Abstract:
Aluminium dross, a byproduct from secondary aluminium production and a classified hazardous waste, has been regulated under Thai regulations. In this study, the dross contains more than 70% aluminium in the oxide form by weight. Recovery of aluminium metal from the dross can reduce production cost and reduce quantity of waste to be managed as well. The objective of this research was to study the process of the aluminium recycling from aluminium dross using a prototype graphite crucible designed by the researcher which was installed at an aluminium factory. The prototype graphite crucible utilizes a graphite crucible embedded in a specially designed heating unit. Each experiment used 5 kg of aluminium dross. Two types of dross were examined; aluminium dross at room temperature and hot skimmed aluminium dross from factory furnace. The aluminium dross extraction at room temperature aluminium recovery 40.42% by weight of aluminium within 60 minutes of melting time. As for the hot aluminium dross, each batch was skimmed out of the factory furnace and immediately poured into the preheated crucible. Preheating temperatures were set to vary from 300 to 900oC. Approximately 44.36% by weight aluminium was recovered with the preheating temperature of crucible furnace between 700 and 900oC with 4 minutes of stirring. Extraction samples from both types of aluminium dross had similar compositions and contained 97-99% aluminum metal when analyzed with an optical emission spectrometer.