Vehicle Construction - Life Cycle Assessment of Magnesium Components

The study analyzed the entire life cycle of magnesium components for transport applications. This includes the production of primary magnesium, alloying, component production, the use phase and the end of life of magnesium components. The focus of the study was on the use of magnesium in passenger vehicles and aircraft components.

Currently, most of the world's primary magnesium metal is produced in China using the Pidgeon process. As magnesium production and in particular the Pidgeon process in China are continuously improved, an update of the LCA study reflecting the current production situation was necessary. Further, the study shows current and primary production projects which have a significant lower CO2 footprint. For this purpose, the International Magnesium Association (IMA) commissioned German Aerospace Center Institute of Vehicle Concepts (DLR) to update the 2013 Life Cycle Assessment (LCA). These are the most important conclusions that emerge from the update:

 

Magnesium Production:

• Emissions from magnesium production in the Pidgeon process have been reduced since 2011, which was the reference year of the 2013 LCA study. Yet, considering a potentially growing market for carbon neutral components in the car market, further improvements in magnesium production need to be achieved with a higher share of renewable energy.

• Further reduction of the overall cradle-to-gate process emissions are possible, e.g. when using FeSi from alternative sourcing, though it is a question of further external factors whether this will happen or not. In future studies on magnesium production and application, the FeSi supply should be subject to further sensitivity analysis.

• If the magnesium is produced via the RIMA (Brazil) or QSLM (China) process, the production emissions are even lower compared the aluminumreference. The magnesium production site in Qinghai, China is a promising way to reduce the impacts from primary magnesium production. First calculations on the greenhouse gas emissions resulted in the lowest greenhouse gas emissions of all magnesium pathways that are currently in operation. The increased output of the Qinghai plant bears the potential of becoming a game changer for the world average magnesium. Other processes in Canada and Australia that are currently in planning stage show similar low CO2 emissions and potential savings.

Magnesium Recycling

• The use of secondary material is a critical factor. Both aluminum and magnesium have established pathways for recycling and reusing scrap from parts production (post-industrial scrap) which is used for high quality secondary alloys. Though aluminum comes with an established end-of-life recycling loop, the actual content of secondary material that comes from end-of-life products into automotive components is less certain. Reuse of industrial scrap and of scrap from end-of-life vehicles are both important. Yet from a product’s LCA perspective, recovery, and reuse of materials from end-of-life vehicles is crucial.

• The share of end-of-life scrap of magnesium needs to be increased in the future. Though it would be technically feasible, a lack of established value-added chains for end-of-life magnesium scrap reduces the potentials of a functional recycling of magnesium parts.

Magnesium Use

• The use of magnesium in both transport applications analyzed in this report results in lower greenhouse gas emissions over the whole life cycle. The source of primary magnesium influences the point where higher emissions of the production phase are compensated. According to present literature (World Aluminium 2017, European Aluminium 2018), aluminum likewise shows a large range of emissions from primary production depending on its geographic source. The actual difference of emissions in such product comparison highly depends on the component characteristics and the material sourcing. Therefore, it is difficult to give generalized statements about the emission savings for these lightweight materials.

• The high fuel reduction potential for aircraft leads to extremely fast amortization of emissions from the production stage. The aviation industry should use more magnesium from this point of view.