Metallurgical Silicon
Silicon dioxide is commonly found in nature. To produce highly pure silicon usable for the solar and semiconductor industry, the silicon has to be reduced from the oxide form via specialized equipment designed for high quality and productivity. This is achieved by smelting raw materials, ensuring the separation of contaminants which could negatively affect the polysilicon or a subsequent step in the supply chain of the semiconductor or photovoltaic industry.
Metallurgical silicon is manufactured using silicon dioxide in the form of quartz and carbon as raw materials in a reduction furnace at temperatures of 2,000° C. During the smelting process a chemical reduction of the silicon dioxide takes place, resulting in metallurgical silicon. The final product reaches a purity of up to 99%, depending on the selected quartz quality.
In the first refining process, the impirities are removed from the metallurgical silicon which is endoped with a specialized catalyst via defect engineering. The higher degree of purity leads to improved quality and performance in polysilicon production.
The second optimization step is granulation, which replaces the widely spread mechanical milling of metallurgical silicon. With average loss rates of 10 – 15 %, milling is technically and environmentally challenging and costly. Thanks to EMS granulating, metallurgical silicon is produced with uniform size distribution and highly reactive engineered surface characteristics and composition for a high performance direct chlorination or hydrochlorination process.
Our tailored solutions can be scaled from 2,500 t/a to 10,000 t/a of poly-production and more.
For EMS manufacturing, centrotherm supplies silicon micro smelting furnaces, refining and granulating equipment as well as appropriate processes, quality management and all engineering services. Furthermore, our experienced team of lean six sigma black belts supports our customers in quality assessment and optimization. According to customer requirements, we offer material analysis, trainings, simulations and further support.
Please contact us to learn more.
