What are Aluminum Scraps?
Aluminum scrap is generated in many steps of the manufacturing process and used 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 re-melted. 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 post-consumer 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.
Production of Aluminum Powders
Processing of Recycled Aluminum to Granules
In recent years, the processing of aluminum scrap (mainly chips and used drink cans) has attracted increasing attention. Aluminum scrap has a complex chemical composition based on aluminum (> 90%). Magnesium, zinc, silicon, iron, etc., are the main impurities. Sources of impurities are the composition of the alloy for producing drink cans (mainly, Al-Mg alloy containing up to 3%–4% Mg) and mechanical impurities that enter into the scrap due to inefficient sorting, classification, and storage of the scrap.
Nowadays, all over the world, the main method of processing aluminum scrap is re-melting in units of various types. The melt is usually cast into ingots. In some cases, the melt is granulated or gas atomized to produce powder of recycled aluminum (for example, APV powders in Russia). These re-melting-casting technologies are rather power-consuming.
Processing of aluminum scrap to powders and granules is an alternative to re-melting scrap to produce ingots. The advantage of this technology is that it is a simpler and cheaper process of producing granules from recycled aluminum. The size of granules is easily regulated by the adjustment of grinders and varies from 1 to 10 mm. Such granules are used more effectively than ingots in ferrous metallurgy for steel DE oxidation.
Scrap Aluminum Insured Wire
Scrap aluminum insulated wire is beginning to take the place of commercial-grade copper MCM. It is used primarily in commercial applications. Like MCM insulated aluminum wire will have individual strands of wire where the aluminum strand is larger than a pencil lead. Aluminum insulated wire is much lighter than MCM copper but like copper, it is very rigid inside the plastic jacketing making it difficult to work with.
Aluminum Radiators
Scrap aluminum radiators are typically very lightweight and are fast replacing all types of aluminum/copper radiators in different practical applications. Aluminum radiators will have either large or small fins depending upon their usage and will be silver in appearance
Typical usage; Car & Truck Radiators, AC Condensers,
Aluminum Radiators Contaminated
Contaminated scrap aluminum radiators are classified as contaminated if they have any trace of materials other than aluminum on them. This means no metal, metal screws, plastic, caulking, etc. Contaminated materials are always going to be worth a fraction of what non-contaminated materials are worth.
Aluminum Cans
There are two easy ways to identify an aluminum can versus a metal can. If you touch a magnet to a metal can it will stick, but it will not stick to an aluminum can. Second, metal cans are much heavier than aluminum cans. Typical usages; Aluminum cans are widely used for both alcoholic beverages and non-alcoholic beverages.
Chrome Aluminum Auto Wheels
Scrap chrome-plated wheels differ from aluminum wheels and are paid on a different pay scale from their dull or painted counterparts. Scrap chrome aluminum wheels typically have a shiny finish to them. To get the highest value for your wheels always make sure to take the wheel weights off of them, and pull out the rubber stems. Typical usage; automobile wheels, truck wheels, and large bus wheels.