IQ

Precious Materials: Recycling at BMW

A beginning but no end: there are hundreds of valuable raw materials to be found in every car. For many years now, BMW has been working on recycling them in ways that are both efficient and eco-friendly. Every material has a story of its own to tell: from its origin and initial use to its recovery and reuse.

Photos
Thomas de Monaco
Words
Michael Seitz

Carbon

Varying lengths of carbon fibre offcuts are produced during the manufacture of body parts for BMW i at the Leipzig plant. The rule here is the longer the fibres, the higher the quality of the offcut and the more varied its possible uses. BMW takes fibre offcuts which have not yet been hardened with resin, and weaves them, for example, into a lightweight, but extremely strong fleece matting for the roofs of BMW i models or as a backing material for the centre console and rear seat shell of the BMW i3. In addition to the use of these production remnants, carbon fibres that have already been bonded with resin can also be recycled. The resin can be eliminated using methods such as pyrolysis, and the fibres that are recovered are then reused in the usual processes.

Body parts for the BMW i and BMW M models

Metal

Steel is by far the most frequently recycled material at BMW. The bodyshop alone accounts for nearly half a million tonnes of steel offcuts every year. Nearly all the material is collected, melted down at the suppliers’ steelworks and manufactured into new bodywork panels there. It is a similar principle to when baking biscuits, where the dough is rolled out again and again until there is nothing left. The plants also collect other materials left over from metalworking, such as aluminium, and have it melted down again by the relevant supplier. In the case of aluminium, this saves the large quantities of electrical energy needed at the bauxite ore processing stage. However, recycled aluminium does become more brittle, meaning it can no longer be used for crash-relevant parts.

Production offcuts from the bodyshop

Plastic

Around a fifth of any vehicle is made up of plastics, which are in turn mainly made from petroleum. All manner of different plastics can be found in cars: BMW recycles them using shredders. Once as many of the fluids, precious metals and hazardous substances as possible have been extracted, baling presses compact the end-of-life vehicles into a 1.5-tonne cube. A 10,000-horsepower shredder eats through as many as 450 of these commodity-rich bundles every hour, reducing them to hundreds of thousands of parts roughly the size of the palm of your hand. This huge mass of shredded material is subsequently sorted by type with virtually no mixing in a series of processes: suspending, floating, sinking, dropping, weighing, throwing or scanning. There are commodity markets for the materials recycled in this way, with prices that vary according to supply and demand. Recycled materials used in new BMW models meet the same high quality standards as plastics made from fresh petroleum.

Coverings for components and in the interior

Precious metals

As regulations become stricter, the technology required for emission control in today’s internal combustion engines is getting more and more sophisticated. This means that a host of precious metals, including platinum, rhodium and palladium, are concealed inside catalytic converters. Manufacturers are remarkably adept at handling these valuable raw materials: inside, the cylindrical exhaust gas purifiers are made up of hundreds of thousands of minute ceramic honeycombs with a total surface area equivalent to three or four football pitches. And spread over this entire area are just two grams of platinum. Despite such small quantities, it is still worth recycling the catalytic converters to retrieve the precious metals. To do so, specialist firms grind the porcelain white inner workings of the catalytic converters into a fine powder, melt it down and use metallurgical treatment methods to separate the individual elements again.

Catalytic converters and electronics

Copper

The wiring harness in a modern sedan alone contains over 35 kilograms of copper. The lithium-ion batteries in many electric cars also include foil made from the valuable metal. And the coils in the electric motors of the BMW i and BMW iPerformance models are likewise made from this metal, which is only found in a few countries worldwide. Experts believe that the rapid expansion of electric mobility will lead to a sharp increase in copper prices. Even today, used copper is big business for vehicle recyclers; it has been selling for several thousand euros a tonne for several years.

Cables, batteries and electric motors

Battery

Long before electric cars and hybrids arrived on the scene, BMW Recycling was already involved in the removal and reutilisation of batteries. Since conventional engine starter batteries contain mainly lead, the products made from recycled batteries included diving jackets and belts. Electric mobility today, on the other hand, is powered by lithium-ion batteries. Due to their large numbers, their value and their weight, it is that much more important that they be recycled. There are, after all, over 200 kilos of batteries in every BMW i3. As these batteries are rarely spent at the end of a car’s life or might be replaced beforehand by a more powerful battery pack, BMW plans to give these used batteries a new lease of life as intermediate storage devices for electrical energy – solar energy, for instance, which could then be supplied to electric vehicles after sunset.

BMW i and hybrid models as well as starter batteries

Fluid

Fluids can be found in many different parts of the vehicle, much to the chagrin of the BMW recyclers. Before the car is compacted and shredded, the fluids have to be individually extracted and disposed of in the appropriate manner. Besides the more obvious fluids, such as petrol, brake fluid or coolant, there is, for example, the hydraulic oil for an automatic soft-top or the suspension control, which can be either awkward to get to or is used throughout the vehicle. The exhaust gas after-treatment system in diesel engines also requires up to 21 litres of additional fluid in the form of AdBlue (urea solution). The increasing electrification of vehicles is making recycling easier as far as fluids are concerned, since electrical systems can replace the hydraulic ones where sufficient power is available, which, in turn, saves fuel.

Oils, brake fluid, coolant or urea

From copper to rubber chips and carbon fibres – turning old into new.

On an industrial estate in the north of Munich there are stocks of crude oil, copper, aluminium, rubber, iron, gold and platinum. These precious raw materials are hidden, though, and are very difficult to get to. They can be found in doors, seats, tyres, engines and exhaust systems. Not too long ago, most people would have called the BMW Recycling and Dismantling Centre nothing more than a scrapyard. These days, though, scrap has long since been rechristened recyclable materials. In view of the planet’s dwindling resources and rising commodity prices, people no longer just throw away high-value industrial products, such as motor vehicles. Scrapping has given way to salvaging.

At the same time, the attitude of many consumers in the developed world has changed as well. Everyday objects are now used as extensively and wisely as possible and are shared and utilised for as long as possible. One of the effects of this transformation is that people are also taking an interest in their vehicle’s life cycle assessment: besides a resource-friendly production process and low fuel consumption during the car’s service life, another crucial factor is the sustainable reuse of the raw materials it contains. Quite apart from this, the recycling rates stipulated by law are becoming increasingly stringent as well. In the EU, for example, manufacturers must guarantee that they will take back end-of-life vehicles and recycle 95 per cent of the materials used.

Even at the development stage, BMW examines the recycling and dismantling of any new technologies, such as hybrid or electrical technology, or future materials such as carbon fibre. While doing so, the company’s specialists occasionally come across processes or appliances that later prove useful to the entire industry – such as a digger with an oversized gripping tool shaped like a spaghetti fork. The digger stabs the fork into the wiring harness in the vicinity of the transmission and then winds the harness together from all corners of the car into a highly valuable 35-kilogram ball of copper.

Rubber

For dismantling companies, the rubber from tyres is a perennial favourite among reusable materials. Easy to remove and with a wide range of possible further uses, it has no lack of potential purchasers. Once the rubber has been shredded and cleaned, the resulting rubber chips are used for products such as the safety matting surrounding playground equipment. But it is not just parents who are keen to avoid sore knees; farmers are, too, which is why they treat their cows to rubber matting and mattresses to make lying down more comfortable for them and keep their joints healthy. After all, a cow’s knee joints have to bear a load of over 400 kilos when it gets to its feet. Thanks to the matting made from old tyres, the cows stand up more willingly and therefore more frequently, meaning they eat more and produce more milk. However, no research has as yet been done on whether they prefer to rest on BMW sports tyres or those of a compact car!

Tyres and insulating materials

06/28/2017