Cadmium is also produced as a by-product in the zinc production process and some secondary cadmium comes from the flue dust generated during the melting of recycled galvanized steel scrap in electric arc furnaces.
镉也作为锌生产过程的副产物产生，某些二次镉即来自在电弧炉中熔化回收的镀锌钢板废料时产生的烟道灰。