RT Journal Article T1 Recycling of hazardous waste from tertiary aluminium industry in a value-added material A1 Gonzalo-Delgado, Laura A1 López-Delgado, Aurora A1 López, Félix Antonio A1 Alguacil, Francisco José A1 López De Andrés, María Sol AB The recent European Directive on waste, 2008/98/EC seeks to reduce the exploitation of natural resources through the use of secondary resource management. Thus the main objective of this study was to explore how a waste could cease to be considered as waste and could be utilized for a specific purpose. In this way, a hazardous waste from the tertiary aluminium industry was studied for its use as a raw material in the synthesis of an added-value product, boehmite. This waste is classified as a hazardous residue, principally because in the presence of water or humidity, it releases toxic gases such as hydrogen, ammonia, methane and hydrogen sulfide. The low temperature hydrothermal method developed permits the recovery of 90% of the aluminium content in the residue in the form of a high purity (96%) A1OOH (boehmite). The method of synthesis consists of an initial HCl digestion followed by a gel precipitation. In the first stage a 10% HCl solution is used to yield a 12.63 g L-1 A13+ solution. In the second stage boehmite is precipitated in the form of a gel by increasing the pH of the acid A13+ solution by adding 1 mol L-1 NaOH solution. Several pH values were tested and boehmite was obtained as the only crystalline phase at pH 8. Boehmite was completely characterized by X-ray diffraction, Fourier transform infrared and scanning electron microscopy. A study of its thermal behaviour was also carried out by thermogravimetric/differential thermal analysis. PB SAGE Publications SN 0734-242X YR 2010 FD 2010-07-28 LK https://hdl.handle.net/20.500.14352/103345 UL https://hdl.handle.net/20.500.14352/103345 LA eng NO Article first published online: July 28, 2010 / Issue published: February 2011.© The Author(s) 2011. Request permissions for this article. NO Ministerio de Educación y Ciencia (España) DS Docta Complutense RD 18 abr 2025