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6. Extraction of thorium:-
Ores :-
ores Chemical name
Thorianite Thorium oxide
Thorite Thorite silicate
Cheralite Silicates and phosphates of Th,
Ca, Ce
monazite Phosphates of Ce, Y, La, Th
7. Extraction of thorium:-
ores :-
• Indian monazite sand is topmost grade in the world ( seacoast of
Kerala state ).
• Extraction of thorium is difficult because rare earth elements are
present in the ore.
• They resemble their chemical properties with thorium.
8. Extraction of thorium:-
Concentration and formation of ThO2 :-
• The ore is freed from major chunks of siliceous impurities either by
mechanical washing or by magnetic separation.
• Treated with conc. Sulphuric acid in cast iron pans.
• The pasty mass is added to cold water and stirred – impurities like
sand and other minerals settle down.
• The clean top solution is separated which contains phosphates of
thorium and rare earth elements.
• This acidic solution is neutralized with alkali.
• We here get precipitates of thorium phosphate.
9. Extraction of thorium:-
Concentration and formation of ThO2 :-
• The precipitates are removed, dissolved in minimum quantity of acid.
• It is then neutralized again to get phosphate of thorium as precipitate.
• It is dissolved in conc. Nitric acid 6 M.
• Treated with KIO3 ( potassium iodate )to get thorium iodate.
• The precipitate is dissolved in HCl and re-precipitated with oxalic
acid.
• It gives thorium oxalate.
• Thorium oxalate is ignited to give thorium oxide.
12. Properties of thorium:-
Melting point is -1750℃.
Amorphous as well as crystalline.
At very low temperature it shows super conducting properties.
Burns brilliantly with sparks (ThO2 )
Highly electropositive.
Combines with hydrogen vigourously forming ThH4
Thorium is radioactive.
13. Uses of thorium:-
Fuel rod manufacture for atomic reactors.
Thorium oxide is used in preparation of incandescent gas.
Medically used in treatment of cancer.
Thorium nitrate is used to estimate fluorides volumetrically using
methyl red indicator.
Only ThO2 is a stable compound of thorium.