silicon metal is differentiated by the content of iron, aluminum and calcium, and is usually divided into 553, 441, 421, 3303, etc., mainly because the content of these elements has an important influence on the physical and chemical properties of silicon, especially in industrial production and application, the content of these impurities needs to be strictly controlled.
Iron (Fe) content: Iron is one of the most common impurities in silicon. High iron silicon (usually refers to iron content exceeding 1%) is usually used in the metallurgical industry, such as making steel alloys, because iron can increase the dissolution temperature of silicon and improve its mechanical properties.
Aluminum (Al) content: The aluminum content affects the electrical properties and chemical stability of silicon. High aluminum silicon is usually used in the foundry industry because aluminum can improve the fluidity and corrosion resistance of silicon.
Calcium (Ca) content: Calcium is another common impurity in silicon, affecting the electrical properties and chemical stability of silicon. Excessive calcium content may cause adverse effects of silicon in the application of the electronics industry.
Therefore, according to the different contents of these impurity elements in silicon, metallic silicon can be divided into different grades or levels to meet the needs of different industrial fields. For example, electronic grade silicon usually requires extremely low impurity content, while metallurgical grade silicon may accept higher impurity content, which can be distinguished and identified by grades.
