An Assessment of Recyclability of Used Aluminium Coffee Capsules

The beginning and the end of the aluminium value chain

“…Cracking of aliphatics and aromatic bonds leads to formation of free hydrogen (H 2 ) and compounds from hydroxyl (-OH) group like cresols and acetic acid (CH 3 COOH). From the off-gas analysis presented in [23], it can be also seen that formation of halogenated compounds are only stable in the gas phase after 300°C.…”

“…As mentioned earlier this must also be combined with a sufficiently high Technical Recovery Rate in order to get a satisfactory Recycling Rate. At the Norwegian University of Science and Technology (NTNU) and the Foundation for Scientific and Industrial Research (SIN-TEF) in our Centre for Research-based Innovation: SFI Metal Production, we do research mainly on the technical aspects of recovery [22][23][24].…”

“…Recycling of collected capsules can, however, be challenging due to their high organic content (coffee residue) and an assessment of suitable recycling methodologies is hence required. An investigation [23] following the procedure sketched in Figure 17 showed that even supposedly similar units, in this case Nespresso capsules, behave differently. One illustration of this is the result of the thermal pretreatment of heating the capsules to a holding temperature of 500°C and maintaining this for 3 h as shown in Figure 18.…”

“…The total wall thickness was measured to 100 mm consisting of 13 mm of inner and 6 mm of outer coating. Intermetallic Al-Fe-Si precipitates are present in the matrix[23].…”

Coffee capsule impacts and recovery techniques: A literature review

“…Hicks 5 • The study found that the capsule system did not have an exceptionally greater environmental impact than the other conventional systems • The consumption of electricity in standby (leaving the coffee machine in ready to brew mode) can determine a significant increase in the environmental impact, suggesting the significant importance of consumer habits Ktori et al 34 • Spent coffee grounds pyrolysis could be the solution to valorize wastes • Need for an automatic approach to coffee separation Tonelli et al 28 • Polypropylene capsules are found to have the most impact across all of the categories considered, followed respectively by aluminium and biodegradable capsules. • Aluminium capsule is the best food packaging material in terms of oxygen barrier properties compared to the thickness of packaging • Aluminium capsule cannot be recycled if it is not separated from the coffee • The Aluminium production è molto energivora • The PP capsule is the most impactful one for all the categories considered, due to the packaging system Abuabara et al 35 • Diverse policies and strategies for resource recovery from used coffee capsules are needed to achieve some key results: behavioural change, expansion of urban collecting points, incentive program, communicate and commit to customers de Bomfim et al • Agricultural cultivation, packaging production and beverage preparation are stages of high environmental impact • The combination of high coffee concentration with high packaging ratio by volume of beverage causes a high environmental impact Domingues et al 40 • PP filter and the capsule body are the most interesting materials to recycle, and those with good properties • A process is required that reduces time and manpower for separating the aluminium and the lid from the rest of the parts of the capsule Gokelma et al 24 • Different coloured capsules have different metal yields during remelting • The behaviour of the coatings play a role in oxidation during remelting • Presence of coffee that dropped the yield drastically (tends to zero with full coffee residue)…”