Production of polysilicon using physical methods in China

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Production of polycrystalline silicon by physical methods in China: Solar-grade polycrystalline silicon technology is divided into two main categories: chemical methods and physical methods. The physical processing method, also known as the metallurgical method, involves using physical techniques to remove impurities from metallurgical-grade silicon without altering its fundamental properties. Physical methods are cost-effective and are regarded as the stars of the future to replace the production of high-purity polysilicon. It is reported that small quantities of polysilicon produced by physical methods are already on the market, but the uniformity, stability, scalability of polysilicon manufactured through physical methods, as well as the rapid decline in its photovoltaic conversion efficiency, remain critical issues that need to be addressed urgently. A large number of enterprises and research institutions in China have devoted themselves to tackling these challenges. Based on the internet, this article collects and presents below some of the progress and achievements of domestic companies involved in the production of polysilicon using physical methods (in no particular order). 1. Gao Wenxiu from Henan Xuntianyu Company uses the \"Fangcheng physical method\", which, compared to traditional chemical methods, requires only 1/3 of the electricity consumption, 1/10 of the water consumption, and 1/6 of the production costs. In April 2006, pilot production of polycrystalline silicon using physical methods was successful, and all of the 4-6N grade high-purity polycrystalline silicon produced that year was exported. The company’s technology for purifying high-purity polycrystalline silicon using physical methods not only overcame the high-energy-consumption bottleneck in China’s solar industry but also enabled exports for the first time, establishing China’s position in the global photovoltaic industry chain. With the industrialization of this technology, the cost of products has been significantly reduced. Its unique environmentally friendly, energy-saving, and safe production processes have filled a gap in the domestic market, bringing it to an internationally leading level. 2. Fuyuan Silicon Industry Co., Ltd., Xiao Shiping: Through the joint efforts of various parties, on July 20, the pilot production of 6N polycrystalline silicon was successfully carried out by Badaojiang Fuyuan Silicon Industry Co., Ltd. in Baishan City, Jilin Province, in collaboration with Shanghai Solar Technology Co., Ltd. (which is affiliated with the A-share listed company Aerospace Electromechanical). Fuyuan Silicon Industry Co., Ltd. uses high-purity silica and carbon for carbothermal reduction; by adding flocculating fluxes and barium salts to the silicon melt and then refining it with oxygen injection, impurities in the silicon melt can be effectively removed. Subsequent chemical purification, vacuum refining, and directional solidification are used to produce polysilicon material suitable for solar applications. The completion and operation of the 1,000-ton solar-grade polysilicon project at Baodaojiang Fuyuan Silicon Industry Co., Ltd. in Baishan City will successfully break through the technological blockades imposed by the West, exerting a significant positive impact on China’s information industry and its domestic industries. The 1,000-ton solar-grade polysilicon project of Fuyuan Silicon Industry Co., Ltd. in Badaojiang, Baishan City, utilizes a self-developed \"physical method\" purification technology; the production cost is expected to be only 2/3 of that in foreign countries, resulting in a 2/3 reduction in total investment. 3. Nan’an Sanjing Silicon Products Refining Co., Ltd., Zheng Zhixiong. Nan’an Sanjing currently covers an area of 190,000 square meters and operates across the entire solar energy industry chain, including mining, purification and refinement of industrial silicon and metal silicon, as well as export and research activities. Its annual processing capacity for metal silicon is 40,000 tons, with sales volume in 2007 amounting to approximately 25,000 tons. Once the public service platform is completed, it will be the company with the most complete industrial chain in China. The current number of employees is 700. On December 31, 2007, the company successfully produced its first large-size single-crystalline silicon rod. Cao Jianlin, Vice Minister of the Ministry of Science and Technology, offered his congratulations, stating that this marked the first successful step in the production of solar cells using low-cost, high-purity silicon produced by physical methods, with full independent intellectual property rights in Fujian Province. It further strengthened China’s leading position in silicon purification technologies using physical methods. 4. Shanghai Guangji Silicon Materials Co., Ltd./Dawu Silicon Optoelectronics Industrial Park Co., Ltd.: Pengda Silicon Gate Co., Ltd. uses a three-step metallurgical process to produce polysilicon of grades 6N–9N. The polysilicon project in Dawu County, Xiaogan is being built with an investment of 80 million yuan by Shanghai Guangji Silicon Materials Co., Ltd. Self-developed and trial-produced polycrystalline silicon material for solar cells with a silicon content of 99.9999%. Shanghai Guangji Silicon Materials Co., Ltd. has put into operation in Dawu County, Hubei Province, the technology for \"producing solar polysilicon via a three-step process\", and has achieved profitability. 5. Yiyang Jingxin New Energy Technology Industry Co., Ltd. – Gao Tianguo/Xu Yuesheng. On May 2, 2007, Hunan Yiyang Jingxin Technology Co., Ltd. produced its first \"crystal rod\". The creation of this single-crystalline silicon \"ingot\" weighing 55 kilograms marks the maturity of the technology for purifying silicon materials used in solar cells through metallurgical methods, and it will lay a solid foundation for the development of the photovoltaic industry. Currently, the bottleneck restricting the development of solar cells is semiconductor silicon material, and only 2 companies in China are capable of producing it. “Jingxin Technology is a leading high-tech new materials enterprise introduced to Yiyang City, mainly engaged in the research, development, and production of monocrystalline silicon and polycrystalline silicon materials for solar cells. “The first phase of Jingxin Technology’s plan aims to achieve an annual production capacity of 1,600 tons of polysilicon and 600 tons of monocrystalline silicon, with an expected annual output value of over 2 billion yuan. 6. Zhejiang Bijing Technology Co., Ltd., Li Qiao: The company uses purification technologies with independent intellectual property rights to produce solar-grade polycrystalline silicon and monocrystalline silicon. Compared to traditional production methods, this technology offers advantages such as low cost, high efficiency, low investment, no pollution, and high purity (6N-7N), thereby ensuring the company’s leading position in terms of technology and profits within the industry. (Zhejiang Daily, 2008-07-30) Zhejiang Bijing Technology Co., Ltd., founded by Li Qiao, has developed a process for purifying crystalline silicon from metallurgical silicon, achieving a purity level of over 99.9999%, thereby overcoming the raw material \"bottleneck\" that hindered the development of China’s photovoltaic industry. Next, Shangyu Longbai Group will also collaborate with Li Qiao to invest 800 million yuan in a solar cell production project. 7. Zhang Shiping from Hebei Shanggui Photovoltaic Materials Co., Ltd. has been dedicated to the development and industrialization of metallurgical methods for the production of solar-grade polycrystalline silicon since 2005. Building on the cutting-edge technological capabilities of various foreign companies, it has developed a number of proprietary technologies in areas such as vacuum melting phosphorus removal processes, melting oxidation for boron and carbon removal, and automated precision directional solidification processes. It has designed and manufactured pilot-scale production equipment for solar-grade polycrystalline silicon with a monthly production capacity of 2 tons, and is currently constructing a production line capable of producing 200 tons per year of 6N solar-grade polycrystalline silicon. Its technologies for silicon material purification and single-crystalline silicon production are at the international advanced level. 8. Jingmen Jiawei Solar Company, Ding Kongxian (September 4, 2006; source: Duodao Communications). Jingmen High-Tech Zone will adopt the polycrystalline silicon production technology developed by the Chinese Academy of Sciences and owned by it as intellectual property, with an investment of $15 million in total, of which $4 million will be invested in the initial phase. Upon reaching full production capacity, the project will have an initial production capacity of 300 tons per year of solar-grade polysilicon. 9. Jingzhan (Nanchang) Technology Co., Ltd., Luo Yingming. The establishment of Jingzhan (Nanchang) Technology Co., Ltd. in the Nanchang Economic Development Zone in 2004 marked the end of Jiangxi’s history without any microelectronics manufacturing industry. The polysilicon production process used by Jingzhan is different from the traditional Siemens method; the Jingzhan method employed by Jingzhan Technology is a physical process that offers advantages in terms of environmental friendliness, lower energy consumption, and reduced costs. By the end of 2008, the production volume is expected to reach 180 tons, with the annual production capacity for solar polysilicon set at 3,000 tons. With its independently developed \"Jingzhan Method\", Jingzhan Company stands out among global photovoltaic enterprises, delivering a distinct \"Nanchang voice\" within the rapidly evolving photovoltaic industry. This extraction method consumes **less electricity than the other two methods, causes almost no environmental pollution, and reduces costs by nearly half while maintaining the purity of crystalline silicon products; it is referred to in the industry as the \"third method for extracting crystalline silicon in the world.\" 10. Shanghai Pro New Energy, Shi Jun: Pro Company utilizes a completely new process based on its own intellectual property rights to produce solar-grade polycrystalline silicon materials using its proprietary CP method patents. These materials are designed specifically for use in solar applications, offering users silicon materials with high photovoltaic conversion efficiency. The CP method refers to the chemophysical method. The CP method invented by Pro Company for the production of solar polysilicon utilizes a range of proprietary technologies such as high-temperature smelting, extracorporeal refining, hydrometallurgy, powder metallurgy, vacuum metallurgy, and ion exchange to remove various impurities. This process ultimately purifies the silicon material to achieve a solar-grade polysilicon purity of 6N–7N, and it also features patented production processes for polysilicon ingot casting. The entire production process produces no polluting emissions and has low energy consumption. The energy required to produce polycrystalline silicon per unit of weight is only 1/5 of that in the Siemens process. According to the product description on its website, the company has 5.7N products. 11. Ningxia Yinxing Polysilicon Co., Ltd., a subsidiary in which Yinxing Energy holds shares, produces solar-grade polysilicon. This polysilicon has been used to manufacture solar cell modules, which are currently being tested and operated at the Yinchuan Solar Photovoltaic Test Station owned by Ningxia Power Generation Group Co., Ltd., the company’s controlling shareholder. The power plant was officially connected to the grid for power generation on September 15, 2008. The company organized a research team to carry out independent research on purification technologies for solar-grade polycrystalline silicon, and made significant breakthroughs in the production technologies using metallurgical-physical methods for solar-grade polycrystalline silicon and monocrystalline silicon, breaking the international technological monopoly. Currently, polysilicon used in solar power plants owned by Silver Star Energy’s subsidiaries has been successfully connected to the power grid for electricity generation. This is a power plant built using solar cells manufactured by people from Ningxia with proprietary production technologies for polysilicon and monocrystalline silicon; it is currently the largest solar photovoltaic high-voltage grid-connected power plant in the northwest. 12 Jiake Solar Silicon (Xiamen) Co., Ltd. Founded in September 1999, Jiake Company has been dedicated to the research, development, production, and sales of solar silicon and metallic silicon products since its inception. It is one of the industry leaders that have succeeded in overcoming the shortage of solar silicon materials through innovative technologies, and it is also one of the main exporters of metallic silicon products in China, ranking among the top in terms of export volume nationwide. Jiakē solar silicon is also one of the few types of silicon in China that have been successfully produced on a large scale for commercial use through metallurgical purification methods. 13. Jinzhou New Century Quartz Glass Co., Ltd. This company has independently developed a low-cost technology for producing solar-grade polysilicon materials using chemical-physical methods; this technology overcomes the challenges associated with low-cost production of solar-grade polysilicon, addresses the issues of high investment and long construction times involved in polysilicon production, and breaks through the foreign restrictions on China’s access to key polysilicon production technologies. 14. Chu Junhao from the Shanghai Institute of Technical Physics, Chinese Academy of Sciences, is currently establishing a company focused on solar photovoltaic cell materials. Leveraging its technical expertise in thin-film solar cells and building on the advanced techniques for purifying polysilicon through physical methods, it provided significant support for the research and development of polysilicon, a key material used in solar photovoltaic systems, by investing in and taking shares in Henan Xuntianyu Technology Development Co., Ltd. 15. Xinguang Silicon Industry Technology Co., Ltd. It is reported that Xinguang Silicon Industry currently uses the improved Siemens process; in addition to this relatively mature technology, physical methods for silicon purification and membrane-based polycrystalline silicon technologies are also continuously advancing. 16. Emei Semiconductor Materials Factory: At present, Emei Semiconductor uses the modified Siemens method for polycrystalline silicon production. In addition to this well-developed modified Siemens technique, physical methods for silicon purification as well as wax-based polycrystalline silicon production techniques are also constantly evolving. Amorphous silicon and thin-film solar cells, which serve as alternatives to polycrystalline silicon solar cells, are also seeing continuous technological advancements. 17. Jining CGS Polysilicon Project: As the R&D center of the CG Group, SG Technology Development Co., Ltd. plans to invest in building a polysilicon production facility with an annual capacity of 15,000 tons in Jiaxiang County, Jining City. Sinosteel Group Company is mainly engaged in the scientific and technological development, processing, and trading of metallurgical mineral resources. The author speculates that Sinosteel Group’s polysilicon project will make full use of its advantages in smelting, that is, it will adopt the physical method. 18. A company in Guiyang: Wang Ya/Li Jian (December 10, 2008, Jinqian Online – Guizhou Daily). In order to promote sustained and stable growth in investment in technological upgrades, Guiyang has made efforts to accelerate the start of construction on a number of projects. Relevant departments at the municipal level have adopted a joint meeting system to assist enterprises with the various procedures required for starting construction, thereby creating “green channels” to facilitate the commencement of key projects. In just the past week alone, a series of projects with high technical standards, independent intellectual property rights, good investment returns, and strong capacity to drive economic development have begun operations. These include projects in the fields of biotechnology in Yikang Pharmaceutical, the industrialization of new drug categories, the development of a cost-effective method for producing polycrystalline silicon using physical processes – a technique that is unique in China – as well as the renovation of Linquan Motor’s production lines for compound permanent magnet motors. Once completed, these projects will help to optimize and upgrade Guiyang’s industrial structure. The above are merely companies that follow the physical method as gathered by me from the Internet. Of course, there are many more researchers working on the production of polysilicon using this physical method; these include institutions such as universities and research institutes. However, due to strict confidentiality measures, their work does not make it into the news. Perhaps one day, some unexpected breakthroughs will emerge.