2. Extraction of Titanium

3. Introduction Of Titanium
 It is a transition metal.
 Member of group four in periodic table.
 it’s atomic number is 22.
 It’s mass number is 47.87
 It has 5 stable isotopes with mas number 46-50 respectively.
 It also has 4 unstable isotopes with mass number 43,44,45 and 51.

4. History And Occurrence
 It was discovered by William Gregor 1791 in England .
 He recognized it to be present to ilmenite (FeTio3) from black sand due to its
non-magnetic nature.
 It is derived from Greek word titans.
 In 1795 a German chemist martin klaproth is discovered it from rutile named
it titanium after titans.
 In 1910 hunter prepared metal by heating TiCl4 with sodium.
 It is 0.6% of the earth’s crust.
 It is 9th in order of abundance after oxygen and other 7 metals.
 It’s main ores are rutile(TiO2), ilmenite(FeTio3) and sphene (CaTiSiO5).

5. Properties
 It’s color is silvery metallic .
 It is solid at room temperature.
 Its M.P is (1668°C) and B.P is (3287°C).
 Its density is 4.506g/cm3.
 Strength of pure Ti decreases by 50% by increasing temperature up to 200°C.
 It is light weight, corrosive resistant and can withstand at very high
temperature.
 It is less resistant to corrosion in strongly reducing media.

6. Extraction
 The main source of Ti extraction is rutile.
 Rutile is converted into Ti by following processes:
1. Chloride process
2. Reduction with Carbon
3. Electro winning

7. Chloride process
 In this process rutile is converted into TiCl₄
 Calcined coke is used as reducing agent as it has low ash content
 Because of low volatile contents of coke no HCl will found
 TiO₂ + 2Cl₂ +C = TiCl₄ + CO₂
 Because of the rise in temperature CO will form from CO₂ and carbon from
coke.
 So we should introduce oxygen with Cl to maintain temperature at 800-
1200°C.
 Coke consumption per ton of TiO₂ is 250 to 300 Kg

8. Production of titanium sponge
Crude TiCl₄
Preheating
Distillation <136°C SiCl₄,SnCl₄
H₂S, Cu Agitation and precipitation 90°C VOCl₂
Distillation >136°C FeCl₃,AlCl₃
Pure TiCl₄

9. Purification of TiCl₄
 As the ore contains different impurities they either may be elements or
dust.
 The elements form chlorides and are solid at room temperature.
 These chlorides & dust are removed from TiCl₄ by distillation.
 Some chlorides like VCl₄,VOCl₃ can not be removed by distillation as
they have close boiling points.
 They are reduced to form solid low value VCl₄ & VOCl₃
 Reducing agents may be Cu,H₂S, hydrocarbons & amines
 In TiCl₄ there should be V less than 5 ppm

10. Oxidation of TiCl₄
 TiO2 used in chloride process is not pure so we form TiCl₄ for its
purification.
 Now we have to make TiO₂ again
 So we oxidize TiCl₄
 TiCl₄ + O₂ = TiO₂ + 2Cl₂
 It is a weakly exothermic reaction, temperature of reaction should be high
 Temperature > 1000°C can be achieved by heating O₂
 Hot TiCl₄ & O₂ are fed into a reaction chamber separately
 They must be mixed rapidly & completely to give a high reaction rate
 The Cl can be removed either by liquefaction or by flushing N₂ or air

11. Reduction of TiO₂:
 The reduction of titanium dioxide by carbon is only possible above 6000°c.
 A complete reduction of titanium dioxide is only possible with alkaline
earth metal.
 By dissolution of excess ca and cao in Hcl at 600-1200°C in a vacuum o
content of 0.1-0.3% in Ti is obtained.
 Reduction with CaH₂ at 600-700°C gives TiH₂, which decompose at 900°C
in to Ti and H₂.

12. Reduction of Ticl₄(Kroll process):
 Reduction is as
 TiCl₄+2Mg Ti+2MgCl₂
 It is discovered by Kroll.
 Mg boil at 1120°C and MgCl₂ melts at 711°C the resulting temperature range and
the high purity of Mg are advantages.
 The reactor constructed of plain c steel and (Cr- Ni) steel and interior was clean
by brushing or a (Ti) coated.
 The reactor is charged with oxide free lumps of Mg and filled with (Ar) and (Mg) is
melted at 651°C.

13. Continued
 When temperature reaches 700°C, purified TiCl₄ is run in slowly
form above or blown in as a vapour, such that a reaction
temperature of 850-950°C.
 The Ti sponge is deposited in the reactor walls and form the solid
cake above the molten Mg.
 The molten MgCl₂ collects beneath Mg and is drown of.
 The Mg raises through the pours cake to it surface by capillary
action and reacts their gaseous TiCl₄.

14. Continued
 Temperature must not exceed 1025°C to prevent the reaction between Ti
and Fe of reactor.
 The amount of Ticl₄ reacted are 10-50% as some of Mg and Mgcl₂ in the Ti
sponge .
 Excess of Ticl₄ leads to the formation of lower Ti chlorides and FE
chloride.
 Generally temp ranges 850-950°C the lower temp give large reaction
time and pure sponge.
 And removing Mgcl₂ and when temp falls to 200°C the vessel is opened in
dry room because Mgcl₂ and Ticl₄ are hygroscopic.
 Crude sponge is purified by vacuum distillation and rarely leaching is used.
 Leaching solution is H₂o Hcl and HNO₃.

16. Thermal decomposition of Ti halide:
 The old process of VAN Arkel and DEBORE in which TiI₄ is decomposed on
electrically heated tungsten wise at 1000˚C.
 If wires of single Ti are used then high purity can be obtained.
 Librated I₂ reacted with corrode Ti to regenerate TiI₄.In same vessel
below 200˚C Over above 500˚Cabove 200˚C
 Lower Ti iodized are formed witch only act as Ti carries above 500c
because of low volatility. Highest purity Ti is produced by crud Ti or Ti
scrap.

17. Continued
 Very high purity Ti there also be obtained by thermal disproportionation
of Ti chloride and bromide.
 by passing TaCl₄ vapor over Ti containing material at 950-1500˚C
 Ti chloride is formed.
 Ticl₂ vapor is condensed and is decomposed at 100O˚C
 2TiCl₂ Ti+TiCl₄
 TiCl₄ is fed back to the process .

18. Electro wining
 High affinity of Ti for O₂ and H₂ prevents its deposition from aqueous
solution hence molten salt electrolyses can be used .
 Only halides are suitable for electrolyses Ti tetraflouride combine with
alkali metal and alkaline earth metal fluoride to form complex hexafloro
titanates and these compound decomposed below there melting point
with the removal Ti tetrachloride .
 These compound can be used in molten salt electrolyses as a component
of molten salt bath .
 We add oxide to salt bath, oxygen pick up by the titanium metal must be
prevented by using low temperature by separating the anode to cathode
and by turbulence in electrolyte.

19. Processing of scrap metal
 For mass production of Ti , Ti scrap should be used
 This scrap is produced during the production of semi finished products, their
processing to finish products
 This scrap may be mixed with sponge & compressed.
 It may also be welded with sponge.
 This scrap can also be added to the melt in small pieces along with sponge.
 The scrap may also be used to produce Ti instead of mixing it with Ti sponge.
 Untreated scrap can be added to steel, Ni, Al, Cu & Zn alloys.

20. Uses
 Titanium alloys are used in aircraft.
 These are also being used in naval ships, space crafts & missiles.
 In steel alloys to reduce grain size and as a deoxidizer.
 In stainless steel to reduce carbon content.
 Because it is considered to be physiologically inert, the metal is used in joint
replacement implants such as hip ball.

21. Uses
 Since titanium is non-ferromagnetic, it is used for long term implants & surgical
instruments for use in image-guided surgery.
 95% of titanium is consumed for the production of TiO₂ which is used in paint, rubber,
paper and many other materials.
 TiO₂ is also used heat exchangers, airplane motors, bone pins and other things requiring
light weight metals or metals that resist corrosion or high temperatures.
 Due to excellent resistance to sea water, TiO₂ is used to make propeller shafts.