Preparation and extraction of Titanium

 

Titanium(Ti)

•  Atomic Number: 22
•  Atomic weight: 47.867

Physical Properties:

•       lustrous transition metal with silver colour
•       low density
•       high strength
•       Resistant to corrosion in sea water, aqua regia and chlorine.

Chemical properties:

• Titanium is corroded by concentrated acids.
• Titanium is readily reacts with oxygen in the presence of air at 1200^o  c and it is also reacts with halogens and absorbed hydrogens.      

Occurrence:

              Titanium is obtained as oxides in most igneous rocks and sediments derived from them , in living things and natural bodies of water, sand, clay and mostly provided by  0.44 percent in the earth crust .illuminite and rutile is  the most two  commercial minerals. Because of its reactivity , the preparation of the pure titanium is difficult. Titanium cannot be obtained by the reduction of oxide with carbon because a very stable carbide is produced continuously and the metal is reactive with oxygen and nitrogen at elevated temperatures. The pure titanium is obtained from its mineral ores using by the Kroll and hunter process.

EXTRACTION OF TITANIUM:

              ORE: Rutile, TiO₂

              The titanium is extracted by the conversion of titanium (IV) oxide (TiO₂) into titanium (IV) chloride. This titanium chloride is reduced by using either magnesium or sodium.

STEP I:

CONVERSION:

              The ore rutile (TiO₂) is converted in the presence of chlorine and coke at the temperature of about 100^oc.

TiO₂ + 2Cl₂ +2C →TiCl4 + 2CO

              The other metal chloride are also formed by this method because of other metal compounds in the ore. By using the fractional distillation method, the pure titanium (IV)chloride metal is separated from the other chlorides. This pure metal is stored in dry tanks only. Because titanium chloride is easily reacted with oxygen in the presence of air and it produced titanium oxide and fumes of hydrogen chloride.

STEP II:

REDUCTION:

              In the reaction vessel containing the molten magnesium. Titanium chloride (TiCl4) is passed into the vessel in an argon atmosphere and then the temperature is increased to above 1000oc. The reduction process is acts on very slow so that the process is extended for two more days. When its cool the reaction mixture is crushed. For removing the excess of magnesium chloride, we need to add the dilute hydrochloric acid into the reaction mixture. After that all the magnesium chloride is dissolved in the presence of water. The remaining titanium is purified in the further process.

TiCl₄ + 2Mg →Ti + 2MgCl₂

USES:

              Titanium is used in parts of jet engines , Golf clubs, fuel tanks, aircraft bodies, landing gears, tennis rackets, bicycle and so forth.