Saint Petersburg Mining University, Saint Petersburg, Russia:

V. N. Brichkin, Head of Department of Metallurgy
V. M. Sizyakov, Professor
I. S. Oblova, Associate Professor
D. V. Fedoseev, Postgraduate Student

E-mail (common): kafmet@spmi.ru

The growth of consumption of finely dispersed aluminum hydroxide and aluminum oxide based materials having specified properties has resulted in the development of diverse methods for their production thereof. A lot of these technologies have not been intended for mass production of such products and require further adaptation to the operational metallurgical complex. The modern process of alumina production that includes alkaline aluminate solution forming and their subsequent processing by means of well known production techniques has a great problem solving ability. Analysis of mass crystallization regularities allows developing some technological principles of deposition of finely-dispersed aluminum hydroxides from alumina production solutions. The significance of both the main technological factors and the physicochemical nature of the aluminate solutions for directional formation of the fractional composition of deposition has been highlighted. From experimental studies the dynamic nature of the boundary of the metastable aluminate solutions for the following system Na₂O – Al₂O₃ – CO₂ – H₂O and its expansion at reduced temperature have been established. This makes it possible to predict the preservation of this dependence on the system Na₂O – Al₂O₃ – H₂O. The substantial changes in the kinetics of aluminum oxide deposition from alkaline aluminate solutions of alumina production and fractional composition of the products obtained have been shown with the decrease of the temperature of the carbonization process in the range from 30 to 10 ^oC. That provides an assumption about the dual mechanism of stable crystalline nucleation formation at lowtemperatures as well as the possibility of obtaining finely-dispersed deposition on this basis within neutralizing of aluminate solutions having industrial composition.
This research was funded by the Russian Science Foundation under the Grant Agreement No. 18-19-00577 dated April 26, 2018 covering basic research and exploratory studies.

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