Synthesis of α-Alumina Developed from Waste Aluminium using Precipitation Technique

The heated aluminium containers were added to a solution of 8.0 M H₂SO₄ solution, which eventually yielded a solution of Al₂(SO₄)₃ after a series of stepwise precipitation reactions. Al₂(SO₄)₃ was presented in large quantities of H₂SO₄ in the white semi-fluid solution; there were some unreacted aluminium parts. The solution was subjected to filtration and then mixed with anion in a ratio of 2:3, this resulted in the formation of a white layer Al₂(SO₄)₃•18H₂O. Thereafter, Al₂(SO₄)₃•18H₂O was calcined in an electric oven for 2 h at various calcination temperatures (500, 700, 900, 1100, and 1300°C). The mixtures were heated and cooled at a rate of 10°C/min. XRD was employed to investigate variations in temperature and determination of elemental accumulation of alumina produced. Ah(SO₄)₃•18H₂O was due to a series of aluminium compositions produced from dehydration. All transitions from low temperatures to aluminium phases were converted to high-temperature α-Al₂O₃. The results obtained from X-ray disintegration showed that the α-Al₂O₃ phase was obtained at a reaction temperature of about 1150°C and above. (paper)