The life cycle of an aluminum UBC is just 60 days from “can to can.”
In this short time, a beverage can goes from the grocery store shelf to the consumer, and then on to a recycling facility where it can be remelted into can sheet and reformed into another aluminum beverage can with exactly the same physical characteristics as the original can. Because aluminum can be recycled with no degradation in quality, aluminum cans are the ideal product for a closed-loop approach to recycling.
RUNSUN is the world’s leading manufacturer of aluminum recycling machines, and we have developed a highly efficient aluminum can recycling process that ensures maximum productivity, low energy usage and the highest-quality finished product. The recycling process takes place in four basic steps:
Stage 1 – Can Shredding
In the first step, bales of aluminum cans are shredded into pieces the size of a walnut in a 1,000-horsepower shredder. The shreds are then passed through a magnetic drum separator to remove any steel that may have been mixed into the bale.
Stage 2 – De-coating
Following the can shredding process, any lacquer or paint on the aluminum is removed by blowing hot air (around 550°C) through the shreds on a slowly moving insulated conveyor. The exhaust gases from this process are first passed through an afterburner and then used to heat incoming process air via a heat exchanger, minimizing the energy requirements of the system.
Stage 3 – Melting
After being de-coated, the aluminum shreds are then fed into melting furnaces containing submerged stirrers that create a vortex in the pool of molten aluminum and drag the shreds quickly down into the melt. This process achieves rapid melting rates and high yields.
The furnaces have fuel-efficient, state-of-the-art regenerative burners and burner management systems to reduce the amount of energy used and the impact on the environment. They are also equipped with permanent magnet’s tirrers, which ensure an even temperature and composition by promoting metal circulation within the furnaces. The stirring process ensures the highest-quality end product.
Stage 4 – Aluminum Casting
The molten metal is transferred into a holding furnace, where it is treated to remove impurities before casting the aluminum. Ingots are cast by tilting the holding furnace and pouring the molten metal into a casting unit. The metal is treated in a two-stage process to remove any remaining microscopic non-metallic particles and gases, with chemical composition and metal cleanliness tested on each cast.
As the metal flows into the molds, it is chilled by jets of cool water pumped around and through the base of the mold. The aluminum ingot solidifies gradually during the casting process, which takes approximately three hours. The finished 18-ton ingots, each containing approximately 1.5 million used cans, are shipped to a mill for rolling into the sheet from which aluminum can makers subsequently produce new cans and the whole process begins again.
Our aluminum recycling facilities are regulated by the environmental authorities of the countries in which we operate and also must meet our own strict control measures. All of the waste gases from the shredding, de-coating, melting and holding operations are removed from the plant and treated in purpose-built emission abatement facilities, including cold dust collection systems and hot dust scrubbers. The cold dust scrubbers are used to remove the exhaust gases from the shredding and conveying operations while the hot dust scrubbers control the gases from the de-coating, melting and holding furnaces.
Aluminum scrap other than used beverage cans (UBCs) is recycled through a similar process with various upgrading and processing technologies.
