Aluchemie anodes are high-grade blocks of carbon which our customers use in an electrolytic process. The aluminium smelters send a current through the anodes as a result of which molten aluminium is produced. This is known as the Hall-Heroult process.
Our production process
The process starts at our own quay where the raw materials are delivered by ship. The materials include petroleum cokes and coal tar pitch, as well as anode butts which our customers return for recycling. The dock cranes load the raw materials into storage silos. Next we take samples so our laboratory can verify the quality of the raw materials.
These raw materials are milled, screened and mixed in the Paste & Moulding Department. The mixture is then moulded into “green” anodes. Process monitoring is essential in this part of our plant. Our operators and systems check throughout the day that the product quality meets the defined requirements.
To give the product the required properties, such as conductivity and reactivity, the green anodes are fired in furnaces for two weeks, with a carefully monitored time/temperature profile. This process is known as calcination. The anodes stay in one place while the burners are moved across the furnace. This ensures acurate process control during the heating, calcining and cooling of the anodes. The off-gasses are cleaned in the off-gas treatment unit, using regenerative thermal oxidation.
The calcined anodes are then transported to the Finishing Department where their quality is checked, they are cleaned and then prepared for shipping. Finally they are loaded onto ships for transport to our customers.
The anode dimensions are always tailored to each customer’s production line.
An anode weighs 750 to 1500 kg and is up to 1.5 metres long. The anode dimensions are always tailored to each customer’s production line. The same applies to properties such as density, conductivity and reactivity. At the aluminium smelter conductive rods are mounted in the holes in the anodes. This allows the electricity to flow through our anode and the electrolysis bath to produce aluminium. During the aluminium smelting process the anodes are gradually consumed. A small part, the butt, is left over, and is returned to Aluchemie for recycling.
At Aluchemie we are always looking for opportunities to improve our processes. The Aluchemie Business System (ABS) is based on Lean and Six Sigma. All team members can contribute to improvements in the business, through projects and systems to submit suggestions. There are also awards for the best contributions.