LLC “RUSAL Engineering-Technological Center”, Saint Petersburg, Russia:

V. S. Burkat, Director of Ecological Department
T. V. Burkat, Researcher of Ecological Department, e-mail: Tatiyana.Burkat@rusal.com

Institute of Silicate Chemistry of Russian Academy of Sciences, Saint Petersburg, Russia:
A. E. Lapshin, Deputy Director for Science

We studied the composition, structure and properties of ore-thermal furnaces' siliceous dust. Specific surface of this dust was studied by nitrogen adsorption method using BET equation and comprises 19 m²/g to 24 m²/g. Phase composition was studied by X-ray diffraction method. The siliceous dust consists of crystalline and amorph phase. The major part of crystalline phase is silicon carbide. The “halo” in diffractogram initial area (2~ 16–26 grad) indicates presence of amorth phase in samples. Crystalline and amorph phase ratio calculation was conducted using Rietveld method. The amount of crystalline phase in dust samples varies from 3% to 46%. This fact can be explained by variability of technological process parameters, which may influence dusting. Crystalline phase is predominated by silicon carbide (Moissanite 3С), which weight content is 48% to 70% (calculated as 100% crystalline phase). Silicon dioxide content varies on the average from 30% to 50%. In some samples crystal silicon (Si) is present. Studies of surface properties on FTIS spectrophotometer by Shimadzu showed that the spectrum has principal intense bands in the region of 1100 cm^–1, 800 cm–1 and 560 cm–1. 1100 cm^–1 band is typical for Si–O linkage stretching vibrations. 800 cm^–1 and 560 cm^–1 bands can be referred to [SiO₄] tetrahedral structure formation. Particles size and shape, and siliceous dust dispersity were determined by transmission electronic microscopy method. Dust particles have regular spherical shape. Particles’ dominant size is from 50 to 150 nm. Siliceous dust absorption spectrum permits assuming the presence of small number of ОН-groups.

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