In the process of zinc production by the method of hydro-metallurgy, after the hot treatment stage, which leads to the absorption of cobalt (Co) and manganese (Mn), the cold filtration stage. Cool refining is a term that reduces the temperature of the solution to about 15 degrees and is about 70 to 74 degrees compared to the previous one. In this step, the cementation of nickel (Ni) and cadmium (Cd) by the zinc powder are cemented and removed from the solution. The cake produced in this stage is called nickel-cadmium cake or cold cake, depending on the quality of the soil used, the amount of these elements varies in cake and is mainly in the range of 40 to 55 percent, nickel 2 to 3 percent, and cadmium 3 to 6 percent.
Usually, this waste is collected in 1 to 1.5 tons of jumbo bags.
Washed nickel cake:
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.