During the zinc refining process, cement copper is obtained when adding

- a reducing agent i.e. Zinc powder, Fe-powder, Al-powder, H2, ...- to the Copper loaded Zinc Sulphate solution and precipitation (cementation) of a Copper-rich precipitate.

- a neutralizing agent (e.g. Zinc oxide, Na(OH), ...).to the Copper loaded Zinc Sulphate solution and precipitation (hydrolysis) of a Copper-rich precipitate.

- Cu+ containing solution to a Cl- containing Zinc Sulphate solution, or a reducing agent if the Zinc Sulphate solution is Cu++ rich, and precipitation of a CuCl rich precipitate

The copper loaded Zinc Sulphate solution (ZnSO4 solution,  EC 273-723-4) obtained from the leaching -intermediate step undergoes redox reactions to purify it from copper content. In the redox reactions reducing agent (i.e. Zinc powder, Fe-powder, Al-powder, H2, ...)  and neutralizing agent (e.g. Zinc oxide, Na(OH), ...) are used with the  Cu+ and Cl- containing Zinc Sulphate solution. Ratios of redox agents  are adapted depending on the elemental composition o f the copper loaded zinc sulphate solution (EC 273-723-4), to ensure efficient purification from  copper, allowing extraction of Cu and Cu-compounds from the feed.

Cementation is a precipitation process in which ions are reduced to zero valence at a solid metallic interface and is used to refine the zinc leach solutions from the copper. During the hydrometallurgical production of metal and/or metal-compounds, redox-potential variations (cementation) result in the selective precipitation of a'copper-precipitate’ that concentrate copper and copper-compounds. Cement copper is obtained when adding:
- a reducing agent i.e. Zinc powder, Fe-powder, Al-powder, H2, ...- to the Copper loaded Zinc Sulphate solution and precipitation (cementation) of a Copper-rich precipitate.
- a neutralizing agent (e.g. Zinc oxide, Na(OH), ...).to the Copper loaded Zinc Sulphate solution and precipitation (hydrolysis) of a Copper-rich precipitate.
- Cu+ containing solution to a Cl- containing Zinc Sulphate solution, or a reducing agent if the Zinc Sulphate solution is Cu++ rich, and precipitation of a CuCl rich precipitate                                                                                                                                                                                After settling step, the precipitate is optionally re-pulped in a second reaction tank with a slightly acidic sulphate solution in order to dissolve the excess of unreacted zinc powder and potentially co-precipitated cadmium. The cement copper is further sent to industrial copper installations for further extraction of copper.  

Insoluble copper intermediate, obtained by purification of zinc sulphate solution via cementation (redox process) and further used to extract copper. Source material is always the zinc sulphate solution intermediate ( EC 273-723-4), purified from its copper content by means of reducing or neutralizing agents (depending on the solution elemental composition) to obtain a copper intermediate that will be further processed in the Cu industry (for Cu extraction).