REACTIVITY OF ALUMINUM OXIDE PRECURSORS FOR SOLID-PHASE FORMATION OF MgAl2O4 SPINEL

The reactivity of various alumina precursors in the reaction of magnesia spinel formation is compared: industrial powders (corundum powder KP, alumina: metallurgical GC, non-metallurgical G-00, reactive RG) and the xerogel combustion product from aluminum nitrate with citric acid under conditions of mechanical activating treatment and without it. The infrared spectra of corundum and periclase after mechanical treatment of various types (impact-abrasion in a planetary mill, abrasion in a ball-ring mill) were analyzed. It has been found that short-term action not only activated the components, but also contributed to the destruction of adsorption compounds at the preparation stage. The effect of mechanical activation of reagents on spinel yield was analyzed. It has been established that the alumina xerogel combustion product without annealing was X-ray amorphous, which suggested its high chemical activity. When using it, a more complete binding of initial reagents into the product was found compared to a mixture of periclase and corundum. Even in the absence of mechanical activation of the components, it was possible to achieve a high spinel yield (up to 80%). The obtained values of the effective reaction rate constants indicated a greater efficiency of mechanical treatment, including an impact component, with the combined activation of periclase and corundum/alumina. Co-treatment of reagents in a planetary mill (PM) made it possible to increase the reaction rate by 6-6.5 times, while abrasion in a ball-ring mill was only 1.7 times. Pretreatment of one component of the initial mix in PM was the most expedient for periclase, since it allowed to speed up the reaction by ~ 5 times, and is also the most profitable energetically and technologically due to the treatment of only one component of reduced hardness. The use of xerogel combustion product in the spinel synthesis was very effective, because it accelerated the process by ~4 times even without preliminary activation by mechanical means. For citation: Filatova N.V., Kosenko N.F., Artyushin A.S., Maloivan M.S., Zonina I.I., Vlasenkov A.S. Reactivity of aluminum oxide precursors for solid-phase formation of MgAl2O4 spinel. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 15-24. DOI: 10.6060/ivkkt.20246712.7152.