%0 Book Section
%T Synthesis of alumina based on industrial waste material
publisher CVR – Centro para a valorização de Resíduos
%D 2011
%U 978-989-97429-1-8
%@ https://hdl.handle.net/20.500.14352/45312
%X A hazardous waste generated in slag milling process by the aluminium industry was usedas a raw material for the synthesis of alumina, α-Al2O3. This waste is considered ashazardous material in the European legislation due to the release of toxic gases(hydrogen, ammonia, methane and hydrogen sulphide) in the presence of water. Theprocess developed in this work allows to obtaining 1 ton of alumina from 4 tons ofhazardous waste and generates an inert solid residue consisting principally of spinel,corundum and quartz with possible uses in cements or glass industry. This processconsisted of two steps: in the first one, nearly 90% of aluminium present in the waste isrecovered as a nanocrystalline boehmite, γ-AlOOH by hydrothermal treatment of thewaste. In the second step, the alumina is obtained by calcination of the boehmite at1400ºC in air. The chemical composition of the alumina obtained consisted of 95% Al2O3,3.3% Fe2O3, 0.8% SiO2 and other minor oxides to balance.
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