Physical purification methods produce polysilicon with a purity of over 99.9999%

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The physical purification method enables the production of polysilicon with a purity of over 99.9999%. The physical purification method developed independently by the Shanghai Institute of Physical Science allows for the production of solar cell silicon products with a purity of over 99.9999%, while consuming only 1/3 of the electricity and 1/10 of the water required by the \"Siemens chemical method\". This not only establishes China as a leader in the field of solar energy raw materials but also enables exports to countries such as Japan and Germany for the first time, thus securing China’s position in the international photovoltaic industry chain. Solar energy is a \"rising industry\" around the world. According to the **Medium- and Long-Term Development Plan for Renewable Energy**, by 2010 China’s installed solar power capacity is expected to rise from the current level of less than 100,000 kW to 400,000 kW, and by 2020 it will reach 2.2 million kW, indicating great potential for development. The basic material for this industry is solar cells, and the basic material for solar cells is high-purity polycrystalline silicon; at present, China relies to a large extent on imports from countries such as Germany and Japan. Due to the supply falling short of demand in the global polysilicon market in recent years, imports have not only seen rising prices but also faced numerous restrictions. Scientists and technicians in Shanghai have been working on this project since 2004. The purity of polycrystalline silicon used in solar cells is required to be much higher than 99.9%; expressed as \"N\" to indicate the number of 9s after the decimal point, it must be 4N or higher. Currently, the German “Siemens chemical method” is widely used around the world for purification; although it yields high purity, it requires a lot of energy and is not environmentally friendly. A team led by Gao Wenxiu from the Shanghai Institute of Technical Physics, Chinese Academy of Sciences, took a different approach and invented a \"physical method\" for purification, achieving a purity level of over 4N and thereby breaking the technical monopoly. Some samples, as determined by the Japanese side, have a purity as high as 5N–6N. The cross-regional industry-academia-research approach enables laboratory achievements to be rapidly industrialized in suitable environments. As a country rich in silicon ore, it has for a long time exported raw materials at low prices while importing high-purity products at high prices. Within Fangcheng County, Nanyang City, Henan Province, silica reserves amounting to 50 million tons have been detected, and these raw materials are awaiting further processing. Shanghai and Henan complement each other’s strengths perfectly; together they established Xuntianyu Technology Co., Ltd. There, finished products can be produced within just a few months, with production costs being only 1/6 of those in foreign countries. Not only have domestic solar companies flocked here, but also companies such as Mitsubishi of Japan, Itabashi and Soko K.K., as well as AG Solar of Switzerland, have come in groups to discuss matters; long-term supply cooperation agreements were reached, and the products are now being exported to Japan, Germany, and Switzerland. The project is initially planned to produce 2,000 tons per year, which accounts for half of the domestic market demand, with the international market share also expected to increase significantly.