电热法制高纯硅及其炉外精炼的研究
发布时间：2018-11-17 06:35
【摘要】：随着全球传统能源的日益枯竭和环境污染问题的日益严重,世界各国纷纷发展新能源,其中太阳能因其分布广泛、资源丰富、清洁无污染等优点,被认为是21世纪最重要的新能源。在世界各国政策的积极扶持下,太阳能光伏产业迅速发展,使得对太阳能级多晶硅的需求大增。由于目前制备多晶硅的主要方法西门子法存在着能耗高、成本高,严重地制约了光伏产业的发展,因此研究低成本的太阳能级多晶硅的制备方法具有重要意义。 现在多晶硅的主流技术改良西门子法主要掌握在美、日、德等国手中,他们对该行业形成了技术封锁、市场垄断。我国没有掌握改良西门子法的核心技术,多晶硅主要依赖于进口。在太阳能级晶体硅的切片过程中,约50wt%的晶体硅被切磨成高纯硅粉成为了切割废料。如能将废料中的高纯硅粉加以回收并作为制备太阳能级晶体硅的原料,这对缓解我国太阳能级晶体硅的紧缺、减少晶体硅的进口具有重要意义,而且还能够减少切割粉带来的环境污染,提高了资源利用率。 本文首先以太阳能级多晶硅切割废料的硅富集料为原料,用电热法制备高纯硅,再对高纯硅进行炉外精炼,为制备太阳能级多晶硅奠定基础。本文主要研究内容包括：切割废料的物性研究；硅富集料的酸洗除杂；硅富集料电热法制备高纯硅；炉外精炼除杂的研究。获得的主要结果如下： (1)切割废料的物性研究：通过XRD、XRF、化学定量分析、粒度分析等对切割废料物性进行了研究,结果表明：切割废料中含硅30.50wt%,碳化硅34.90wt%,水和聚乙二醇26.63wt%,铁及其氧化物5.36wt%,其他2.61wt%,粒度主要集中在1.0～23.8μm范围内。 (2)硅富集料的酸洗除杂：考察了浸出时间、浸出温度、盐酸浓度等因素对硅富集料中铁浸出率的影响。通过正交实验得到了酸洗除杂的最佳工艺条件,浸出时间为3h,浸出温度为70℃,浸出液浓度为15wt%,搅拌速度为150r/min,液固比为4：1,在此条件下铁浸出率可达97.00wt%,硅富集料中的铁含量由6.84wt%降低到了0.22wt%。 (3)硅富集料电热法制备高纯硅：将从切割废料中获得的硅富集料进行电弧熔炼,获得了高纯硅。通过XRD、XRF、SEM等方法对产物的进行检测,结果表明：产物硅沉积在坩埚底部,组织致密,产物的主要相是硅,其中Fe、Al、B、P等杂质含量很低,杂质Fe、Al主要分布在晶界处。 (4)向熔融硅中通入高纯Ar对除硼不显著,对除磷有一定效果,对硼、磷的脱除率分别为4%、29%；通入高纯Ar和20℃水蒸汽的混合气体对硼、磷的脱除有一定效果,在通气时间为150min时,硼、磷含量均达到最低,硼磷的脱除率分别为53%、43%；通入高纯Ar和90℃水蒸汽的混合气体的后,对硼、磷的脱除显著,硼磷去除率分别为72%、69%。 通过这些研究表明将酸洗除杂后的硅富集料采用电热法可制备出硼、磷含量很低的高纯硅,然后通过炉外精炼可降低硼、磷含量,实验结果证明此工艺是可行的,将来如果再辅助以真空精炼、定向凝固等工艺就可以将硅的纯度进一步提高,从而达到太阳能级多晶硅的纯度要求。
[Abstract]:With the increasing depletion of the global traditional energy and the increasing environmental pollution, the world has developed new energy, in which the solar energy is considered to be the most important new energy in the 21st century because of its wide distribution, rich resources and no pollution. With the positive support of the world's national policies, the solar PV industry has developed rapidly so that the demand for solar-level polysilicon is greatly increased. Because of the high energy consumption, high cost and serious restriction of the development of the photovoltaic industry, the method for preparing the low-cost solar-grade polycrystalline silicon is of great significance because of the high energy consumption and high cost. Now, the mainstream technology of polycrystalline silicon improves the Siemens method, which is mainly in the hands of the United States, Japan and Germany, and they have formed a technical blockade and market for the industry. Monopoly. Our country has not mastered the core technology of the modified Siemens method, and the polysilicon mainly depends on In the process of slicing the solar-grade crystalline silicon, about 50wt% of the crystalline silicon is cut into high pure silicon powder to be cut The high-purity silicon powder in the waste material can be recycled and used as a raw material for preparing the solar-grade crystalline silicon, which is of great significance for relieving the shortage of the silicon of the solar-grade crystalline silicon in China and reducing the import of the crystalline silicon, and also can reduce the environmental pollution caused by the cutting powder and improve the resource. In this paper, the silicon-enriched material of the solar-grade polycrystalline silicon cutting waste is used as the raw material, and the high-purity silicon is prepared by the electric heating method, and then the high-purity silicon is subjected to the external refining of the furnace, so as to prepare the solar-grade polycrystalline silicon. The main content of this paper is to study the physical properties of the cutting waste materials, the acid-washing and impurity removal of the silicon-rich material, the preparation of the high-purity silicon by the silicon-enriched material electric heating method, and the external refining of the furnace. impurity-removing study The results are as follows: (1) Physical property of cutting waste: The physical properties of cutting waste are studied by XRD, XRF, chemical quantitative analysis, particle size analysis and so on. The results show that the cutting waste contains 30. 50wt% of silicon, 34. 90wt% of silicon carbide, water and polyethylene glycol. 268.63wt%, iron and its oxide 5.36wt%, and the other 2.61wt%, the particle size is mainly concentrated in 1. 0-2. 3. (2) Acid-washing and impurity removal of silicon-rich material: The factors such as leaching time, leaching temperature and hydrochloric acid concentration were investigated. The optimum technological conditions of acid-washing and impurity removal were obtained by orthogonal experiment, the leaching time was 3 h, the leaching temperature was 70 鈩，
本文编号：2336779
[Abstract]:With the increasing depletion of the global traditional energy and the increasing environmental pollution, the world has developed new energy, in which the solar energy is considered to be the most important new energy in the 21st century because of its wide distribution, rich resources and no pollution. With the positive support of the world's national policies, the solar PV industry has developed rapidly so that the demand for solar-level polysilicon is greatly increased. Because of the high energy consumption, high cost and serious restriction of the development of the photovoltaic industry, the method for preparing the low-cost solar-grade polycrystalline silicon is of great significance because of the high energy consumption and high cost. Now, the mainstream technology of polycrystalline silicon improves the Siemens method, which is mainly in the hands of the United States, Japan and Germany, and they have formed a technical blockade and market for the industry. Monopoly. Our country has not mastered the core technology of the modified Siemens method, and the polysilicon mainly depends on In the process of slicing the solar-grade crystalline silicon, about 50wt% of the crystalline silicon is cut into high pure silicon powder to be cut The high-purity silicon powder in the waste material can be recycled and used as a raw material for preparing the solar-grade crystalline silicon, which is of great significance for relieving the shortage of the silicon of the solar-grade crystalline silicon in China and reducing the import of the crystalline silicon, and also can reduce the environmental pollution caused by the cutting powder and improve the resource. In this paper, the silicon-enriched material of the solar-grade polycrystalline silicon cutting waste is used as the raw material, and the high-purity silicon is prepared by the electric heating method, and then the high-purity silicon is subjected to the external refining of the furnace, so as to prepare the solar-grade polycrystalline silicon. The main content of this paper is to study the physical properties of the cutting waste materials, the acid-washing and impurity removal of the silicon-rich material, the preparation of the high-purity silicon by the silicon-enriched material electric heating method, and the external refining of the furnace. impurity-removing study The results are as follows: (1) Physical property of cutting waste: The physical properties of cutting waste are studied by XRD, XRF, chemical quantitative analysis, particle size analysis and so on. The results show that the cutting waste contains 30. 50wt% of silicon, 34. 90wt% of silicon carbide, water and polyethylene glycol. 268.63wt%, iron and its oxide 5.36wt%, and the other 2.61wt%, the particle size is mainly concentrated in 1. 0-2. 3. (2) Acid-washing and impurity removal of silicon-rich material: The factors such as leaching time, leaching temperature and hydrochloric acid concentration were investigated. The optimum technological conditions of acid-washing and impurity removal were obtained by orthogonal experiment, the leaching time was 3 h, the leaching temperature was 70 鈩，
本文编号：2336779
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