17. Solvent Extraction Mineral Fusion with K 2 CO 3 Extraction
with H 2 O Filtrate Residue (K 3 [NbO 4 ] &K 3 [TaO 4 ])
(Insoluble hydroxide of Fe & Mn ) Treated with CO 2 Filter off
Filtration Filtrate Precipitate (Nb 2 O 5 & Ta 2 O 5 ) Removed
Dissolved in HF acid containing KF Fractional Crystallisation Less
soluble K 2 TaF 7 More soluble K 2 NbOF 5 Electrolysis
18. Krolls Method 2NbCl 5 +5Mg2Nb+5MgCl 2 Nb NbCl 5
+NaClNb-metal Nb 2 O 5 +AlNb-Al alloyNb 5NbC+Nb 2 O+7Nb+5CO
19. Rocket missiles Optical glass Air welding rods Petroleum
equipments With steel Nuclear reactor Gel engines Electronics