In some zinc mills, the primary feed for zinc production is nickel cake. After acid removal, nickel cake decreases its zinc (Zn) by 10 to 15 percent, and increases its nickel content by 4 to 6 percent, and cadmium It rises to 15-25%. Unfortunately, in some workshops, this cake is used non-principled and dangerous, and zinc (Zn) and cadmium (Cd) are burnt in the furnace, and its nickel is concentrated to 80%, which is very dangerous and polluting the environment.