金属硅，也称为晶体硅或工业硅，主要用作有色基合金的添加剂。金属硅是由石英和焦炭在电炉中制成的产品。主要成分中硅的含量约为98% (包括硅的99.99% 也包含在金属硅中)，其他杂质有铁、铝、钙等。
常用的等级有553/441/3303/2202/411/421等。
| 硅金属 | ||||
| 等级/规格 | Si | 铁 | Al | Ca |
| ≥ | ≤ | |||
| 97 | 97% | 1.0%-2.0% | 0.5% | 0.3% |
| 553 | 98.5% | 0.5% | 0.5% | 0.3% |
| 441 | 99% | 0.4% | 0.4% | 0.1% |
| 421 | 99.2% | 0.4% | 0.2% | 0.1% |
| 411 | 99.3% | 0.4% | 0.1% | 0.1% |
| 3303 | 99.3% | 0.3% | 0.3% | 0.03% |
| 2202 | 99.5% | 0.2% | 0.2% | 0.02% |
| 1101 | 99.7% | 0.1% | 0.1% | 0.01% |
| 2502 | 99.4% | 0.25% | 0.25% | 0.02% |
