Reduction leaching of cobalt slag

The cobalt slag produced by the nickel electrolysis system is purified. The main elemental composition is shown in Table 1.

Table 1 cobalt residue content of the main metal element

Metals such as Co, Ni, Cu, and Fe are mainly present in the form of oxygen oxides in the cobalt slag. The pH is adjusted to 1.5 to 1.7 with sulfuric acid at a liquid to solid ratio of (3 to 4):1 and mechanical or blast agitation. , passed through SO _{2 to} reduce dissolution. However, before the initial introduction of SO ₂ , oxygen is evolved due to oxidation of Cl ^− , and Ni, Co and Cu are divalently separated into the solution during the reduction leaching, and part of Fe is oxidized to trivalent when the drum air is stirred and leached. The main chemical reactions can be expressed as:

In air with stirring drum, a partial oxidation of ferrous ions can occur, such as:

The components of the reducing leachate are listed in Table 2.

Table 2 Main components of cobalt slag reduction leachate