RE: Why is Aluminum Scrap in High Demand?
toyota1515 > 06-09-2023, 07:32 AM
Aluminum scrap is generated in many steps of the manufacturing process and use by the end user. During manufacturing, aluminum material is lost from the process either during the melting step to form dross or in one of the many machining operations applied to the aluminum piece. Based on Figure 2.5.25, it makes the most sense to return a scrap material to the same alloy or at least the same family whenever possible. In a manufacturing operation, this is normally a simple operation. When the machining operations take place within the aluminum mill, the scrap is always returned to the cast house and remelted. When the scrap is generated at a subsequent manufacturing operation, it is highly likely that the scrap will return to a recycling operation and will normally be returned to the original alloy since the pedigree is known. This type of scrap has the highest value due to its known pedigree. Manufacturing scraps could include stamping skeletons, machine turnings, scrapped pieces due to imperfections, or any other form due to a multitude of reasons. Once the part is installed in a larger assemblage or is delivered to a customer, the traceability of the part decreases. Typically, postconsumer scrap is a mixture of alloys and sometimes even a mixture of metals. Some scrap types, like Used Beverage Containers (UBCs), are easily identified, but most postconsumer scrap is at best identified between one of several broad categories.
At one time, the use of recycled or secondary scrap was a very small portion of the entire aluminum metal stream. However over the past 20 years in the United States, the contribution of aluminum recycling has remained steady, as domestic primary aluminum capacity has been replaced by imported metal. As an example, US usage of secondary Al in the past 20 years has accounted for 15–20% of the total metal input. The US domestic consumption for aluminum by source is presented in Figure 2.5.26 [32].