Scrap Car Recycling Technology
With current scrap car collection technology, metals can be recycled indefinitely without losing any of their properties. In most cases scrap metal is shredded and sent to a steel mill where it can be reprocessed and used in the manufacture of goods such as new cars or construction materials. Considering 76% by weight of the average car is metal, recycling end of life cars is a very environmentally friendly option. Recycling metal uses about 74% less energy than making new steel, according to the Environmental
Shredded steel comprises around 70% of the output from shredders, 25% is shredder fluff and the remainder is known as heavy media. Recycled steel has the added benefit of being cheaper, since new ore doesn’t have to be mined to produce it. All steel produced today has at least 25% recycled steel in it, and some products are made entirely from recycled steel. So in addition to the economic and environmental benefits recycling cars is a vital link in the world’s industrial infrastructure.
Under current legislation car batteries cannot be sent to landfill sites without going through a prolonged clean up procedure. On arrival at the plants the battery casings are stripped and the plastic is granulated and reformed into new casings. The chemicals are separated; lead content is melted and reformed into new battery plates, which are then placed into new batteries.
Glass can be recycled indefinitely as its fabric does not depreciate when reproduced. Broken or wasted glass is collected and taken to a glass recycling plant, where it is monitored for purity and contaminants are removed. The glass is crushed into tiny particles and added to a raw material mix in a furnace. Recycled glass is also used in the construction industry as aggregates and glassphalt. Aggregates are used for landscape garden design such as plant pot dressings and glassphalt is a road-laying material containing up to 30% recycled glass.
Windshields are different; they are made of laminated glass – two pieces glued together using an inside layer (PVB). Traditionally recycling of windshields has been difficult because of the plastic laminated films. Recently a cost effective process has been introduced to remove the PVB layer and for it to be recycled. The recycling process for PVB is a simple procedure of melting and reshaping it.
Rubber recovery can be a difficult process but there are many reasons why rubber should be reclaimed; recovered rubber can cost half that of natural or synthetic rubber, it has some properties that are better than those of virgin rubber, producing rubber from recycling requires less energy in the total production process than virgin material, and it is an excellent way to dispose of unwanted rubber products.
Under the European Landfill Directive whole tyres and shredded tyres can no longer be sent to landfill for disposal. Every day in Britain over 100,000 worn tyres are taken off cars, vans and trucks. This totals about 40 million tyres (440,000 tonnes) per year. About 70% of these tyres are diverted from landfill, 26% are reused as re-treads, 46% are reclaimed for other forms of reuse or recycling such as chemical recovery; the process of heating waste rubber reclaim, treating it with chemicals and then processing the rubber mechanically. Untreatable rubber is incinerated for ‘energy recovery’, which is a low-grade, undesirable option that cannot be achieved without pollution and contribution to climate change. The rest (28%) is landfilled or stockpiled, and represents a major waste problem.
There are numerous different plastics used in a variety of car components: for example polypropylene is used to make car bumpers, polycarbonate for interior mouldings and polyester for seat belts.
There are about 39 different types of basic plastics used to make a car today. About 75% of the plastic (by weight) is supplied by about 10 of these plastics. Around 10% (100kg) of a vehicle’s weight is made up of plastic which has the potential to be recycled and hence generate income for the dismantler. Plastics capable of being recycled are sorted, shredded, washed, melted and pelletised for future use. Plastic is either melted down directly and moulded into a new shape, or shredded into flakes and then melted down before being processed into granulates.
The business of recovering catalytic converters in the UK is developing quickly based upon a more established US model. The steel from the exhaust and the precious metals from the cat are all extracted in the process. Platinum, rhodium and palladium can be recovered for reuse, predominantly in the production of new catalytic convertors.
The disposal of fluids from end-of-life vehicles is a major issue, as the inappropriate treatment of fluids can be extremely damaging to the environment. Moreover, recycling fluids from scrap cars could also provide us with a valuable energy source. For example, it is estimated that waste oil from nearly 3 million car oil changes in the UK is not collected. If this was collected properly it could meet the annual energy needs of 1.5 million people.
There are numerous types of fluids that can be removed from cars: for example engine oil, transmission oils, anti-freeze, hydraulic oils, fuel and suspension fluid.
Most of the oil collected from end-of-life vehicles is processed, and burnt as a fuel in power stations or industry. First, they distil the oil to remove the water. After that, evaporation separates out the contaminants and additives. Finally, the oil is super-heated to re-infuse the hydrocarbon molecules with hydrogen atoms. Recycled oil can go through various other stages of processing, such as distillation, depending on its intended use.
Hydraulic oils, such as brake fluid, should not be mixed with engine oil, but the process of recycling is similar. The oil is aerated and allowed to separate so that the excess water can be removed. It is then passed through a filter which removes contaminants, such as metal, dirt and silicon.
Antifreeze can be recycled using specialist equipment. Chemicals are added which separate the additives, and the antifreeze is then passed through a filter that removes the old additives and any other debris which has accumulated. Finally, new additives are mixed in and green dye added, creating reusable antifreeze which will last for up to two years.