Abstract. Several samples of dusts from steel and coke plants (collected mostly with electro fi lters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specifi c magnetic susceptibility  varied in a wide range: from 59 to above 7000 × 10 −8 m 3 kg −1 . The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high  was obtained for metallurgical dusts. The Mössbauer spectra and X-ray diffraction patterns point to the presence of the following phases containing iron: hematite and oxidized magnetite (in coke and metallurgical dusts as well as metallurgical slurry), traces of magnetite fi ne grains fraction (in metallurgical dusts), amorphous glassy silicates with paramagnetic Fe 3+ and Fe 2+ ions, traces of pyrrhotite (in coke dusts), -Fe and nonstoichiometric wüstite (in metallurgical slurry), as well as ferrihydrite nanoparticles (in bog iron ore). For individual samples of metallurgical dusts, the relative contributions of Fe 2+/3+ ions in octahedral B sites and Fe 2+ ions in tetrahedral A sites in magnetite spinel structure differs considerably.

Abstract. Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic fi eld. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (T a ). At higher T a , hematite was the dominant phase in the nanowires.

Abstract. The investigations of iron-containing phases existing in fl y ashes were performed using transmission Mössbauer spectrometry. The examined samples of fl y ashes were collected from different coal combustion systems, that is, stoker-fi red boiler in municipal heating plant and pulverized coal boiler in power plant. Several phases are identifi ed in the samples: iron oxides, paramagnetic aluminosilicate glass with Fe 3+ ions and Al 2 O 4 --type spinel with Fe 2+ ions. It was pointed out that proportions of contents of phases strongly depend not only on the combustion temperature but also on the way of ash collection.

Iron speciation analysis of fly coal ashes was performed using transmision Mössbauer spectrometry as well as chemical methods. The investigated samples of ashes came from stoker-fired boiler and pulverized-fuel boiler (of significantly higher combustion temperature). The Mössbauer spectra show noticeable differences in iron-bearing phases content. In the first case aluminosilicate glass dominates, whereas in the second one-a spinel-type phase.

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