Do you wanna be rich?

We can help you!

Let's see a video first which teaches you the way to be rich!

Electrorefining

Phyllis ZhangDiana GaoCindy Zhang

Electrorefining is the process of purifying a metal by electrolysis.

+

Slab of impure copper containing such impurities as: Zn, Pb, Ag(Anode)

Pure Cu(Cathode)

- DC power supply

CuSO4(aq)

CuSO4(aq)

Pure Cu(Cathode)

DC power supply

- +

Cu, Zn, Pb, Ag

Examine the following cell

Zn2+

Zn2+

Pb2+

Cu2+

Cu2+

Cu2+

Cu2+

Cu2+

Cu2+ Cu2+

The cathode reaction:

The Cu2+ in solution is preferentially reduced at the cathode but none of the Pb2+ or Zn2+ can be reduced.(Cu2+ exists in larger amounts and has a higher reduction potential than Zn2+ and Pb2+.)

In summary:

No metals above Cu on the table can oxidize and go into solution, and no metal below Cu on the chart can reduce and come back out of solution. As a result, only Cu is involved in both the oxidation and reduction.

Impure anode pure cathode

Exercise----P246

An aqueous solution of SnSO4 was electrolyzed using tin electrodes. The anode contained a few percent of silver, copper and zinc as impurities. Which substances(s) will be oxidized at the anode? Which substances(s) will be reduced at the cathode?

Applications

leadcopper

goldsilverzinc

aluminiumchromium

cobaltmanganese

the rare-earth and alkali metals

Bibliography:the video:http://v.youku.com/v_show/id_XMjk5MDEwMTM2.html

the pictures:http://image.baidu.com

information:http://en.wikipedia.org/wiki/Electrorefining

That's all! Thank you!

Zn

Cu

Ag

Au

Pt

Pb