Tronox is a public limited company registered under the laws of the State of
Western Australia. We are a global leader in the production and marketing of
titanium bearing mineral sands and titanium dioxide (“TiO2”) pigment,
and the world’s largest producer of natural soda ash. Titanium feedstock
is primarily used to manufacture TiO2. Our TiO2 products are critical components
of everyday applications such as paint and other coatings, plastics, paper,
and other uses, and our related mineral sands product streams include titanium
feedstock, zircon, and pig iron. Zircon, a hard, glossy mineral, is used for
the manufacture of ceramics, refractories, TV screen glass, and a range of other
industrial and chemical products. Pig iron is a metal material used in the steel
and metal casting industries to create wrought iron, cast iron, and steel.
We produce natural soda ash from a mineral called trona, which we mine, at
two facilities we own near Green River, Wyoming. At these facilities we process
the trona ore into chemically pure soda ash and specialty sodium products such
as sodium bicarbonate (baking soda) and sodium sesquicarbonate (S- Carb ®
and Sesqui™). We sell soda ash directly to customers in the United States,
Canada and the European Community, European Free Trade Association and South
African Customs Union and to the American Natural Soda Ash Corporation (“ANSAC”),
a non-profit foreign sales association in which we and two other U.S. soda ash
producers are members. ANSAC then resells the soda ash to customers around the
world. Our soda ash is used primarily by customers in the glass, detergent,
and chemicals manufacturing industries. We use a portion of our soda ash at
Green River to produce specialty sodium products such as sodium bicarbonate
and sodium sesquicarbonate that have uses in food, animal feed, pharmaceutical,
and medical applications.
In June 2012, Tronox Limited issued Class B ordinary shares (“Class B
Shares”) to Exxaro Resources Limited (“Exxaro”) and one of
its subsidiaries in consideration for 74% of Exxaro’s South African mineral
sands business, and the existing business of Tronox Incorporated was combined
with the mineral sands business in an integrated series of transactions whereby
Tronox Limited became the parent company (the “Exxaro Transaction”).
At December 31, 2016, Exxaro held approximately 44% of the voting securities
of Tronox Limited. Exxaro has agreed not to acquire any additional voting shares
of Tronox Limited if, following such acquisition, Exxaro will have a voting
interest in Tronox Limited of 50% or more unless Exxaro brings any proposal
to make such an acquisition to the Board of Directors of Tronox Limited on a
confidential basis. In the event an agreement regarding the proposal is not
reached, Exxaro is permitted to make a takeover offer for all the shares of
Tronox Limited not held by affiliates of Exxaro, subject to certain non-waivable
conditions. See Note 23 of notes to consolidated financial statements for additional
information regarding Exxaro transactions.
We currently operate our business in two operating and reportable segments,
TiO2 and Alkali.
Our TiO2 operations have a combined annual production capacity of approximately
750,000 metric tons (“MT”) of titanium feedstock, which is comprised
of 91,000 MT of rutile and leucoxene, 220,000 MT of synthetic rutile, and 410,000
MT of titanium slag. Our TiO2 operations also have the capability to produce
approximately 220,000 MT of zircon and 221,000 MT of pig iron.
Titanium Feedstock - Ilmenite, rutile, leucoxene, titanium slag and synthetic
rutile are all used primarily as feedstock for the production of TiO2. Titanium
feedstock can be segmented based on the level of titanium contained within the
feedstock, with substantial overlap between each segment. Different grades of
titanium feedstock have similar characteristics. As such, TiO2 producers generally
source and supply a variety of feedstock grades, and often blend them into one
feedstock. The lower amount of titanium used in the TiO2 manufacturing process,
the more feedstock required and waste material produced. Naturally occurring
high-grade titanium minerals required for the production of TiO2 are limited
in supply. Two processes have been developed commercially: one for the production
of titanium slag and the other for the production of synthetic rutile. Both
processes use ilmenite as a raw material, and involve the removal of iron oxides
and other non-titanium material.
Titanium Slag - Ilmenite at KZN Sands and Namakwa Sands is processed further
through direct current arc furnaces to produce titanium slag with a titanium
content of approximately 86% to 89%. The smelting process comprises the reduction
of ilmenite to produce titanium slag and pig iron. Ilmenite and anthracite are
fed in a tightly controlled ratio into an operating furnace where the endothermic
reduction of ilmenite occurs. The resultant titanium slag has a lower density
than the iron, and separation of the two liquid products occurs inside the furnace.
The slag and iron are tapped periodically from separate sets of tapholes located
around the circumference of the furnace. Slag is tapped into steel pots and
cooled for several hours in the pots before the slag blocks are tipped out.
The blocks are subsequently transported to the blockyard where they are cooled
under water sprays for a number of days. They are then crushed, milled, and
separated according to size fractions, as required by the customers. The tapped
pig iron is re-carburized, de-sulfurized, and cast into ingots or “pigs”.
High Purity Pig Iron - The process by which ilmenite is converted into titanium
slag results in the production of high purity iron containing low levels of
manganese. When iron is produced in this manner, the molten iron is tapped from
the ilmenite furnace during the smelting process, alloyed by adding carbon and
silicon and treated to reduce the sulfur content, and is then cast into pigs.
The pig iron produced as a co-product of our titanium slag production is known
as low manganese pig iron.
Synthetic Rutile Production -Ilmenite may also be upgraded into synthetic rutile.
Synthetic rutile, or upgraded ilmenite, is a chemically modified form of ilmenite
that has the majority of the ferrous, non-titanium components removed, and is
also suitable for use in the production of titanium metal or TiO2 using the
chloride process. Ilmenite is converted to synthetic rutile in a two-stage pyrometallurgical
and chemical process. The first stage involves heating ilmenite in a large rotary
kiln. Coal is used as a heat source and, when burned in an oxygen deficient
environment, it produces carbon monoxide, which promotes a reducing environment
that converts the iron oxide contained in the ilmenite to metallic iron. The
intermediate product, called reduced ilmenite, is a highly magnetic sand grain
due to the presence of the metallic iron. The second stage involves the conversion
of reduced ilmenite to synthetic rutile by removing the metallic iron from the
reduced ilmenite grain. This conversion is achieved through aeration (oxidation),
accelerated through the use of ammonium chloride as a catalyst, and acid leaching
of the iron to dissolve it out of the reduced ilmenite. Activated carbon is
also produced as a co-product of the synthetic rutile production process.
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