• Casthouse dross

Before aluminum is cast into products, all impurities on the surface of metal must be removed in the foundry furnace. These impurities, called dross, are recycled internally or shipped to a subcontractor who extracts the aluminum and returns it to us.




Aluminum dross originates in casthouse mixing furnaces. The volume generated is determined mainly by the quantity of bath drawn from pots along with molten aluminum, the mixing furnace operations and the production of value-added products. An Alcoa technical group comprised of experts in each of the Québec smelters, as well as experts from the Smelting Centre of Excellence, is currently engaged in sharing best practices for reducing dross and recycling it internally.


This detailed work, which began in 2011, explains the increase in recycling from 2011 to 2014. In 2015, internal recycling did decrease, notably due to technological upgrades in the Baie-Comeau casthouse. The Baie-Comeau and Deschambault Smelters hold the required permits to recycle a portion of their dross derived. Innovation is underway at the Bécancour Smelter in order to significantly reduce dross production.