Industrial Electrolysis Applications: Metal Refining and Plating

Industrial Applications of Electrolysis

Electrolytic processes have significant applications in the industrial field. Some of these include:

• The acquisition of active metals.
• Metallic coatings.
• The purification of metals.

Metallic Coatings

Through electrolysis, it is possible to deposit a thin layer of metal onto another metal. This process is called electroplating and has many applications, including:

• Gold and silver coatings: Used for the aesthetic beautification of various objects.
• Zinc, nickel, chromium, and copper coatings: Designed to provide protection for metal objects against corrosion.

In zinc coating (galvanization), the electrolyte is a salt of the metal, the anode is formed by a pure zinc bar, and the cathode is the workpiece to be coated. The metal is deposited as a result of a reduction half-reaction:

Zn²⁺(aq) + 2e^- → Zn(s)

Electrolytic Copper Purification

Once metals are extracted via metallurgical procedures, it is often necessary to undergo a refining process to make them useful for specific applications. This is the case for copper, whose utility as a conductor depends largely on its degree of purity.

The purification of copper is carried out electrolytically: the electrolyte is a soluble copper salt (CuSO₄), the anode is a doped copper bar, and the cathode is a plate of pure copper. By maintaining a proper potential, the anode copper is oxidized and passes into the solution, where it is deposited on the cathode:

• Oxidation at the anode: Cu(s) → Cu²⁺(aq) + 2e^-
• Reduction at the cathode: Cu²⁺(aq) + 2e^- → Cu(s)

Impurities contained in the metal, such as other metals that often accompany copper ores, do not deposit on the cathode. Active metal ions like Fe²⁺ or Zn²⁺ remain in the solution, while noble metals such as Ag, Au, and Pt fall to the bottom of the container to be collected for later use.