorganic salt was introduced.The orthogonal tests were carried out with different sediment time and solid-to-liquid ratio,and the recycled silicon was purified by hydrochloric acid and hydrofluoric acid followed by ingot casting at 1500～1600℃.X-ray diffraction（XRD）,X-ray fluorescence（XRF）and Particle size analyzer were adopted to investigate the influence of sediment condition on the recycled silicon.It is demonstrated that the Si and SiC content of the sample is respectively up to 88.52%and 11.46%under condition of solid-to-liquid ratio 0.06 and 5 h for sediment time.Silicon ingot purity reaches 98.71%after casting,and recovery ratio of Si achieves 43.33%.%为提高在切割废料中高纯硅的回收率,对沉降方法和条件进行了优化.根据单/多晶硅切割废料浆的物理、化学性质,在m（水）∶m（聚乙二醇）=（8～9）∶1、含有少量无机盐的水溶液体系中,在不同沉降时间和不同固液配比的条件下进行正交试验,通过盐酸、氢氟酸进行除杂,最后在1 500～1 600℃下进行硅的铸锭.通过X射线衍射、元素分析和粒径分析研究沉降条件对于最终回收产物的影响.研究表明：在固液比为0.06、沉降时间5 h的条件下,沉降并经过除杂得到的微粉中硅质量分数达到88.52%,碳化硅质量分数为11.46%,富集的微粉经铸锭得到的硅锭纯度为98.71%,硅的回收率达到43.33%.