Abstract

This case report investigates the recycling of used aluminium coffee capsules to maximise melting yields without adding primary aluminium, thereby promoting closed-loop recycling. Capsules differing in comminution degree and thereby organic content were dried, partly pyrolysed and remelted in a crucible induction furnace with NaCl-KCl-CaF₂ salt flux. Melting yields ranged from 50-95wt.%, with pyrolysis significantly enhancing performance. The recovered metal consisting of approx. 98wt.% Al was successfully rolled into 0.1mm thin sheets in a mini rolling mill by applying intermediate annealing steps. The study demonstrates an effective route for aluminium capsule recycling, right through to the production of new aluminium sheets.

Keywords:Aluminium recycling; Coffee capsules; Pyrolysis; Smelting salt; Remelting; Closed-loop recycling

Abbreviations:NFM: Nonferrous Metallurgy; Approx: Approximately; Al: Aluminium; Si: Silicon; Fe: Iron; Cu: Copper; Mn: Manganese; NaCl: Sodium Chloride; KCl: Potassium Chloride; CaF₂: Calcium Fluoride; wt.%: Weight Percent; mm: Millimeter; °C: Degree Celsius