Aluminium industry

Our refractories provide the right solution for all aluminium plants.
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THE CORUNDUM CHALLENGE

Aluminium has a strong affinity for oxygen, which leads to different mechanisms of oxidation of molten aluminium alloys.

The bath surface passivation stops the process at the interface with the furnace atmosphere, but the reaction can proceed at the surface of refractory or in its burden layers. This results in the development of corundum, which can be prevented by the targeted usage of modern refractories.

Dalmia Seven product range contains the right blend of additives to ensure these mechanisms are working correctly.We can support aluminium plants and furnace makers with the choice of the right products, with precise instructions how to realize linings and to reduce the corundum formation or other problematic issues.

The cycle of aluminium metal processing is complex and made by various types of furnaces which melt, treat, refine, remelt and reprocess aluminium products, semi-finished products and scrap in many steps. The primary aluminium production industry extracts metallic aluminium from minerals. Afterwards aluminium is reprocessed by different factories, which use several type of furnaces for the production of aluminium products or semi-finished products. It is in these remelting stages that modern refractory products are mainly used, while the primary aluminium production relies on refractory bricks.

Aluminium Industry And Types Of Equipment

Dalmia Seven can offer solutions for the entire aluminium industry. Products for primary aluminium are mainly shaped products such as fireclay bricks, insulating bricks and alumina bricks, which can be supplied by Seven Refractories in case of need, but are not mentioned in this brochure, which focuses on monolithic products.

Refractories for Aluminium

Aluminium has a strong affinity for oxygen, which leads to different mechanisms of oxidation of molten aluminium alloys. The bath surface passivation stops the process at the interface with the furnace atmosphere, but the reaction can proceed at the surface of refractory or in its burden layers. This results in the development of corundum, which can be prevented by the targeted usage of modern refractories.

2-mechanisms

There are two areas where corundum may form:

  • At the bath surface because of direct oxidation 4 Al (melt) + 3 O2 → 2 Al2O3
  • In the refractory starting from the liquid contact surface (under the bath level), because of the higher affinity to oxygen of metallic aluminium diffused from the bath into refractory according to the reaction: 4 Al (diff) + 3 SiO2 → 2 Al2O3 + 3 Si

“Corundum formation” occurs at the intersection of refractory lining. It consists of a composite rich in aluminium/aluminium oxide, which grows by oxido-reduction.