Classification and Reactivity of Secondary Aluminum Production Waste

Aluminum production wastes (APW) are produced during the recycling of aluminum scrap and dross. They are frequently disposed in dry form at Subtitle D nonhazardous waste landfills, where they may react adversely with liquids. Depending on the APW composition and landfill environment, the exothermic reaction can cause sustained temperature increases that inhibit normal anaerobic biodegradation. A constant pressure calorimeter test was developed to simulate the APW reaction in a basic environment and quantify the reactivity. APW reactivity was investigated under varying strengths of sodium hydroxide and particle size. Bench-scale calorimeter experiments show that concentrations greater than 4M NaOH oxidize metallic aluminum and increase temperatures rapidly to 100°C. Lower NaOH concentrations, such as 1M NaOH, are recommended to quantify the APW reaction in a constant pressure calorimeter. APW in neutral solutions was found to be stable, but reducing APW particles through ball-milling exacerbated reactivity.