Transcript elkim_03

15/16 Semester genap
Teknik Elektrokimia
Instructor: Rama Oktavian
Email: [email protected]
Office Hr.: T. 11-12, Th. 08-10; 13-15, F. 08-10; 13-15
Teknik elektrokimia
Electrorefining
An electrochemical technique suitable for refining
metals produced by electrowinning or smelter.
The anode is the impure metal
Teknik elektrokimia
Electrorefining
a piece of impure metal is made the anode of
the cell. It is oxidized to the cation and then
reduced to the pure metal at the cathode.
Electrorefining technique is used to obtain
ultrapure silver, lead and copper.
Teknik elektrokimia
Electrorefining
Impure metal is oxidized at the anode and
pure metal is reduced at the cathode.
Teknik elektrokimia
Electrorefining
Teknik elektrokimia
Aqueous Electrorefining
aqueous processes presently predominate due
to their ease of handling, more developed
chemistry and familiarity with aqueous
process liquors and electrolytes
Teknik elektrokimia
Aqueous Electrorefining
Teknik elektrokimia
Electrorefining of copper
Teknik elektrokimia
Electrorefining of copper
Main reaction
Teknik elektrokimia
Electrorefining of copper
Metal distribution during electrorefining
Teknik elektrokimia
Electrorefining of copper
Metal distribution during electrorefining
Teknik elektrokimia
Electrorefining of copper
Teknik elektrokimia
Electrorefining of copper
Electrolyte composition
Teknik elektrokimia
Electrorefining of copper
Operating condition
Teknik elektrokimia
Electrorefining of copper
Refining of electrolyte
- removing copper, As and Sb by cathodic deposition in
separate electrochemical cells with insoluble anodes
-
the neutralization of the free sulfuric acid by dissolving
copper
- the electrolyte is freed from Cu, As and Sb by electrolysis
in a separate cell and from Ni, Zn and Fe by evaporation
Teknik elektrokimia
Electrorefining of copper
Processing of anodic slime
- Copper is removed from the anodic slime by dissolution in
hot dilute sulfuric acid with air circulation
- Silver of 99.99 % purity is extracted from the alloy by the
process of anodic dissolution in a solution of silver nitrate
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Fluorine (F)
- Halogen family that has atomic number 9
- an extremely reactive element and reacts with itself to
form Fluorine Gas
- the 13th most abundant element by weight
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Fluorine (F)
Fluorine is found in earth’s crust in different forms:
- Fluorspar or Fluorite (CaF2)
- Fluoroapatite [3(Ca3 (PO4)2.CaF2)]
- Cryolite (Na3AlF6)
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Uses of Fluorine (F)
- required for the preparation of uranium(VI) fluoride
- used for manufacture of chlorofluorocarbons (CFCs)
which are used as refrigerant, aerosol propellants and
foaming agent in polymers
- Fluoroalkene an important compound of Fluorine on
polymerization gives Teflon
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Production of Fluorine (F)
- Electrolysis is the only method for the isolation of the
element fluorine
Overall reaction:
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Production of Fluorine (F)
- Electrolysis is the only method for the isolation of the
element fluorine
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Production of Fluorine (F)
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Production of Fluorine (F)
Teknik elektrokimia
Electrolytic preparation of inorganic compound
Production of Fluorine (F)