World Mineral Production - NERC Open Research Archive - Natural ...

TITANIUM
Characteristics
Titanium is the ninth most abundant element in the Earth’s
crust. It is a hard, silver-coloured metal which is light, yet very
strong. It has a high melting point (1668 °C), very high
corrosion resistance, low coefficient of expansion, high
electrical resistivity and is non-magnetic.
Ilmenite and rutile are the two predominant titanium minerals
extracted commercially. Rutile (TiO2) is a fairly pure form of
titanium dioxide with 95-100 per cent TiO 2 while ilmenite
(FeTiO3) normally contains around 50 per cent TiO 2.
Leucoxene is an alteration product of ilmenite which has high
TiO 2 content, typically around 90 per cent.
Titanium mineral deposits are classified as primary rock
deposits and sedimentary deposits. Primary rock deposits
occur in massif-type anorthosites and layered mafic intrusions.
Important anorthosite deposits include the Lac Allard deposit,
Quebec, Canada and the Tellnes deposit in Norway. The
layered mafic deposits are less commercially viable due to
intergrowth of magnetite with the ilmenite.
Weathering of igneous rocks, chemical alteration of mineral
grains, fluvial transportation, deposition and subsequent
reworking of titanium minerals has created high-grade
deposits of these heavy minerals on present and past river beds
and, particularly, shorelines. Sedimentary deposits of this type,
often called heavy mineral sands or black sands, are the
predominant source of titanium and include the deposits of the
Murray Basin, Australia; Richards Bay, South Africa; Sierra
Leone and Sri Lanka.
Titanium dioxide is produced by either the chlorination of
rutile, or of synthetic rutile produced from ilmenite, to form
titanium tetrachloride which is then oxidised, or by the
sulphation of ilmenite which is then hydrolysed to yield the
dioxide. To produce metal, titanium tetrachloride is passed
over a bath of molten magnesium which captures the chlorine
to give a porous product called titanium sponge (the Kroll
process). This is remelted into ingots. Ilmenite may also be
processed by smelting to form titanium slag, an intermediate
product that is then treated by the sulphate process
The US Geological Survey (Gambogi, 2008) estimates global
reserves of titanium minerals at 730 million tonnes. The
largest reserves are in China (mainly primary rock deposits),
Australia (heavy mineral sands) and South Africa (heavy
mineral sands).
Uses
Around 95 per cent of titanium is used as titanium dioxide
(TiO2) pigment. It is white, with good opacity, chemically and
thermally stable, and non-toxic. The predominant market is as
an additive in paint, both as a white pigment and an opacifier.
It is also used as a pigment and opacifying agent in plastics,
paper, coatings and inks. There are also non-pigment uses for
titanium dioxide. Ultrafine particles can be transparent and
scatter light, lending to its use as a functional filler in metallic
paints and sun screen creams, for example. It is used in
batteries and in the manufacture of a range of titanium
chemicals.
The metal has a range of physical properties that make it
useful in many applications. It is light, strong, and biocompatible
with the human body. It is therefore suitable for
use in dental and surgical implants, such as pacemakers and
90
joint replacements, as well as jewellery and spectacle frames
that do not cause skin irritation. Titanium metal and its alloys
are used in aerospace – for both engines and airframes – as
they are considerably lighter and stronger than steel. The most
commonly-used titanium aerospace alloy contains six per cent
aluminium and four per cent vanadium. High resistance to
corrosion makes titanium a suitable metal to use in the
manufacture of chemical process plant and in marine
applications. It is used in sporting goods, such as golf clubs,
and in architecture, e.g the Guggenheim Museum, Bilbao,
Spain.
Ferrotitanium, which typically contains 70 per cent titanium, is
used in the production of stainless steel as a deoxidiser and
stabiliser, while other titanium alloys have a wide range of
specialised uses including superconductors and shape-memory
alloys.
Titanium minerals are used in fluxes for coating welding
electrodes. Consumption is estimated at around 110 000
tonnes TiO 2, but future growth in demand may be limited as
less is needed in the new continuous welding process (Murphy
and Frick, 2006). Titanium minerals are also used as flux in
iron and steel smelting and ilmenite, due to high density, may
be used in drilling muds.
World production in 2006
In 2006, sixteen countries produced titanium minerals and
total production was around 12.2 million tonnes. This
comprised 11.6 million tonnes of ilmenite and 0.6 million
tonnes of rutile and leucoxene. The total TiO2 content is
estimated as 6.1 million tonnes, representing an increase of 13
per cent on 2005 and a 22 per cent increase in five years.
Australia is the world’s leading producer, with 2.4 million
tonnes of ilmenite, 0.2 million tonnes of rutile and 0.1 million
tonnes of leucoxene. Canada is the second largest producer
and South Africa is third. The combined output of these
countries makes up almost 60 per cent of world ilmenite
production and 85 per cent of rutile/leucoxene.
Production restarted in Sierra Leone, after a decade of
inactivity.
Prices
TiO2 pigment average prices for the 2006 ranged from
US$1388 per tonne (Chinese exports, f.o.b.) to US$2148 per
tonne (European imports, c.i.f.). The prices in 2007, up to
September 2007, averaged US$1484 and US$2246,
respectively. Australian exports (f.o.b.) averaged US$1877 in
2006 and US$1902 for the first nine months of 2007 (TZM,
2007).
According to the Metal Bulletin database (Metal Bulletin,
2008), the price of rutile has varied little in recent years.
Rutile, bulk concentrates, minimum 95 per cent TiO 2, f.o.b.
Australia, is currently in the range US$475–500. Ilmenite,
bulk concentrate, minimum 54 per cent TiO2, Europe, f.o.b.,
has been US$75–85 since mid-2005.
Ferro-titanium prices (ferro-titanium 70 per cent; maximum
4.5 per cent Aluminium; Metal Bulletin free market US$ per
kg Titanium; d/d Europe) declined fairly steadily after two
peaks of around US$ 27-33 per kilogramme in 2005. Through
2006, the price fell from US$17–18 to US$14.8–15.3, and by
the end of 2007 it was US$7.65–8.1. As for metal, titanium