Reactions analysis during the synthesis of pseudo-boehmite as precursor of gamma-alumina
•We follow reactions phenomena occurring during synthesis of pseudo-boehmite.•We find reactor operation conditions, so that the final quality of the pseudo-boehmite produced is ensured.•We confirm that two main reactions occur during synthesis of pseudo-boehmite, when aluminum sulfate and ammonium hydroxide react.•We propose two control variables, temperature and pH, to improve the selectivity to pseudo-boehmite synthesis.
Pseudo-boehmite is the best precursor during synthesis of gamma alumina, because only the removal of water by calcination at about 447 °C is required. The control of operating variables during synthesis of pseudo-boehmite: the supersaturation of the solutions is a factor of special importance, additionally the pH, temperature, impurities and nature of the reagents  and . Ensure purity of this material and these variables determine the morphology, texture and it structures of the precipitate. Therefore, it is relevant to follow phenomena that occur during synthesis, in order to predict yield and quality of the final product. In this work, synthesis of pseudo-boehmite was developed by the method of precipitation, using industrial grade aluminum sulfate supersaturated solution and concentrated ammonium hydroxide (28%) as reactants; this known method was improved decreasing reaction temperature below the boiling point of ammonia. Temperature control of the reactant medium was reached by data acquisition and automatic manipulation of the heating medium. It is shown that operating the reactor at isothermal conditions ensures the final quality of the pseudo-boehmite produced.Figure optionsDownload full-size imageDownload high-quality image (234 K)Download as PowerPoint slide
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Journal: Catalysis Today - Volume 271, 1 August 2016, Pages 207–212