Capacity: 8.000 tons/year (view Block Flow Diagram)

Raw materials:

•     • silicofluoric acid (20-40%)
•     • aluminium hydroxides
•     • sodium fluorosilicate
•     • calcinated soda

Product: synthetic cryolite

•     • fluort content: min. 52,5%
•     • aluminium content: min. 12,5 %
•     • sodium content: max. 33,0%
•     • fineness: under 100 mesh

Technology: own development - Built in 1972, rebuilt in 1988-89.

Status: working

Typical operating requirements per metric ton of cryolite

•     • silicofluoric acid solution: 0,40 tons
•     • aluminium hydroxides: 0,48 tons
•     • sodium fluorosilicate: 0,47 tons
•     • calcinated soda: 0,58 tons
•     • steam:4 GJ
•     • gas:66 gn m3
•     • electic power:440 KWh
•     • technological water: 14 m3

Equipment list:

Process of NaF                pieces                 size

calcinated soda store       1                        90 m3

slurry maker                   2                        10 m3

reactor                           3                        4 m3

dissolver                         3                        5 m3

buffer tank                      2                        60 m3

filter                               1                        120 m2

storage tank                    2                        120 m3

 

 

Process of AlF3                pieces                  size

ilicofluoric acid solutions   5                         150 m3

reactor                           3                         4 m3

centrifuge                       2                         2,5 m2

storage tank                    2                         60 m3

 

 
Process of cryolite            pieces                  size

reactor                            1                        120 m3

settler                             2                         7 m3

filter                                2                         4 m2

vaccum pump                   2
   
dryer-calcinator                 1   

classifier                           1   

cryolite                             2                         160 m3

packing machines              2
   

 

Grinding mill

Brief process description. The technology is own developed and has 4 parts.

•     • Production of AlF3 solution: The solution of aluminium-fluoride is produced by mixing and heating of silicofluoric acid solution and aluminium hydroxides. The amorphous silicon dioxode which arises in the reaction is removed by centrifuging. The clear solution of aluminium-fluoride is diluted by water from 120 gram pro litre to 45 gram pro litre.
•     • Production of NaF solution: The sodium-carbonate is dissolved than sodium fluorosilicate is added to it. The reaction takes place in heated and mixed reactors while NaF solution arises with amorphous SiO2 content. SiO2 is filtered out and the clear NaF solution is used for the production of cryolite.
•     • Production of cryolite: The crystal cryolite is produced in mixed and heated reactor from the clear solutions of AlF3 and NaF. The end -product is filtered from the liquid layer.
•     • Drying, calcinating, classification, packing: During these processes water is extracted from the humid cryolite and the product is classified and packed by granulometry.

Comments: Per metric ton of cryolite arises 420 kg SiO2 (66% moisture content, 1 % F content) during the production of NaF, and during the production of AlF3 arises 205 kg SiO2 (30% moisture content, 1% F content), which materials are hazardous for the environment.From these wastes, after making them harmless with CaCO3 and CaO, is made a soil-improving material which contains CaSiO3.