A material added in small amounts during a chemical or metallurgical process to absorb impurities.
吸气剂以少量加入化学或冶金过程中用来吸收杂质的物质
Pig iron is converted into steel by removing most but not all the impurities.
生铁变成钢要除掉大部分而不是全部的杂质。
Workers are removing impurities from silver.
工人们正去除银中的杂质。
