Peculiarities of the Formation of Compounds and Phases in the Al2O3–MO (M = Mg, Ca, Sr, Ba) Systems during Treatment in Water Fluids

Authors:
Publisher website
Google Scholar
Abstract
The formation of mixed oxides in the Al2O3–MO (M = Mg, Ca, Sr, Ba) systems by heat treatment and treatment with water fluids (WFs) is studied. It is shown that during the high-temperature treatment of mixtures of aluminum hydroxide Al(OH)3 with group 2 metal nitrates, mainly MAl2O4 aluminates are formed, sometimes with an admixture of aluminates of a different composition. If the same mixtures are pretreated in WF (400°C, fluid density 0.2 g/cm3), the composition of the sample is more complex because of dehydration and partial structuring of the Al-containing component during the treatment in the WF medium. It is demonstrated that the addition of ammonia to WF has a stimulating effect on the formation of double oxides, primarily due to the alkaline hydrolysis of the Group II metal salts and the formation of their hydroxides; and the reduction of nitrates and nitrites with ammonia is likely to be a secondary process.

This publication has 9 references indexed in Scilit: