Electrolytic Purification of Copper When metals are extracted from their ores, they are not very pure.

Electrolysis can be used to purify them. This is known as electrolytic purification.

To purify copper, we perform electrolysis of aqueous copper(II) sulfate, but using copper electrodes.

Electrodes which react with the electrolyte or products of electrolysis are called reactive electrodes.15.4 Industrial Applications of Electrolysis*

Electrolysis of Aqueous Copper(II) Sulfate Using Reactive Copper Electrodes15.4 Industrial Applications of Electrolysiscopper anodecopper cathodeCuSO4(aq)The ions present in aqueous copper(II) sulfate are:

Cu2+, SO42 , H+ and OH *

Electrolysis of Aqueous Copper(II) Sulfate Using Reactive Copper ElectrodesAt the anode:

OH ions and SO42 ions are attracted to the anode.

Since copper is not an inert electrode, the anode dissolves: Cu(s) Cu2+(aq) + 2e The anode decreases in mass.15.4 Industrial Applications of Electrolysiscopper anodecopper cathodeCuSO4(aq)*

At the cathode:

H+ ions and Cu2+ ions are attracted to the cathode.

Cu2+ ions are preferentially discharged as copper metal (atoms).

Cu2+(aq) + 2e Cu(s)The cathode increases in mass.15.4 Industrial Applications of ElectrolysisElectrolysis of Aqueous Copper(II) Sulfate Using Reactive Copper Electrodescopper anodecopper cathodeCuSO4(aq)*

Summary The Cu2+ ions that are discharged at the cathode come mainly from the anode.There is no net loss of Cu2+ ions from the solution.The colour and concentration of copper(II) sulfate remain unchanged.15.4 Industrial Applications of ElectrolysisElectrolysis of Aqueous Copper(II) Sulfate Using Reactive Copper Electrodescopper anodecopper cathodeCuSO4(aq)*

The Extraction Process There are mainly three steps of the extraction process: Dissolution of copper carbonate, formation of copper sulfate and electrolysis of copper sulfate. *

Role PlayYou guys will now get to role play the electrolysis of aqueous copper(II) sulfate copper electrodes.

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Action Time*

Analog Role PlayTarget ElectrolysisIndividual studentsOxygen, sulfur and carbon atomsFour students linking armsCarbonate ionIndividual labelled studentCopper ionBook resting on students shoulderElectronStudents separatingDissolutionLinking with one armSingle BondLinking with two armDouble BondChairPositive electrodeChair with books on itNegative electrode

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