【摘要】：隨著全球傳統(tǒng)能源的日益枯竭和環(huán)境污染問(wèn)題的日益嚴(yán)重,世界各國(guó)紛紛發(fā)展新能源,其中太陽(yáng)能因其分布廣泛、資源豐富、清潔無(wú)污染等優(yōu)點(diǎn),被認(rèn)為是21世紀(jì)最重要的新能源。在世界各國(guó)政策的積極扶持下,太陽(yáng)能光伏產(chǎn)業(yè)迅速發(fā)展,使得對(duì)太陽(yáng)能級(jí)多晶硅的需求大增。由于目前制備多晶硅的主要方法西門子法存在著能耗高、成本高,嚴(yán)重地制約了光伏產(chǎn)業(yè)的發(fā)展,因此研究低成本的太陽(yáng)能級(jí)多晶硅的制備方法具有重要意義。 現(xiàn)在多晶硅的主流技術(shù)改良西門子法主要掌握在美、日、德等國(guó)手中,他們對(duì)該行業(yè)形成了技術(shù)封鎖、市場(chǎng)壟斷。我國(guó)沒(méi)有掌握改良西門子法的核心技術(shù),多晶硅主要依賴于進(jìn)口。在太陽(yáng)能級(jí)晶體硅的切片過(guò)程中,約50wt%的晶體硅被切磨成高純硅粉成為了切割廢料。如能將廢料中的高純硅粉加以回收并作為制備太陽(yáng)能級(jí)晶體硅的原料,這對(duì)緩解我國(guó)太陽(yáng)能級(jí)晶體硅的緊缺、減少晶體硅的進(jìn)口具有重要意義,而且還能夠減少切割粉帶來(lái)的環(huán)境污染,提高了資源利用率。 本文首先以太陽(yáng)能級(jí)多晶硅切割廢料的硅富集料為原料,用電熱法制備高純硅,再對(duì)高純硅進(jìn)行爐外精煉,為制備太陽(yáng)能級(jí)多晶硅奠定基礎(chǔ)。本文主要研究?jī)?nèi)容包括：切割廢料的物性研究；硅富集料的酸洗除雜；硅富集料電熱法制備高純硅；爐外精煉除雜的研究。獲得的主要結(jié)果如下： (1)切割廢料的物性研究：通過(guò)XRD、XRF、化學(xué)定量分析、粒度分析等對(duì)切割廢料物性進(jìn)行了研究,結(jié)果表明：切割廢料中含硅30.50wt%,碳化硅34.90wt%,水和聚乙二醇26.63wt%,鐵及其氧化物5.36wt%,其他2.61wt%,粒度主要集中在1.0～23.8μm范圍內(nèi)。 (2)硅富集料的酸洗除雜：考察了浸出時(shí)間、浸出溫度、鹽酸濃度等因素對(duì)硅富集料中鐵浸出率的影響。通過(guò)正交實(shí)驗(yàn)得到了酸洗除雜的最佳工藝條件,浸出時(shí)間為3h,浸出溫度為70℃,浸出液濃度為15wt%,攪拌速度為150r/min,液固比為4：1,在此條件下鐵浸出率可達(dá)97.00wt%,硅富集料中的鐵含量由6.84wt%降低到了0.22wt%。 (3)硅富集料電熱法制備高純硅：將從切割廢料中獲得的硅富集料進(jìn)行電弧熔煉,獲得了高純硅。通過(guò)XRD、XRF、SEM等方法對(duì)產(chǎn)物的進(jìn)行檢測(cè),結(jié)果表明：產(chǎn)物硅沉積在坩堝底部,組織致密,產(chǎn)物的主要相是硅,其中Fe、Al、B、P等雜質(zhì)含量很低,雜質(zhì)Fe、Al主要分布在晶界處。 (4)向熔融硅中通入高純Ar對(duì)除硼不顯著,對(duì)除磷有一定效果,對(duì)硼、磷的脫除率分別為4%、29%；通入高純Ar和20℃水蒸汽的混合氣體對(duì)硼、磷的脫除有一定效果,在通氣時(shí)間為150min時(shí),硼、磷含量均達(dá)到最低,硼磷的脫除率分別為53%、43%；通入高純Ar和90℃水蒸汽的混合氣體的后,對(duì)硼、磷的脫除顯著,硼磷去除率分別為72%、69%。 通過(guò)這些研究表明將酸洗除雜后的硅富集料采用電熱法可制備出硼、磷含量很低的高純硅,然后通過(guò)爐外精煉可降低硼、磷含量,實(shí)驗(yàn)結(jié)果證明此工藝是可行的,將來(lái)如果再輔助以真空精煉、定向凝固等工藝就可以將硅的純度進(jìn)一步提高,從而達(dá)到太陽(yáng)能級(jí)多晶硅的純度要求。
[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，

本文編號(hào)：2336779