Recycling of aluminum from fibre metal laminates
Recycling of aluminum alloy scrap obtained from delaminated fibre metal laminates (FMLs) was studied through high temperature refining in the presence of a salt flux. The aluminum alloy scrap contains approximately mass fraction w(Cu) = 4.4%, w(Mg) = 1.1% and w(Mn) = 0.6% (2024 aluminum alloy). The main objective of this research is to obtain a high metal yield, while maintaining its original alloy compositions. The work focuses on the metal yield and quality of recycled Al alloy under different refining conditions. The NaCl-KCl salt system was selected as the major components of flux in the Al alloy recycling. Two different flux compositions were employed at NaCl to KCl mass ratios of 44:56 and 70:30 respectively, based on either the eutectic composition, or the European preference. Different additives were introduced into the NaCl-KCl system to study the effect of flux component on recycling result. Although burning and oxidation loss of the alloying elements during re-melting and refining take place as the drawbacks of conventional refining process, the problems can be solved to a large extent by using an appropriate salt flux. Experimental results indicate that Mg in the alloy gets lost when adding cryolite in the NaCl-KCl salt system, though the metal yield can reach as high as 98%. However, by adding w(MgF2) = 5% into the NaCl-KCl salt system (instead of using cryolite) all alloying elements were well controlled to its original composition with a metal yield of almost 98%.
Recycling of distributed aluminium turning scrap
Abstract The relationship between scrap type and its recoverable metal content can play a crucial role in industrial recycling processes. In this paper, the recyclability of different aluminium turnings has been experimentally studied. Various categories of scrap were melted at 800 °C to recover aluminium metal with the protective salt flux of NaCl–KCl–Na 3 AlF 6 under nitrogen atmosphere. In order to understand the melting behaviour, thermo-gravimetric analysis was applied to investigate the weight loss during the melting process. It is shown that the difficulty of recycling the selected aluminium scrap depends on scrap type, scrap size distribution, contaminant, and the ratio of surface area to body volume. Lower distribution mean value, more non-metallic contaminates (oil, plastics), smaller size and higher ratio of surface area to body volume generally led to a lower metal yield. The effect of cryolite addition on the metal yield was also studied, especially for the scrap with higher ratio of surface area to body volume. It was shown that the accumulation of the metal beads was improved with higher amount of cryolite addition. A simple statistical approach is presented to correlate metal yield to scrap properties for inclusion in process optimisation and control models.
Meromorphic function sharing a small function with a homogeneous differential polynomial
Abstract In this paper, we consider a Brück-type result for a homogeneous differential polynomial generated by a meromorphic function.