title: Phase transformations of α-alumina made from waste aluminum via a precipitation technique.
abstract: We report on a recycling project in which α-Al(2)O(3) was produced from aluminum cans because no such work has been reported in literature. Heated aluminum cans were mixed with 8.0 M of H(2)SO(4) solution to form an Al(2)(SO(4))(3) solution. The Al(2)(SO(4))(3) salt was contained in a white semi-liquid solution with excess H(2)SO(4); some unreacted aluminum pieces were also present. The solution was filtered and mixed with ethanol in a ratio of 2:3, to form a white solid of Al(2)(SO(4))(3)·18H(2)O. The Al(2)(SO(4))(3)·18H(2)O was calcined in an electrical furnace for 3 h at temperatures of 400-1400 °C. The heating and cooling rates were 10 °C /min. XRD was used to investigate the phase changes at different temperatures and XRF was used to determine the elemental composition in  the alumina produced. A series of different alumina compositions, made by repeated dehydration and desulfonation of the Al(2)(SO(4))(3)·18H(2)O, is reported. All transitional alumina phases produced at low temperatures were converted to α-Al(2)O(3) at high temperatures. The X-ray diffraction results indicated that the α-Al(2)O(3) phase was realized when the calcination temperature was at 1200 °C or higher.
authors.affiliation: Department of Physics, Faculty of Science, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia. khamirul@science.upm.edu.my
authors.forename: Khamirul Amin
authors.initials: KA
authors.lastname: Matori
authors.forename: Loy Chee
authors.initials: LC
authors.lastname: Wah
authors.forename: Mansor
authors.initials: M
authors.lastname: Hashim
authors.forename: Ismayadi
authors.initials: I
authors.lastname: Ismail
authors.forename: Mohd Hafiz Mohd
authors.initials: MH
authors.lastname: Zaid
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D011232:Chemical Precipitation; D006358:Hot Temperature; D010087:Oxides / Q000737:chemistry; D044367:Phase Transition; D059027:Recycling; D014866:Waste Products; D014961:X-Ray Diffraction
chemical_list: D010087:Oxides; D014866:Waste Products; D000535:Aluminum; D000537:Aluminum Oxide