The Microstructure of Aluminum Alloys Obtained by Reclamation of 
Aluminum Composite Scraps 
P. Moldovan, C. Dumitrescu, N. Panait, G. Popescu, University „Politehnica“ of Bucharest, 
Romania 
The aim of this work was represented by the separation and recovery of aluminum alloys from silicon 
82 carbide (SiC) particles reinforced composite scraps, such as: melt loss and skim, saw chips, cuttings 
150 and rejected materials. This purpose was realized using different types of fluxes and argon injection. 
The chemical composition of the AlSi9Mg/SiCw@) scraps was: Si 9.2%, Mg 0.44%, Mn 0.4%, Al 
balance, impurities like Fe 0.49%, Cu 0.11%, Ni 0.15%, Ti 0.12%, other elements 0.14%, and with a 
silicon carbide volume fraction of 5.12 % SiC and also 1.66% SiC [1]. 
Ternary flux powder (48% NaCl, 42% KCI and 10% NaF), in doses of 10 and 20 wt.% of the total 
charge, was used in order to recover aluminum form this scraps [2]. The flux powder was preheated at 
673 K, and after that introduced in the scrap melt. After that, the melt was mechanically stirred, the 
stirring time being of 5 minutes, at a temperature of 998 K. At this temperature the ternary flux pass 
into a liquid state. During stirring, dry argon was bubbled into the melt (<5 ppm moisture), absorbing 
the hydrogen from the melt and floating the silicon carbide and inclusion particles. Stirring and argon 
injection was maintained until complete dewetting of the silicon carbide particles have been achieved 
[3]. 
When dewetting takes place, a large amount of powdery dross appear. This dross was skimmed 
ara continuously during the injection of the argon in the melt bath. The dross was filtered using ceramic 
pl foam filters (10 ppi). 
The reclamation efficiencies (n) was determined using the equation: 
ng AEN liquid 
gointed to drastic Nye = —2-100, [%] and , 
jersion of extremly Mita 
ıd solution 
Mave = —=+100, [%] 
alloys is of great Myasc 
Aubilization of te where mye, My, and myc are mass of the metallic phases, mass of the matrix and respectively mass of 
fic properties IM the metal-matrix composites. 
The values obtained during experiments are presented in Table 1. From the data presented in this table 
we can conclude that, when we used 20% of ternary salt the recovery of aluminum alloy was more than 
97%. 
Lael ned 
(H 
2 
755