Is sodium fluoride electrolyzed

In 1807, the English chemist Humphry Davy (1778–1829) was the first to carry out a melt-flow electrolysis. In this way he was able to extract the element potassium from potassium hydroxide. He obtained the sodium through fused-salt electrolysis of sodium hydroxide in a platinum dish. A subsequent experiment is described in several experiment books. Zinc bromide electrolysis is often carried out in class to show that bromine vapors and a zinc tree are formed on an electrode. [Literature 1] The principle is based on the fact that electrically charged ions can move freely in molten salts and these can be oxidized or reduced by an electric current. The alkali metals potassium, rubidium and cesium, on the other hand, are represented by a reduction with other metals. Potassium can be produced, for example, by reducing potassium chloride with sodium. [Literature 2]
  
 



  
Sodium or lithium are nowadays obtained by fused-salt electrolysis of sodium or lithium chloride in a Downs cell. This process goes back to a patent from 1902, which James C. Downs applied for. [Literature 5] As a flux for lowering the melting point to about 600 ° C, calcium chloride CaCl2 and barium chloride BaCl2 used. The melt of a Downs cell contains 30 to 40% by mass of sodium chloride and 60 to 70% of the flux mixture. The electrolytic cell consists of a steel container that is lined with stones on the inside. The graphite anode is surrounded by an iron cathode in a ring shape. The temperature of the melt is around 600 ° C, the electrolysis takes place at around seven volts and currents of more than 40,000 amperes. [Literature 2 and 3] A bell made of nickel catches the chlorine generated on the graphite anode. A wire mesh hangs from the bell as a diaphragm. This separates the chlorine gas from the sodium produced and prevents the potentially violent reverse reaction. The liquid sodium collects at the top of the diaphragm and is removed through an iron riser pipe. To produce one ton of sodium, around 2.6 tons of sodium chloride and 10,000 kilowatt hours of electrical energy are required. [Literature 3] The sodium obtained is transported in heated wagons or containers and melted under paraffin oil for further processing. [Literature 4]
   
  
Reaction equation 
 
Reduction at the cathode  2 Well+ + 2e  2 Well
Oxidation on the anode 2 cl  Cl2 + 2 e 
Overall response 2 NaCl 2 Na + Cl2 
  
    
The positively charged sodium ions migrate to the negatively charged iron cathode, they accept electrons and are reduced to sodium atoms. The negatively charged chloride ions migrate in the melt to the positively charged graphite anode. They give off electrons and are oxidized to chlorine atoms.
  
  
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