What Happened to that Power Cord I Recycled?
Most people get a very limited view into the recycling process. For most of us, we get to see the recycling truck haul away our recyclables or we may drop off material at a recycling yard and see the material unloaded, but we typically get no insight into how those recyclables are returned into the manufacturing chain. One of the purposes of this blog is to pull back the curtain on the recycling industry to provide interested individuals a more sophisticated understanding of how materials are recycled. For this entry, we are going to look at how electrical cords and wires are recycled.
Not all Power Cords and Wire are the Same
One of the complexities involved in recycling any material is the amount of variance that exists in the product stream. By its very nature, recycling takes place at the end-of-life of a product. Not all products come from the same source and not all products have the same lifespan. A recycling yard is, in effect, a graveyard. Like a traditional graveyard, a recycling yard is receiving items of all ages and backgrounds. Some items received may enter the facility in the original packaging, having never been used; while other items may have been buried for over a hundred years. The hodgepodge nature of what is recycled is certainly reflected in the wire and cable received at most scrap yards. At Colorado Industrial Recycling, we receive wire and cable that literally stretches the entire history of the use of electrical power. As you can imagine, how wires and cables are manufactured has changed significantly over the years. Moreover, wire used for one purpose requires a different manufacturing process than wire used for something else. For example, what we receive from a residential home is usually very different from what we may receive from a large utility company.
These different types of wire have very different material compositions. For instance, most wire and cable are designed to use copper as a conduit. However, there are some types of cable that might use aluminum instead, or even a combination of both copper and aluminum. These differences become even more stark when it comes to what is used to form the insulation and jacketing of the wire. This material varies from manufacturer to manufacturer, sometimes involving plastics, rubber, petroleum jellies, steel, or even paper. Finally, the ratio between the metal content and the content of the insulation and jacketing will vary substantially from one type of wire to the next. Depending upon the wire, the metal content can represent as little as 15% of the weight, or as much as 92% of the material. At the end of the day, each of these differences must be identified and factored into how the recycler will isolate out the base materials of the product so they can be recycled.
Sorting the Wire
Given the differences in composition, the first step in the recycling process involves sorting the product. There are literally hundreds of different types of wire sent into the recycling stream. From a practical standpoint it does not make sense to sort each type of wire into its own distinct category. At Colorado Industrial Recycling, we have simplified our operations by consolidating the wire into one of fifteen primary categories.
When wire arrives from the supply in a comingled state, sorting is a pretty horrible experience. Anyone that has tried to untangle a drawer of spare power cables has a pretty good idea what it is like sorting wire at a recycling facility. Unfortunately, our team must perform this sorting activity on an industrial level. Generally, this will involve dumping a glob of wire on a sorting pad, spreading the pile out with a mini excavator, and then attacking the pile with a pair of wire cutters.
Given the labor required to sort thousands and thousands of pounds of wire, we always prefer to receive wire already sorted. When the customer sorts the wire before recycling it, we have to invest far less labor to preparing it for processing. For this reason, most recycling facilities will pay higher prices for material that arrives sorted and categorized.
Separation of the Metals and the Insulation and Jacketing
Once the wire is sorted, the next step in the recycling process involves the separation of the copper, aluminum, and other metals contained in the wire from the insultation and jacketing. How this is accomplished varies significantly from one processing facility to the next. Some small operations may use wire strippers to cut the insulation and remove it from each individual strand. A wire stripping operation can generally process a few hundred pounds of wire in a day.
For recycling operations that deal in larger volumes, a more industrial approach is required. In developing countries that lack safeguards to protect workers and the environment, this is sometimes done by simply burning the wire in burn pits. The rudimental process melts off the jacketing and insulation from the copper or aluminum. These operations have been identified as some of the most toxic environments on earth, exposing workers to deadly fumes and polluting the air and water.
In the United States, the processing of wire is done in a more sophisticated manner. That said, not all processing plants utilize the same technology. Some recycling plants utilize equipment that is several decades old. While this dated technology can get the job done, there are still some environmental and health and safety concerns related to air pollution, wastewater, and high energy costs. Thankfully, technology has changed a lot in recent years. Colorado Industrial Recycling operates a plant manufactured from Eldan Recycling, a firm based out of Denmark. The Eldan technology takes advantage of the latest in computer technology to regulate the process in an efficient manner. This helps mitigate some of the environmental impacts associated with the process. The Eldan plant produces virtually no air pollution, no wastewater, and requires relatively little electricity. The system is also capable of processing large quantities of material. Depending upon the product, the Eldan plant can process up to 50,000 lbs. of wire in an eight hour shift. With the high level of automation, the plant can operate with just two technicians.
How the Eldan Plant Works
In conceptualizing how wire is processed through the Eldan plant, it is helpful to think of the process like you are baking a cake. Just like a baker must follow a recipe, picking and choosing between ingredients, we too follow recipes, mixing and matching different types of wire and cable, to produce specific yield levels of copper or aluminum chops. Like a baker, our recipes have become more sophisticated over time.
Once we have the feedstock wire sorted and prepped (our ingredients), the first step In the process is to feed the wire into a piece of machinery we refer to as “the Super Chopper”. The Super Chopper chops the wire into pieces roughly six to twelve inches in length. The chopped wire is then sent through a magnetic sorter designed to extract steel contaminates. The chopped wire is then transported inside our plant and dumped into a hopper. From there, the material goes through a rasper system that will reduce it further until the material is in pieces about a quarter of an inch in length. As it exits the rasper system, the material is passed through another magnetic sorter to remove any ferrous metals that managed to make it through the first magnet. The material is then conveyed into a silo that feeds into a granulator. The granulator can size the wire into a sand-like composition. The material is then transported through a pneumatic tube to a separation table. The separation table vibrates to separate the copper or aluminum from the plastics and other material in the jacketing and insultation. Just like when panning for gold, the shaking of the table allows the heavier metals to go to the bottom, allowing the lighter insulation to rise to the top where it will be captured by a vacuum system. The plastics and other material in the insulation material is then sent through a baghouse filtration system, before ultimately being deposited into a roll-of container. On the other end of the separation table, the copper or aluminum chops are dropped onto a conveyor system. The chops pass through one more small magnet sorter before ultimately being dumped into a box. In the end, you end up with what looks like sand, but is in fact 97% to 99.9% copper or aluminum depending upon the type of wire.
Once the metal is separated from the jacketing and insulation, the separated metal is ready to go to a foundry. A foundry represents the final stage in the recycling process. At the foundry, the recycled metal is purified into known specifications and cast in preparation for manufacturing. To achieve this aim, the metal chops are first grouped with scrap pieces with similar properties and then sent to a furnace. The furnace is heated to the appropriate melting point of the copper or aluminum. This process separates impurities from the copper or aluminum that form into a waste matter known as slag. The purified molten metal that remains is then tested and further refined to meet desired quality standards.
Once the molten metal achieves the necessary characteristics, it Is ready for casting. There are many different methodologies used for casting. The choice of casting method will determine the mechanical and physical properties, size, thickness, and surface of the product produced. How the metal is cast will ultimately be dictated by the manufacturers targeting the copper or aluminum good for their production process.
Like all metal, the copper or aluminum found in cable and wire can be recycled an infinite amount of times. Returning this discarded material back into raw goods ready for the manufacturer obviously requires a sophisticated, multifaceted, process. Despite the complexity of the process, recycling metal continues to be much cheaper and much more efficient than what is required when extracting virgin metals from the earth. Using recycled metals reduces the cost of production for manufacturers, with a carbon impact significantly less than that produced by the mining industry.