Bauxite Resources Limited

BAU Share Price
$0.200: Up 0.000 (0.00%)

Bauxite Alumina Aluminum

Bauxite

What is bauxite?

Bauxite is ore from which aluminium can be extracted. The name 'bauxite' is derived from the French village of "Les Baux" where it was first discovered in 1821.

Most bauxite, including Australian bauxites, are lateritic, formed by intense weathering of various rock formations. The alumina in lateritic bauxite is mainly in the form of gibbsite, an aluminum oxide trihydrate. Other bauxites contain boehmite and diaspore which are monohydrates.

Bauxite production

World output of bauxite in 2007 was 207Mt, a rise of 10.5% on the previous year, due principally to increased output in India, Indonesia and China. Bauxite production has increased annually since 1998 at an average rate of almost 6%pa. With the exception of a 1.7% decline in 2004, world alumina production has increased annually since 1994, and was about 77Mt in 2007. The average year-on-year increase in output between 1994 and 2007 was 5.2%, and since 2004 has increased at about 10%pa, largely because of rising Chinese production. (Roskill Report 2007).

In 2007, Australia was the top producer of bauxite with almost one-third of world share, followed by China, Brazil, Guinea and Jamaica. Although aluminium demand is rapidly increasing, known reserves are sufficient to meet the needs for a considerable time. Increased aluminium recycling, which has the advantage of lowering the energy costs of production, will help extend bauxite reserves.

(x1000 tonne, Numbers for 2007 estimated)
Country	Mine production		Reserves	Reserve base
Country	2006	2007	Reserves	Reserve base
Australia	62,300	64,000	5,800,000	7,900,000
People's Republic of China	21,000	32,000	700,000	2,300,000
Brazil	21,000	24,000	1,900,000	2,500,000
Guinea	14,500	14,000	7,400,000	8,600,000
Jamaica	14,900	14,000	2,000,000	2,500,000
India	12,700	13,000	770,000	1,400,000
Russia	6,600	6,000	200,000	250,000
Venezuela	5,500	5,500	320,000	350,000
Suriname	4,920	5,000	580,000	600,000
Kazakhstan	4,800	4,900	360,000	450,000
Greece	2,450	2,400	600,000	650,000
Other countries	5,460	6,800	3,400,000	4,000,000
World total (rounded)	178,000	190,000	25,000,000	32,000,000

Source: U.S. Geological Survey, Mineral Commodity Summaries, January 2008

Characteristics Of Darling Range Bauxite
The three structural forms of bauxite are Gibbsite, Boehmite and Diaspore. Gibbsite is a true aluminium hydroxide and Boehmite and Diaspore are both aluminium-oxide-hydroxides.
Extreme lateritic weathering in the Darling Range has resulted in the formation of the trihydrate bauxite Al(OH)3, Gibbsite (Refer Figure 1: Typical Darling Range Cross Section)

Figure 1: Typical Darling Range Cross Section
The typical ore structure of Darling Range Bauxite is illustrated in Figure 1: Typical Darling Range Bauxite Ore Structure.

Benefits of Darling Range Bauxite
In an Alumina Refinery bauxite is digested using the Bayer Process and involves washing the ore with a pressurized hot solution of sodium hydroxide (caustic soda). Two reasons why refineries that use Darling Range Bauxite operate in the lowest production cost quartile are:

Less Energy Consumption – the Gibbsite nature of the Darling Range Bauxite requires lower refinery operating temperature and pressure. (Refer Figure 2: Process Requirements).
Less Caustic Soda Wastage – note the low level of reactive silica minimises the caustic soda wastage. In addition the loss of Alumina is reduced.

	Gibbsite	Boehmite	Diaspore
Temperature Degrees Celcius	145°C	250°C	Note 1
Pressure psi	75psi	550 psi	Note 1

Figure 2: Processing Requirements
(Note 1: Diaspore Bauxite is extracted using the Bayer Sinter process and the temperature and pressure requirements are materially higher than Gibbsite and Boehmite digestion requirements.)

Figure 3: Typical Darling Range Bauxite Ore Structure

Related Images

Tenement E70/3003 showing gravel operations

Degraded Farmland Tenements E70/3197 & E70/3195