Electrorefining of Copper

Cu (impure) → Cu²⁺ + 2e⁻ → Cu (pure)

Overview

Impure copper anodes (99.5%) dissolve electrochemically while pure copper (99.99%) deposits at the cathode from CuSO₄/H₂SO₄ electrolyte. Impurities either remain in solution or fall as anode slime (containing gold, silver, platinum). The voltage required is only 0.2–0.3 V since the same reaction occurs at both electrodes.

Participants

Role	Substance	Coefficient	State
Reactant	Copper Cu	1	(s)
Product	Copper Cu	1	(s)

Everyday Example

All the copper wiring in your home was refined to 99.99% purity by this electrorefining process.

Industrial Importance

About 80% of the world's copper (20 million tonnes/year) is electrorefined. Precious metals recovered from anode slime significantly offset costs.

Properties

Type: Electrochemical
Reversible: No
Energy: Endothermic
ΔH: 0.0 kJ/mol

Related Reactions

Alkaline Battery Discharge Anodizing of Aluminum Cathodic Protection (Zinc Sacrificial Anode) Chlor-Alkali Electrolysis Chrome Electroplating Copper Electroplating Daniell Cell (Zinc-Copper Galvanic Cell) Electrochemical CO₂ Reduction to CO Electrochemical Machining (ECM) Electrolysis of Molten NaCl (Downs Process)

Frequently Asked Questions

What is the equation for Electrorefining of Copper?

The balanced equation is: Cu (impure) → Cu²⁺ + 2e⁻ → Cu (pure).

What type of reaction is Electrorefining of Copper?

Electrorefining of Copper is a electrochemical reaction.

Is Electrorefining of Copper exothermic or endothermic?

Electrorefining of Copper is endothermic (absorbs energy). The enthalpy change (ΔH) is 0.0 kJ/mol.