Aluminum Can Recycling in the Systemized Closed-loop
The recycling of aluminum can is explained mainly from the stand point of closed-loop recycling that used beverage can (UBC) is returned to reproduce as a raw material of alloy for aluminum can. Since the energy from remelted aluminum by recycled UBC saves up to 95% of the over-all energy required for primary aluminum production, the economical effect is very large. If the recycling system does not act on an economical rule, it would be very difficult for us to realize the UBC recycling. From this concept, to reduce melt loss, namely, to gain high recovery rate of metal from UBC scrap is necessary. Both to collect high quality UBC and to determine the conditions of delaquering and remelting are very important. Not only a study of metal-recovery method from the dross formed in the melt furnace while remelting, but also a utilizing study to pass without carrying the remaining ash after the dross treatment to the reclaimed land are required. Judging from the metal balance in view of Mg and Mn content to return aluminum alloy for can in the closed-loop, up to about 75% of Can to Can ratio is acceptable to use properly both 3000 series for body and 5000 series for end. As a future issue, however, the development of aluminum alloy to increase the usage of recycled metal is important. Currently, 5042 and 5021 alloys are beginning to use for end stock. It is ultimately desirable that an uni-alloy such as 5017 alloy is developed. The higher UBC recycling ratio will be, the more the environmental loads will be remarkably reduced as shown in Life Cycle Analysis. It is concluded that aluminum can is the product to be able to enter in the closed-loop system in comparison with other packaging containers.