IBA is the inert fraction output, coming from the combustion of domestic waste. This bottom ash, from waste incinerators, contains up to 90% mineral traces. In terms of mass, iron comprises most of the metal present in the IBA, followed by aluminium, zinc, and nickel, which are separated and stored separately.
At the end of the combustion process, the inert fraction output (IBA – Incinerator bottom ash) reaches the end of the moving grate and falls into a water bath.
The cooling process extinguishes the bottom ash, facilitating the handling and minimising the dust issues.
Upon arrival at one of our processing facilities, the IBA is quarantined, stored, and left to mature for 6-8 weeks.
After maturation, magnetic separation is one of the first steps in the bottom ash sorting system: the main goal is to remove the ferrous metals. There are many different types and setups of magnetic separation. The most common in bottom ash sorting are magnetic drum and overhead suspension magnets. Another important step is the sieving process to guarantee an accurate fractioning of the bottom ash.
The non-ferrous fraction is then separated using an eddy current technique for sorting non-magnetic metals from the material stream. The eddy current machine consists of a conveyor with a non-magnetic drum. The drum is equipped with an internal rotating set of magnets. The magnets inside the drum create repulsive forces, pushing non-ferrous metals on a path away from the drum.
With a low melting point at 660°C, on visual inspection, aluminium can be found as melted and re-solidified particles or rocks.
This happens to aluminium foil that is converted into small droplets during the incineration process Some larger and thicker aluminium packaging items can still be partially recognised as they retain their shape.
The heterogeneous nature of the processed material is due to the diversified conditions present in the combustion chamber, (some relatively cooler regions in the furnace).
The stock can contain all kind of aluminium packing:
We can currently provide this material in three different fractions:
The chemical composition of aluminium alloys formulated from recycled material is strictly related to the quality of the recovered aluminium. Recycled aluminium usually contains increased levels of impurities such as Fe and Mn, compared to primary aluminium, so the alloy formulation can be more difficult to manage
The combustion process does not burn the aluminium but it passives (oxidises) the surface forming Al2O3 (alumina). This outer alumina layer offers a major advantage as it prevents the remaining processed aluminium from further oxidation.
The collected stock is stored in the open air, on cement flooring. It can be loaded loose into a 20’ heavy-duty container.
Please feel free to contact us for further details