Large-scale high-value utilization of polysilicon by-products

Thread Content

Large-scale high-value utilization of polysilicon by-products: Through diligent efforts, Sichuan Yinbang Silicon Industry Co., Ltd. has developed an effective method for the large-scale and continuous high-value utilization of polysilicon by-product silicon tetrachloride. It has built China’s first pilot production line for the treatment of silicon tetrachloride using a continuous, closed, energy-efficient, and high-performance tower-based chemical process. This achievement passed the evaluation of scientific and technological achievements in Sichuan Province last week. Mou Haobin, the company’s leader, revealed yesterday that the enterprise is currently planning an industrialization project with a capacity of 50,000 tons. Mou Haobin explained that the pilot project for treating polysilicon byproduct silicon tetrachloride using the tower-type chemical method has an annual processing capacity of 4,500 tons, thereby overcoming the technical challenge that had prevented China from producing high-purity organic silicon intermediates with a purity of over 99.9% on a continuous basis. This project has passed the joint inspection by the relevant departments at the **, provincial, and municipal levels. Product testing results show that the purity is ≥99.997%, and the residual acid value is less than 0.007‰, which are on par with the specifications of similar products from companies in Germany, the United States, and Japan, representing an internationally advanced level. Currently, the main methods for treating silicon tetrachloride in China are hydrogenation and combustion, but the scale of treatment is limited; most of the silicon tetrachloride is released into the environment where it is treated through hydrolysis. This process generates large amounts of low-quality precipitated silica, which poses significant potential environmental hazards. The chemical treatment technology developed by this company involves reacting silicon tetrachloride with lower aliphatic alcohols under specific process conditions to produce high-purity organosilicon intermediates – alkoxysilane products. The new technology has three key advantages: first, unlike the batch intermittent reaction processes used with other technologies, Yinbang Silicon Industry employs a continuous, closed-tower chemical treatment method, **which reduces the emission of polluting gases during the processing process ； Secondly, distillation is used for purification after the reaction, which **increases** the purity of the product, raising it from 99.5% to over 99.9% ； Thirdly, the use of a continuous tower reactor ensures the continuous and stable progress of the reaction. It is reported that Yinbang Silicon Industry will commence the construction of its second-phase production facility with an annual capacity of 10,000 tons in April. This includes a project for producing 30,000 tons per year of silicone intermediates, as well as an expansion project designed to process 42,000 tons per year of polysilicon by-products, produce 40,000 tons per year of alkoxy silanes, and 85,000 tons per year of 31% industrial hydrochloric acid. Using high-purity alkoxy silanes as raw materials, this facility will also produce 30,000 tons per year of special silicone oils, silicone chemicals, and other downstream products. Once the second-phase industrialization project is completed, the by-products from polysilicon manufacturers in Leshan will be able to be utilized in high-value applications and as resources.