EXTRACTION OF TITANIUM

CONTENTS

INTRODUCTION

TITANIUM-DISCOVERY AND NAMING

OCCURRENCE AND PROPERTIES

RUTILE

STRUCTURE

EXTRACTION OF TITANIUM FROM RUTILE

ILMENITE

LUNAR ILMENITE

DECOMPOSITION OF ILMENITE BY CONCENTRATED KOH SOLUTION UNDER ATMOSPHERIC PRESSURE

MICROWAVE REDUCTION OF OXIDISED ILMENITE CONCENTRATES

APPLICATIONS

PRECAUTIONS

CONCLUSION

INTRODUCTION

Titanium Ore:Any mineral from which titanium is extracted, principally ilmenite (FeTiO3) and rutile (TiO2).Brazil, India, and Canada are major producers. Both these ore minerals are found either in rock formations or concentrated in heavy mineral sands. The current usage of titanium on a world-wide basis is as follows•Air frames•Missiles and spacecraft•Chemical process industries•Jet engine component

TITANIUM-DISCOVERY AND NAMING

Titanium was discovered in 1791 by the English clergyman William Gregor (1761-1817). He attempted a chemical analysis of the mineral ilmenite and found a portion that he was unable to classify as one of the existing elements.

Four years later that German chemist Martin Heinrich Klaproth returned to an investigation of ilmenite and isolated the new element.

He suggested the name of titanium for the element in honor of the Titans, mythical giants who ruled the Earth until they were overthrown by the Greek gods.

TITANIUM-OCCURRENCE

Titanium is in the earth's crust with an abundance estimated at about 0.63%. The most common sources of titanium are ilmenite, rutile, and titanite.

The metal is often obtained commercially as a byproduct of the refining of iron ore.

It can be produced from its ores by electrolyzing molten titanium chloride (TiCl4)

TITANIUM-PROPERTIES

Titanium exists in two allotropic forms, one of which is a dark gray, shiny metal

The other allotrope is a dark gray amorphous powder.

The metal has a melting point of 3,051°F (1,677°C), a boiling point of 5,931°F (3,277°C), and a density of 4.6 g/cm3.

PROPERTIES

At room temperature, titanium tends to be brittle, although it becomes malleable and ductile at higher temperatures.

Chemically, titanium is relatively inactive. At moderate temperatures, it resists attack by oxygen, most acids, chlorine, and other corrosive agents.

RUTILE.

Rutile is a mineral composed primarily of Titanium dioxide,TiO2.

Three rarer polymorphs of TiO2 are known:

anatase (sometimes known by the obsolete name 'octahedrite'), a tetragonal mineral of pseudo-octahedral habit;

brookite, an orthorhombic mineral; and

eclogites.

Rutile has among the highest refractive indices of any known mineral and also exhibits high dispersion.Natural rutile may contain up to

10% iron. Rutile derives its name from the Latin rutilus, red, in reference to the deep red color observed in some specimens when viewed by transmitted light.

OCCURRENCE-RUTILE

Rutile is a common accessory mineral in high temperature metamorphous rocks and igneous rocks.

Rutile is the preferred polymorph of TiO2 because it has the lowest molecular volume of the three polymorphs.It is thus the primary titanium bearing phase in most high pressure metamorphic rocks.

Rutile in quartz

STRUCTURE OF RUTILE

Rutile has a body centered tetragonal unit cell.

It has a density of 4240 kg/m3

The titanium cations have a co- ordination number of 6 meaning they are surrounded by an octahedron of 6 oxygen atoms.

The oxygen anions have a co-ordination number of 3 resulting in a trigonal planar co-ordination.The unit cell of rutile. Ti atoms are grey; O atoms are red

SYNTHETIC RUTILE

Synthetic rutile was first produced in 1948 and was sold under a variety of names.

Very pure synthetic rutile is transparent and almost colorless (slightly yellow) in large pieces.

Synthetic rutile can be made in a variety of colors by doping, although the purest material is almost colorless. The high refractive index(2.62-2.90) gives an adamantine lusture and strong refraction that leads to a diamond-like appearance.

Rutile is seldom used in Jewellery because it is not very hard (scratch-resistant), measuring only about 6 on the mohs hardness scale.

It has dispersion 6.5 times that of diamond which gives it an exceptional display of fire, and far too much to be diamond.

EXTRACTION OF TITANIUM FROM RUTILE

Conversion of titanium(IV) oxide, TiO2, into titanium(IV) chloride, TiCl4

The ore rutile (impure titanium(IV) oxide) is heated with chlorine and

coke at a temperature of about 900°C.Reaction:TiO2+2Cl2+2C→TiCl4+2CO

Very pure liquid titanium(IV) chloride can be separated from the other chlorides by fractional distillation under an argon or nitrogen atmosphere, and is stored in totally dry tanks.Titanium(IV) chloride is a typical covalent chloride. It is a colorless liquid which fumes in moist air due to reaction with water to give titanium (IV) oxide and fumes of hydrogen chloride. Everything has to be kept very dry to prevent this happening.

FRACTIONATION:Titanium tetrachloride is purified by distillation (BP 136.4) to.

remove iron chloride.Reduction of the titanium (IV) chloride

1. Reduction by sodium

The titanium(IV) chloride is added to a reactor in which very pure sodium has been heated to about 550°C - everything being under an inert argon atmosphere. During the reaction, the temperature increases to about 1000°C.The product formed is called titanium sponge.

Reaction:TiCl4+4Na→Ti+4NaClAfter the reaction is complete, and everything has cooled (several days in total - an obvious inefficiency of the batch process), the mixture is crushed and washed with dilute hydrochloric acid to remove the sodium chloride.

Reduction by magnesium:The method is similar to using sodium, but this

time the reaction is:TiCl4+ 2Mg→Ti+2MgCl2The magnesium chloride is removed from the titanium by distillation under very low pressure at a high temperature.

Melting:Titanium sponge is melted under argon to produce ingots.

C

Red Heat

800 ⁰C

impurity of Mg and MgCl2

Spongy metallic Tiheat

1000⁰CTi sponge

(free of Mg)

fused

Under ArTi ingots

molten Mg or NaUnder Ar

TiCl4 TiCl4 + CO2 (with FeCl3 impurity)

FractionationTiO2 +Cl2

Kroll Process

Titanium Dioxide Producers in India

Company Technology Route

Grade Installed Cap.,TPA

Travancore Titanium Products Ltd.

NL/Trioxide(Sulphate)

Anatase 24,500

Kolmak Chemicals Ltd.

Indigenous(Sulphate)

Anatase 2,400

Kerala Minerals & Metals Ltd.

KMML(Chloride)

Rutile 22,000

Kilburn Chemicals Ltd.

(Sulphate)

Anatase 3,960

Total Capacity 52,800

Comparison of Consumption Patterns of Titanium Dioxide (%):

Region→Industry

USA Western Europe

Rest of World

India

Paintings & Coatings

51 62 75 68

Paper 24 9 4 6Plastics

14 18 8 10

Others

11 11 13 16

ILMENITE:

Ilmenite is a weakly magnetite titanium-iron oxide mineral which is iron-black or steel-gray.

It is a crystalline iron titanium oxide (FeTiO3).

It crystallizes in the trigonal system, and it has the same crystal structure as hematite.

LUNAR ILMENITE

Ilmenite has been found in Moon rocks, and is typically highly enriched in magnesium .

In 2005 NASA used the Hubble Space Telescope to locate potentially ilmenite-rich locations.

This mineral could be essential to an eventual Moon base, as ilmenite would provide a source of iron and titanium for the building of structures and essential oxygen extraction.

DECOMPOSITION OF ILMENITE BY CONCENTRATED KOH SOLUTION UNDER ATMOSPHERIC PRESSURE

A new process was provided for decomposition of ilmenite by concentrated KOH solution under atmospheric pressure.

Approximately 80–85% of the titanium could be leached from the ilmenite ore under the optimal conditions.

PROCEDURE

The reaction of ilmenite with concentrated KOH solution led to the formation of potassium titanate (K4Ti3O8) and iron oxide

Reaction:3FeTiO3 + 4KOH → K4Ti3O8 + 3FeO + 2H2O

The titanium extraction was calculated by dissolving the sample in HCl, and the dissolution took place according to the following reaction:

Reacton:K4Ti3O8 + FeO + 12HCl → 3TiOCl2 + FeCl2 + 4KCl + 6H2O

MICROWAVE REDUCTION OF OXIDISED ILMENITE CONCENTRATES

Microwave energy has potential for the speedy and efficient heating of minerals and in a commercial context may provide savings in both time and energy.

The oxidation and reduction of iron in ilmenite concentrates between the ferrous and ferric states has been found to greatly enhance its chemical activity.

When reduced to the correct extent, iron can be preferentially extracted to yield a titanium rich beneficiate suitable for use as a feed for the production of titanium dioxide (TiO2) pigments.

APPLICATIONS

Pigment:Titanium dioxide is the most widely used white pigment because of its brightness and very high refractive index (n = 2.7).

Titanium dioxide is used to mark the white lines on the tennis courts of the All England Lawn Tennis and Croquet Club, best known as the venue for the annual grand slam tennis tournament The Championships, Wimbledon

As a photocatalyst

APPLICATIONS

Titanium dioxide, particularly in the anatase form, is a photocatalyst under ultraviolet light. Recently it has been found that titanium dioxide, when spiked with nitrogen ions, or doped with metal oxide like tungsten trioxide, is also a photocatalyst under visible and UV light.

It is also used in the Graetzel cell, a type of chemical solar cell.

APPLICATIONS

For wastewater remediation:

TiO2 offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors:

The process occurs under ambient conditions very slowly, direct UV light exposure increases the rate of reaction.

The formation of photocyclized intermediate products, unlike direct photolysis techniques, is avoided.

Oxidation of the substrates to CO2 is complete.

The photocatalyst is inexpensive and has a high turnover

Aerospace and marine:Due to their high tensile strength to density ratio high corrosion resistance and ability to withstand moderately high temperatures without creeping, titanium alloys are used in aircraft, armor plating, naval ships, spacecraft, and missiles.

The SR-71 "Blackbird" was one of the first aircraft to make extensive use of titanium within its structure, paving the way for its use in modern military and commercial aircraft.

APPLICATIONS

PRECAUTIONS

It does, however, have a tendency to bio-accumulate in tissues that contain silica.

Titanium can catch fire when a fresh, non-oxidized surface comes in contact with liquid oxygen.

CONCLUSION

Future advances in titanium manufacture are likely to be found in the development of new alloys, the reduction in production costs, and the application to new industries.Work is also being done on finding the optimal composition of various titanium alloys.Researchers have been investigating different methods for titanium purification. . Recently, scientists at Cambridge University announced a method for producing pure titanium directly from titanium dioxide.