Aluminum foil is made of Al and little other elements like Fe or Si. As a leading aluminum products manufacturer in China, we’ll melt the aluminum rolled metal sheets/rolls. Cured between large cooling rollers. In the last rolling process, the two layers of aluminum foil both went through milling. One side that contacts the polishing roller becomes bright, and the other is dull. Whether you use the bright or dull foil, it’s the same.
Aluminum Foil Core Composition
Aluminum foil is composed of pure aluminum. Aluminum is a silvery and light metal. It has great corrosion resistance, soft and thermal conductivity. For producing aluminium foil, aluminum is processed into thin rolls, typically between 0.006 and 0.2mm（6mic-200mic) thick.
Commercial aluminum foil is made from 92%-99% aluminum. The household aluminum foil is made using 99% pure aluminum. Industrial foil may contain amounts of other elements, such as silicon, iron, or manganese. Some foil rolls contain other elements to enhance strength, heat resistance, or formability.
How Is Aluminum Foil Manufacturered?
Rolling aluminum raw material into thin aluminum sheets is aluminum foil manufacturing. Here’s step-by-step:
Step 1: Mining and Refining Bauxite
Aluminum foil production begins with bauxite. Many countries like Australia, China and Guinea all mine bauxite. Through the Bayer process, bauxite is refined into alumina.
Step 2: Smelting Pure Aluminum
Next, alumina is dissolved in molten cryolite and subjected to intense electricity. This process made alumina into liquid aluminum and oxygen. The molten aluminum is cast into ingots or rolled coils for further processing.
Step 3: Rolling
To produce foil, aluminum ingots are rolled into thin rolls/sheets:
- Hot rolling: Ingots are heated to 500-600℃ and through rollers to reduce thickness to 2-6mm.
- Cold rolling: The rolls are thinned using tandem rolling mills. Lubricants and coolants prevent overheating.
- Annealing: Periodic annealing restores ductility, preventing cracks during rolling.
Step 4: Finishing
The foil is trimmed, annealed, and coated. Advanced sensors detect holes or thickness variations, ensuring consistency.
Key Features of Aluminum Foil Product
The special features of aluminum foil depend on its composition and manufacturing process:
- Barrier Properties: Aluminum foil isolates oxygen, water, and bacteria. It keeps your food fresh and extends shelf life. In addition to packaging fruits, vegetables and meat, it can also keep liquid drinks nutritious and fresh.
- Heat Conductivity: Aluminum foil has good thermal conductivity. When you use household foil for roasting, you’ll find the foil heats quickly and evenly. At the same time, thermal insulation is so popular. For example, aluminum foil is often laminated with other materials to form composite materials, such as bubble film aluminum foil or foam aluminum foil.
- Food Grade Safety: Aluminum foil passed through high heat kills all bacteria. The foil surface will not have any impurities. It can touch food directly, no harm to the human body.
- Soft and Flexible: Aluminum foil is light and soft and can be folded into any shape. Kitchen aluminum foil rolls can be used to wrap any food and are durable.
Aluminum Foil Types
Not all aluminum foil is created equal. Variations in thickness, alloy composition, and surface treatments.
Standard Household Foil
- Thickness: 10–15 microns (0.01–0.015 mm)
- Characteristics:
- Lightweight and highly flexible.
- Easy to tear but sufficient for everyday use.
- Applications:
- Wrapping food (e.g., sandwiches, leftovers).
- Covering baking dishes.
- Grilling vegetables or fish.
Heavy-duty Foil
- Thickness: 15–30 microns (0.015–0.03 mm)
- Characteristics:
- More durable and puncture-resistant.
- Withstands higher temperatures.
- Applications:
- Freezer storage (prevents freezer burn).
- Roasting meats in ovens.
- Insulating pipes.
Industrial Foil
- Thickness: 50–200 microns (0.05–0.2 mm)
- Characteristics:
- Rigid and mechanically strong.
- Often laminated or coated for specialized uses.
- Applications:
- HVAC duct insulation.
- Battery casing in electric vehicles.
- Thermal shielding.
Common Questions
Does Aluminum Foil Contain Toxic Materials?
Pure aluminum food foil is non-toxic and safe for food contact. However, acidic or salty foods may cause minimal aluminum leaching, which is generally within safe limits by regulatory bodies like the FDA.
Why Does Foil Have A Shiny And A Dull Side?
The side touching the polished roller becomes shiny, while the inner side remains matte.
Can Aluminum Foil Be Recycled?
Yes! Clean aluminum foil is recyclable without losing quality. However, food residues can influence recycling batches, so rolling the used foil into a ball and check local recycling guidelines.
