Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon

This article is a comparative study of metallurgical characteristics of the different aluminium alloys gotten through recycling of recovered aluminium in Cameroon. A simple experimental device for the foundry of secondary aluminium blend, of very good quality built around a movable charcoal furnace is presented. It enables better energy efficiency, a better distribution of the heat around the crucible and indirectly assures good quality of the products obtained, while respecting the economic constraints and users' safety. Six refining methods are proposed by the addition of polyvinyl chloride (method A), coke rich in carbon CHS (method C), ammonium chloride NH4Cl (method E), manganese dioxide MnO (method T), acrylic nitrite (C2H3Cl)n (method P) and sodium chloride NaCl (method S). A critical analysis of the different recycling techniques is presented as well as a proposed process of melting and refining that enables the obtaining products with high degrees of purity. The results are then compared to the results obtained from the industrial methods of aluminium refining such as fractional crystallization (FC), granular filtration (GF) and dissolution in a metal solvent (DS). The later (DS) gives the rate of 6.540% of accumulated alloy elements and enables the best purification (93.460%), while the NaCl gives the lowest global rate of additive elements (9.478%), with the best purity index (90.522%) amount the proposed methods. Results obtained show that this method of refining improves the metallurgical properties of secondary aluminium alloy blends and guarantees better safety, as well as reducing the risks of environmental pollution.