Chloride process
Encyclopedia
The chloride process is used to separate titanium
from its ores. In this process, the feedstock is chlorinated at 1000 °C with carbon
and chlorine
gas, giving titanium tetrachloride
. Typical is the conversion starting from the ore ilmenite
:
The process is a variant of a carbothermic reaction
, which exploits the reducing power of carbon.
Other impurities are converted to the respective chlorides as well but they are less volatile than TiCl4. The titanium tetrachloride is purified by distillation
. It can be subsequently oxidized in an oxygen
flame or plasma to give the pure titanium dioxide. Alternatively, via the Kroll process
, the purified titanium tetrachloride can be reduced with magnesium
to give titanium
metal.
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
from its ores. In this process, the feedstock is chlorinated at 1000 °C with carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
gas, giving titanium tetrachloride
Titanium tetrachloride
Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is an unusual example of a metal halide that is highly volatile...
. Typical is the conversion starting from the ore ilmenite
Ilmenite
Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....
:
- 2 FeTiO3 + 7 Cl2 + 6 C → 2 TiCl4 + 2 FeCl3 + 6 CO
The process is a variant of a carbothermic reaction
Carbothermic reaction
Carbothermic reactions use carbon as reducing agent, usually for metal oxides. These chemical reactions are usually conducted at several hundreds of degree Celsius. Such processes are applied for production of the elemental forms of many elements. Carbothermic reactions are not however useful for...
, which exploits the reducing power of carbon.
Other impurities are converted to the respective chlorides as well but they are less volatile than TiCl4. The titanium tetrachloride is purified by distillation
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
. It can be subsequently oxidized in an oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
flame or plasma to give the pure titanium dioxide. Alternatively, via the Kroll process
Kroll process
Kroll Process is a pyrometallurgical industrial process used to produce metallic titanium. It was invented by William J. Kroll in Luxembourg. After moving to the United States, Kroll further developed the method for the production of zirconium...
, the purified titanium tetrachloride can be reduced with magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
to give titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
metal.