Cryolite (Na3AlF6)

Cryolite (Na3AlF6) is used in the manufacture of aluminium as a flux in the electrolytic baths of the molten metal. Historically, cryolite was used exclusively as the flux material, but has been replaced by aluminium fluoride. However, when pot lines are stared cryolite is used as all or part of the flux material.

 

Many processes for the manufacture of Na3AlF6 from HF have been described. This product can also be made from low value fluorine sources; such as effluent gases from phosphorous or superphosphate plants (H2SiF6).

 

CHENCO has developed an economical, successfully working process to produce Na3AlF6 via H2SiF6 route or via sodiumhexafluosilicate (Na2SiF6) route.

The process is carried out according to the following stages:

  • Preparation of NaF solution
  • Preparation of AlF3 solution
  • Reaction of NaF and AlF3
  • Drying and calcination

 

  

Advantages of the CHENCO cryolite process: 

  • Flexible process

    • Can be used for NaF only
    • Can be used for cryolite
    • Or can be used for both products, NaF and cryolite

  • Low cost
  • High quality
  • Raw material flexibility - NaOH, Na2CO3 or NH3