Aluminum ore specific weight: density and weight of 1 m³

Aluminum is one of the most widespread metals on our planet, but it is not found in pure form. Chemically active Al atoms form numerous compounds with other substances. Aluminum-bearing ores rank third by volume of occurrence in the earth’s crust.

In the post-Soviet region, bauxites are considered the most suitable and widely developed raw material. Extracting aluminum from natural raw materials is a complex process that requires large amounts of electricity.

Composition of Aluminum Ore. Aluminum Ore Weight

Bauxite, a fairly complex rock, contains aluminum hydroxide compounds, oxides, silicates and Fe hydroxides, compounds of titanium, silicon and other elements. Bauxite aluminum ore may also contain calcium and magnesium carbonates, small amounts of sodium and potassium compounds, as well as vanadium, chromium and some other substances; pyrite particles may also occur.

• The chemical composition of bauxites varies widely; it depends on the mineralogical forms of Al hydroxide and impurities. The main substance forming the ore is alumina (Al2O3). Metallic aluminum is extracted from it. The second main component is iron oxide (Fe2O3). In industrial bauxites, alumina content must be more than 30%; only in this case is development economically justified.

• The appearance of bauxites is clay-like or stony rock. The structure of aluminum ores can be very diverse: dense earthy, stony, porous, with round inclusions. Bauxite color is also diverse, from white to dark red or brick-brown. Greenish-gray and almost black, yellow, variegated rocks with blue or red-violet inclusions may also occur.

• The specific weight of aluminum ore (bauxite), or its density, ranges from 1.2 g/cm³ in rocks with low silica and Fe content to 2.5-3.3 g/cm³ in heavy, dense, ferruginous, stony bauxites.

• Bauxite hardness is 2-7.

• A distinctive feature of clay-like bauxites that helps identify the rock as aluminum ore is that, when mixed with water, clay-like bauxites do not form a plastic mass.

The largest bauxite reserves are concentrated in Guinea: according to the USGS 2026 estimate, about 7.4 billion tons out of roughly 29 billion tons of world reserves. Large reserves are also found in Australia, Vietnam, Indonesia, Brazil, Jamaica and other countries. Some deposits lie close to the surface, so they are mined by open-pit methods and transported for processing. In some areas, ores occur deeper and may require underground mining.

Alumina is a loose powdery substance obtained by the Bayer process from high-quality bauxites with low silica content. But for the next stage of aluminum production, another substance is needed: cryolite. Natural cryolite reserves in the world are extremely small, so modern metallurgy uses artificial cryolite obtained by the interaction of hydrofluoric acid with aluminum hydroxide and sodium hydroxide, also known as caustic soda.

The aluminum production process consists of three main stages:

• mining aluminum ore;

• processing the rock into alumina, or aluminum oxide;

• obtaining metallic aluminum through electrolysis.

The weight of aluminum ore required to obtain one ton of aluminum reaches 4-5 tons, approximately 2 tons of alumina.