Aluminium is the second-most used metal on the planet and the most widely used in the production of beverage cans. Aluminium products are in peak demand by consumer companies who use the metal for various purposes such as packaging of food, medicine, electric power transmission, in sea transportation, electronics and construction processes. This makes aluminium a highly valued metal. Aside from its positive impact on modern lifestyle, aluminium has high scrap value and requires very little energy costs to recycle. To this end, it is preferable by many for its convenience and recyclability. Used beverage cans constitute the majority of aluminium scrap that is used for recycling, at approximately 37 percent of all scrap. The steady rise of aluminium is expected to reach 70 million tons by the year 2020 on a global level. This level of demand means that the recycling process must be efficient, energy-saving and at a reduced cost.
Origins of Aluminium recycling
The practice of aluminium recycling is not a new concept. It was a common practice in the early 1900s and was especially widespread during the Second World War. However, it was not until the 1960s when beverage cans became popular that the idea of recycling became mainstream to the public. The main advantage of Aluminium recycling is that it’s cheap and can be recycled lossless for many times. Beverage cans are currently the main source for recycled aluminium. Other sources for recycled aluminium include automobiles, aircraft, cookware, computers, bicycles and boats. Aluminium is considered a high value metal because of its strong and lightweight property coupled with high thermal conductivity. Additionally, during the recycling process, it does not lose its quality or transmute to another element. It remains in its pure form.
The Recycling Process
- The next stage of aluminium recycling involves shredding. After sorting is completed, aluminium blocks are taken to the next stage for processing. Here, the blocks are passed through a conveyor belt where they are led to a shredding machine. The shredder tears the aluminium into small pieces. This is important in order to get rid of previous coloring and decoration on the aluminium. Also, shredding makes it easier to melt the metal in the furnace. To further ensure that there are no traces of steel in the aluminium, the shredded pieces are passed through a magnet. Steel is magnetic and hence any traces will be attracted to the magnet. This process ensures that the recycled aluminium meets the required quality standards.
- The shredded pieces are passed through a specialized de-coater using a conveyor system. This process detaches any decorations and colors on the shredded aluminium. Very hot air is blown through the shredded pieces to the extent that decorations and colors vaporize and become gaseous. The paints, coatings and inks on the cans are removed and cleaned.
De-coated shreds are fed into the furnace heated up to 7000C which is the lowest melting point for most metals. Aluminium melts at this temperature. Certain chemicals are added to the molten aluminium during this stage. This helps achieve the right chemical composition for the next stage. Any impurities in the molten aluminium float on the surface which can be easily removed using a specialized scraping tool.
The molten aluminium is then turned into ingots in the holding furnace. Ingots are pure aluminium blocks which are cast into a suitable shape ready for further processing. The holding furnace tilts to pour the molten metal into blocks. A single ingot could be made up of about 1.6 million aluminium cans.
- The ingots are then lifted from the casting pit using an overhead crane and loaded onto tracks ready for transportation into the rolling mills. Once in the rolling mills, they are rolled out into sheets of aluminium, which are about 1/100 inch thick. These thin sheets are then ready for use by can manufacturers. In a span of five weeks, the recycled aluminium is already on the shelves of your stores and supermarket. The process is then repeated with minimal loss of quality of the aluminium.
The Benefits of Aluminium Recycling
The practice of Aluminium recycling has been around since the turn of the 20th century. It has proven to be a cost-effective method of acquiring pure aluminium as opposed to electrolysis of aluminium oxide. The recycling process saves about 95 percent of the energy required to acquire new aluminium through electrolysis. As such, it is easy and beneficial to the environment at large. Here are some other advantages of aluminium recycling.
- Recycled aluminium uses only 5 percent of the energy required to obtain new aluminium from bauxite ore through electrolysis. This is a cost-effective method that contributes significantly to energy conservation.
- Preserves the supply of aluminium in the earth’s crust. Since aluminium is found in the earth’s crust in the form of bauxite ore, recycling reduces the need for mining. This ensures there is a continuous supply of aluminium for future use.
- Aluminium can be recycled infinitely without losing its quality or wearing out. This lossless nature of aluminium means it can be reused and recycled countless times. For this reason, consumer companies and car manufacturers prefer aluminium since it provides a cost-efficient option.
- Aluminium recycling reduces landfills and waste. Many countries have dug huge landfills for dump sites and waste management. Beverage cans made of aluminium are a major waste material in the landfills. By recycling these drinking cans there is reduction in the spread of landfills. This further prevents serious environmental hazards associated with waste and landfills such as toxic emissions.
- Due to the ever-increasing demand for aluminium packaging, recycling beverage cans offers a handy solution that is cheap and beneficial to the environment. The recycling process is incredibly cheaper than obtaining aluminium through mining and electrolysis of bauxite.
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